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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 469 records · Page 26

All sources NASA NTRS DOE OSTI

NASA NTRS2008

Gas Core Reactor Numerical Simulation Using a Coupled MHD-MCNP Model

Analysis is provided in this report of using two head-on magnetohydrodynamic (MHD) shocks to achieve supercritical nuclear fission in an axially elongated cylinder filled with UF4 gas as an energy source for deep space missions. The motivation for each aspect of the design is explained and supported by theory and numerical simulations. A subsequent report will provide detail on relevant experimental work to validate the concept. Here the focus is on the theory of and simulations for the proposed gas core reactor conceptual design from the onset of shock generations to the supercritical state achieved when the shocks collide. The MHD model is coupled to a standard nuclear code (MCNP) to observe the neutron flux and fission power attributed to the supercritical state brought about by the shock collisions. Throughout the modeling, realistic parameters are used for the initial ambient gaseous state and currents to ensure a resulting supercritical state upon shock collisions.

Kazeminezhad, F.↗

NASA NTRS2008

Verification of a Constraint Force Equation Methodology for Modeling Multi-Body Stage Separation

This paper discusses the verification of the Constraint Force Equation (CFE) methodology and its implementation in the Program to Optimize Simulated Trajectories II (POST2) for multibody separation problems using three specially designed test cases. The first test case involves two rigid bodies connected by a fixed joint; the second case involves two rigid bodies connected with a universal joint; and the third test case is that of Mach 7 separation of the Hyper-X vehicle. For the first two cases, the POST2/CFE solutions compared well with those obtained using industry standard benchmark codes, namely AUTOLEV and ADAMS. For the Hyper-X case, the POST2/CFE solutions were in reasonable agreement with the flight test data. The CFE implementation in POST2 facilitates the analysis and simulation of stage separation as an integral part of POST2 for seamless end-to-end simulations of launch vehicle trajectories.

Tartabini, Paul V.↗

NASA NTRS2011

Modeling Multibody Stage Separation Dynamics Using Constraint Force Equation Methodology

This paper discusses the application of the constraint force equation methodology and its implementation for multibody separation problems using three specially designed test cases. The first test case involves two rigid bodies connected by a fixed joint, the second case involves two rigid bodies connected with a universal joint, and the third test case is that of Mach 7 separation of the X-43A vehicle. For the first two cases, the solutions obtained using the constraint force equation method compare well with those obtained using industry- standard benchmark codes. For the X-43A case, the constraint force equation solutions show reasonable agreement with the flight-test data. Use of the constraint force equation method facilitates the analysis of stage separation in end-to-end simulations of launch vehicle trajectories

Tartabini, Paul V.↗

NASA NTRS2016

Development of Constraint Force Equation Methodology for Application to Multi-Body Dynamics Including Launch Vehicle Stage Seperation

The objective of this report is to develop and implement a physics based method for analysis and simulation of multi-body dynamics including launch vehicle stage separation. The constraint force equation (CFE) methodology discussed in this report provides such a framework for modeling constraint forces and moments acting at joints when the vehicles are still connected. Several stand-alone test cases involving various types of joints were developed to validate the CFE methodology. The results were compared with ADAMS(Registered Trademark) and Autolev, two different industry standard benchmark codes for multi-body dynamic analysis and simulations. However, these two codes are not designed for aerospace flight trajectory simulations. After this validation exercise, the CFE algorithm was implemented in Program to Optimize Simulated Trajectories II (POST2) to provide a capability to simulate end-to-end trajectories of launch vehicles including stage separation. The POST2/CFE methodology was applied to the STS-1 Space Shuttle solid rocket booster (SRB) separation and Hyper-X Research Vehicle (HXRV) separation from the Pegasus booster as a further test and validation for its application to launch vehicle stage separation problems. Finally, to demonstrate end-to-end simulation capability, POST2/CFE was applied to the ascent, orbit insertion, and booster return of a reusable two-stage-to-orbit (TSTO) vehicle concept. With these validation exercises, POST2/CFE software can be used for performing conceptual level end-to-end simulations, including launch vehicle stage separation, for problems similar to those discussed in this report.

Pamadi, Bandu N.↗

NASA NTRS2017

NASA Requirements for Ground-Based Pressure Vessels and Pressurized Systems (PVS)

The purpose of this document is to ensure the structural integrity of PVS through implementation of a minimum set of requirements for ground-based PVS in accordance with this document, NASA Policy Directive (NPD) 8710.5, NASA Safety Policy for Pressure Vessels and Pressurized Systems, NASA Procedural Requirements (NPR) 8715.3, NASA General Safety Program Requirements, applicable Federal Regulations, and national consensus codes and standards (NCS).

Greulich, Owen Rudolf↗

NASA NTRS2018

A Benchmark Example for Delamination Propagation Predictions Based on the Single Leg Bending Specimen Under Quasi-Static and Fatigue Loading

Benchmark examples based on Single Leg Bending (SLB) specimens with equal and unequal bending arm thicknesses were used to assess the performance of delamination prediction capabilities in finite element codes. First, the development of the quasi-static benchmark cases using the Virtual Crack Closure Technique (VCCT) is discussed in detail. Second, based on the quasi-static benchmark results, additional benchmark cases to assess delamination propagation under fatigue loading are created. Third, the application is demonstrated for the commercial finite element code Abaqus Standard 2018. The benchmark cases are compared to results obtained from VCCT-based, automated quasi-static propagation analysis. A comparison with results from automated fatigue propagation analysis was not performed at this point since the current version of Abaqus does not include this capability under variable mixed-mode conditions. In general, good agreement between the results obtained from the quasi-static propagation analysis and the benchmark results were achieved. Overall, the benchmarking procedure proved valuable for analysis verification.

Krueger, Ronald↗

NASA NTRSDate not supplied

A Benchmark Example for Delamination Propagation Predictions Based on the Single Leg Bending Specimen under Quasi-static and Fatigue Loading

Ronald Krueger↗

NASA NTRSDate not supplied

The Detection of Aromatic Amino Acids in CR Chondrites Suggests They are Prebiotically Plausible

Amino acids (AAs) are the building blocks of proteins and are essential for life on Earth. Sources of AAs on early Earth range from exogenous sources such as delivery from extraterrestrial materials(i.e., meteorites, interplanetary dust particles, comets, etc.) to endogenous sources including chemical reactions in hydrothermal vents or atmospheric mixtures. Analyses of AAs of extraterrestrial origin from meteorites and laboratory studies of simulated prebiotic environments revealed that a diverse set of abiotically produced AAs may have been present on early Earth. However only a fraction of these AAs is found within the proteins of living organisms. Of the22 genetically encoded (proteinogenic) AAs, 20 occur in the standard genetic code (SGC) and are used by nearly all living organisms to build proteins. The universality of this AA alphabet suggests the presence and incorporation of these specific AAs occurred early in the evolution of life.

A. S. Burton↗

NASA NTRS2021

NASA Engineering and Safety Center Technical Bulletin No. 21-05: Industry Recommendations from Arecibo Observatory Zinc Spelter Socket Joint Failure Analysis

A structural analysis and forensic investigation concluded that the Arecibo Observatory M4N socket joint failure in August 2020 was primarily due to cumulative damage caused by initially low structural design margins and a high percentage of sustained load, resulting in zinc creep deformation, progressive internal socket wire damage, and eventual loss of joint capacity. Open spelter sockets of this type are used throughout industry in stay cables. Recommendations are proposed to prevent failures of similar socket joints, including verification of positive stress margins in socket joint wires for all failure modes, periodic visual inspections with pass/fail criteria for zinc extrusion that are tied to structural qualification, and revisiting codes/ industry standards to capture lessons learned.

Arecibo Observatory↗

DOE OSTI2016

Clean Cities Technical Assistance Project (Tiger Teams)

This two-page fact sheet describes Clean Cities' technical assistance (Tiger Teams) capabilities and projects, both completed and ongoing. Tiger Teams are a critical element of the Clean Cities program, providing on-the-ground consultation to help inform program strategies. The knowledge Tiger Team experts gain from these experiences often helps inform other alternative fuels activities, such as needed research, codes and standards revisions, and new training resources.

33 ADVANCED PROPULSION SYSTEMS↗

DOE OSTI2016

Wireless Occupancy Sensors for Lighting Controls: An Applications Guide for Federal Facility Managers

This guide provides federal facility managers with an overview of the energy savings potential of wireless lighting occupancy sensors for various room types, cost considerations, key steps to successful installation of wireless sensors, pros and cons of various technology options, light source considerations, and codes and standards.

energy savigns↗

DOE OSTI2016

Building America FY 2016 Annual Report: Building America Is Driving Real Solutions in the Race to Zero Energy Homes

The U.S. Department of Energy (DOE) Building America Program enables the transformation of the U.S. housing industry to achieve energy savings through energy-efficient, high-performance homes with improved durability, comfort, and health for occupants. Building America bridges the gap between the development of emerging technologies and the adoption of codes and standards by engaging industry partners in applied research, development, and demonstration of high-performance solutions.

2016↗

DOE OSTI2016

A High-Granularity Approach to Modeling Energy Consumption and Savings Potential in the U.S. Residential Building Stock

Building simulations are increasingly used in various applications related to energy efficient buildings. For individual buildings, applications include: design of new buildings, prediction of retrofit savings, ratings, performance path code compliance and qualification for incentives. Beyond individual building applications, larger scale applications (across the stock of buildings at various scales: national, regional and state) include: codes and standards development, utility program design, regional/state planning, and technology assessments. For these sorts of applications, a set of representative buildings are typically simulated to predict performance of the entire population of buildings. Focusing on the U.S. single-family residential building stock, this paper will describe how multiple data sources for building characteristics are combined into a highly-granular database that preserves the important interdependencies of the characteristics. We will present the sampling technique used to generate a representative set of thousands (up to hundreds of thousands) of building models. We will also present results of detailed calibrations against building stock consumption data.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2017

Energy Storage Systems: A Manufacturer’s Perspective

From a manufacturer’s perspective, Eric Gallant of GS Battery presents a case study of energy storage installations, emphasizing energy storage in terms of its impact on people’s lives, as well as changes in such related areas as evolving codes and standards.

25 ENERGY STORAGE↗

DOE OSTI2018

On the Need for a Unified and Collaboratively Developed Residential Building Simulation Platform: Preprint

Residential building energy simulations are becoming ever more pervasive; they form the basis of energy efficient building design, zero energy goals, codes and standards, home certification and ratings industries, utility programs, regional/state planning, and technology assessments. And yet the residential building simulation community is highly fragmented with a patchwork of simulation engines with varying models, inputs, assumptions, and results. This inconsistency degrades confidence in these tools, increases industry-wide development and maintenance costs, and slows the availability of new efficiency technology models. The need for collaboration on an impartial, transparent, and capable residential building simulation platform has never been greater. But to develop and maintain a state-of-the-art simulation platform requires a dedicated and sustained investment. By leveraging existing resources and expertise from multiple entities/regions, a unified and collaboratively developed simulation platform can provide increased levels of energy efficiency at an accelerated pace. This paper presents the advantages and disadvantages of a unified residential building simulation platform in relationship to four real-world examples (RESNET HERS ratings, utility programs, California's Title 24, and DOE). The paper covers recent developments and improved capabilities that may move us closer to an ideal simulation platform and what challenges remain. The hope is to spur a frank and honest dialogue about how to work together towards the vision of achieving deeper and more reliable energy savings in the residential buildings industry.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2018

Advanced Reactor Regulatory Development Status Report for FY 2018

This report provides a summary status of various INL-supported activities leading to the Nuclear Regulatory Commission (NRC) publication of regulatory guidance for advanced (non-light water reactor) designs. This regulatory guidance includes new design criteria designated as advanced reactor design criteria as proposed by a U.S. Department of Energy (DOE) national laboratory team to the NRC. The advanced reactor design criteria guidance was developed in response to requests from industry. The guidance is intended to provide a basis from which future advanced reactor developers and license applicants can build principle design criteria to address regulatory requirements in their specific license applications. In addition, this report provides the current status for a number of advanced non-light water reactor (non-LWR) regulatory framework development activities, including functional containment performance criteria, advanced reactor codes and standards development, and the Regulatory Technology Development Plan.

42 ENGINEERING↗

DOE OSTI2019

Evaluating the Incident Energy of Arcs in Photovoltaic DC Systems: Comparison Between Calculated and Experimental Data

Solar Photovoltaic (PV) systems have permeated the energy generation world at a very high rate, some of the safety codes and standards are still lagging in accurately assessing the hazards and risks associated with PV array arcing energies. Safety professionals and maintenance workers using NFPA 70E have utilized the Doan, Stokes & Oppenlander or Enrique models, meant to determine arc energies in DC power systems using the maximum power method. These methods may lead to overestimating the energy available in PV systems. Since PV modules/arrays are non-linear, current limited DC devices, some of these calculation methods may overestimate the arcing energy available to small PV arrays. This paper will validate current arc energy models for PV systems by comparing experimental and calculated data. This data will help modify the current NFPA 70E models related to smaller solar arrays. Understanding where the real safety threshold for DC arc flash in PV systems exists will help maintenance and safety professionals better prepare for a variety of work related activities. This paper will analyze real arc data taken for PV systems <1000VDC and <60amps and compare this to the calculated models in 70E. Using these comparisons, it may be possible to reduce the safety hazard severity and thus relax the PPE requirements for installation and maintenance crews.

14 SOLAR ENERGY↗

DOE OSTI2019

Solar Research Spotlight: Systems Integration

This Solar Energy Technologies Office fact sheet provides an overview of the systems integration subprogram, which funds research and development projects in five broad, interrelated focus areas: planning and operation, solar plus X, power electronics, sensing and communication, and codes and standards.

Solar Energy Technologies Office fact sheet, syste↗