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All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Characterization of the naive murine antibody repertoire using unamplified high-throughput sequencing

Antibody specificity and diversity are generated through the enzymatic splicing of genomic gene segments within each B cell. Antibodies are heterodimers of heavy- and light-chains encoded on separate loci. We studied the antibody repertoire from pooled, splenic tissue of unimmunized, adult female C57BL/6J mice, using high-throughput sequencing (HTS) without amplification of antibody transcripts. We recovered over 90,000 heavy-chain and over 135,000 light-chain immunoglobulin sequences. Individual V-, D-, and J-gene segment usage was uniform among the three mouse pools, particularly in highly abundant gene segments, with low frequency V-gene segments not being detected in all pools. Despite the similar usage of individual gene segments, the repertoire of individual B-cell CDR3 amino acid sequences in each mouse pool was highly varied, affirming the combinatorial diversity in the B-cell pool that has been previously demonstrated. There also was some skewing in the V-gene segments that were detected depending on chromosomal location. This study presents a unique, non-primer biased glimpse of the conventionally housed, unimmunized antibody repertoire of the C57BL6/J mouse.

Science & Technology - Other Topics↗
DOE OSTI2026

XMark: Reliable Multi-Bit Watermarking for LLM-Generated Texts

Multi-bit watermarking has emerged as a promising solution for embedding imperceptible binary messages into Large Language Model (LLM)-generated text, enabling reliable attribution and tracing of malicious usage of LLMs. Despite recent progress, existing methods still face key limitations: some become computationally infeasible for large messages, while others suffer from a poor trade-off between text quality and decoding accuracy. Moreover, the decoding accuracy of existing methods drops significantly when the number of tokens in the generated text is limited, a condition that frequently arises in practical usage. To address these challenges, we propose XMark, a novel method for encoding and decoding binary messages in LLM-generated texts. The unique design of XMark’s encoder produces a less distorted logit distribution for watermarked token generation, preserving text quality, and also enables its tailored decoder to reliably recover the encoded message with limited tokens. Extensive experiments across diverse downstream tasks show that XMark significantly improves decoding accuracy while preserving the quality of watermarked text, outperforming prior methods. The code will be made publicly available upon acceptance.

Xu, Jiahao [University of Nevada, Reno]↗
DOE OSTI2012

Novel Steels for High Temperature Carburizing (Final Scientific Report)

This program was undertaken to develop a microalloy-modified grade of standard carburizing steel that can successfully exploit the high temperature carburizing capabilities of current commercial low pressure (i.e. 'vacuum') carburizing systems. Such steels can lower the amount of energy required for commercial carburizing operations by reducing the time required for deep-case carburizing operations. The specific technical objective of the work was to demonstrate a carburizing steel composition capable of maintaining a prior austenite grain size no larger than ASTM grain size number 5 after exposure to simulated carburizing conditions of 1050°C for 8 hr. Such thermal exposure should be adequate for producing carburized case depths up to about 2 mm. Such carburizing steels are expected to be attractive for use across a wide range of industries, including the petroleum, chemical, forest products, automotive, mining and industrial equipment industries. They have potential for reducing energy usage during low pressure carburizing by more than 25%, as well as reducing cycle times and process costs substantially. They also have potential for reducing greenhouse gas emissions from existing low pressure carburizing furnaces by more than 25%. High temperature carburizing can be done in most modern low pressure carburizing systems with no additional capital investment. Accordingly, implementing this technology on carburizing furnaces will provide a return on investment significantly greater than 10%. If disseminated throughout the domestic carburizing community, the technology has potential for saving on the order of 23 to 34 trillion BTU/year in industrial energy usage. Under the program, two compositions of microalloyed, coarsening-resistant low alloy carburizing steels were developed, produced and evaluated. After vacuum annealing at 1050°C for 8 hrs and high pressure gas quenching, both steels exhibited a prior austenite ASTM grain size number of 5.0 or finer. For comparison, a control alloy of similar composition but without the microalloy additions exhibited a duplex prior austenite grain size with grains ranging from ASTM grain size 3 down to ASTM grain size 1 after similar processing and thermal exposure. These results confirm the potential for using microalloy additions of Ti, B, Nb, Al, rare earths and/or N for austenite grain size control in Cr-Mo (i.e. 4000-series) low alloy carburizing steels. They also demonstrate that these microalloy additions will not compromise the processability of the steel; all three materials produced under the program could be hot worked readily using normal steel processing protocols. To fully realize the technical and commercial potential of these steels, there is a need to continue development work using larger-scale heats. These larger-scale heats are needed to provide adequate material for fatigue testing of quenched and tempered alloys, to conduct more complete investigations of potential alloy chemistries and to provide additional material for processing studies. It will also be beneficial to carefully review intellectual property issues associated with this family of steels, since existing Japanese patent literature suggests that significant microstructural and/or process characterization work may be needed on new materials to confirm that these materials fall outside existing patent claims.

02 PETROLEUM↗
DOE OSTI2012

The Solar Energy Consortium of New York Photovoltaic Research and Development Center

Project Objective: To lead New York State to increase its usage of solar electric systems. The expected outcome is that appropriate technologies will be made available which in turn will help to eliminate barriers to solar energy usage in New York State. Background: The Solar Energy Consortium has been created to lead New York State research on solar systems specifically directed at doubling the efficiency, halving the cost and reducing the cost of installation as well as developing unique form factors for the New York City urban environment.

14 SOLAR ENERGY↗
DOE OSTI2012

SCWR Once-Through Calculations for Transmutation and Cross Sections

It is the purpose of this report to document the calculation of (1) the isotopic evolution and of (2) the 1-group cross sections as a function of burnup of the reference Super Critical Water Reactor (SCWR), in a format suitable for the Fuel Cycle Option Campaign Transmutation Data Library. The reference SCWR design was chosen to be that described in [McDonald, 2005]. Super Critical Water Reactors (SCWR) are intended to operate with super-critical water (i.e. H2O at a pressure above 22 MPa and a temperature above 373oC) as a cooling – and possibly also moderating – fluid. The main mission of the SCWR is to generate lower cost electricity, as compared to current standard Light Water Reactors (LWR). Because of the high operating pressure and temperature, SCWR feature a substantially higher thermal conversion efficiency than standard LWR – i.e. about 45% versus 33%, mostly due to an increase in the exit water temperature from ~300oC to ~500oC – potentially resulting in a lower cost of generated electricity. The coolant remains single phase throughout the reactor and the energy conversion system, thus eliminating the need for pressurizers, steam generators, steam separators and dryers, further potentially reducing the reactor construction capital cost. The SCWR concept presented here is based on existing LWR technology and on a large number of existing fossil-fired supercritical boilers. However, it was concluded in [McDonald, 2005], that: “Based on the results of this study, it appears that the reference SCWR design is not feasible.” This conclusion appears based on the strong sensitivity of the design to small deviations in nominal conditions leading to small effects having a potentially large impact on the peak cladding temperature of some fuel rods. “This was considered a major feasibility issue for the SCWR” [McDonald, 2005]. After a description of the reference SCWR design, the Keno V 3-D single assembly model used for this analysis, as well as the calculated results, are presented. Additionally, the follwing information, presented in the appendixes, is intended to provide enough guidance that a researcher repeating the same task in the future should be able to obtain a vector of nuclei and cross sections ready for insertion into the transmutation library without any need for further instructions: (1) Complete TRITON/KENO-V input used for the analysis; (2) Inputs and detailed description of the usage of the OPUS utility, used to postproces and to extract the nuclei concentrations for the transmutation library; (3) Inputs and detailed description of the usage of the XSECLIST utility, used to postproces and to extract the 1-group cross sections for the transmutation library; (4) Details of an ad-hoc utility program developed to sort the nuclei and cross sections for the transmutation library.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2012

How to Plug In a Supercomputer: Quantifying Power Consumption at Scale [Slides]

Power is becoming an increasingly important concern for large super computercenters. However,todate,therehavebeenadearthofstudiesof power usage “in the wild”—on production supercomputers running pro duction workloads. In this talk, we present the initial results of an effort to characterize the power usage of three Top100 supercomputers at Los Alamos National Laboratory: Cielo, Roadrunner, and Luna (#18, #22, and #64, respectively, on the November 2012 Top500 list). Power measure ments taken both at the switchboard level and within the compute racks are presented and discussed.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2013

Initial Leak Analysis for Water Main from the Back Gate to TA-39

This investigation was undertaken in an effort to understand both the growth of LANL water consumption in recent years and to explain the 27% of LANL water usage that, in a recent audit, was accounted for as unknown usage plus leaks. The hypothesis is that LANL's old water mains are the cause due to their age and their hub-and-spigot sealing systems that are known to develop small leaks. Los Alamos County Utilities reports leak rates in the 10 to 15% range, varying with season, and their system engineers believe this is largely due to aging hub-and-spigot mains.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Today's Leaders for a Sustainable Tomorrow

Today's Leaders for a Sustainable Tomorrow is a collaboration of five residential environmental learning centers (Audubon Center of the North Woods, Deep Portage Learning Center, Laurentian Environmental Center, Long Lake Conservation Center and Wolf Ridge Environmental Learning Center) that together increased energy efficiency, energy conservation and renewable energy technologies through a number of different means appropriate for each unique center. For energy efficiency upgrades the centers installed envelope improvements to seal air barriers through better insulation in walls, ceilings, windows, doors as well as the installation of more energy efficient windows, doors, lighting and air ventilation systems. Through energy sub-meter monitoring the centers are able to accurately chart the usage of energy at each of their campuses and eliminate unnecessary energy usage. Facilities reduced their dependence on fossil fuel energy sources through the installation of renewable energy technologies including wood gasification, solar domestic hot water, solar photovoltaic, solar air heat, geothermal heating and wind power. Centers also installed energy education displays on the specific renewable energy technologies used at the center.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2013

Site Specific Reference Person Parameters and Derived Concentration Standards for the Savannah River Site

The purpose of this report is twofold. The first is to develop a set of behavioral parameters for a reference person specific for the Savannah River Site (SRS) such that the parameters can be used to determine dose to members of the public in compliance with Department of Energy (DOE) Order 458.1 “Radiation Protection of the Public and the Environment.” A reference person is a hypothetical, gender and age aggregation of human physical and physiological characteristics arrived at by international consensus for the purpose of standardizing radiation dose calculations. DOE O 458.1 states that compliance with the annual dose limit of 100 mrem (1 mSv) to a member of the public may be demonstrated by calculating the dose to the maximally exposed individual (MEI) or to a representative person. Historically, for dose compliance, SRS has used the MEI concept, which uses adult dose coefficients and adult male usage parameters. Beginning with the 2012 annual site environmental report, SRS will be using the representative person concept for dose compliance. The dose to a representative person will be based on 1) the SRS-specific reference person usage parameters at the 95th percentile of appropriate national or regional data, which are documented in this report, 2) the reference person (gender and age averaged) ingestion and inhalation dose coefficients provided in DOE Derived Concentration Technical Standard (DOE-STD-1196-2011), and 3) the external dose coefficients provided in the DC_PAK3 toolbox.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2012

Hooper Bay Housing Analysis and Energy Feasibility Report

Sea Lion applied for and received a grant from the Department of Energy (DOE) towards this end titled Energy Efficiency Development and Deployment in Indian Country. The initial objectives of the Hooper Bay Energy Efficiency Feasibility Study were to demonstrate a 30% reduction in residential/commercial energy usage and identify the economic benefits of implementing energy efficiency measures to the Tribe through: (1) partnering with Whitney Construction and Solutions for Healthy Breathing in the training and hire of 2 local energy assessors to conduct energy audits of 9 representative housing models and 2 commercial units in the community. These homes are representative of 52 homes constructed across different eras. (2) partnering with Cold Climate Housing Research Center to document current electrical and heating energy consumption and analyze data for a final feasibility report (3) assessing the economics of electricity & heating fuel usage; (4) projecting energy savings or fossil fuel reduction by modeling of improvement scenarios and cost feasibility The following two objectives will be completed after the publication of this report: (5) the development of materials lists for energy efficiency improvements (6) identifying financing options for the follow-up energy efficiency implementation phase.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2013

Infrastructure, Components and System Level Testing and Analysis of Electric Vehicles (CRADA Final Report)

Battery technology is critical for the development of innovative electric vehicle networks, which can enhance transportation sustainability and reduce dependence on petroleum. This cooperative research proposed by Better Place and NREL will focus on predicting the life-cycle economics of batteries, characterizing battery technologies under various operating and usage conditions, and designing optimal usage profiles for battery recharging and use.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

New Manufacturing Method for Paper Filler and Fiber Material

The use of fillers in printing and writing papers has become a prerequisite for competing in a global market to reduce the cost of materials. Use of calcium carbonates (ranging from 18% to 30%) as filler is a common practice in the paper industry but the choices of fillers for each type of papers vary widely according to its use. The market for uncoated digital printing paper is one that continues to introduce exciting growth projections. and it is important to understand the effect that new manufacturing methods of calcium carbonates have on the energy efficiency and paper production. Research conducted under this award showed that the new fiber filler composite material has the potential to increase the paper filler content by up to 5% without losing mechanical properties. Benefits of the technology can be summarized as follows for a 1% filler increase per metric ton of paper produced: (i) production cost savings over $12, (ii) Energy savings of 100,900 btu, (iii) CO 2 emission savings of 33 lbs, and additional savings for wood preparation, pulping, recovery of 203593 btu with a 46lbs of CO 2 emission savings per 1% filler increase. In addition the technology has the potential to save: (i) additional $3 per ton of bleached pulp produced, (ii) bleaching energy savings of 170,000 btu, (iii) bleaching CO 2 emission savings of 39 lbs, and (iv) additional savings for replacing conventional bleaching chemicals with a sustainable bleaching chemical is estimated to be 900,000 btu with a 205 lbs of CO 2 emission savings per ton of bleached pulp produced. All the above translates to a estimated annual savings for a 12% filler increase of 296 trillion buts or 51 million barrel of oil equivalent (BOE) or 13.7% of the industries energy demand. This can lead to a increase of renewable energy usage from 56% to close to 70% for the industry sector. CO 2 emission of the industry at a 12% filler increase could be lowered by over 39 million tons annually. If the new technology could be implemented for bleaching process a total annual estimated energy savings potential of 64 trillion buts or 11 million barrel of oil equivalent (BOE) equal to 3% of the paper industries energy demand could be realized. This could lead to a increase of renewable energy usage from 56% to close to 60% for the industry. CO 2 emissions could be lowered by over 7.4 million tons annually. It is estimated that an installed system could also yield a 75 to 100% return of investment (ROI) rate for the capital equipment that need to be installed for the fiber filler composite manufacturing process.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Compatibility Study for Plastic, Elastomeric, and Metallic Fueling Infrastructure Materials Exposed to Aggressive Formulations of Isobutanol-blended Gasoline

The Energy Independence and Security Act (EISA) of 2007 is an omnibus energy policy law designed to move the United States toward greater energy security and independence. A key provision of EISA is the Renewable Fuel Standard (RFS), which requires the nation to use 36 billion gallons per year (BGPY) of renewable fuel in vehicles by 2022. Ethanol is the most widely used renewable fuel, and increasing the allowable ethanol content from 10% to 15% is expected to push renewable fuel consumption to as much as 21 BGPY. Therefore, a large portion of the 36 billion gallon requirement can be met by increasing the ethanol content in gasoline to 15%. However, raising the ethanol content to 15%, by itself, will still not fully meet the RSF requirement, and concerns have been raised that this increase in ethanol may not be entirely compatible with current and legacy materials used in standard gasoline fueling systems. In the summer of 2008, the U.S. Department of Energy (DOE) recognized the need to assess the impact of intermediate blends of ethanol on the fueling infrastructure, specifically those systems located at the fueling station. A short time later (March 2009), Growth Energy (a coalition of ethanol producers and supporters) requested a waiver from the U.S. Environmental Protection Agency (EPA) to allow the use of 15% ethanol in gasoline. In 1981 the EPA approved a waiver (known as the OCTAMIX waiver) that allowed other alcohol types (such as methanol) to be blended with gasoline as long as the resulting fuel blend was substantially similar to gasoline. Another requirement is that the fuel oxygen content cannot exceed 3.7 wt %. Currently, this requirement limits ethanol in gasoline to 10 vol %. The corresponding oxygen equivalent for isobutanol is 16 vol %; therefore, isobutanol offers a pathway towards meeting the RFS requirement by allowing greater biofuel usage than can be achieved by ethanol alone. In fact, the United States has already hit the “blend wall” for ethanol, the point at which virtually all gasoline sold is E10 and no remaining market is left for ethanol, meaning that the country cannot substantially increase ethanol usage unless the EPA allows for higher levels of ethanol or until E85 use is expanded significantly. Butamax Advanced Biofuels, LLC has developed proprietary technologies to convert corn into isobutanol. Much of the infrastructure already existing at ethanol plants can be readily converted to produce isobutanol instead. The focus of this investigation was to compare the compatibility of fueling infrastructure materials (such as elastomers, plastics, and metals) to test fuels representing E10 and E15 and their corresponding oxygen equivalents with isobutanol (iBu16 and iBu24). Butamax sponsored a research project at Oak Ridge National Laboratory (ORNL) to perform empirical studies using aggressive fuel formulations representing 16 and 24% isobutanol. The results contained within this report include a solubility analysis for each material type and fuel formulation and empirical results for elastomers, plastics, and metals. Data obtained from the preceding ethanol compatibility studies on these materials are included for additional interpretation and summary.

Kass, Michael D.↗
DOE OSTI2013

EEB Hub Regional Sankey Diagram: Philadelphia Authority for Industrial Development Historical and Forecast Energy by Planned Use at the Philadelphia Navy Yard

The Energy Efficient Buildings Hub (EEB Hub) is a DOE-funded center, focused on improving the energy use in commercial and large-scale residential buildings. One of the Hub’s goals has been to develop the means and methods to reduce energy use in commercial buildings by 20 percent by 2020. Understanding energy use in buildings is a key component to managing energy use at multiple scales, from the building to the city, to the region. Sankey diagrams are an accessible tool to visualize energy flows, and help identify opportunities to deploy energy saving technologies. A campus-level Sankey diagram was previously generated from 2010-2011 data for ~100 metered Navy Yard buildings to quantify natural gas and electricity usage by principal building activity. As these properties are renovated, the energy consumption and building principal activities are being updated and modified. To depict the multi-year time lapse of regional electricity distribution in the Navy Yard, LLNL generated Sankey diagrams using data from 36 properties (buildings, developments, equipment) used to develop Philadelphia Authority for Industrial Development’s (PIDC) Navy Yard Master Energy Plan (NYEMP). The diagrams presented in this report depict ~10 building use types and the yearly changes in forecasted usage in GWh from 2011 to 2022. The forecast captures increases in regional energy use from planned building additions and renovations and yearly increases for existing buildings. From 2009 to 2022, there is approximately 5.6 million square feet of planned additions and renovations. The largest addition of properties are for office (~ 2.3 million square feet for dedicated office, and larger for shared office space) and residential space (~1 million square feet). Until 2014, the largest user of energy is for flex space, reaching a forecasted 11.4 GWh. In 2015-2016, the largest forecasted user is for a data center reaching ~25.7 GWh. After 2016, the largest consumers are either for office space (reaching 63.2 GWh forecast in 2022), or heavy industry (68 GWh forecast in 2022).

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2012

Recovery Act: Electrochromic Glazing Technology: Improved Performance, Lower Price (Final Report)

The growing dependency of the US on energy imports and anticipated further increases in energy prices reinforce the concerns about meeting the energy demand in the future and one element of a secure energy future is conservation. It is estimated that the buildings sector represents 40% of the US's total energy consumption. And buildings produce as much as one third of the greenhouse gas emissions primarily through fossil fuel usage during their operational phase. A significant fraction of this energy usage is simply due to inefficient window technology. Electrochromic (EC) windows allow electronic control of their optical properties so that the transparency to light can be adjusted from clear to dark. This ability to control the amount of solar energy allowed into the building can be advantageously used to minimize lighting, heating and air conditioning costs. Currently, the penetration of EC windows into the marketplace is extremely small, and consequently there is a huge opportunity for energy savings if this market can be expanded. In order to increase the potential energy savings it is necessary to increase the quantity of EC windows in operation. Additionally, any incremental improvement in the energy performance of each window will add to the potential energy savings. The overall goals of this project were therefore to improve the energy performance and lower the cost of dynamic (EC) smart windows for residential and commercial building applications. This project is obviously of benefit to the public by addressing two major areas: lowering the cost and improving the energy performance of EC glazings. The high level goals for these activities were: (i) to improve the range between the clear and the tinted state, (ii) reduce the price of EC windows by utilizing lower cost materials, (iii) lowering the U-Value, and (iv) ensure the proposed changes have no detrimental effect to the proven durability of the window. SAGE Electrochromics Inc. is the only company in the US which has a track record of producing EC windows, and presently has a small operational factory in Faribault MN which is shipping products throughout the world. There is a much larger factory currently under construction close by. This project was targeted specifically to address the issues outlined above, with a view to implementation on the new high volume manufacturing facility. Each of the Tasks which were addressed in this project is relatively straightforward to implement in this new facility and so the benefits of the work will be realized quickly. The research described here has helped to understand and provide solutions to several interesting and previously unresolved issues of the technology as well as make progress in areas which will have a significant impact on energy saving. In particular several materials improvements have been made, and tasks related to throughput and yield improvements have been completed. All of this has been accomplished without any detrimental effect on the proven durability of the SageGlass EC device. The project was divided into four main areas: 1. Improvement of the Properties of the EC device by material enhancements (Task 2); 2. Reduce the cost of production by improving the efficiency and yields of some key manufacturing processes (Task 3); 3. Further reduce the cost by significant modifications to the structure of the device (Task 4); 4. Ensure the durability of the EC device is not affected by any of the changes resulting from these activities (Task 5). A detailed description of the activities carried out in these areas is given in the following report, along with the aims and goals of the work. We will see that we have completed Tasks 2 and 3 fully, and the durability of the resulting device structure has been unaffected. Some of Task 4 was not carried out because of difficulties with integrating the installation of the required targets into the production coater due to external constraints not related to this project. We will also see that the durability of the devices produced as a result of this work was largely unaffected by the changes made here, and so we can conclude that the objectives of Task 5 have also been fulfilled. As a result, the future production of EC windows has benefited greatly from this work. We anticipate higher volumes and better yields for devices with an improved EC performance from the new high volume manufacturing facility currently under construction at SAGE.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Automated Cache Performance Analysis And Optimization

While there is no lack of performance counter tools for coarse-grained measurement of cache activity, there is a critical lack of tools for relating data layout to cache behavior to application performance. Generally, any nontrivial optimizations are either not done at all, or are done ”by hand” requiring significant time and expertise. To the best of our knowledge no tool available to users measures the latency of memory reference instructions for particular addresses and makes this information available to users in an easy-to-use and intuitive way. In this project, we worked to enable the Open|SpeedShop performance analysis tool to gather memory reference latency information for specific instructions and memory addresses, and to gather and display this information in an easy-to-use and intuitive way to aid performance analysts in identifying problematic data structures in their codes. This tool was primarily designed for use in the supercomputer domain as well as grid, cluster, cloud-based parallel e-commerce, and engineering systems and middleware. Ultimately, we envision a tool to automate optimization of application cache layout and utilization in the Open|SpeedShop performance analysis tool. To commercialize this software, we worked to develop core capabilities for gathering enhanced memory usage performance data from applications and create and apply novel methods for automatic data structure layout optimizations, tailoring the overall approach to support existing supercomputer and cluster programming models and constraints. In this Phase I project, we focused on infrastructure necessary to gather performance data and present it in an intuitive way to users. With the advent of enhanced Precise Event-Based Sampling (PEBS) counters on recent Intel processor architectures and equivalent technology on AMD processors, we are now in a position to access memory reference information for particular addresses. Prior to the introduction of PEBS counters, cache behavior could only be measured reliably in the aggregate across tens or hundreds of thousands of instructions. With the newest iteration of PEBS technology, cache events can be tied to a tuple of instruction pointer, target address (for both loads and stores), memory hierarchy, and observed latency. With this information we can now begin asking questions regarding the efficiency of not only regions of code, but how these regions interact with particular data structures and how these interactions evolve over time. In the short term, this information will be vital for performance analysts understanding and optimizing the behavior of their codes for the memory hierarchy. In the future, we can begin to ask how data layouts might be changed to improve performance and, for a particular application, what the theoretical optimal performance might be. The overall benefit to be produced by this effort was a commercial quality easy-to- use and scalable performance tool that will allow both beginner and experienced parallel programmers to automatically tune their applications for optimal cache usage. Effective use of such a tool can literally save weeks of performance tuning effort. Easy to use. With the proposed innovations, finding and fixing memory performance issues would be more automated and hide most to all of the performance engineer expertise ”under the hood” of the Open|SpeedShop performance tool. One of the biggest public benefits from the proposed innovations is that it makes performance analysis more usable to a larger group of application developers. Intuitive reporting of results. The Open|SpeedShop performance analysis tool has a rich set of intuitive, yet detailed reports for presenting performance results to application developers. Our goal was to leverage this existing technology to present the results from our memory performance addition to Open|SpeedShop. Suitable for experts as well as novices. Application performance is getting more difficult to measure as the hardware platforms they run on become more complicated. This makes life difficult for the application developer, in that they need to know more about the hardware platform, including the memory system hierarchy, in order to understand the performance of their application. Some application developers are comfortable in that sceario, while others want to do their scientific research and not have to understand all the nuances in the hardware platform they are running their application on. Our proposed innovations were aimed to support both experts and novice performance analysts. Useful in many markets. The enhancement to Open|SpeedShop would appeal to a broader market space, as it will be useful in scientific, commercial, and cloud computing environments. Our goal was to use technology developed initially at the and Lawrence Livermore National Laboratory combined with the development and commercial software experience of the Argo Navis Technologies, LLC (ANT) to form a powerful combination to delivery these objectives.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2012

Composite Materials for Hazard Mitigation of Reactive Metal Hydrides.

In an attempt to mitigate the hazards associated with storing large quantities of reactive metal hydrides, polymer composite materials were synthesized and tested under simulated usage and accident conditions. The composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride. Composites with vinyl-containing siloxane oligomers were also polymerized with and without added styrene and divinyl benzene. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride reduced the inherent hydrogen storage capacity of the material. The composites were found to be initially effective at reducing the amount of heat released during oxidation. However, upon cycling the composites, the mitigating behavior was lost. While the polymer composites we investigated have mitigating potential and are physically robust, they undergo a chemical change upon cycling that makes them subsequently ineffective at mitigating heat release upon oxidation of the metal hydride. Acknowledgements The authors would like to thank the following people who participated in this project: Ned Stetson (U.S. Department of Energy) for sponsorship and support of the project. Ken Stewart (Sandia) for building the flow-through calorimeter and cycling test stations. Isidro Ruvalcaba, Jr. (Sandia) for qualitative experiments on the interaction of sodium alanate with water. Terry Johnson (Sandia) for sharing his expertise and knowledge of metal hydrides, and sodium alanate in particular. Marcina Moreno (Sandia) for programmatic assistance. John Khalil (United Technologies Research Corp) for insight into the hazards of reactive metal hydrides and real-world accident scenario experiments. Summary In an attempt to mitigate and/or manage hazards associated with storing bulk quantities of reactive metal hydrides, polymer composite materials (a mixture of a mitigating polymer and a metal hydride) were synthesized and tested under simulated usage and accident conditions. Mitigating the hazards associated with reactive metal hydrides during an accident while finding a way to keep the original capability of the active material intact during normal use has been the focus of this work. These composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride, in this case a prepared sodium alanate (chosen as a representative reactive metal hydride). It was found that the polymerization of styrene and divinyl benzene could be initiated using AIBN in toluene at 70°C. The resulting composite materials can be either hard or brittle solids depending on the cross-linking density. Thermal decomposition of these styrene-based composite materials is lower than neat polystyrene indicating that the chemical nature of the polymer is affected by the formation of the composite. The char-forming nature of cross-linked polystyrene is low and therefore, not an ideal polymer for hazard mitigation. To obtain composite materials containing a polymer with higher char-forming potential, siloxane-based monomers were investigated. Four vinyl-containing siloxane oligomers were polymerized with and without added styrene and divinyl benzene. Like the styrene materials, these composite materials exhibited thermal decomposition behavior significantly different than the neat polymers. Specifically, the thermal decomposition temperature was shifted approximately 100 °C lower than the neat polymer signifying a major chemical change to the polymer network. Thermal analysis of the cycled samples was performed on the siloxane-based composite materials. It was found that after 30 cycles the siloxane-containing polymer composite material has similar TGA/DSC-MS traces as the virgin composite material indicating that the polymer is physically intact upon cycling. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride in the form of a composite material reduced the inherent hydrogen storage capacity of the material. This reduction in capacity was observed to be independent of the amount of charge/discharge cycles except for the composites containing siloxane, which showed less of an impact on hydrogen storage capacity as it was cycled further. While the reason for this is not clear, it may be due to a chemically stabilizing effect of the siloxane on the metal hydride. Flow-through calorimetry was used to characterize the mitigating effectiveness of the different composites relative to the neat (no polymer) material. The composites were found to be initially effective at reducing the amount of heat released during oxidation, and the best performing material was the siloxane-containing composite which reduced the heat release to less than 50% of the value of the neat material. However, upon cycling the composites, all mitigating behavior was lost. The combined results of the flow-through calorimetry, hydrogen capacity, and thermogravimetric analysis tests lead to the proposed conclusion that while the polymer composites have mitigating potential and are physically robust under cycling, they undergo a chemical change upon cycling that makes them ineffective at mitigating heat release upon oxidation of the metal hydride.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Evaluating Energy Savings in All-Electric Public Housing in the Pacific Northwest, Tacoma, Washington (Fact Sheet)

This project analyzes the cost effectiveness of energy savings measures installed by a large public housing authority in Salishan, a community in Tacoma Washington. Research focuses on the modeled and measured energy usage of the first six phases of construction, and compares the energy usage of those phases to phase 7. Market-ready energy solutions were also evaluated to improve the efficiency of affordable housing for new and existing (built since 2001) affordable housing in the marine climate of Washington State.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗