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Assessment of changes in aquatic macrophyte occurrence following introduction of triploid grass carp in a North Texas reservoir

Description: The objectives of this project were to measure changes in frequency of occurrence of submerged macrophytes over the first two growing seasons following stocking with triploid grass carp at two fish per acre and to measure differences in macrophyte biomass between areas excluded from herbivory and adjacent control sites after 16 months following establishment of exclosures. The project also seeks to measure concentrations of fluridone following the herbicide treatment, and to compare two methods of aquatic vegetation sampling.
Date: August 1997
Creator: Bickel, Ken (Kenneth E.)
Partner: UNT Libraries

Impact of support system failure limitations on probabilistic safety assessment and in regulatory decision making

Description: When used as a tool for safety decision making, Probabilistic Safety Assessment (PSA) is as effective as it realistically characterizes the overall frequency and consequences of various types of system and component failures. If significant support system failure events are omitted from consideration, the PSA process omits the characterization of possible unique contributors to core damage risk, possibly underestimates the frequency of core damage, and reduces the future utility of the PSA as a decision making tool for the omitted support system. This paper is based on a review of several recent US PSA studies and the author's participation in several International Atomic Energy Agency (IAEA) sponsored peer reviews. 21 refs., 2 figs., 1 tab.
Date: January 1, 1990
Creator: Bickel, J.H.
Partner: UNT Libraries Government Documents Department

A null-steering viewpoint of interferometric SAR

Description: Interferometric synthetic aperture radar (IFSAR) extends the two-dimensional imaging capability of traditional synthetic aperture radar to three-dimensions by using an aperture in the elevation plane to estimate the 3-D structure of the target. The operation of this additional aperture can be viewed from a null-steering point of view, rather than the traditional phase determination point of view. Knowing that IFSAR can be viewed from the null-steering perspective allows one to take advantage of the mathematical foundation developed for null-steering arrays. In addition, in some problems of interest in IFSAR the null-steering perspective provides better intuition and suggests alternative solutions. One example is the problem of estimating building height where layover is present.
Date: May 2, 2000
Creator: Bickel, Douglas L.
Partner: UNT Libraries Government Documents Department

Precomparator and postcomparator errors in monopulse.

Description: Monopulse radar is a well-established technique for extracting accurate target location information in the presence of target scintillation. It relies on the comparison of at least two patterns being received simultaneously by the antenna. These two patterns are designed to differ in the direction in which we wish to obtain the target angle information. The two patterns are compared to each other through a standard method, typically by forming the ratio of the difference of the patterns to the sum of the patterns. The key to accurate angle information using monopulse is that the mapping function from the target angle to this ratio is well-behaved and well-known. Errors in the amplitude and phase of the signals prior and subsequent to the comparison operation affect the mapping function. The purpose of this report is to provide some intuition into these error effects upon the mapping function.
Date: February 1, 2013
Creator: Bickel, Douglas Lloyd
Partner: UNT Libraries Government Documents Department

Antarctica X-band MiniSAR crevasse detection radar : final report.

Description: This document is the final report for the Antarctica Synthetic Aperture Radar (SAR) Project. The project involved the modification of a Sandia National Laboratories MiniSAR system to operate at X-band in order to assess the feasibility of an airborne radar to detect crevasses in Antarctica. This radar successfully detected known crevasses at various geometries. The best results were obtained for synthetic aperture radar resolutions of at most one foot and finer. In addition to the main goal of detecting crevasses, the radar was used to assess conops for a future operational radar. The radar scanned large areas to identify potential safe landing zones. In addition, the radar was used to investigate looking at objects on the surface and below the surface of the ice. This document includes discussion of the hardware development, system capabilities, and results from data collections in Antarctica.
Date: September 1, 2007
Creator: Sander, Grant J. & Bickel, Douglas Lloyd
Partner: UNT Libraries Government Documents Department

Antarctica X-band MiniSAR Crevasse Detection Radar : draft final report.

Description: This document is the final report for the 2009 Antarctica Crevasse Detection Radar (CDR) Project. This portion of the project is referred to internally as Phase 2. This is a follow on to the work done in Phase 1 reported on in [1]. Phase 2 involved the modification of a Sandia National Laboratories MiniSAR system used in Phase 1 to work with an LC-130 aircraft that operated in Antarctica in October through November of 2009. Experiments from the 2006 flights were repeated, as well as a couple new flight tests to examine the effect of colder snow and ice on the radar signatures of 'deep field' sites. This document includes discussion of the hardware development, system capabilities, and results from data collections in Antarctica during the fall of 2009.
Date: August 1, 2010
Creator: Sander, Grant J. & Bickel, Douglas Lloyd
Partner: UNT Libraries Government Documents Department

Fire Doors for Noncoal Mines

Description: Report issued by the U.S. Bureau of Mines discussing the development and use of fire doors in non-coal mines. As stated in the abstract, "this report discusses current fire-door technology in the context of the underground mine environment and the design, fabrication, lab testing, and in-mine field testing of a mine-worthy fire door" (p. 1). This report includes tables, illustrations, and photographs.
Date: 1987
Creator: Bickel, Kenneth L. & Pomroy, William H.
Partner: UNT Libraries Government Documents Department

Determination of absolute interferometric phase using the beam-amplitude ratio technique

Description: Determination of the absolute phase difference (i.e., not modulo 2{pi}) is a key problem in interferometric synthetic aperture radar (IFSAR) for topographic mapping. One way of solving this problem requires use of a technique different from the basic interferometry to resolve a `coarse` angle measurement that lies within the IFSAR ambiguity angle. The method investigated in this paper involves taking advantage of the difference in the amplitude ratio versus elevation angle that occurs when the elevation beams of the two IFSAR antennas are pointed in slightly different directions. The performance of the technique is a function of the angular separation of the two beams, the elevation beamwidth, and the symmetry of the two beam-amplitude patterns. The performance required of the technique is set by the ambiguity angle of the interferometer. This paper presents an analysis of the beam-amplitude ratio technique and shows experimental results.
Date: March 1, 1996
Creator: Bickel, D.L. & Hensley, W.H.
Partner: UNT Libraries Government Documents Department

A 3-D SAR approach to IFSAR processing

Description: Interferometric SAR (IFSAR) can be shown to be a special case of 3-D SAR image formation. In fact, traditional IFSAR processing results in the equivalent of merely a super-resolved, under-sampled, 3-D SAR image. However, when approached as a 3-D SAR problem, a number of IFSAR properties and anomalies are easily explained. For example, IFSAR decorrelation with height is merely ordinary migration in 3-D SAR. Consequently, treating IFSAR as a 3-D SAR problem allows insight and development of proper motion compensation techniques and image formation operations to facilitate optimal height estimation. Furthermore, multiple antenna phase centers and baselines are easily incorporated into this formulation, providing essentially a sparse array in the elevation dimension. This paper shows the Polar Format image formation algorithm extended to 3 dimensions, and then proceeds to apply it to the IFSAR collection geometry. This suggests a more optimal reordering of the traditional IFSAR processing steps.
Date: March 1, 2000
Partner: UNT Libraries Government Documents Department

Interferometric SAR phase difference calibration: Methods and results

Description: This paper addresses the steps necessary to determine and maintain the phase calibration of a two-channel interferometric synthetic aperture radar (IFSAR). The method, setup, and accuracy of four different calibration techniques are compared. The most novel technique involves pointing the interferometric baseline at nadir and imaging a lake surface. The other techniques include measuring various flat surfaces in traditional side-looking IFSAR maps, in-flight closed-loop calibration path measurements, and static laboratory measurements. Initial results indicate that, using combinations of these measurements, it is possible to maintain the interferometric phase calibration of Sandia National Laboratories` K{sub U} Band IFSAR to better than 3 degrees. The time variability of various parts of the calibration and requirements for recalibration are also discussed.
Date: December 31, 1993
Creator: Bickel, D. L. & Hensley, W. H.
Partner: UNT Libraries Government Documents Department

Advanced Simulation and Computing FY08-09 Implementation Plan, Volume 2, Revision 0.5

Description: The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the surety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with current and future non-nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of current facilities and programs along with new experimental facilities and computational enhancements to support these programs. The Advanced Simulation and Computing Program (ASC)1 is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, to study advanced nuclear-weapons design and manufacturing processes, to analyze accident scenarios and weapons aging, and to provide the tools to enable Stockpile Life Extension Programs (SLEPs) and the resolution of Significant Finding Investigations (SFIs). This requires a balanced resource, including technical staff, hardware, simulation software, and computer science solutions. In its first decade, the ASC strategy focused on demonstrating simulation capabilities of unprecedented scale in three spatial dimensions. In its second decade, ASC is focused on increasing its predictive capabilities in a three-dimensional simulation environment while maintaining the support to the SSP. The program continues to improve its unique tools for solving progressively more difficult stockpile problems (focused on sufficient resolution, dimensionality and scientific details); to quantify critical margins and uncertainties (QMU); and to resolve increasingly difficult analyses needed for the SSP. Moreover, ASC has restructured its business model from one that was very successful in delivering an initial capability to one that is integrated and focused on requirements-driven products that address long-standing technical questions related to enhanced predictive capability in the simulation tools. ASC must ...
Date: September 13, 2007
Creator: Kusnezov, D; Bickel, T; McCoy, M & Hopson, J
Partner: UNT Libraries Government Documents Department

Coal liquefaction process research quarterly report, October-December 1979

Description: This quarterly report summarizes the activities of Sandia's continuing program in coal liquefaction process research. The overall objectives are to: (1) provide a fundamental understanding of the chemistry of coal liquefaction; (2) determine the role of catalysts in coal liquefaction; and (3) determine the mechanism(s) of catalyst deactivation. The program is composed of three major projects: short-contact-time coal liquefaction, mineral effects, and catalyst studies. These projects are interdependent and overlap significantly.
Date: March 1, 1980
Creator: Bickel, T.C.; Curlee, R.M.; Granoff, B.; Stohl, F.V. & Thomas, M.G.
Partner: UNT Libraries Government Documents Department

Tangential Velocity Measurement Using Interferometric MTI Radar

Description: An Interferometric Moving Target Indicator radar can be used to measure the tangential velocity component of a moving target. Multiple baselines, along with the conventional radial velocity measurement, allow estimating the true 3-D velocity vector of a target.
Date: November 1, 2002
Partner: UNT Libraries Government Documents Department

The effect of scattering from buildings on interferometric SAR measurements

Description: The determination of elevation models of buildings using interferometric synthetic aperture radar (IFSAR) is an important area of active research. The focus of this paper is on some of the unique scattering mechanisms that occur with buildings and how they affect the IFSAR height measurement and the coherence. The authors will show by theory and examples that the various data products obtained from IFSAR can be used to aid in interpreting building height results. They will also present a method that they have used successfully in mapping buildings in Washington D.C.
Date: June 1, 1997
Creator: Bickel, D.L.; Hensley, W.H. & Yocky, D.A.
Partner: UNT Libraries Government Documents Department

The Stopping Power of Amorphous and Channelled Silicon at All Energies as Computed with the Binary Encounter Approximation

Description: This thesis utilizes the binary encounter approximation to calculate the stopping power of protons penetrating silicon. The main goal of the research was to make predictions of the stopping power of silicon for low-energy and medium-energy channelled protons, in the hope that this will motivate experiments to test the theory developed below. In attaining this goal, different stopping power theories were compared and the binary encounter approach was applied to random (non-channelled) and high-energy channelled protons in silicon, and these results were compared with experimental data.
Date: December 1994
Creator: Bickel, David, 1970-
Partner: UNT Libraries

The Fractal Stochastic Point Process Model of Molecular Evolution and the Multiplicative Evolution Statistical Hypothesis

Description: A fractal stochastic point process (FSPP) is used to model molecular evolution in agreement with the relationship between the variance and mean numbers of synonymous and nonsynonymous substitutions in mammals. Like other episodic models such as the doubly stochastic Poisson process, this model accounts for the large variances observed in amino acid substitution rates, but unlike other models, it also accounts for the results of Ohta's (1995) analysis of synonymous and nonsynonymous substitutions in mammalian genes. That analysis yields a power-law increase in the index of dispersion and an inverse power-law decrease in the coefficient of variation with the mean number of substitutions, as predicted by the FSPP model but not by the doubly stochastic Poisson model. This result is compatible with the selection theory of evolution and the nearly-neutral theory of evolution.
Date: May 1997
Creator: Bickel, David R. (David Robert)
Partner: UNT Libraries

Battery energy storage and superconducting magnetic energy storage for utility applications: A qualitative analysis

Description: This report was prepared at the request of the US Department of Energy`s Office of Energy Management for an objective comparison of the merits of battery energy storage with superconducting magnetic energy storage technology for utility applications. Conclusions are drawn regarding the best match of each technology with these utility application requirements. Staff from the Utility Battery Storage Systems Program and the superconductivity Programs at Sandia National contributed to this effort.
Date: November 1, 1993
Creator: Akhil, A. A.; Butler, P. & Bickel, T. C.
Partner: UNT Libraries Government Documents Department

On-line assessment of mixing in an acid waste neutralization system

Description: The acid was neutralization system at Sandia National Laboratories treats process waste water from the Microelectronics Development Laboratory (MDL). The system consists of two 9,500 liter stirred tank reactors in series with an approximate feed rate of 3.17 L/s. The tanks are equipped with 320 W mixers with single impellers. pH sensors in each tank control acid and caustic delivery pumps. Sporadic excursions outside the required range of pH 5 to 11 were observed. Tracer experiments using methylene blue dye were performed during normal MDL operations to assess mixing in the individual reactors and the system. Tracers were injected as instantaneous pulses into the reactors and time dependent concentrations were measured in the effluent. Dimensionless exit age distributions were obtained which were similar to distributions for continuous stirred tank reactors (CSTR). These age distributions were extended to predict fluoride concentrations. The data indicate a separate fluoride collection system will be required to meet local environmental safety and health (ES H) regulations. Results from these tracer experiments have lead to cost effective design improvements in our neutralization system. 4 refs., 8 figs., 1 tab.
Date: January 1, 1990
Creator: Brown, N.E.; Resnick, P.J. & Bickel, T.C.
Partner: UNT Libraries Government Documents Department

Risk analysis of highly combustible gas storage, supply, and distribution systems in PWR plants

Description: This report presents the evaluation of the potential safety concerns for pressurized water reactors (PWRs) identified in Generic Safety Issue 106, Piping and the Use of Highly Combustible Gases in Vital Areas. A Westinghouse four-loop PWR plant was analyzed for the risk due to the use of combustible gases (predominantly hydrogen) within the plant. The analysis evaluated an actual hydrogen distribution configuration and conducted several sensitivity studies to determine the potential variability among PWRs. The sensitivity studies were based on hydrogen and safety-related equipment configurations observed at other PWRs within the United States. Several options for improving the hydrogen distribution system design were identified and evaluated for their effect on risk and core damage frequency. A cost/benefit analysis was performed to determine whether alternatives considered were justifiable based on the safety improvement and economics of each possible improvement.
Date: June 1, 1993
Creator: Simion, G. P.; VanHorn, R. L.; Smith, C. L.; Bickel, J. H.; Sattison, M. B. & Bulmahn, K. D.
Partner: UNT Libraries Government Documents Department

Large P body-like RNPs form in C. elegans oocytes in response to arrested ovulation, heat shock, osmotic stress, and anoxia and regulated by the major sperm protein pathway

Description: Article on large P body-like RNPs forming in C. elegans oocytes in response to arrested ovulation, heat shock, osmotic stress, and anoxia and regulated by the major sperm protein pathway.
Date: June 1, 2008
Creator: Jud, Molly C.; Czerwinski, Michael J.; Wood, Megan P.; Young, Rachel A.; Gallo, Christopher M.; Bickel, Jeremy S. et al.
Partner: UNT College of Arts and Sciences

Detecting DNA regulatory motifs by incorporating positional trendsin information content

Description: On the basis of the observation that conserved positions in transcription factor binding sites are often clustered together, we propose a simple extension to the model-based motif discovery methods. We assign position-specific prior distributions to the frequency parameters of the model, penalizing deviations from a specified conservation profile. Examples with both simulated and real data show that this extension helps discover motifs as the data become noisier or when there is a competing false motif.
Date: May 4, 2004
Creator: Kechris, Katherina J.; van Zwet, Erik; Bickel, Peter J. & Eisen,Michael B.
Partner: UNT Libraries Government Documents Department

MGAU: A new analysis code for measuring {sup 235}U enrichments in arbitrary samples

Description: We have developed a computerized analysis method for determining {sup 235}U enrichment in uranium items where no suitable reference standards exist or where nonreproducible conditions make calibration impossible. The method requires no calibrations and is capable of accuracies of 1--2% in only a few minutes.
Date: January 14, 1994
Creator: Gunnink, R.; Ruhter, W. D.; Miller, P.; Goerten, J.; Swinhoe, M.; Wagner, H. et al.
Partner: UNT Libraries Government Documents Department