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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,171 records · Page 65
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

System Dynamics Analysis of Strategies to Reduce Energy Use in Aluminum-Intensive Sectors

Aluminum is one of the most widely used materials in industry, with applications in buildings, vehicles, aircraft, and consumer products. Its ubiquity is also on the rise: aluminum is beginning to supplant steel in lightweight vehicles and aircraft, and is used in many green or LEED-certified buildings. Although aluminum tends to be highly recycled, particularly by manufacturers of aluminum products, the sector as a whole is still far from a closed system. As a result, the increase in aluminum consumption also means an increase in primary aluminum production-an energy-intensive process-and an increase in consumption of the raw material bauxite, which in the U.S. is almost entirely imported. Our objectives for this study are to identify and analyze aluminum sector technologies and practices that reduce the energy required to manufacture aluminum products and reduce U.S. dependence on imported aluminum and bauxite. To accomplish these objectives, we will develop a system dynamics (SD) model of aluminum production, use and recycling in key application areas, including aerospace, ground vehicles and consumer products. The model will cover the entire aluminum supply chain as it exists in the U.S., from bauxite importing and refining, to the manufacture of products, to the product use phase and end-of-life processing steps. Aluminum flows throughout the model will be determined by the annual domestic demand for each application area as well as demand projections that extend to 2030. Energy consumption will be tracked based on the flows of aluminum through each step of the supply chain. Using the SD model, we will evaluate several technologies and practices that have the potential to reduce energy consumption and reliance on imported bauxite. These include implementation of advanced primary aluminum production technologies, increased recycling within and between application areas, increased material efficiency and increased product lifetimes. Each of these strategies results in short term reductions in energy use, and every strategy except the advance production technologies will also reduce the need for imported bauxite. This model differs from other SD models previously built to study aluminum stocks and flows in two key areas- alloy recycling and product lifetimes. Aluminum recycling is frequently complicated by the need to maintain quality of many different alloys, especially in aerospace applications. This necessitates scrap sorting and product disassembly to avoid contamination; advanced recycling processes of this type are one of the strategies to be evaluated. Product lifetime similarly complicates aluminum recycling, as products with longer lifetimes yield smaller recycling streams compared to disposable or short lifetime products, such as soda cans. When these additional complexities are accounted for in the SD model, a more realistic idea of the short term and long term impacts of the various strategies can be captured, as can any potential synergies and trade-offs between the strategies. Results of the analysis will indicate which strategy, or combination of strategies, yields the lowest cumulative energy consumption and bauxite consumption required to satisfy current and future demand for aluminum products.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2017

Roofline Analysis in the Intel® Advisor to Deliver Optimized Performance for applications on Intel® Xeon Phi™ Processor

In this session we show, in two case studies, how the roofline feature of Intel Advisor has been utilized to optimize the performance of kernels of the XGC1 and PICSAR codes in preparation for Intel Knights Landing architecture. The impact of the implemented optimizations and the benefits of using the automatic roofline feature of Intel Advisor to study performance of large applications will be presented. This demonstrates an effective optimization strategy that has enabled these science applications to achieve up to 4.6 times speed-up and prepare for future exascale architectures. # Goal/Relevance of Session The roofline model [1,2] is a powerful tool for analyzing the performance of applications with respect to the theoretical peak achievable on a given computer architecture. It allows one to graphically represent the performance of an application in terms of operational intensity, i.e. the ratio of flops performed and bytes moved from memory in order to guide optimization efforts. Given the scale and complexity of modern science applications, it can often be a tedious task for the user to perform the analysis on the level of functions or loops to identify where performance gains can be made. With new Intel tools, it is now possible to automate this task, as well as base the estimates of peak performance on measurements rather than vendor specifications. The goal of this session is to demonstrate how the roofline feature of Intel Advisor can be used to balance memory vs. computation related optimization efforts and effectively identify performance bottlenecks. A series of typical optimization techniques: cache blocking, structure refactoring, data alignment, and vectorization illustrated by the kernel cases will be addressed. # Description of the codes ## XGC1 The XGC1 code [3] is a magnetic fusion Particle-In-Cell code that uses an unstructured mesh for its Poisson solver that allows it to accurately resolve the edge plasma of a magnetic fusion device. After recent optimizations to its collision kernel [4], most of the computing time is spent in the electron push (pushe) kernel, where these optimization efforts have been focused. The kernel code scaled well with MPI+OpenMP but had almost no automatic compiler vectorization, in part due to indirect memory addresses and in part due to low trip counts of low-level loops that would be candidates for vectorization. Particle blocking and sorting have been implemented to increase trip counts of low-level loops and improve memory locality, and OpenMP directives have been added to vectorize compute-intensive loops that were identified by Advisor. The optimizations have improved the performance of the pushe kernel 2x on Haswell processors and 1.7x on KNL. The KNL node-for-node performance has been brought to within 30% of a NERSC Cori phase I Haswell node and we expect to bridge this gap by reducing the memory footprint of compute intensive routines to improve cache reuse. ## PICSAR is a Fortran/Python high-performance Particle-In-Cell library targeting at MIC architectures first designed to be coupled with the PIC code WARP for the simulation of laser-matter interaction and particle accelerators. PICSAR also contains a FORTRAN stand-alone kernel for performance studies and benchmarks. A MPI domain decomposition is used between NUMA domains and a tile decomposition (cache-blocking) handled by OpenMP has been added for shared-memory parallelism and better cache management. The so-called current deposition and field gathering steps that compose the PIC time loop constitute major hotspots that have been rewritten to enable more efficient vectorization. Particle communications between tiles and MPI domain has been merged and parallelized. All considered, these improvements provide speedups of 3.1 for order 1 and 4.6 for order 3 interpolation shape factors on KNL configured in SNC4 quadrant flat mode. Performance is similar between a node of cori phase 1 and KNL at order 1 and better on KNL by a factor 1.6 at order 3 with the considered test case (homogeneous thermal plasma).

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2017

Deep Interactive Learning with Sharkzor

Sharkzor is a web application for machine-learning assisted image sort and summary. Deep learning algorithms are leveraged to infer, augment, and automate the user’s mental model. Initially, images uploaded by the user are spread out on a canvas. The user then interacts with the images to impute their mental model into the applications algorithmic underpinnings. Methods of interaction within Sharkzor’s user interface and user experience support three primary user tasks: triage, organize and automate. The user triages the large pile of overlapping images by moving images of interest into proximity. The user then organizes said images into meaningful groups. After interacting with the images and groups, deep learning helps to automate the user’s interactions. The loop of interaction, automation, and response by the user allows the system to quickly make sense of large amounts of data.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

2018 DOE Solid-State Lighting Project Portfolio

The 2018 Solid-State Lighting Project Portfolio provides an overview of all SSL projects that have been funded by DOE since 2000. Projects that were active during 2017 are found in the main body of this report, and all historic projects can be found in the appendix. Within these sections, project profiles are sorted by technology type (i.e., LED or OLED) and then by performer name. A profile is provided on each project. Each profile includes a brief technical description, as well as information about project partners, funding, and the research period. This report is updated annually, although the research described in the Portfolio changes periodically as new projects are initiated and existing ones are concluded.

SSL, lighting, project, LED, OLED, portfolio, awar↗
DOE OSTI2018

ADAPT

The purpose of the ADAPT code is to generate Dynamic Event Trees (DET) using a user specified set of simulators. ADAPT can utilize any simulation tool which meets a minimal set of requirements. ADAPT is based on the concept of DET which uses explicit modeling of the deterministic dynamic processes that take place during a nuclear reactor plant system (or other complex system) evolution along with stochastic modeling. When DET are used to model various aspects of Probabilistic Risk Assessment (PRA), all accident progression scenarios starting from an initiating event are considered simultaneously. The DET branching occurs at user specified times and/or when an action is required by the system and/or the operator. These outcomes then decide how the dynamic system variables will evolve in time for each DET branch. Since two different outcomes at a DET branching may lead to completely different paths for system evolution, the next branching for these paths may occur not only at separate times, but can be based on different branching criteria. The computational infrastructure allows for flexibility in ADAPT to link with different system simulation codes, parallel processing of the scenarios under consideration, on-line scenario management (initiation as well as termination), analysis of results, and user friendly graphical capabilities. The ADAPT system is designed for a distributed computing environment; the scheduler can track multiple concurrent branches simultaneously. The scheduler is modularized so that the DET branching strategy can be modified (e.g. biasing towards the worst-case scenario/event). Independent database systems store data from the simulation tasks and the DET structure so that the event tree can be constructed and analyzed later. ADAPT is provided with a user-friendly client which can easily sort through and display the results of an experiment, precluding the need for the user to manually inspect individual simulator runs.

Reynolds, John↗
DOE OSTI2018

Preventing the Cyber Zombie Apocalypse

Cybercrime rates are on the rise, but what exactly does that mean? Cybercrime is any sort of crime using a computer—simple enough. And now that most people in the United States have a computer or access to one, cybercrime is more common than ever. Los Alamos National Laboratory has been working on cybersecurity techniques, processes and tools to prevent and detect cyberattacks.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

Chapter 4 - Mechanical Fractionations of Biomass Feedstocks for Enhanced Pretreatment and Conversion. In the book Biomass Preprocessing and Pretreatments for Production of Biofuels: Mechanical, Chemical and Thermal Methods.

Living plant biomass consists of multiple types of tissues and organs, each performing unique and essential physical or biological functions in the living plant. Because of these differences in form and function, these tissues and organs can retain these unique physical and chemical properties after senescence or harvest. Properties such as ash composition, ash content, carbohydrate content, lignin content, density, and recalcitrance can vary widely between plant parts and tissues. Mechanical fractionation of biomass feedstocks has the potential to take advantage of these naturally occurring differences to produce physically or chemically unique fractions that have higher or lower value within specific biochemical or thermochemical conversion platforms. Mechanical fractionation techniques that have shown promise include density separations in air or liquid, size separations, and automated sorting. Density separations, such as air classification, separate based on particle density, size, and shape. Size separations are highly dependent upon size reduction techniques, however anatomical differences can affect particle size. The chemical and physical properties of the resulting fractions help determine their optimal use. These unique fractions can be used directly or treated as ingredients and blended with other feedstocks or fractions of feedstocks to meet cost, quality, or conversion specifications.

09 BIOMASS FUELS↗
DOE OSTI2018

GoldenEye: stream-based network packet inspection using GPUs

High-performance packet analysis systems have attracted great interest as tools to deal with security concerns in high-speed networks. Recently, researchers have utilized GPUs to improve packet processing performance. However, most existing work has been targeted at per-packet analysis level. Flow-centric operations have been challenging for GPUs because they require sequential operations and large buffers for flow reassembly. In this work, we present the GoldenEye GPU Packet Processing System (GoldenEye), a deep packet inspection (DPI) system that tracks out-of-order TCP packets and provides streambased signature matching. When a batch of packets arrives, GoldenEye sorts packets into flow-reassembled streams and normalizes retransmission through a GPU-implemented reordering module. For signatures that straddle batch boundaries, GoldenEye couples a small set of metadata with a functionallyequivalent minimal regular expression retrieval algorithm to connect the partial matches. Results show that GoldenEye can reassemble tens of millions of packets/sec and conduct stateful DPI operations on TCP streams at multi-ten Gbit/sec rates.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2017

Los Alamos works on a biologically realistic computer network

Brain neuroscientists and computer scientists call this field neuromimetic computing—building computers inspired by how the cerebral cortex of the brain works. Its cortical processes rely on billions of small biological “switches,” called neurons. To learn, they store and process information. Using an approach called neural networks, researchers are developing computers that simulate neurons and their interconnections. Then computers can learn about their surroundings, interpret data, and make predictions based on it. In practice, however, researchers attempting to simulate neural processing at anything close to the scale and complexity of the brain’s cortical circuits have been stymied by limitations on computer memory and computational power. All that has changed with the new Trinity supercomputer at Los Alamos, which became fully operational in mid-2017. Trinity has unique capabilities designed for the stockpile stewardship mission, which includes highly complex nuclear simulations that have replaced the testing of nuclear weapons. All this capability means Trinity allows a fundamentally different approach to large-scale cortical simulations, enabling an unprecedented leap in the ability to model neural processing. To test that capability on a limited-scale problem, computer scientists and neuroscientists at Los Alamos created a “sparse prediction machine” that runs on a neural network on Trinity. A sparse prediction machine is designed to work like the brain: researchers expose it to data—in this case, various videos of a car driving down a road—without labeling the data in any way. Then the program sorts through that data frame by frame, focuses on the important information, and develops a prediction about the car’s motion. With Trinity’s power, the Los Alamos team simulates the way a brain handles information in its neurons but uses the fewest neurons at any given moment to explain the information at hand. That’s the “sparse” part, and it makes the brain very efficient—and, hopefully, a computer more efficient, too.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2017

Real-time, In-line Assessment of Flow Performance for Compressible and Anisotropic Bulk Solids

Feeding and handling problems have been recognized as a major contributor to low production of renewable cellulosic ethanol in the US, which achieved only 7% of nameplate capacity in 2016. Current methods that assess material feeding and handling properties require multiple hours to complete, making them ill-suited for quality assurance and control (QA/QC) in production environments. This talk presents a method, based upon a custom hopper with adaptable geometry, to assess feeding and handling behavior of materials in a production or receiving line in real-time, so that those properties can be used to either sort material or adjust preprocessing conditions to ensure that incoming material meet feeding and handling specifications. Flow properties are determined by continually adjusting the size of the outlet in a plane-flow hopper to maintain a constant fill level in the hopper. The angle of the hopper walls can also be adjusted to tune the geometry to different materials. Tests conducted at approximately 1,000 lbs per hour indicate that this method readily assesses the flow performance differences of corn stover and pine wood due to changes in particle size from 3 to 13 mm and due to changes in moisture content from 10 to 20%. Comparison of this method with shear tests using an automated Schulze ring shear indicate that this method is more sensitive for determining differences in flowability performance than traditional shear tests for corn stover and pine wood. Test results, including wall pressure measurements, are compared to simulations and indicate that this method shows promise for in-line quantitative estimation of the flow properties of compressible and anisotropic materials, including bulk density, cohesion, and internal angle of friction.

09 BIOMASS FUELS↗
DOE OSTI2019

Full flow retrieval optimized packet capture

A packet capture system may copy packets from an interface to a bucket. When the bucket is full of packets, a new bucket for incoming packets may be started, and the full bucket may be indexed. During the indexing, each packet may be sorted in the bucket by flow, and each flow may be indexed. Once indexing is complete, the packets are written to a flow ordered FCAP file and the indexes are written to disk. The flow ordered nature of the FCAP file combined with the indices and their associated search algorithms allow for rapid retrieval of captured flows.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2019

18. Combining experiment and simulation to study complex biomimetic membranes

The three-dimensional architecture of biological membranes has functional consequences for the living cell. In the outer leaflet of the plasma membrane, lipids are thought to self-organize into domains enriched in high-melting lipids and cholesterol. Currently, there is much evidence implicating these lipid domains in a variety of membrane processes, including protein sorting, cell signaling, and the maintenance of membrane physical properties. Cells also actively maintain an asymmetric distribution of different lipid types between their plasma membrane inner and outer leaflets, resulting in monolayers with different fluidities and charge densities. Moreover, it is an open question how these and other bilayer properties are coupled, if at all. A variety of biophysical techniques are being employed to interrogate both lateral and transverse bilayer structures with sub-nanometer resolution. Molecular dynamic simulations are also used to probe the membrane’s finer details, providing a glimpse of membrane organization with atomic resolution. In this chapter, we present a discussion of these two approaches to investigate the organization of complex biomimetic membranes and present recent examples of how they have been used to complement each other.

Katsaras, John↗
DOE OSTI2019

Hot page selection in multi-level memory hierarchies

Systems, apparatuses, and methods for sorting memory pages in a multi-level heterogeneous memory architecture. The system may classify pages into a first “hot” category or a second “cold” category. The system may attempt to place the “hot” pages into the memory level(s) closest to the systems' processor cores. The system may track parameters associated with each page, with the parameters including number of accesses, types of accesses, power consumed per access, temperature, wearability, and/or other parameters. Based on these parameters, the system may generate a score for each page. Then, the system may compare the score of each page to a threshold. If the score of a given page is greater than the threshold, the given page may be designated as “hot”. If the score of the given page is less than the threshold, the given page may be designated as “cold”.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2019

Global distributed file append using log-structured file system

Techniques are provided for globally appending data from a group of distributed processes to a shared file using a log-structured file system. Data generated by a plurality of processes in a parallel computing system are appended to a shared file by storing the data to the shared file using a log-structured file system (such as a Parallel Log-Structured File System (PLFS)); and generating an index entry for the data, the index entry comprising a logical offset entry and a timestamp entry indicating a time of the storage, wherein the logical offset entry is resolved at read time. The logical offset entry can be populated with an append placeholder that is resolved when the shared file is read. At read time, a plurality of the index entries associated with the shared file can be sorted using the timestamp entry to deliver the requested shared file to a requesting application.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2019

Fluid-based gating mechanism with tunable multiphase selectivity and antifouling behavior

A gating mechanism that uses a capillary stabilized liquid as a reversible, reconfigurable gate that fills and seals pores in the closed state, and creates a non-fouling, liquid-lined pore in the open state is disclosed. Theoretical modeling and experiments demonstrate that for each transport substance, the gating threshold—the pressure needed to open the pores—can be rationally tuned over a wide pressure range. This enables realizing in one system differential response profiles for a variety of liquids and gases, even letting liquids flow through the pore while preventing gas from escaping. These capabilities allow dynamic modulation of gas-liquid sorting and to separate multi-phase mixtures, with the liquid lining ensuring sustained antifouling behavior. Because the liquid gating strategy enables efficient short-term and long-term operation and can be applied to a variety of pore structures and membrane materials, and to nano, micro as well as macroscale fluid systems, the gating systems is useful in a wide range of applications.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Single-cell raman spectroscopy for the non-destructive, non-invasive analysis of cells and cellular components

Raman spectra of cells, such as normal human T- and B-cells from peripheral blood or human tonsil and the corresponding transformed cells are obtained by optically trapping the cells and obtaining their Raman spectra. The trapped cells can be subjected to one, two, or more different excitation wavelengths, and each wavelength of the corresponding Raman spectra can be stored in a separate channel. In preferred embodiments, two spectra are subtracted from each other to give a difference spectrum and each channel is analyzed independently to characterize the trapped cell. Alternatively, the Raman spectrum can be subjected to Principal Component Analysis (PCA) in order to characterize the trapped cell. The trapped cell thus classified can be sorted, or further manipulated.

Chan, James W.↗
DOE OSTI2019

Circulating fluidized bed connected to a desublimating heat exchanger

Condensable vapors such as carbon dioxide are separated from light gases in a process stream. The systems and methods employ a circulating fluidized particle bed cooled by an out-bed heat exchanger to desublimate the solid form of condensable vapors from the process stream. Gas and solids may be sorted in a separator, and the solids may then be subcooled in a heat exchanger. The condensable vapors may be condensed on the bed particles or in the heat exchanger while the light gases from the process stream, which are not condensed, form a separated light-gas stream.

Baxter, Larry↗
DOE OSTI2018

Where do particle names come from?

One of the most difficult things in learning particle physics for the first time is to understand all of the various names. There are dozens and dozens and sometimes many names can apply to one particle or a single name can apply to many particles. It’s all very confusing. Luckily, Fermilab’s Dr. Don Lincoln made this video to help you sort it all out.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗