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All sourcesNASA NTRSDOE OSTI
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↗
DOE OSTI2020

Optimizing the violacein biosynthetic pathway using droplet microfluidics

© 17CBMS-0001. We have developed a microfluidic platform that uses aqueous droplets suspended in an oil phase as discrete reaction chambers to carry out molecular biology steps. It integrates and automates all critical procedures of synthetic biology including combinatorial gene assembly, transformation by electroporation, addition of selection medium, culture, assay and sorting on a single device.

Gach, PC↗
DOE OSTI2020

Computer processing through distance-based quality score method in geospatial-temporal semantic graphs

A computer-implemented method of improving processing of overhead image data by a processor using a distance-based quality score in a geospatial-temporal semantic graph. An allowable range for each attribute in the subgraph search template is defined. For each match in a comparison, attribute values of each match element are compared against the preferred range and the allowable range to compute a corresponding distance of each match attribute from the subgraph search template. A corresponding overall match quality score is determined for each match from the subgraph search template, wherein determining the corresponding overall match qualities is performed using a corresponding required quality score and a corresponding optional quality score. All corresponding overall match quality scores are sorted into an ordered list and then displayed.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2020

Petrophysical and geomechanical properties of gas hydrate-bearing sediments recovered from Alaska North Slope 2018 Hydrate-01 Stratigraphic Test Well

Knowledge of petrophysical and geomechanical properties of gas hydrate-bearing sediments are essential for predicting reservoir response due to gas production from gas hydrate reservoirs. That information will be critical parameters for designing production well completion such as specification of depressurization pump, water storage tank, and mesh size of sand screen. In December 2018, Stratigraphic Test Well Hydrate-01 was drilled in the western part of the Prudhoe Bay Unit, Alaska North Slope as part of the technical planning effort for a future long-term production test by collaborative team of DOE/NETL, USGS, and MH21-S (Boswell et al., 2020, Collett et al., 2020, Okinaka et al., 2020). Data set of logging-while-drilling (LWD) were acquired (Haines et al., 2020, Suzuki et al., 2019) and core sampling depth was determined on-site.Side-wall pressure coring was conducted to recover gas hydrate-bearing sediments from two reservoir sections named Unit-B and Unit-D. A total of 34 cores were successfully recovered by 5 runs of a wire-line deployed pressure corer (CoreVault® System - Halliburton). Core analysis scheme of this project are shown in Figure 1. All cores were quenched in liquid nitrogen while at high pressure in the laboratory of Stratum Reservoir, LLC. at Anchorage (Figure 1, a)). And the cores were removed from the pressure corer autoclave with temperature support of dry ice and stored under liquid nitrogen at atmospheric pressure. 19 damaged cores were processed to index property measurements directly such as grain size, grain density. 4 of another 17 cores were depressurized and trimmed for making a plug to analyze petrophysical properties of host sediments. Unsteady-state permeability test was conducted to obtain relative water permeability to gas and core scale NMR T2 distribution measurement was performed for evaluating pore size distribution at Houston (Figure 1, b)). Remained high quality 13 cores were preserved with gas hydrate for advanced laboratory analysis. National Institute of Advanced Industrial Science and Technology, as a part of the Japanese National Hydrate Research Program (MH21-S, funded by Ministry of Economy, Trade and Industry), received the samples at Sapporo, Japan for advanced core analysis. High-resolution X-ray CT was used to analyze the quality of the samples, which showed undisturbed lithological layers. Cores were lathed into cylindrical shape and distributed for multi property measurements (Figure 1, c)).<p>As a result, sediment from Unit-D is categorized as silty sand at ~37% porosity with ~80% gas hydrate saturation. An average hydration number n = 6.16 was measured by Raman spectroscopy. An average intrinsic permeability of ~400 mD and in situ effective permeability (with hydrate) on the order of ~10 mD. The Unit B recovered cores consisted of well sorted sand at ~40% porosity with ~95% gas hydrate saturation. An average intrinsic permeability of ~1 Darcy and in situ effective permeability on the order of ~30 mD was measured for the Unit B cores. There was a small permeability reduction due to porosity loss with increasing effective stress that simulated consolidation behavior along with depressurization in the highly permeable sandy sediment. The apparent minimum change in porosity and permeability may be caused by the low compressibility of quartz sand grains in the recovered cores. XRD and thermal conductivity analysis also suggested high quartz content. Triaxial compression tests established internal friction angles based on the Mohr-Coulomb's failure criterion, which are 40° for hydrate-bearing sediment and 29.8° for hydrate free sediment.</p>

Yoneda, Jun↗
DOE OSTI2021

Creating the First Interactive Mobility Data Landscape

As the world continues to be driven increasingly driven by data, the ways this data is sorted and collected is critical for researchers and specification creators. In the world of mobility data, there are few if any de jure standards connecting data, and there is little knowledge on the gaps that exist in the data. In this project we have created an interactive landscape where mobility data and data specifications can be categorized and organized in an easy-to-use living document.

ADVANCED PROPULSION SYSTEMS↗

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