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At least 1,279 records · Page 71

Study on utilization of advanced composites in commercial aircraft wing structures. Volume 1: Executive summary

The effort required by commercial transport manufacturers to accomplish the transition from current construction materials and practices to extensive use of composites in aircraft wings was investigated. The engineering and manufacturing disciplines which normally participate in the design, development, and production of an aircraft were employed to ensure that all of the factors that would enter a decision to commit to production of a composite wing structure were addressed. A conceptual design of an advanced technology reduced energy aircraft provided the framework for identifying and investigating unique design aspects. A plan development effort defined the essential technology needs and formulated approaches for effecting the required wing development. The wing development program plans, resource needs, and recommendations are summarized.

Sakata, I. F.↗

The alignment-distribution graph

Implementing a data-parallel language such as Fortran 90 on a distributed-memory parallel computer requires distributing aggregate data objects (such as arrays) among the memory modules attached to the processors. The mapping of objects to the machine determines the amount of residual communication needed to bring operands of parallel operations into alignment with each other. We present a program representation called the alignment-distribution graph that makes these communication requirements explicit. We describe the details of the representation, show how to model communication cost in this framework, and outline several algorithms for determining object mappings that approximately minimize residual communication.

Chatterjee, Siddhartha↗

The role of overset grids in the development of the general purpose CFD code

A discussion of the strengths and weaknesses of overset composite grid and solution technology is given, along with a sampling of current work in the area. Major trends are identified, and the observation is made that generalized and hybridized overset methods provide a natural framework for combining disparate mesh types and physics models. Because of this, the author concludes that overset methods will be the foundation for the general purpose computational fluid dynamics programs of the future.

Belk, Davy M.↗

Distributions of Orbital Elements for Meteoroids on Near-Parabolic Orbits According to Radar Observational Data

Some results of the International Heliophysical Year (IHY) Coordinated Investigation Program (CIP) number 65 Meteors in the Earth Atmosphere and Meteoroids in the Solar System are presented. The problem of hyperbolic and near-parabolic orbits is discussed. Some possibilities for the solution of this problem can be obtained from the radar observation of faint meteors. The limiting magnitude of the Kharkov, Ukraine, radar observation program in the 1970 s was +12, resulting in a very large number of meteors being detected. 250,000 orbits down to even fainter limiting magnitude were determined in the 1972-78 period in Kharkov (out of them 7,000 are hyperbolic). The hypothesis of hyperbolic meteors was confirmed. In some radar meteor observations 1 10% of meteors are hyperbolic meteors. Though the Advanced Meteor Orbit Radar (AMOR, New Zealand) and Canadian Meteor Orbit Radar (CMOR, Canada) have accumulated millions of meteor orbits, there are difficulties in comparing the radar observational data obtained from these three sites (New Zealand, Canada, Kharkov). A new global program International Space Weather Initiative (ISWI) has begun in 2010 (http://www.iswi-secretariat.org). Today it is necessary to create the unified radar catalogue of nearparabolic and hyperbolic meteor orbits in the framework of the ISWI, or any other different way, in collaboration of Ukraine, Canada, New Zealand, the USA and, possibly, Japan. Involvement of the Virtual Meteor Observatory (Netherlands) and Meteor Data Centre (Slovakia) is desirable too. International unified radar catalogue of near-parabolic and hyperbolic meteor orbits will aid to a major advance in our understanding of the ecology of meteoroids within the Solar System and beyond.

Kolomiyets, S. V.↗

A COTS-Style Acquisition Strategy for Human Exploration Beyond LEO

The Evolvable Mars Campaign presents a long term strategy for NASA's Journey to Mars within a capability driven framework. By comparing each element to a set of criteria, this paper reviews the potential of acquiring those capabilities using a strategy similar to the Commercial Orbital Transportation Services program. The paper presents the criteria, assesses the elements against those criteria, and then discusses the suitability of each element to being developed using this acquisition strategy. Throughout the campaign, certain capabilities are well suited to being developed in this manner while others are not. This assessment is a snapshot in time, and should be revisited as the campaign and/or commercial capabilities change. This paper will explore each of these elements in the campaign and discuss how the COTS development andacquisition strategy could or could not be applied to those elements. This assessment will be based on theservices or functionality required in the campaign, and will use the best practices discussed above to create acase for or against a COTS-style acquisition strategy for each given element.

Arney, Dale↗

Critical roles of Cu(OH)2 in low-temperature moisture-induced degradation of Cu-SAPO-34 SCR catalyst: Correlating reversible and irreversible deactivation

Cu-SAPO-34 selective catalytic reduction (SCR) catalyst deactivates upon exposure to water vapor at temperatures lower than 100 °C, which deteriorates its application prospects. The deactivation under cycled aging-regeneration conditions can be categorized into two stages, namely reversible and irreversible deactivation. Based on SCR reaction tests, and characterizations with diffuse reflection infrared Fourier transform spectroscopy (DRIFTS), NH3 temperature-programmed desorption (NH3-TPD) and H2 temperature-programmed reduction (H2-TPR), it is concluded that the transformation of SCR active isolated Cu(II) ions to Cu(OH)2 is critical to both types of deactivation. Within the frame of reversible deactivation, Cu(OH)2 is converted back to SCR active Cu(II) ions by interacting with Brønsted acid sites during high-temperature regeneration. However, interactions between Cu(OH)2 and hydrolyzed framework Al lead to the formation of CuAl2O4-like species, causing permanent loss of active Cu(II) ions and thus, irreversible deactivation. The authors from Tsinghua University would like to acknowledge the financial support from projects of China Science and Technology Exchange Centre (No. 2016YFE0126600) and the National Key R&D Program of China (No. 2017YFC0211102). YM also acknowledges Tsinghua Scholarship for Overseas Graduate Studies for a visit to the Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for the US Department of Energy (DOE) under contract DE-AC05-76RL01830. FG is supported by DOE, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office.

Cu-SAPO-34, low-temperature deactivation, reversib↗

A Comprehension Based Analysis of Autoflight System Interfaces

This cooperative agreement supported Dr. Peter Polson's participation in two interrelated research programs. The first was the development of the Situation-Goal-Behavior (SGB) Model that is both a formal description of an avionics system's logic and behavior and a representation of a system that can be understood by avionics designers, pilots, and training developers. The second was the development of a usability inspection method based on an approximate model, RAFIV, of pilot interactions with the Flight Management System (FMS). The main purpose of this report is to integrate the two models and provide a context in order to better characterize the accomplishments of this research program. A major focus of both the previous and this Cooperative Agreement was the development of usability evaluation methods that can be effectively utilized during all phases of the design, development, and certification process of modern avionics systems. The current efforts to validate these methods have involved showing that they generate useful analyses of known operational and training problems with the current generation of avionics systems in modern commercial airliners. This report is organized into seven sections. Following the overview, the second section describes the Goal-Situation-Behavior model and its applications. The next section summarizes the foundations of the RAFIV model and describes the model in some detail. The contents of both these sections are derived from previous reports referenced in footnotes. The fourth section integrates these two models into a complete design evaluation and training development framework. The fifth section contains conclusions and possible future directions for research. References are in Section 6. Section 7 contains the titles and abstracts of the papers paper describing in more detail the results of this research program.

Palmer, Everett↗

Operating a Crewed Spacecraft in the Age of Commercial Space Using Private/Government Partnership

Fifty years after humans completed a large-scale United States government-funded and government-engineered effort of landing humans on the moon, human spaceflight has entered a new paradigm. Private companies are now investing their own money and taking on an ever-increasing role in human spaceflight, in partnership with the U.S. government. This paper will describe the development of one of these partnerships through the lens of its mission operations team. As part of the Commercial Crew Program (CCP), NASA selected Boeing’s CST-100 Starliner as one of the next generation of crewed vehicles. Boeing opted to partner with the US Government for their Starliner operations by contracting with NASA’s Mission Control teams in the Flight Operations Directorate (FOD) at the Johnson Space Center to create its own Mission Operations (MO) flight controllers. Partnering with FOD provided benefits to both Boeing and NASA while also creating new challenges. MO brought over 60 years of crewed spaceflight experience and infrastructure to Boeing’s new program. Within certain legal constraints, MO was able to work closely and efficiently with their FOD counterparts who were performing both integration duties and, under the auspices of the CCP, insight of the contractors, in this case Boeing. Involvement of NASA as the Boeing operations agent did lead to what management deemed a ‘healthy tension’ within FOD, challenging old processes and often creating better, more robust teamwork. Successful development of the framework and boundaries of both the legal aspects and the oversight tensions has been one of the keys to developing a successful corporate/government partnership. Due to the highly automated nature of the Starliner, the MO organization was designed to be much smaller than previous NASA’s flight control teams for past programs. NASA has learned through the decades that spacecraft design and operations need to be as flexible and forgiving as possible. NASA’s Commercial Crew Program was established to sponsor corporate development of economical vehicles that could get humans to and from low Earth orbit. These companies, of course, need to meet contractual obligations in providing a safe means of transporting astronauts to the International Space Station (ISS), but also need to do so in a manner that leads to the venture resulting in a profit at the same time. Through MO’s involvement in the development of this spaceflight paradigm shift, there are ample lessons to be conveyed to future teams and programs working to develop similar missions.

Robert C Dempsey↗

Operating a Crewed Spacecraft in the Age of Commercial Space Using Private/Government Partnership

Fifty years after humans completed a large-scale United States government-funded and government-engineered effort of landing humans on the moon, human spaceflight has entered a new paradigm. Private companies are now investing their own money and taking on an ever-increasing role in human spaceflight, in partnership with the U.S. government. This paper will describe the development of one of these partnerships through the lens of its mission operations team. As part of the Commercial Crew Program (CCP), NASA selected Boeing’s CST-100 Starliner as one of the next generation of crewed vehicles. Boeing opted to partner with the US Government for their Starliner operations by contracting with NASA’s Mission Control teams in the Flight Operations Directorate (FOD) at the Johnson Space Center to create its own Mission Operations (MO) flight controllers. Partnering with FOD provided benefits to both Boeing and NASA while also creating new challenges. MO brought over 60 years of crewed spaceflight experience and infrastructure to Boeing’s new program. Within certain legal constraints, MO was able to work closely and efficiently with their FOD counterparts who were performing both integration duties and, under the auspices of the CCP, insight of the contractors, in this case Boeing. Involvement of NASA as the Boeing operations agent did lead to what management deemed a ‘healthy tension’ within FOD, challenging old processes and often creating better, more robust teamwork. Successful development of the framework and boundaries of both the legal aspects and the oversight tensions has been one of the keys to developing a successful corporate/government partnership. Due to the highly automated nature of the Starliner, the MO organization was designed to be much smaller than previous NASA’s flight control teams for past programs. NASA has learned through the decades that spacecraft design and operations need to be as flexible and forgiving as possible. NASA’s Commercial Crew Program was established to sponsor corporate development of economical vehicles that could get humans to and from low Earth orbit. These companies, of course, need to meet contractual obligations in providing a safe means of transporting astronauts to the International Space Station (ISS), but also need to do so in a manner that leads to the venture resulting in a profit at the same time. Through MO’s involvement in the development of this spaceflight paradigm shift, there are ample lessons to be conveyed to future teams and programs working to develop similar missions.

Robert C. Dempsey↗

Operating a Crewed Spacecraft in the Age of Commercial Space Using Private/Government Partnership

Fifty years after humans completed a large-scale United States government-funded and government-engineered effort of landing humans on the moon, human spaceflight has entered a new paradigm. Private companies are now investing their own money and taking on an ever-increasing role in human spaceflight, in partnership with the U.S. government. This paper will describe the development of one of these partnerships through the lens of its mission operations team. As part of the Commercial Crew Program (CCP), NASA selected Boeing’s CST-100 Starliner as one of the next generation of crewed vehicles. Boeing opted to partner with the US Government for their Starliner operations by contracting with NASA’s Mission Control teams in the Flight Operations Directorate (FOD) at the Johnson Space Center to create its own Mission Operations (MO) flight controllers. Partnering with FOD provided benefits to both Boeing and NASA while also creating new challenges. MO brought over 60 years of crewed spaceflight experience and infrastructure to Boeing’s new program. Within certain legal constraints, MO was able to work closely and efficiently with their FOD counterparts who were performing both integration duties and, under the auspices of the CCP, insight of the contractors, in this case Boeing. Involvement of NASA as the Boeing operations agent did lead to what management deemed a ‘healthy tension’ within FOD, challenging old processes and often creating better, more robust teamwork. Successful development of the framework and boundaries of both the legal aspects and the oversight tensions has been one of the keys to developing a successful corporate/government partnership. Due to the highly automated nature of the Starliner, the MO organization was designed to be much smaller than previous NASA’s flight control teams for past programs. NASA has learned through the decades that spacecraft design and operations need to be as flexible and forgiving as possible. NASA’s Commercial Crew Program was established to sponsor corporate development of economical vehicles that could get humans to and from low Earth orbit. These companies, of course, need to meet contractual obligations in providing a safe means of transporting astronauts to the International Space Station (ISS), but also need to do so in a manner that leads to the venture resulting in a profit at the same time. Through MO’s involvement in the development of this spaceflight paradigm shift, there are ample lessons to be conveyed to future teams and programs working to develop similar missions.

Robert C. Dempsey↗

Optimal Gas-Electric Energy System Decarbonization Planning

As energy utilities implement climate change mitigation policies, system planners require strategies for achieving affordable emissions reductions. Coordinated planning of electric power and natural gas systems will allow synergistic investments to address cross-sector operational constraints, competing uses for net-zero emissions fuels, and shifts in energy demands across energy carriers. In this study, we develop a novel optimization program that finds the cost-minimizing mix of infrastructure expansion or reduction across gas and electric systems to satisfy sector-specific emissions constraints. Alongside energy supply resources, our framework allows for central-planning of end-use equipment stocks to allow switching between gas and electric appliances upon failure or premature replacement. The proposed model is used to simulate case study scenarios for a benchmark 24-pipe gas network coupled to a 24-node power system test network. We find that electrification of greater than 80% of core gas demands is a component of the least-cost solution for modeled energy systems. Despite this substitution, the gas system is maintained to service difficult-to-electrify customers and to deliver net-zero emissions gas to electricity generators in times of peak electricity demand. Restricting electrification of gas appliances increases reliance on power- to-gas technologies and increases annual costs by 15% in 2040. Neglecting constraints on pipeline blending of hydrogen can produce a misleading result that relies on hydrogen blend fractions of greater than 50%. In all cases, we find the average costs of delivered gas increase nearly 5-fold across the decarbonization transition, highlighting the importance of future work investigating cost-allocation strategies for ensuring an equitable energy transition.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

Stochastic Microgrid Scheduling With Chance‐Constrained Resilience Consideration

Traditionally, it is assumed that microgrids transition seamlessly from grid‐connected operation to islanded mode in the event of sudden main grid outages. In reality, the islanding process, especially unintentional islanding, is rarely seamless. Instead, it is subject to voltage and frequency fluctuations caused by the instantaneous disconnection of the point of common coupling (PCC) switch, variations in loads and renewable generation output and even the protection tripping of distributed energy resources (DERs). To mitigate these fluctuations and facilitate a smooth islanding process, we propose a stochastic microgrid scheduling model that incorporates chance‐constrained resilience measures. Specifically, the resilience measure is defined as the probability of successful islanding (PSI), that is, the probability that a microgrid can mitigate the generation‐demand imbalance caused by the disconnection of the PCC switch, variations in load and renewable generation and DER tripping. This measure is modelled using chance constraints. Unlike existing reliability and resilience indices, which typically neglect the possibility of microgrid/DER failure under extreme events and assume their survival while primarily focussing on reducing impact duration or magnitude, the proposed PSI‐based framework explicitly addresses microgrid and DER survival during the islanding transition. The formulated nonlinear chance constraints are approximated using a multiinterval approach and equivalently represented as a mixed‐integer linear programming (MILP) formulation. Case study results validate the proposed method, showing that the PSI estimation error is reduced to less than 8%, compared to approximately 28% with existing methods. Various sensitivity analyses on the DER tripping rate and PSI settings were performed to validate the robustness of the proposed method. In particular, the necessity of accounting for DER tripping in the PSI calculation was demonstrated.

chance constrained optimization↗

Calibrating a finite-strain phase-field model of fracture for bonded granular materials with uncertainty quantification

To study the mechanical behavior of mock high explosives, an experimental and simulation program was developed to calibrate, with quantified uncertainty, a material model of the bonded granular material Idoxuridine and nitroplasticized Estane-5703. This paper reports on the efficacy of such a framework as a generalizable methodology for calibrating material models against experimental data with uncertainty quantification. Additionally, this paper studies the effect of two manufacturing temperatures and three initial granular configurations on the unconfined compressive behavior of the resulting bonded granular materials. In each of these cases, the same calibration framework was used; in that, hundreds of high-fidelity direct numerical simulations using a new, graphics processing unit-enabled, high-performance finite element method software, Ratel, were run to calibrate a finite-strain phase-field fracture model against experimental data. It was found that manufacturing temperature influenced the elastic response of the mock high explosives, with higher temperatures yielding a stiffer response. By contrast, it was found that the initial configuration of the grains had a negligible impact on the overall behavior of the mock high explosives though it remains possible that local damage accumulation within the specimens could be altered by the initial configurations. Overall, the calibration framework was successful at creating well-calibrated models, showing its usefulness as an engineering and scientific tool.

36 MATERIALS SCIENCE↗

Data for Zheng et al. (2025), "AquaMEND: Reconciling multiple impacts of salinization on soil carbon biogeochemistry"

Soil salinization, exacerbated by climate change, poses a global threat to coastal ecosystems and soil function. Salinity affects soil carbon cycling by directly impacting microbial activity and indirectly altering soil physicochemical properties, but current models inadequately represent these complexities. This dataset contains the observational and modeling data from Zheng et al. (2025), which described a process-based modeling framework that couples soil solution chemistry with microbial carbon cycling reactions to study the impacts of soil salinization. This conceptual model is implemented numerically into the open-source geochemical program PHREEQC 3.0 (Parkhurst and Appelo, 2013). This dataset consists of: - Figure2_AquaMEND_salinity_buffer: Contains model simulation outputs to assess the impact of three different cation exchange and surface complexation processes on salinity buffering (Fig. 2 from Zheng et al. 2025). - Figure3_Salinity_function: Contains salinity function fitting for literature data (Fig. 3 from Zheng et al. 2025). - Figure4_AquaMEND_microbial_mechanisms: Contains model simulation outputs for testing various microbial process-based hypotheses related to soil salinization, including microbial mortality, carbon use efficiency (CUE), extracellular enzyme activity, and other microbial mechanisms (Fig. 4 from Zheng et al. 2025). - Figure5_AquaMEND_Redox: Contains on model simulation outputs to evaluate shifts among key redox processes, such as aerobic respiration, sulfate reduction, and methanogenesis (Fig.5 from Zheng et al. 2025). - Figure6_AquaMEND_sorption: Contains on model simulation outputs for investigating the effects of salinity on dissolved organic matter (DOM) sorption and desorption processes (Fig. 6 from Zheng et al. 2025). - Figure7_AquaMEND_process_couple: Contains on model simulation outputs for exploring coupled biotic-abiotic processes and their interactions (Fig. 7 from Zheng et al. 2025). - data: Includes datasets used to develop salinity response functions and evaluate salinity buffering capacity. Datasets for MEND model calibration. - database: Contains the `.dat` file required by PHREEQC for model execution. - README.md: A Markdown plain text file describing the computational tools and directories. Files are a mixture of plain text CSV (comma-separated value) and plain text *.dat files written by the model; no special software is required to read them.

EARTH SCIENCE > AGRICULTURE > SOILS > SOIL SALINIT↗

A Multi-Scale Inference, Estimation, and Prediction Engine for Earth System Modeling

We posit that AI methods can be leveraged to significantly enhance the predictive skill of forward Earth system modeling (ESM) activities. A hybrid framework incorporating traditional ESM modeling, inference methods, and AI techniques could make better use of both measured and computed information as well as computational resources by targeting inference tasks at program priorities, such as the predictability of precipitation extremes. This runtime pathway to closing the simulation/analysis-data/model improvement loop will streamline the traditional offline pathway to model improvement, which is based on domain science expertise, while suggesting guidance for further observations and measurements.

58 GEOSCIENCES↗

Energy Storage for Social Equity Roundtable Report

In support of the Office of Electricity Energy Storage program, Pacific Northwest National Laboratory (PNNL), hosted a roundtable to explore the relationship between energy equity and energy storage. Flexible and available at any scale, energy storage offers a useful framework and starting point in a larger conversation around energy equity. Through storage, we can imagine more broadly how improvements and investments in the grid can respond to social and health challenges and increase affordability, reliability, and community value in the future. The roundtable featured keynotes and conversations with people leading the charge in transitioning our energy system to a more equitable, affordable, accessible, and sustainable future. This event was presented in collaboration with Sandia National Laboratories.

25 ENERGY STORAGE↗

CalderaCast User Manual Version 1.0

CalderaCast is a user-friendly web-based tool for electrical-load forecast, providing stakeholders with a fully customizable decision-support framework that estimates the likely power draw from a possible future electric-vehicle (EV) charging station at a given location on a given day along an alternative fuel corridor (AFC). These EV charging profiles are accurately modeled in CalderaCast using the Caldera software framework developed by Idaho National Laboratories (INL), reflecting the realistic charging levels observed in actual charge events. This tool was developed as part of the National Electric Vehicle Infrastructure (NEVI) program, which is quickly generating substantial interest from would-be charging station operators (CSO), large and small electric utilities, and state transportation planners, some of whom had not seriously considered EV charging previously. All these entities—with or without background in EV infrastructure—must estimate the electricity load that a proposed charging station will generate. This load forecast is critically important for a utility to properly assess the capacity of their distribution network to support the proposed station or properly size grid upgrades for potential load growth due to future EV adoption, vehicle technology improvements, or station growth. This document describes each aspect of the CalderaCast tool and provides guidance to users who are interested in utilizing the tool for their work.

24 - POWER TRANSMISSION AND DISTRIBUTION↗