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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Performing Verification and Validation in Reuse-Based Software Engineering

The implementation of reuse-based software engineering not only introduces new activities to the software development process, such as domain analysis and domain modeling, it also impacts other aspects of software engineering. Other areas of software engineering that are affected include Configuration Management, Testing, Quality Control, and Verification and Validation (V&V). Activities in each of these areas must be adapted to address the entire domain or product line rather than a specific application system. This paper discusses changes and enhancements to the V&V process, in order to adapt V&V to reuse-based software engineering.

Addy, Edward A.↗
NASA NTRS2001

Structuring Formal Requirements Specifications for Reuse and Product Families

In this project we have investigated how formal specifications should be structured to allow for requirements reuse, product family engineering, and ease of requirements change, The contributions of this work include (1) a requirements specification methodology specifically targeted for critical avionics applications, (2) guidelines for how to structure state-based specifications to facilitate ease of change and reuse, and (3) examples from the avionics domain demonstrating the proposed approach.

Heimdahl, Mats P. E.↗
NASA NTRS2008

Record Management and Design Reuse

Government mandated records management requirements apply to retention and long term archival of a wide variety of records. Part of the attention is on permanent accession and retention by the U.S. National Archives and Records Administration (NARA) but interim requirements for storage by the source agency are included. As government agencies and the Department of Defense move toward implementations, additional goals often include saving design data for reuse. This paper briefly reviews the government records management requirements then investigates candidate meanings of 'reuse' and proposes an enhanced design records retention approach. The recommended strategy that emerges is, for a given program or product family, to invest in rich and readily re-executable preservation of design artifacts for one or two subsequent generations, then downgrade the data in utility through conversions, ultimately reaching the NARA minimum standard for permanent historical-interest archives.

permanent accession↗
NASA NTRS2010

A General Algorithm for Reusing Krylov Subspace Information. I. Unsteady Navier-Stokes

A general algorithm is developed that reuses available information to accelerate the iterative convergence of linear systems with multiple right-hand sides A x = b (sup i), which are commonly encountered in steady or unsteady simulations of nonlinear equations. The algorithm is based on the classical GMRES algorithm with eigenvector enrichment but also includes a Galerkin projection preprocessing step and several novel Krylov subspace reuse strategies. The new approach is applied to a set of test problems, including an unsteady turbulent airfoil, and is shown in some cases to provide significant improvement in computational efficiency relative to baseline approaches.

Carpenter, Mark H.↗
NASA NTRS2011

Software Reuse Methods to Improve Technological Infrastructure for e-Science

Social computing has the potential to contribute to scientific research. Ongoing developments in information and communications technology improve capabilities for enabling scientific research, including research fostered by social computing capabilities. The recent emergence of e-Science practices has demonstrated the benefits from improvements in the technological infrastructure, or cyber-infrastructure, that has been developed to support science. Cloud computing is one example of this e-Science trend. Our own work in the area of software reuse offers methods that can be used to improve new technological development, including cloud computing capabilities, to support scientific research practices. In this paper, we focus on software reuse and its potential to contribute to the development and evaluation of information systems and related services designed to support new capabilities for conducting scientific research.

Marshall, James J.↗
NASA NTRS2017

Reusing JPSS Ground System Components to Process Aura Ozone Monitoring Instrument Science Products

New Earth observation instruments are planned to enable advancements in Earth science research over the next decade. Diversity of Earth observing instruments and their observing platforms will continue to increase as new instrument technologies emerge and are deployed as part of National programs such as Joint Polar Satellite System (JPSS), Geostationary Operational Environmental Satellite system (GOES), Landsat as well as the potential for many CubeSat and aircraft missions. The practical use and value of these observational data often extends well beyond their original purpose. The practicing community needs intuitive and standardized tools to enable quick unfettered development of tailored products for specific applications and decision support systems. However, the associated data processing system can take years to develop and requires inherent knowledge and the ability to integrate increasingly diverse data types from multiple sources. This paper describes the adaptation of a large-scale data processing system built for supporting JPSS algorithm calibration and validation (CalVal) node to a simplified science data system for rapid application. The new configurable data system reuses scalable JAVA technologies built for the JPSS Government Resource for Algorithm Verification, Independent Test, and Evaluation (GRAVITE) system to run within a laptop environment and support product generation and data processing of AURA Ozone Monitoring Instrument (OMI) science products. Of particular interest are the root requirements necessary for integrating experimental algorithms and Hierarchical Data Format (HDF) data access libraries into a science data production system. This study demonstrates the ability to reuse existing Ground System technologies to support future missions with minimal changes.

Science Data Systems↗
DOE OSTI2020

Uncovering Access, Reuse, and Sharing Characteristics of I/O-Intensive Files on Large-Scale Production HPC Systems

Large-scale high-performance computing (HPC) applications running on supercomputers produce large amounts of data routinely and store it in files on multi-PB shared parallel storage systems. Unfortunately, storage community has a limited understanding of the access and reuse patterns of these files. This paper investigates the access and reuse patterns of I/O-intensive files on a production-scale supercomputer.

Patel, Tirthak↗
DOE OSTI2021

Fabrication of thin-film electronic devices with non-destructive wafer reuse

Thin-film electronic devices such as LED devices and field effect transistor devices are fabricated using a non-destructive epitaxial lift-off technique that allows indefinite reuse of a growth substrate. The method includes providing an epitaxial protective layer on the growth substrate and a sacrificial release layer between the protective layer and an active device layer. After the device layer is released from the growth substrate, the protective layer is selectively etched to provide a newly exposed surface suitable for epitaxial growth of another device layer. The entire thickness of the growth substrate is preserved, enabling continued reuse. Inorganic thin-film device layers can be transferred to a flexible secondary substrate, enabling formation of curved inorganic optoelectronic devices.

Forrest, Stephen R.↗
DOE OSTI2023

Cache management based on reuse distance

A cache of a processor includes a cache controller to implement a cache management policy for the insertion and replacement of cache lines of the cache. The cache management policy assigns replacement priority levels to each cache line of at least a subset of cache lines in a region of the cache based on a comparison of a number of accesses to a cache set having a way that stores a cache line since the cache line was last accessed to a reuse distance determined for the region of the cache, wherein the reuse distance represents an average number of accesses to a given cache set of the region between accesses to any given cache line of the cache set.

Yin, Jieming↗
DOE OSTI2020

US Potable Water Reuse System Costs

This submission contains a set of U.S.-specific potable reuse capital and operations and maintenance (O&M) cost data ($2020) found in published presentations and reports from engineering consulting firms, utility and water agency press releases or websites, and literature. For any unbuilt facilities, the reported costs found in technical documents are mostly engineer estimates and may be subject to change as construction proceeds. This data set contains a mix of both facility specific and total capital costs, which include conveyance infrastructure. Note that this dataset does not include detailed cost breakdowns for each of the facilities. This submission also contains the sources used to build this dataset in pdf format.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2022

High‐Efficiency Solar Cells Grown on Spalled Germanium for Substrate Reuse without Polishing

Abstract Radical reduction of III–V device costs requires a multifaceted approach attacking both growth and substrate costs. Implementing device removal and substrate reuse provides an opportunity for substrate cost reduction. Controlled spalling allows removal of thin devices from the expensive substrate; however, the fracture‐based process currently generates surfaces with significant morphological changes compared to polished wafers. 49 single junction devices are fabricated across the spalled surface of full 50 mm germanium wafers without chemo‐mechanical polishing before epitaxial growth. Device defects are identified and related to morphological spalling defects—arrest lines, gull wings, and river lines—and their impact on cell performance using physical and functional characterization techniques. River line defects have the most consistent and detrimental effect on cell performance. Devices achieve a single junction efficiency above 23% and open‐circuit voltage of 1.01 V, demonstrating that spalled germanium does not need to be returned to a pristine, polished state to achieve high‐quality device performance.

14 SOLAR ENERGY↗
DOE OSTI2021

$\mathrm{PPT}$-Multicore: performance prediction of Open$\mathrm{MP}$ applications using reuse profiles and analytical modeling

In this report we present PPT-Multicore, an analytical model embedded in the Performance Prediction Toolkit (PPT) to predict parallel applications’ performance running on a multicore processor. PPT-Multicore builds upon our previous work towards a multicore cache model. We extract LLVM basic block labeled memory trace using an architecture-independent LLVM-based instrumentation tool only once in an application’s lifetime. The model uses the memory trace and other parameters from an instrumented sequentially executed binary. We use probabilistic and computationally efficient reuse profiles to predict the cache hit rates and runtimes of OpenMP programs’ parallel sections. We model Intel’s Broadwell, Haswell, and AMD’s Zen2 architectures and validate our framework using different applications from PolyBench and PARSEC benchmark suites. The results show that PPT-Multicore can predict cache hit rates with an overall average error rate of 1.23% while predicting the runtime with an error rate of 9.08%.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2023

Analysis of backwash settings to maximize net water production in an engineering-scale ultrafiltration system for water reuse

Ultrafiltration (UF) has been widely utilized as water pretreatment for different applications especially in water reuse. The UF system operation is characterized by a filtration phase, where particles accumulate on the membrane surface resulting in an increase in the transmembrane pressure (TMP) and a cleaning phase, where foulants are removed through cleaning cycles including physical backwash and chemical-enhanced backwash (CEB). In this study, data from an engineering-scale UF system treating reclaimed wastewater were used to assess the impact of backwashing on the filtration process. TMP backwash trigger, backwash duration, and CEB frequency were purposely varied for a cycle-by-cycle investigation on the net water production, water recovery, initial operating TMP, and filtration cycle duration. As the TMP backwash trigger was varied between 62 and 145kPa, the maximum net water production (63 m 3 /d) was achieved at 103kPa and water recovery remained relatively constant at approximately 92%. Backwash durations of 45, 65, and 85s were performed where both net water production and water recovery yielded similar results (~63 m 3 /d and ~ 91%) compared with 103kPa TMP backwash trigger. The CEB frequency was also lowered from one every three backwashes (1/3) to 1/6 and 1/12 and resulted in decreased net water production and water recovery while the initial TMP increased. Interestingly, the total number of CEBs remained approximately constant regardless of their frequency. In conclusion, results suggest that CEB is an important fouling control process to maximize water production.

42 ENGINEERING↗
DOE OSTI2025

Seeding Advanced Treated Wastewater for Purposes of Direct Potable Reuse

Direct potable reuse (DPR) is a promising solution to address water scarcity. However, a better understanding of how introducing advanced treated water (ATW) affects microbial communities present in distribution systems is needed. Here, in this study, we measured changes to the microbial water quality in simulated distribution systems that were conditioned using treated, unimpaired surface water (SW) and then transitioned to ATW. In addition, we investigated whether adding a biological filtration step would seed the microbial community of the ATW and whether the influence would persist in the simulated distribution systems. We found that the bulk water in the ATW-fed distribution systems had lower cell counts and ATP concentrations and a distinct microbial community (based on 16S amplicon sequencing) compared to the SW-fed or the seeded ATW-fed systems. However, biofilm community composition and biomass remained consistent regardless of the feedwater. Increased microbial biomass and diversity were present in the seeded ATW, with several amplicon sequence variants identified as being introduced by the biological filter. Our results suggest that directly introducing ATW to distribution systems could disturb the existing microbial community. Preparing ATW for distribution via biological filtration may deliver more predictable and stable microbial water quality than introducing unseeded ATW.

16S↗
DOE OSTI2020

Today’s Energy Challenges, Tomorrow’s Solutions: Circular Economy: Designing to Reduce, Reuse, and Upcycle

Transitioning to a Circular Economy the days of creating, using, and disposing of materials are rapidly coming to a close. This linear economy is not only inefficient and unsustainable, but the scarcity of resources we ultimately will face will make it impossible to maintain. That's why NREL is dedicating resources to research that will underpin a circular economy - designing materials with reducing, reusing, and upcycling in mind for energy-relevant and energy-intensive materials, processes, and technologies. This effort will help mitigate supply issues, promote upcycling, reduce waste, and add value to end-of-life products.

circular economy↗
DOE OSTI2021

Circular Economy for Energy Materials: Designing to Reduce, Reuse, and Upcycle for a More Sustainable Planet

Our global economy is on the cusp of a dramatic transformation away from a traditional linear approach - making, using, and landfill disposing of goods - to a more circular one where end of life is considered at the onset and the concepts of reducing, reusing, and chemically recycling or upcycling of goods becomes the new norm. Conventional/mechanical recycling is applicable to some materials but is underused and ineffective for a true circular economy vision. This vision ensures raw materials are used once to produce a product; and, at end of life, the product is chemically recycled back to its core building blocks to enable an infinite loop of product manufacture, use, deconstruction, and remanufacture.

CEEM↗