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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

MSD CoP Webinar: Confronting Climate Change Complexity: Intersectionality, Integration, and Innovative Governance

Context: This webinar was hosted by the MultiSector Dynamics Community of Practice (MSD CoP; https://multisectordynamics.org). Abstract: Climate impacts increasingly unfold in interlinked systems of people, nature, and infrastructure. The cascading consequences are revealing sometimes surprising connections, and prospects for climate responses also depend on complex interactions. In this presentation, we will introduce key findings from the United States Fifth National Climate Assessment and build upon them to suggest a framework for understanding and responding to complex climate challenges. This approach involves: (1) integration of disciplines and expertise to understand how intersectionality shapes complex climate impacts and the wide-ranging effects of climate responses, (2) collaborations among diverse knowledge holders to improve responses and better encompass intersectionality, and (3) sustained experimentation with and learning about governance approaches capable of handling the complexity of climate change. We outline actionable steps for climate research to incorporate these pillars, as is increasingly necessary for confronting climate complexity and sustaining equitable, ideally vibrant climate futures. Presenters : Katharine J. Mach, Kripa Jagannathan, Carlos E. Martín, and Linda Shi Moderator: Pat M. Reed (MSD CoP Facilitation Team) This webinar was held on: March 28th, 2024 from 1-2 PM ET

Mach, Katharine J.↗
NASA NTRS1974

Stress intensity factors for deep cracks emanating from the corner formed by a hole intersecting a plate surface

A technique consisting of a marriage between stress freezing photoelasticity and a numerical method was used to obtain stress intensity factors for natural cracks emanating from the corner at which a hole intersects a plate surface. Geometrics studied were: crack depth to thickness ratios of approximately 0.2, 0.5, and 0.75; crack depth to crack length ratios of approximately 1.0 to 2.0. All final crack geometries were grown under monotonic loading and growth was not self similar with most of the growth occurring through the thickness under remote extension. Stress intensity plate surface K sub s factors were determined at the intersection of the flaw border with the plate surface K sub s and with the edge of the hole K sub h. Results showed that for the relatively shallow flaws K sub h approximately equal to 1.5 K sub s, for the moderately deep flaws K sub h approximately equal to K sub s, and for the deep flaws K sub h approximately equal to 0.5 K sub s, revealing a severe sensitivity of K to flaw geometry.

Mcgowan, J. J.↗
NASA NTRS1974

Stress intensity factors for deep cracks emanating from the corner formed by a hole intersecting a plate surface

A technique consisting of freezing photo-elasticity and a numerical method was used to obtain stress intensity factors for natural cracks emanating from the corner at which a hole intersects a plate surface. Geometries studied were: (1) crack depth to thickness ratios of approximately 0.2, (2) 0.5 and 0.75; (3) crack depth to crack length ratios of approximately 1.0 to 2.0; and (4) crack length to hole radius ratios of about 0.5 to 2.0. All final crack geometries were grown under monotonic loading and growth was not self similar, with most of the growth occuring through the thickness under remote extension. Stress intensity factors were determined at the intersection of the flaw border.

Mcgowan, J. J.↗
NASA NTRS1977

Comment on the relation between the nonadiabatic coupling and the complex intersection of potential energy curves

Simple relations are discussed that provide a correspondence between the complex intersection of two potential surfaces and the nonadiabatic coupling matrix element between those surfaces. These are key quantities in semiclassical and quantum mechanical theories of collision induced electronic transitions. Within the two state approximation, the complex intersection is shown to be directly related to the location and magnitude of the peak in the nonadiabatic coupling. Two cases are considered: the avoided crossing between two potential surfaces; and the spin orbit interaction due to a P-2 halogen atom. Comparisons are made between the results of the two-state model and the results of ab initio quantum chemical calculations.

Jaffe, R. L.↗
NASA NTRS1977

Comment on the relation between the nonadiabatic coupling and the complex intersection of potential energy curves

Simple relations are discussed that provide a correspondence between the complex intersection of two potential surfaces and the nonadiabatic coupling matrix element between those surfaces. These are key quantities in semiclassical and quantum-mechanical theories of collision-induced electronic transitions. Within the two-state approximation, the complex intersection is shown to be directly related to the location and magnitude of the peak in the nonadiabatic coupling. Two cases have been considered: (1) the avoided crossing between two potential surfaces, and (2) the spin-orbit interaction due to a 2P halogen atom. Comparisons are made between the results of the two-state model and the results of ab initio quantum chemical calculations.

Jaffe, R. L.↗
NASA NTRS1977

SEAHT: A computer program for the use of intersecting arcs of altimeter data for sea surface height refinement

The SEAHT program is designed to process multiple passes of altimeter data with intersecting ground tracks, with the estimation of corrections for orbital errors to each pass such that the data has the best overall agreement at the crossover points. Orbit error for each pass is modeled as a polynomial in time, with optional orders of 0, 1, or 2. One or more passes may be constrained in the adjustment process, thus allowing passes with the best orbits to provide the overall level and orientation of the estimated sea surface heights. Intersections which disagree by more than an input edit level are not used in the error parameter estimation. In the program implementation, passes are grouped into South-North passes and North-South passes, with the North-South passes partitioned out for the estimation of orbit error parameters. Computer core utilization is thus dependent on the number of parameters estimated for the set of South-North arcs, but is independent on the number of North-South passes. Estimated corrections for each pass are applied to the data at its input data rate and an output tape is written which contains the corrected data.

Allen, C. P.↗
NASA NTRS1977

A solution to the surface intersection problem

An application-independent geometric model within a data base framework should support the use of Boolean operators which allow the user to construct a complex model by appropriately combining a series of simple models. The use of these operators leads to the concept of implicitly and explicitly defined surfaces. With an explicitly defined model, the surface area may be computed by simply summing the surface areas of the bounding surfaces. For an implicitly defined model, the surface area computation must deal with active and inactive regions. Because the surface intersection problem involves four unknowns and its solution is a space curve, the parametric coordinates of each surface must be determined as a function of the arc length. Various subproblems involved in the general intersection problem are discussed, and the mathematical basis for their solution is presented along with a program written in FORTRAN IV for implementation on the IBM 370 TSO system.

Timer, H. G.↗
NASA NTRS1977

Fibre intersections in a planar randomly oriented fibre composite

The interaction of fibers in a randomly oriented fiber composite is a key factor in determining the mechanical properties of some composites. A theoretical model is presented by means of which values of the mean and the variance of fiber intersections in a planar randomly oriented fiber composite are predicted. These predictions are compared with the mean and variance obtained from a computer simulation of the fiber intersection process.

Williams, J. H., Jr.↗
NASA NTRS1979

A new traffic control design method for large networks with signalized intersections

The paper presents a traffic control design technique for application to large traffic networks with signalized intersections. It is shown that the design method adopts a macroscopic viewpoint to establish a new traffic modelling procedure in which vehicle platoons are subdivided into main stream queues and turning queues. Optimization of the signal splits minimizes queue lengths in the steady state condition and improves traffic flow conditions, from the viewpoint of the traveling public. Finally, an application of the design method to a traffic network with thirty-three signalized intersections is used to demonstrate the effectiveness of the proposed technique.

Leininger, G. G.↗
NASA NTRS1987

The regression intersection method of adjusting image data for band ratioing

Estimation of the combined path radiance and sensor offset terms is essential in adjusting multispectral image radiance measurements for band ratioing. Commonly applied techniques for making this estimate have required assumptions or ancillary information regarding the reflectance properties of surface materials. This paper presents a technique that is unique in that it provides absolute (not just relative) statistically-derived estimates without the use of ancillary information. It is termed the regression intersection method (RIM). RIM is based on contrasts between the spectral properties of various homogeneous areas in rugged terrain. These areas are selected by examination of the image data alone. Bispectral regression (first principal component) lines are determined for each area and are projected, in pairs, to intersection points. Ideally, the coordinates of these points must equal the measurements for zero ground radiance since that is the only condition under which spectrally different materials can have the same radiance values. The median result from several site-pair and band-pair comparisons is used in order to statistically mitigate noise and minor variations due to natural variability. Tests show that the method is successful in determining correction values for the image data that result in maximum removal of the topographic effect in ratio images.

Crippen, Robert E.↗
NASA NTRS1988

Direct simulation of three-dimensional hypersonic flow about intersecting blunt wedges

The general three-dimensional direct simulation Monte Carlo method is used to study the hypersonic flow around two blunt wedges that intersect at a 90 deg angle. Results are obtained for the transitional flow regimes found at 85 and 100 km altitude with a reentry velocity of 7.5 km/s. The disturbance field in front of the double-wedge body is found to be larger than that produced by a single wedge. Surface pressures and flow densities are higher near the wedge intersection, whereas surface heating and shear streses are greater at locations removed from the corner. Results also show that three-dimensional flow structure occurs only near the wedge corner, and that the flow monotonically approaches the limiting two-dimensional wedge flow case in the spanwise direction.

Celenligil, M. Cevdet↗
NASA NTRS1989

Kinematics at the Intersection of the Garlock and Death Valley Fault Zones, California: Integration of TM Data and Field Studies

Kinematic relationships at the intersection of the southern Death Valley and Garlock fault zones were examined to identify and delineate the eastern structural boundary between the Mojave and the Basin and Range geologic terrains, and to construct a model for the evolution of this boundary through time. In order to accomplish this, satellite imagery was combined with field investigations to study six areas in the vicinity of the intersection, or possible extensions, of the fault zones. The information gathered from these areas allows the test of various hypotheses that were proposed to explain the interaction between the Death Valley and Garlock fault zones.

Verosub, Kenneth L.↗
NASA NTRS1989

Thematic Mapper and field investigations at the intersection of the Death Valley and Garlock fault zones, California

Analysis of processed images and detailed field investigations have provided significant information concerning the late-Pliocene and Quaternary evolution of the intersection of the Garlock and Death Valley fault zones. The imagery was used to determine patterns of sedimentation and age relationships on alluvial fans and to determine the geometry, styles of deformation, and relative ages of movements on major and minor faults in the study area. The field investigation often confirmed the inferences drawn from the images and provided additional tectonic and geomorphologic data about the Quaternary deformation of the region. All the data gathered in the course of this project support the contention that the Garlock fault zone terminates in the Avawatz Mountains and that the Death Valley fault zone continues south of the intersection for at least 50 km, forming the eastern boundary of the Mojave province.

Brady, Roland H., III↗
NASA NTRS1995

Anomalous Symmetries Of The Rovibrational Levels of HO2: Consequences Of A Conical Intersection

We show that the geometric phase arising from a conical intersection of the lowest potential energy surfaces of HO2 causes its bending vibrational wavefunctions to be double valued, which allows them to be locally symmetric on one side of the intersection and locally antisymmetric on the other. The material of the proposed publication was reviewed and the technical content will not reveal any information not already in the public domain and will not give any foreign industry or government a competitive advantage.

Barclay, V. J.↗
DOE OSTI2020

Deep Learning-Based Queue-Aware Eco-Approach and Departure System for Plug-In Hybrid Electric Buses at Signalized Intersections: A Simulation Study

Eco-Approach and Departure (EAD) has been considered as a promising eco-driving strategy for vehicles traveling in an urban environment, where information such as signal phase and timing (SPaT) and geometric intersection description is well utilized to guide vehicles passing through intersections in the most energy-efficient manner. Previous studies formulated the optimal trajectory planning problem as finding the shortest path on a graphical model. While this method is effective in terms of energy saving, its computation efficiency can be further enhanced by adopting machine learning techniques. In this paper, we propose an innovative deep learning-based queue-aware eco-approach and departure (DLQ-EAD) system for a plug-in hybrid electric bus (PHEB), which is able to provide an online optimal trajectory for the vehicle considering both the downstream traffic condition (i.e. traffic lights, queues) and the vehicle powertrain efficiency. Based on optimal solutions obtained from the graph-based trajectory planning algorithm (GTPA), a deep neural network (DNN) is developed to learn the optimal vehicle speed for the next time step given its current state. It is demonstrated that the trained DNN can provide energy-efficient trajectories with high computational efficiency and high flexibility adopting to dynamic changes in the surrounding environment. To address the impact of downstream traffic, a queue prediction model is further developed using data from radars and connected vehicles (CVs), as well as signal timing data from SPaT messages. A comprehensive simulation study in the microscopic traffic modeling software PTV VISSIM shows that the proposed DLQ-EAD can achieve 18.7%-24.0% energy efficiency improvements for a single PHEB on various traffic congestion levels. The proposed queue prediction model can be of practical significance even at low penetration rates of CVs. Specifically, additional energy savings of 2.0%-8.2% can be further achieved with 20% vehicles in the network.

Ye, Fei↗
DOE OSTI2022

Intersections of Disadvantaged Communities and Renewable Energy Potential: Analyses to Inform Equitable Investment Prioritization

Renewable energy development can bolster local economies through job creation, local tax revenues, and reduced energy costs; however, communities most in need of economic development and employment opportunities often see lower levels of renewable energy deployment. Megan Day and Liz Ross, along with their co-authors and supported by NREL's Sustainable Communities Catalyzer, identified areas where disadvantaged community indicators intersect with high potential for renewable energy deployment. Through a geospatial intersection of energy burden, environmental hazard, and sociodemographic data with the technical generation potential and levelized cost of energy for multiple renewable energy technologies, we identified trends across disadvantaged community indicators and renewable energy deployment potential. Combining metrics across several tools, including the State and Local Planning for Energy (SLOPE) platform, the Low-Income Energy Affordability (LEAD) tool, and the Environmental Justice Screening and Mapping (EJSCREEN) tool, we compiled a dataset that can be used to inform national- and state-level energy-related assistance programs, economic development efforts, and infrastructure programs seeking to prioritize investments in disadvantage communities.

catalyzer↗
DOE OSTI2022

Intersections of Disadvantaged Communities and Renewable Energy Potential: Analyses to Inform Equitable Investment Prioritization

Renewable energy development can bolster local economies through job creation, local tax revenues, and reduced energy costs; however, communities most in need of economic development and employment opportunities often see lower levels of renewable energy deployment. We sought to identify areas where indicators of disadvantaged communities intersect with high generation potential from cost- effective renewable energy opportunities. This presentation highlights the geospatial intersection of the technical potential and levelized cost of energy for three renewable technologies (residential solar, utility solar, and land-based wind) and three sociodemographic metrics (energy burden, unemployment, and employment in mining, quarrying, and oil and gas extraction). This research and the associated county-level data set are intended to inform national- and state-level energy-related assistance programs, economic development efforts, and infrastructure programs seeking to prioritize investments in disadvantaged communities.

disadvantaged communities↗
DOE OSTI2021

Imaging conical intersection dynamics during azobenzene photoisomerization by ultrafast X-ray diffraction

Significance Vibronic coherences are unique features that emerge in the decisive moments of photochemistry and photophysics. Here we demonstrate how X-ray diffraction can access fundamental information about these coherences. This is enabled by recent developments at free-electron lasers, working toward temporal resolution and single-molecule accessibility of scattering-based measurements. Time-resolved diffraction patterns of the isomerization of azobenzene are simulated. The process is monitored in time via the momentum-space signal, with a special focus on the mixed elastic/inelastic scattering from coherences. We give practical ideas on how this relatively weak contribution to the signal can potentially be retrieved. A direct connection to the real-space movie of the conical intersection dynamics is made, enabling the observation of quantum coherences that direct chemical processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗