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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Performance of a hardened x-ray streak camera at Lawrence Livermore National Laboratory’s National Ignition Facility

Electron tubes continue to provide the highest speeds possible for recording dynamics of hot high-energy density plasmas. Standard streak camera drive electronics and CCD readout are not compatible with the radiation environment associated with high DT fusion yield inertial confinement fusion experiments >10 13 14 MeV DT neutrons or >10 9 n cm -2 ns -1 . Here, we describe a hardened x-ray streak camera developed for the National Ignition Facility and present preliminary results from the first experiment on which it has participated, recording the time-resolved bremsstrahlung spectrum from the core of an inertial confinement fusion implosion at more than 40× the operational neutron yield limit of the previous National Ignition Facility x-ray streak cameras.

47 OTHER INSTRUMENTATION↗
DOE OSTI2012

Lawrence Bragg, microdiffraction and X-ray lasers

We trace the historical development of W. L. Bragg's `law' and the key experimental observation which made it possible using polychromatic radiation at a time when neither X-ray wavelengths nor cell constants were known. This led, through his phasing and solving large mineral structures (without use of a computer), to work on metals, proteins, bubble rafts and his X-ray microscope. The relationship of this to early X-ray microdiffraction is outlined, followed by a brief review of electron microdiffraction methods, where electron-probe sizes smaller than one unit cell can be formed with an interesting `failure' of Bragg's law. We end with a review of recent femtosecond X-ray `snapshot' diffraction from protein nanocrystals, using an X-ray laser which generates pulses so short that they terminate before radiation damage can commence, yet subsequently destroy the sample. Using short pulses instead of freezing, the nexus between dose, resolution and crystal size has been broken, opening the way to time-resolved diffraction without damage for a stream of identical particles.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Grid Optimization Lawrence Livermore Nonlinear Programming

Modelling and solution library for security-constrained AC optimal power flow problems that uses nonlinear programming methods (interior-point methods) and solvers (Ipopt, HiOp). The code is written in C++ and provides parallel computing capabilities in the form of task parallelism (solving contingency problems in parallel). Code can run on a variety of commodity high-performance computing.

Petra, CosminG↗
DOE OSTI2014

Overview of modelling and simulation of metal powder bed fusion process at Lawrence Livermore National Laboratory

The metal laser powder bed fusion additive manufacturing process uses high power lasers to build parts layer upon layer by melting fine metal powders. Qualification of parts produced using this technology is broadly recognised as a significant challenge. Physics based process models have been identified as being foundational to qualification of additively manufactured metal parts. In the present article, a multiscale modelling strategy is described that will serve as the foundation upon which process control and part qualification can be built. This includes a model at the scale of the powder that simulates single track/single multilayer builds and provides powder bed and melt pool thermal data. A second model computationally builds a complete part and predicts manufactured properties (residual stress, dimensional accuracy) in three dimensions. Finally, modelling is tied to experiment through data mining.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Los Alamos National Laboratory and Lawrence Livermore National Laboratory Plutonium Sustainment Monthly Program Report, October 2012 (Revision 8)

In October of 2012 the Plutonium Sustainment program at LANL completed or addressed the following high-level activities: 1) Completed Pollux shipment to DAF in early October in accordance with the Gemini Core Team's schedule. Unpacked Pollux at DAF and supported Gemini team in various tests and inspections. Pollux test and measurement results were all acceptable. Pollux is expected to g to U1A in November. Pu Sustainment no longer has any obligations associated with the Gemini experiment. 2) Presented to Dr. Cook on the successful assembly of the Pollux experimental device as part of the Gemini series. 3) Supported the release of the FY12 Pu Sustainment Program Implementation Plan. 4) Established the FY12 program baseline and allocated funds accordingly. 5) Meetings: a. Hosted the Pu Containment 4 th Quarter Program Review; b. Hosted the Power Supply PRT; c. Traveled to KCP for the W87 Pit IPT. All four MRT L2 Milestones (4622-4625) associated with Plutonium Sustainment are on track for success in FY13.

Nuclear Physics & Radiation Physics(73)↗
DOE OSTI2012

Rare Plant Monitoring and Restoration at the Lawrence Livermore National Laboratory Experimental Test Site, Site 300, Project Progress Report 2007 through 2011

The large-flowered fiddleneck, Amsinckia grandiflora (A. GRAY) GREENE (Boraginaceae), is a rare annual forb native to the California winter annual grasslands. Amsinckia grandiflora germinates with the onset of fall or early winter rain, grows vegetatively throughout the winter, flowers in the early spring, and sets seeds and dies prior to the summer drought, a pattern observed in most of the herbaceous species of the California winter annual grasslands (Heady, 1990). Of the fifteen species in the genus recognized by Ray and Chisaki (1957a, 1957b), A. grandiflora is one of four heterostylous species with highly restricted distributions that are likely ancestors of the weedy, widespread, and homostylous congeners (Ray and Chisaki, 1957a, 1957b; Shoen et al., 1997). As a heterostylous species, A. grandiflora produces pin and thrum flower forms (also known as morphs) (Figure A1). Each individual plant has only one type of flower. An exerted stigma and anthers within the corolla tube characterize pin flowers. Thrum flowers have the opposing morphology, with the stigma within the corolla tube and exerted anthers. Characteristic of the genus, each flower morph has four ovaries at the base of the style, each of which matures into a seed, known as a nutlet. Thus, each flower can produce a maximum of four nutlets.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Lawrence Livermore National Laboratory: Laboratory Directed Research and Development (FY2012 Annual Report)

The LDRD annual report for fiscal year 2012 (FY12) provides a summary of LDRD funded projects for the fiscal year and consists of two parts: Overview: A broad description of the LDRD Program, highlights of accomplishments and awards for the year, program statistics, and the LDRD portfolio-management process. Project Summaries: A summary of each project, submitted by the principal investigator. Project summaries include the scope, motivation, goals, relevance to DOE/NNSA and LLNL mission areas, the technical progress achieved in FY12, and a list of publications that resulted from the research.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2013

Multifamily Individual Heating and Ventilation Systems, Lawrence, Massachusetts (Fact Sheet)

The conversion of an older Massachusetts building into condominiums illustrates a safe, durable, and cost-effective solution for heating and ventilation systems that can potentially benefit millions of multifamily buildings. Merrimack Valley Habitat for Humanity (MVHfH) partnered with U.S. Department of Energy Building America team Building Science Corporation (BSC) to provide high performance affordable housing for 10 families in the retrofit of an existing mass masonry building (a former convent). The original ventilation design for the project was provided by a local engineer and consisted of a single large heat recovery ventilator (HRV) located in a mechanical room in the basement with a centralized duct system providing supply air to the main living space and exhausting stale air from the single bathroom in each apartment. This design was deemed to be far too costly to install and operate for several reasons: the large central HRV was oversized and the specified flows to each apartment were much higher than the ASHRAE 62.2 rate; an extensive system of ductwork, smoke and fire dampers, and duct chases were specified; ductwork required a significant area of dropped ceilings; and the system lacked individual ventilation control in the apartments.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Performance Characteristics of HYDRA - a Multi-Physics simulation code from Lawrence Livermore National Laboratory

HYDRA is used to simulate a variety of experiments carried out at the National Ignition Facility (NIF) [4] and other high energy density physics facilities. HYDRA has packages to simulate radiation transfer, atomic physics, hydrodynamics, laser propagation, and a number of other physics effects. HYDRA has over one million lines of code and includes both MPI and thread-level (OpenMP and pthreads) parallelism. This paper measures the performance characteristics of HYDRA using hardware counters on an IBM BlueGene/Q system. We report key ratios such as bytes/instruction and memory bandwidth for several different physics packages. The total number of bytes read and written per time step is also reported. We show that none of the packages which use significant time are memory bandwidth limited on a Blue Gene/Q. HYDRA currently issues very few SIMD instructions. The pressure on memory bandwidth will increase if high levels of SIMD instructions can be achieved.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2014

Executive Summary of Scientific and Technical Metrics at Lawrence Livermore National Laboratory (Spring 2014)

Publishing research results in the peer-reviewed literature is a key to advancing the frontiers of science and engineering. LLNL scientists and engineers have established a strong record by publishing innovative and impactful journal papers and engaged an impressive array of external collaborators as coauthors. LLNL’s more than 1,100 journal publications in 2012 went up sharply, topping 2011 numbers by 14%. Significantly, this followed a 10% increase in 2011 over 2010. Publication rates in 2013 have kept pace with last year’s extremely strong performance.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2014

Lawrence Livermore National Laboratory: Laboratory Directed Research and Development (Annual Report FY2013)

The LDRD annual report for fiscal year 2013 (FY13) provides a summary of LDRD funded projects for the fiscal year and consists of two parts: Overview: A broad description of the LDRD Program, highlights of accomplishments and awards for the year, program statistics, and the LDRD portfolio-management process. Project Summaries: A summary of each project, submitted by the principal investigator. Project summaries include the scope, motivation, goals, relevance to DOE/NNSA and LLNL mission areas, the technical progress achieved in FY13, and a list of selected publications and presentations that resulted from the research.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2015

Annual Continuation And Progress Report For Nuclear Theory At Lawrence Livermore National Laboratory

Nuclear Theory research under the auspices of the Department of Energy (DOE) Office of Nuclear Physics (NP) is conducted within several funding sources and projects. These include base funding, and early career award, and a collaborative SciDAC-­3 award that is jointly funded by DOE/NP and the Advanced Simulations and Computations (ASC) effort within the National Nuclear Security Agency (NNSA). Therefore, this annual report is organized within the three primary sections covering these projects.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

2014-2016 Avian Point Count and Migration Surveys at Site 300 for the Lawrence Livermore National Laboratory

The primary goals of the surveys were to: 1) collect minutes of bird activity within Site 300, 2) consider relative abundance of the different bird species occurring within the Site, 3) collect behavioral information, and 4) provide compelling evidence to determine the status of the Site as a migration corridor or migration stopover site. To this end, two survey types were conducted: avian point counts were conducted on a monthly basis from February 2014 through January 2016 and migration surveys were conducted over two three-month periods from September 2014 through November 2014, and September 2015 through November 2015. These two surveys types provided the opportunity to observe avian species in a variety of conditions across a two year period. Whenever possible or relevant, the observations of either survey were used to inform and complement the observations of the other survey in pursuit of the above goals. Both survey types are described below.

54 ENVIRONMENTAL SCIENCES↗