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Transportation Energy Pathways LDRD

Barter, Garrett E.; Edwards, Donna M.; Hines, Valerie A.; Reichmuth, David; Westbrook, Jessica; Malczynski, Leonard A.; Yoshimura, Ann S.; Peterson, Meghan; West, Todd H.; Manley, Dawn K.; Guzman, Katherine D.

This report presents a system dynamics based model of the supply-demand interactions between the US light-duty vehicle (LDV) fleet, its fuels, and the corresponding primary energy sources through the year 2050. An important capability of our model is the ability to conduct parametric analyses. Others have relied upon scenario-based analysis, where one discrete set of values is assigned to the input variables and used to generate one possible realization of the future. While these scenarios can be illustrative of dominant trends and tradeoffs under certain circumstances, changes in input values or assumptions can have a significant impact on results, especially when output metrics are associated with projections far into the future. This type of uncertainty can be addressed by using a parametric study to examine a range of values for the input variables, offering a richer source of data to an analyst.The parametric analysis featured here focuses on a trade space exploration, with emphasis on factors that influence the adoption rates of electric vehicles (EVs), the reduction of GHG emissions, and the reduction of petroleum consumption within the US LDV fleet. The underlying model emphasizes competition between 13 different types of powertrains, including conventional internal combustion engine (ICE) vehicles, flex-fuel vehicles (FFVs), conventional hybrids(HEVs), plug-in hybrids (PHEVs), and battery electric vehicles(BEVs).We find that many factors contribute to the adoption rates of EVs. These include the pace of technological development for the electric powertrain, battery performance, as well as the efficiency improvements in conventional vehicles. Policy initiatives can also have a dramatic impact on the degree of EV adoption. The consumer effective payback period, in particular, can significantly increase the market penetration rates if extended towards the vehicle lifetime.Widespread EV adoption can have noticeable impact on petroleum consumption and greenhouse gas(GHG) emission by the LDV fleet. However, EVs alone cannot drive compliance with the most aggressive GHG emission reduction targets, even as the current electricity source mix shifts away from coal and towards natural gas. Since ICEs will comprise the majority of the LDV fleet for up to forty years, conventional vehicle efficiency improvements have the greatest potential for reductions in LDV GHG emissions over this time.These findings seem robust even if global oil prices rise to two to three times current projections. Thus,investment in improving the internal combustion engine might be the cheapest, lowest risk avenue towards meeting ambitious GHG emission and petroleum consumption reduction targets out to 2050.3 Acknowledgment The authors would like to thank Dr. Andrew Lutz, Dr. Benjamin Wu, Prof. Joan Ogden and Dr. Christopher Yang for their suggestions over the course of this project. This work was funded by the Laboratory Directed Research and Development program at Sandia National Laboratories.

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TYPE SAND Report YEAR 2012
DOIOSTI

Leveraging Formal Methods and Fuzzing to Verify Security and Reliability Properties of Large-Scale High-Consequence Systems

Ruthruff, Joseph; Armstrong, Robert C.; Davis, Benjamin G.; Mayo, Jackson R.; Punnoose, Ratish J.

Formal methods describe a class of system analysis techniques that seek to prove specific properties about analyzed designs, or locate flaws compromising those properties. As an analysis capability,these techniques are the subject of increased interest from both internal and external customers of Sandia National Laboratories. Given this lab's other areas of expertise, Sandia is uniquely positioned to advance the state-of-the-art with respect to several research and application areas within formal methods. This research project was a one-year effort funded by Sandia's CyberSecurity S&T Investment Area in its Laboratory Directed Research & Development program to investigate the opportunities for formal methods to impact Sandia's present mission areas, more fully understand the needs of the research community in the area of formal methods and where Sandia can contribute, and clarify from those potential research paths those that would best advance the mission-area interests of Sandia. The accomplishments from this project reinforce the utility of formal methods in Sandia, particularly in areas relevant to Cyber Security, and set the stage for continued Sandia investments to ensure this capabilityis utilized and advanced within this laboratory to serve the national interest.

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TYPE SAND Report YEAR 2012
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Magneto-hydrodynamic detection of vortex shedding for molten salt flow sensing

Kruizenga, Alan M.; Crocker, Robert W.

High temperature flow sensors must be developed for use with molten salts systems at temperatures in excess of 600ÀC. A novel magneto-hydrodynamic sensing approach was investigated. A prototype sensor was developed and tested in an aqueous sodium chloride solution as a surrogate for molten salt. Despite that the electrical conductivity was a factor of three less than molten salts, it was found that the electrical conductivity of an electrolyte was too low to adequately resolve the signal amidst surrounding noise. This sensor concept is expected to work well with any liquid metal application, as the generated magnetic field scales proportionately with electrical conductivity.

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TYPE SAND Report YEAR 2012
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Functionalized ultra-porous titania nanofiber membranes as nuclear waste separation and sequestration scaffolds for nuclear fuels recycle

Schwarz, Haiqing L.

Advanced nuclear fuel cycle concept is interested in reducing separations to a simplified, one-step process if possible. This will benefit from the development of a one-step universal getter and sequestration material so as a simplified, universal waste form was proposed in this project. We have developed a technique combining a modified sol-gel chemistry and electrospinning for producing ultra-porous ceramic nanofiber membranes with controllable diameters and porous structures as the separation/sequestration materials. These ceramic nanofiber materials have been determined to have high porosity, permeability, loading capacity, and stability in extreme conditions. These porous fiber membranes were functionalized with silver nanoparticles and nanocrystal metal organic frameworks (MOFs) to introduce specific sites to capture gas species that are released during spent nuclear fuel reprocessing. Encapsulation into a durable waste form of ceramic composition was also demonstrated.

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TYPE SAND Report YEAR 2012
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Some Logistical Considerations in Designing a System of Deep Boreholes for Disposal of High-Level Radioactive Waste

Brady, Patrick V.; Arnold, Bill W.

Deep boreholes could be a relatively inexpensive, safe, and rapidly deployable strategy for disposing Americaś nuclear waste. To study this approach, Sandia invested in a three year LDRD project entitled “Radionuclide Transport from Deep Boreholes.” In the first two years, the borehole reference design and backfill analysis were completed and the supporting modeling of borehole temperature and fluid transport profiles were done. In the third year, some of the logistics of implementing a deep borehole waste disposal system were considered. This report describes what was learned in the third year of the study and draws some conclusions about the potential bottlenecks of system implementation.

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TYPE SAND Report YEAR 2012
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Automated exploration of the mechanism of elementary reactions

Najm, Habib N.; Zador, Judit

Optimization of new transportation fuels and engine technologies requires the characterization of the combustion chemistry of a wide range of fuel classes. Theoretical studies of elementary reactions — the building blocks of complex reaction mechanisms — are essential to accurately predict important combustion processes such as autoignition of biofuels. The current bottleneck for these calculations is a user-intensive exploration of the underlying potential energy surface (PES), which relies on the “chemical intuition” of the scientist to propose initial guesses for the relevant chemical configurations. For newly emerging fuels, this approach cripples the rate of progress because of the system size and complexity. The KinBot program package aims to accelerate the detailed chemical kinetic description of combustion, and enables large-scale systematic studies on the sub-mechanism level.

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TYPE SAND Report YEAR 2012
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First-Principles Flocculation as the Key to Low Energy Algal Biofuels Processing

Hewson, John C.; Mondy, Lisa A.; Murton, Jaclyn K.; O'Hern, Timothy J.; Parchert, Kylea J.; Pohl, Phillip I.; Williams, Cecelia V.; Wyatt, Nicholas B.; Barringer, David A.; Pierce, Flint; Brady, Patrick V.; Dwyer, Brian P.; Grillet, Anne M.; Hankins, Matthew G.; Hughes, Lindsey; Lechman, Jeremy B.

This document summarizes a three year Laboratory Directed Research and Development (LDRD) program effort to improve our understanding of algal flocculation with a key to overcoming harvesting as a techno-economic barrier to algal biofuels. Flocculation is limited by the concentrations of deprotonated functional groups on the algal cell surface. Favorable charged groups on the surfaces of precipitates that form in solution and the interaction of both with ions in the water can favor flocculation. Measurements of algae cell-surface functional groups are reported and related to the quantity of flocculant required. Deprotonation of surface groups and complexation of surface groups with ions from the growth media are predicted in the context of PHREEQC. The understanding of surface chemistry is linked to boundaries of effective flocculation. We show that the phase-space of effective flocculation can be expanded by more frequent alga-alga or floc-floc collisions. The collision frequency is dependent on the floc structure, described in the fractal sense. The fractal floc structure is shown to depend on the rate of shear mixing. We present both experimental measurements of the floc structure variation and simulations using LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator). Both show a densification of the flocs with increasing shear. The LAMMPS results show a combined change in the fractal dimension and a change in the coordination number leading to stronger flocs.

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TYPE SAND Report YEAR 2012
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Detectability of Neuronal Currents in Human Brain with Magnetic Resonance Spectroscopy

Jones, Howland D.T.; Thomas, Edward V.; Harper, Jason C.

Magnetic resonance spectroscopy has been used in a high-risk, high-payoff search for neuronal current (NC) signals in the free induction decay (FID) data from the visual cortex of human subjects during visual stimulation. If successful, this approach could make possible the detection of neuronal currents in the brain at high spatial and temporal resolution. Our initial experiments indicated the presence of a statistically significant change in the FID containing the NC relative to FIDs with the NC absent, and this signal was consistent with the presence of NC. Unfortunately, two follow-on experiments were not able to confirm or replicate the positive findings of the first experiment. However, even if the result from the first experiment were evidence of NC in the FID, it is clear that its effect is so small, that a true NC imaging experiment would not be possible with the current instrumentation and experimental protocol used here.

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TYPE SAND Report YEAR 2012
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Probability of Loss of Assured Safety in Systems with Multiple Time-Dependent Failure Modes

Pilch, Martin; Sallaberry, Cedric J.

Weak link (WL)/strong link (SL) systems are important parts of the overall operational design of high-consequence systems. In such designs, the SL system is very robust and is intended to permit operation of the entire system under, and only under, intended conditions. In contrast, the WL system is intended to fail in a predictable and irreversible manner under accident conditions and render the entire system inoperable before an accidental operation of the SL system. The likelihood that the WL system will fail to deactivate the entire system before the SL system fails (i.e., degrades into a configuration that could allow an accidental operation of the entire system) is referred to as probability of loss of assured safety (PLOAS). Representations for PLOAS for situations in which both link physical properties and link failure properties are time-dependent are derived and numerically evaluated for a variety of WL/SL configurations, including PLOAS defined by (i) failure of all SLs before failure of any WL, (ii) failure of any SL before failure of any WL, (iii) failure of all SLs before failure of all WLs, and (iv) failure of any SL before failure of all WLs. The effects of aleatory uncertainty and epistemic uncertainty in the definition and numerical evaluation of PLOAS are considered.

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TYPE SAND Report YEAR 2012
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Results 62001–62200 of 99,299
Results 62001–62200 of 99,299