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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 559 records · Page 31

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DOE OSTI2023

Rapid method for computing the mechanical resonances of irregular objects

A solid object's geometry, density, and elastic moduli completely determine its spectrum of normal modes. Solving the inverse problem—determining a material's elastic moduli given a set of resonance frequencies and sample geometry—relies on the ability to compute resonance spectra accurately and efficiently. Established methods for calculating these spectra are either fast but limited to simple geometries, or are applicable to arbitrarily shaped samples at the cost of being prohibitively slow. Here, we describe a method to rapidly compute the normal modes of irregularly shaped objects using entirely open-source software. Our method's accuracy compares favorably with existing methods for simple geometries and shows a significant improvement in speed over existing methods for irregular geometries.

Acoustics↗

DOE OSTI2017

Complex Pupil Masks for Aberrated Imaging of Closely Spaced Objects

Current approach demonstrates the suppression of optical side-lobes and the contraction of the main lobe in the composite image of two object points of the optical system under the influence of defocusing effect when an asymmetric phase edges are imposed over the apodized circular aperture. The resolution of two point sources having different intensity ratio is discussed in terms of the modified Sparrow criterion, functions of the degree of coherence of the illumination, the intensity difference and the degree of asymmetric phase masking. Here we have introduced and explored the effects of focus aberration (defect-of-focus) on the two-point resolution of the optical systems. Results on the aberrated composite image of closely spaced objects with amplitude mask and asymmetric phase masks forms a significant contribution in astronomical and microscopic observations.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2019

Neural Network Astronomy as a New Tool for Observing Bright and Compact Objects

We propose a new method for solving an important problem of astronomy that arises in observations with ultrahigh-angular-resolution interferometers. This method is based on the application of the theory of artificial neural networks. We propose and compute a multiparameter model for a celestial object like Sgr A*. For this model we have numerically constructed a number of probable images for neural network training. After neural network training on these images, the quality of its operation has been tested on another series of images from the same model. We have proven that a neural network can recognize and classify celestial objects (also obtained from interferometers) virtually no worse than can be done by a human.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2018

Recombination in GaAs p–i–n Structures with InGaAs Quantum-Confined Objects: Modeling and Regularities

Photovoltaic structures on the basis of GaAs p–i–n junctions with a different number of In{sub 0.4}Ga{sub 0.6}As layers in the space-charge region forming quantum-confined objects are experimentally and theoretically investigated. For all structures, the dependences of the open-circuit voltage on the solar-irradiation concentration are analyzed. It is shown that the implantation of quantum objects leads to the dominance of recombination in them over recombination in the matrix, which manifests itself in a drop in the open-circuit-voltage. An increase in the number of In{sub 0.4}Ga{sub 0.6}As layers leads to a proportional increase in the recombination rate, which is expressed in a proportional increase in the “saturation” current and corresponds to the model proposed in the study.

36 MATERIALS SCIENCE↗

DOE OSTI2023

A Sequential Quadratic Programming Algorithm for Nonsmooth Problems with Upper- \({\boldsymbol{\mathcal{C}^2}}\) Objective

An optimization algorithm for nonsmooth nonconvex constrained optimization problems with upper- \({\boldsymbol{\mathcal{C}^2}}\) objective functions is proposed and analyzed. Upper- \({\boldsymbol{\mathcal{C}^2}}\) is a weakly concave property that exists in difference of convex (DC) functions and arises naturally in many applications, particularly certain classes of solutions to parametric optimization problems e.g., recourse of stochastic programming and projection onto closed sets. The algorithm can be viewed as an extension of sequential quadratic programming (SQP) to nonsmooth problems with upper- \({\boldsymbol{\mathcal{C}^2}}\) objectives or a simplified bundle method. It is globally convergent with bounded algorithm parameters that are updated with a trust-region criterion. The algorithm handles general smooth constraints through linearization and uses a line search to ensure progress. The potential inconsistencies from the linearization of the constraints are addressed through a penalty method. In conclusion, the capabilities of the algorithm are demonstrated by solving both simple upper- \({\boldsymbol{\mathcal{C}^2}}\) problems and a real-world optimal power flow problem used in current power grid industry practices.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2020

Laika BOSS (Binary Object Scanning System)

Laika BOSS (Binary Object Scanning System), often written as "Laikaboss", is an object scanner and intrusion detection system that strives to be scalable, flexible, and verbose. Its goal is to take arbitrary file input and extract all relevant subfiles and metadata for use in helping analysts determine the function and maliciousness of a file at a glance. This is an extension to the original code developed by Lockheed Martin.

Walkup, Gregory↗

DOE OSTI2022

Incoherent range-based holography of far-distant objects using LIDAR

Los Alamos National Laboratory has developed an incoherent, long-range, sub-centimeter resolution (LIDAR) with which we achieve centimeter-scale reflection holography at extremely long ranges. The system consists of a pulsed laser and photon-counting receiver. This combination yields round-trip time of flight data to illuminate parts of the object of interest. The aggregation of these data for many LIDAR pulses yields a plot with a range on the X axis and reflectance on the Y axis, which we refer to as a range profile. Observing that the range profile is a projection of the reflection map of the object onto the view vector, we collect profiles from a variety of viewing angles and invert these data to form an image. We adapt imaging algorithms from the field of computer aided tomography to suit our application and present results from imaging demonstrations at a 10 km range.

Hoffmann, Mitchell P. (ORCID:0000000170551324)↗

DOE OSTI2018

X-ray tomography of extended objects: a comparison of data acquisition approaches

The penetration power of x-rays allows one to image large objects while their short wavelength allows for high spatial resolution. As a result, with synchrotron sources one has the potential to obtain tomographic images of centimeter-sized specimens with sub-micrometer pixel sizes. However, limitations on beam and detector size make it difficult to acquire such data of this sort in a single take, necessitating strategies for combining data from multiple regions. One strategy is to acquire a tiled set of local tomograms by rotating the specimen around each of the local tomogram center positions. Another strategy, sinogram oriented acquisition, involves the collection of projections at multiple offset positions from the rotation axis followed by data merging and reconstruction. We have carried out a simulation study to compare these two approaches in terms of radiation dose applied to the specimen, and reconstructed image quality. Local tomography acquisition involves an easier data alignment problem, and immediate viewing of subregions before the entire dataset has been acquired. Sinogram oriented acquisition involves a more difficult data assembly and alignment procedure, and it is more sensitive to accumulative registration error. Furthermore, sinogram oriented acquisition is more dose-efficient, it involves fewer translation motions of the object, and it avoids certain artifacts of local tomography.

47 OTHER INSTRUMENTATION↗

DOE OSTI2012

Environmental Management System (EMS) Objectives & Targets: Annual Results Summary – FY2011

Sandia National Laboratories/New Mexico's (SNL/NM) Environmental Management System is the integrated approach for members of the workforce to identify and manage environmental risks. Each Fiscal Year (FY) SNL/NM performs an analysis to identify environmental aspects, and the environmental programs associated with them are charged with the task of routinely monitoring and measuring the objectives and targets that are established to mitigate potential impacts of SNL/NM's operations on the environment. An annual summary of the results achieved towards meeting established objectives and targets provides a connection to, and rational for, annually revised environmental aspects. The purpose of this document is to summarize the results achieved and documented in FY2011.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2013

Testbed Environment for Space Situational Awareness: The world’s most accurate simulation of space debris and orbital object tracking

The Testbed Environment for Space Situational Awareness (TESSA) is a modeling and simulation environment designed for efficient exploration of scenarios involving satellites and space debris and their detection by both ground and space-based radars and optical sensors. TESSA is a Parallelized Discrete Event Simulator optimized for deployment on a large cluster of high-performance computers running Linux. TESSA includes capabilities for predicting the future location of a satellite using the satellite’s current location and velocity, determining an object’s orbit from sensor data, finding new orbital objects, predicting close approaches, determining the probability of collisions, modeling radar and optical and dynamic sensors, and modeling the generation of debris. TESSA also includes a scalable visualization environment implemented as a post-processor on workstation-class platforms.

42 ENGINEERING↗

DOE OSTI2013

Environmental Management System (EMS) Objectives & Targets (Annual Results Summary – FY2012)

Vetter, Douglas Walter↗

DOE OSTI2014

Environmental management system objectives & targets results summary FY 2013

Sandia National Laboratories/New Mexico s (SNL/NM) Environmental Management System is the integrated approach for members of the workforce to identify and manage environmental risks. Each Fiscal Year (FY) SNL/NM performs an analysis to identify environmental aspects, and the environmental programs associated with them are charged with the task of routinely monitoring and measuring the objectives and targets that are established to mitigate potential impacts of SNL/NM s operations on the environment. An annual summary of the results achieved towards meeting established Sandia Corporation and SNL/NM Site-specific objectives and targets provides a connection to, and rational for, annually revised environmental aspects. The purpose of this document is to summarize the results achieved and documented in FY2013.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2016

Environmental Management System Objectives & Targets Results Summary - FY 2015.

Sandia National Laboratories (SNL) Environmental Management System is the integrated approach for members of the workforce to identify and manage environmental risks. Each Fiscal Year (FY) SNL performs an analysis to identify environmental aspects, and the environmental programs associated with them are charged with the task of routinely monitoring and measuring the objectives and targets that are established to mitigate potential impacts of SNL's operations on the environment. An annual summary of the results achieved towards meeting established Sandia Corporation and SNL Site-specific objectives and targets provides a connection to, and rational for, annually revised environmental aspects. The purpose of this document is to summarize the results achieved and documented in FY 2015.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2017

Development of a Repeatable Protocol to Uniformly Coat Internal Complex Geometries of Fine Featured 3D Printed Objects with Ceramic Material, including Determination of Viscosity Limits to Properly Coat Certain Pore Sizes

HEPA filters are commonly used in air filtration systems ranging in application from simple home systems to the more advanced networks used in research and development. Currently, these filters are most often composed of glass fibers with diameter on the order of one micron with polymer binders. These fibers, as well as the polymers used, are known to be fragile and can degrade or become extremely brittle with heat, severely limiting their use in high temperature applications. Ceramics are one promising alternative and can enhance the filtration capabilities compared to the current technology. Because ceramic materials are more thermally resistant and chemically stable, there is great interest in developing a repeatable protocol to uniformly coat fine featured polymer objects with ceramic material for use as a filter. The purpose of this experiment is to determine viscosity limits that are able to properly coat certain pore sizes in 3D printed objects, and additionally to characterize the coatings themselves. Latex paint was used as a surrogate because it is specifically designed to produce uniform coatings.

36 MATERIALS SCIENCE↗

DOE OSTI2017

Multi-objective Optimization of Solar-driven Hollow-fiber Membrane Distillation Systems

Securing additional water sources remains a primary concern for arid regions in both the developed and developing world. Climate change is causing fluctuations in the frequency and duration of precipitation, which can be can be seen as prolonged droughts in some arid areas. Droughts decrease the reliability of surface water supplies, which forces communities to find alternate primary water sources. In many cases, ground water can supplement the use of surface supplies during periods of drought, reducing the need for above-ground storage without sacrificing reliability objectives. Unfortunately, accessible ground waters are often brackish, requiring desalination prior to use, and underdeveloped infrastructure and inconsistent electrical grid access can create obstacles to groundwater desalination in developing regions. The objectives of the proposed project are to (i) mathematically simulate the operation of hollow fiber membrane distillation systems and (ii) optimize system design for off-grid treatment of brackish water. It is anticipated that methods developed here can be used to supply potable water at many off-grid locations in semi-arid regions including parts of the Navajo Reservation. This research is a collaborative project between Sandia and the University of Arizona.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2018

Data Quality Objective Scoping Package In Support of a Remedial Action at Exposure Unit 5 Attachment C, Rev 0 to the Upper East Fork Poplar Creek Soils Remedial Action Work Plan DOE/OR/01-2423&D1

The Department of Energy (DOE), Oak Ridge Office of Environmental Management (OREM), intends to perform characterization of Exposure Unit 5 (EU-5) slabs and soils at the Y-12 National Security Complex (Y-12). This Data Quality Objective (DQO) Scoping Package has been prepared as part of the Upper East Fork Poplar Creek (UEFPC) Soils Remedial Action Work Plan (RAWP) (DOE 2010a) as the planning document for the Dynamic Characterization Strategy (DCS) for soils in EU-5. Y-12 is located at the southeastern boundary of the Oak Ridge Reservation (ORR) and the industrialized area of Y-12 consists of approximately 600 acres located within the UEFPC watershed characterization area. The UEFPC RAWP and this DQO Scoping Package were developed in order to address the remedial action objectives of the Record of Decision for Phase II Interim Remedial Actions for Contaminated Soils and Scrapyard in UEFPC, Oak Ridge, Tennessee, DOE/OR/01-2229&D3 (Soils ROD) (DOE 2006).

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2017

Secondary Phase Objects in As-cast U-10 wt% Zr

U-10Zr castings have shown secondary phase objects when the as-cast material was examined using optical metallography and/or scanning electron microscopy. Attempts to identify these objects indicated they were rich in zirconium, but not in uranium. Exams of other U-10Zr castings in the past had indicated that these were likely Zr-carbides. Because of potential interferences in EDS spectra for carbon and uranium,a more detailed examination is necessary.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2015

Environmental Management System (EMS) Objectives & Targets Annual Results Summary – FY 2014

Sandia National Laboratories/New Mexico’s (SNL/NM) Environmental Management System is the integrated approach for members of the workforce to identify and manage environmental risks. Each Fiscal Year (FY) SNL/NM performs an analysis to identify environmental aspects, and the environmental programs associated with them are charged with the task of routinely monitoring and measuring the objectives and targets that are established to mitigate potential impacts of SNL/NM’s operations on the environment. An annual summary of the results achieved towards meeting established Sandia Corporation and SNL/NM Site-specific objectives and targets provides a connection to, and rational for, annually revised environmental aspects. The purpose of this document is to summarize the results achieved and documented in FY 2014.

54 ENVIRONMENTAL SCIENCES↗