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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 1,027 records · Page 57

Continuum Scale Modeling of Thermal Conductivity in Hyperstoichiometric Uranium Dioxide

Conventional UO{sub 2} nuclear fuel is susceptible to oxidation via the formation of hyperstoichiometric uranium dioxide (UO{sub 2+x}) when exposed to air or high temperature water vapor in the event of a cladding breach during operation or storage. Below 1130 deg. C intermediate oxides U{sub 4}O{sub 9} and U{sub 3}O{sub 7} form; which degrades the thermal conductivity of the fuel. Understanding how the thermal conductivity degrades as a function of oxygen content and phase fractions is an important engineering problem for future fuel performance codes for safe and efficient reactor operation. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Multi-scale modeling of fuel fragmentation and microstructural evolution

An overview of NEAMS program activities to model fuel fragmentation and microstructual evolution to a group of industry attendees at a meeting hosted by EPRI. Topics include atomistic methods to determine grain boundary strength, phase-field fracture modeling to determine critical pressure at grain boundaries, and coupled phase-field-cluster dynamics to model microstructural evolution.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Digital Twin Framework for PIP-II Linac: AI-Driven Multi-Scale Modeling from Ion Source to 800 MeV

The PIP-II linac will enable >1.2 MW beam power for DUNE, requiring unprecedented operational reliability across its warm front-end (RFQ, MEBT) and five distinct SRF sections operating at 162.5/325/650 MHz. We present a comprehensive digital twin framework uniquely combining a fully differentiable fast beam transport code with neural network surrogates trained on high-fidelity PIC simulations, capturing space charge and nonlinear dynamics beyond traditional envelope codes while achieving 10⁴× speedup at <1% accuracy. End-to-end differentiability enables gradient-based optimization across 500+ parameters simultaneously—previously impossible with conventional tools—while the model incorporates static/dynamic errors and serves as a virtual commissioning platform for diverse hardware integration. The framework facilitates reinforcement learning for pulsed/CW mode transitions, predictive maintenance through anomaly detection, and autonomous tuning algorithm development with real-time execution capability. Validation against physics simulations shows excellent agreement for the front-end, with initial results demonstrating potential for 30% commissioning time reduction and proactive fault mitigation, providing a scalable blueprint for operating next-generation high-intensity accelerators.

Pathak, Abhishek [Fermilab] (ORCID:000000021704208↗

Methodology for Fast Iterations of Blade Designs Using Thermoplastic Composite Materials: Preprint

Tidal energy is still in the early research and development phases, therefore the ability to quickly manufacture and evaluate prototype blades with new blade designs and materials is critical. This paper investigates using a Stratasys three-dimensional printer to rapidly prototype scale-model turbine blades by printing the blade tooling and using vacuum-assisted resin transfer molding (VARTM) to manufacture blades. This work outlines a methodology for cost effectively designing and manufacturing model-scale tidal turbine blades to be used in testing campaigns, and for evaluating new thermoplastic composite materials for tidal energy applications. Demonstration blades were designed in ANSYS and manufactured using an infusible thermoplastic resin system called Elium(R). The development of scale-model thermoplastic blades enables research into their fatigue performance in realistic conditions at a cost-effective scale, and manufacturing using 3-D printed tooling enables fast and low-cost blade design iterations.

17 WIND ENERGY↗

Phenomenological aspects of no-scale inflation models

We discuss phenomenological aspects of inflationary models wiith a no-scale supergravity Kähler potential motivated by compactified string models, in which the inflaton may be identified either as a Kähler modulus or an untwisted matter field, focusing on models that make predictions for the scalar spectral index n{sub s} and the tensor-to-scalar ratio r that are similar to the Starobinsky model. We discuss possible patterns of soft supersymmetry breaking, exhibiting examples of the pure no-scale type m{sub 0} = B{sub 0} = A{sub 0} = 0, of the CMSSM type with universal A{sub 0} and m{sub 0} ≠ 0 at a high scale, and of the mSUGRA type with A{sub 0} = B{sub 0} + m{sub 0} boundary conditions at the high input scale. These may be combined with a non-trivial gauge kinetic function that generates gaugino masses m{sub 1/2} ≠ 0, or one may have a pure gravity mediation scenario where trilinear terms and gaugino masses are generated through anomalies. We also discuss inflaton decays and reheating, showing possible decay channels for the inflaton when it is either an untwisted matter field or a Kähler modulus. Reheating is very efficient if a matter field inflaton is directly coupled to MSSM fields, and both candidates lead to sufficient reheating in the presence of a non-trivial gauge kinetic function.

79 ASTRONOMY AND ASTROPHYSICS↗

JT150 1/2-scale nozzle jet noise experiment and comparison with prediction

As part of a program to study flight effects on the exhaust noise of a full scale JT15D engine, static half scale model jet noise experiments were conducted. Acoustic data were recorded for microphone angles of 45 deg to 155 deg with jet conditions for the model scale nozzle corresponding closely to those at 55, 73 and 97 percent of corrected rated speed for the full scale engine. These data are useful for determining the relative importance of jet and core noise in the static full scale engine test data and will in turn allow for a proper evaluation of flight effects on the exhaust noise results. The model scale data are also compared with the coaxial jet noise prediction. Above 1000 Hz, the prediction is nominally 0 to 3 dB higher than the data. The arithmetic mean of the differences between the experimental OASPL and the predicted OASPL for all angles for each run ranged from 0 to -3.2 dB. The standard deviation of all the OASPL differences is 2.2 dB. The discrepancies are greatest at low primary jet velocities and appear to be due to inadequacy in the variable jet density exponent incorporated in the prediction procedure.

Groesbeck, D. E.↗

NASA/Army supported noise source/noise reduction programs at Langley

The helicopter noise research related to noise source mechanism identification and reduction includes many of the critical noise problems experienced by the helicopter. These include blade vortex interaction (BVI) noise, broadband turbulence ingestion noise, rotor blade self noise including trailing edge effects, model scale effects evaluations, and to some degree main rotor/tail rotor interaction noise. Issues that arise from this evaluation are; (1) Broadband noise can be a significant contribution to the overall noise problem. (2) Scale model investigations are an effective means of conducting helicopter noise research; however, more model/flight correlation studies are required to develop a high degree of confidence of the use of scale model results in the design process of helicopters. (3) More detailed investigations identifying critical factors affecting the main rotor/tail rotor noise mechanism are required.

Hoad, D. R.↗

FOCAL Campaign I: Advanced Wind Turbine Control Strategies

Campaign I of the Floating Offshore-wind Controls Advanced Laboratory Experimental Program (FOCAL) aims to generate a dataset enabling the validation of aerodynamic performance of a scaled turbine mounted on a rigid tower in a fixed condition. The turbine considered in the FOCAL testing campaigns is the IEA-Wind 15MW Reference Wind Turbine. This scaled model is capable of simulating advanced blade-pitch control strategies in a high-quality wind field. The turbine is fully instrumented to record a variety of parameters in real time such as structural loads and dynamics. The test data considered was generated at the University of Maine's Harold Alfond Wind and Wave (W2) testing facility. The Load Cases (LC) considered in this testing campaign are as follows: LC 1.X - Constant wind and blade-pitch with varying rotor speeds LC 2.X - Constant wind and rotor speed with varying blade-pitch LC 3.X - Varying wind with active closed-loop control Detailed properties on the modeled system are found in the following reference: Lenfest E., Floating Offshore-wind Controls Advanced Laboratory (FOCAL) Experimental Program - Campaign I: 1:70 Model-scale Testing of the IEA-Wind 15MW Reference Turbine. UMaine ASCC Report Number 23-40-1183. Details on the results of the verification and validation are found in the following reference: Mendoza, Nicole et al., "Verification and Validation of Model-Scale Turbine Performance and Control for the IEA Wind 15 MW Reference Wind Turbine," Energies, vol. 15, no. 20, 2022, https://doi.org/10.3390/en15207649.

17 WIND ENERGY↗

Towards POI-based large-scale land use modeling: spatial scale, semantic granularity, and geographic context

The combination of spatial distribution, semantic characteristics, and sometimes temporal dynamics of POIs inside a geographic region can capture its unique land use characteristics. Most previous studies on POI-based land use modeling research focused on one geographic region and select one spatial scale and semantic granularity for land use characterization. There is a lack of understanding on the impact of spatial scale, semantic granularity, and geographic context on POI-based land use modeling, particularly large-scale land use modeling. In this study, we developed a scalable POI-based land use modeling framework and examined the impact of these three factors on POI-based land use characterization using data from three geographic regions. We developed a unified semantic representation framework for POI semantics that can help fuse heterogeneous POI data sources. Then, by combining POIs with a neural network language model, we developed a spatially explicit approach to learn the embedding representation of POIs and AOIs. We trained multiple supervised classifiers using AOI embeddings as input features to predict AOI land use at different semantic granularities. The classification performance of different land use classes was analyzed and compared across three geographic regions to identify the semantic representativeness of POI-based AOI embedding and the impact of geographic context.

58 GEOSCIENCES↗

Airframe noise of a small model transport aircraft and scaling effects

Airframe noise of a 0.01 scale model Boeing 747 wide-body transport was measured in the Langley Anechoic Noise Facility. The model geometry simulated the landing and cruise configurations. The model noise was found to be similar in noise characteristics to that possessed by a 0.03 scale model 747. The 0.01 scale model noise data scaled to within 3 dB of full scale data using the same scaling relationships as that used to scale the 0.03 scale model noise data. The model noise data are compared with full scale noise data, where the full scale data are calculated using the NASA aircraft noise prediction program.

Shearin, J. G.↗

Application of distorted models in developing scaled structural models

In the design and development of dynamically similar structural models a distorted model of the panel is used. The panel thickness is made larger than that dictated by geometric scaling, and the mass of the panel is decreased by adding mass to the surface of the panel to counteract the additional stiffness obtained by the thickness increase.

White, R. W.↗

Device-scale CFD modeling of gas-liquid multiphase flow and amine absorption for CO2 capture

In this paper we aim to develop a validated device-scale CFD model that can predict quantitatively both hydrodynamics and CO2 capture efficiency for an amine-based solvent absorber column with random Pall ring packing. A Eulerian porous-media approach and a two-fluid model were employed, in which the momentum and mass transfer equations were closed by literature-based empirical closure models. We proposed a hierarchical approach for calibrating the parameters in the closure models to make them accurate for the packed column. Specifically, a parameter for momentum transfer in the closure was first calibrated based on data from a single experiment. With this calibrated parameter, a parameter in the closure for mass transfer was next calibrated under a single operating condition. Last, the closure of the wetting area was calibrated for each gas velocity at three different liquid flow rates. For each calibration, cross validations were pursued using the experimental data under operating conditions different from those used for calibrations. This hierarchical approach can be generally applied to develop validated device-scale CFD models for different absorption columns.

Pan, Wenxiao↗

Space shuttle: Aerodynamic characteristics of a double delta wing space shuttle orbiter (M equals 0.6 - 5.0)

This test program was the first wind tunnel investigation of a double delta wing space shuttle orbiter. The 0.004 scale model used for this test was the first model constructed of this configuration and as such lacked certain refinements incorporated in later models, the principal differences being that the wing is located 0.1 inches model scale further forward than later models and that the nose contours are slightly different.

Ellis, R. R.↗

A non-uniform corrosion model and meso-scale fracture modelling of concrete

Corrosion-induced concrete cracking is a significant durability problem for reinforced concrete structures. Considerable research has been carried out in the last few decades to understand and model the expansion mechanism of the corrosion products around the reinforcing bar and simulate the cracking behaviour of the concrete cover. In this paper, a new corrosion model based on non-uniform corrosion expansion is formulated and validated against experimental data. A meso-scale fracture model, consisting of aggregates, cement paste/mortar and ITZ, is established for the cases of both middle and side reinforcing bars. Under the developed corrosion and concrete fracture model, the cracking phenomena of the concrete cover are accurately simulated. It has been found that the non-uniform corrosion model can be used to express the realistic corrosion rust progression around the reinforcing bar, with the best accuracy. It has also been found that some microcracks occur before they are connected to form the dominating discrete crack which usually appears on the concrete surface. Moreover, the effects of the corrosion variables, as well as other key material and geometric parameters, on surface cracking of concrete are investigated.

36 MATERIALS SCIENCE↗

Techbelt Energy Innovation Center

This project consisted of three main components 1) The primary goal of the project was to renovate and upgrade an existing commercial building to the highest possible environmentally sustainable level for the purpose of creating an energy incubator. This initiative was part of the Infrastructure Technologies Program, through which a sustainable energy demonstration facility was to be created and used as a research and community outreach base for sustainable energy product and process incubation; 2) In addition, fundamental energy related research on wind energy was performed; a shrouded wind turbine on the Youngstown State University campus was commissioned; and educational initiatives were implemented; and 3) The project also included an education and outreach component to inform and educate the public in sustainable energy production and career opportunities. Youngstown State University and the Tech Belt Energy Innovation Center (TBEIC) renovated a 37,000 square foot urban building which is now being used as a research and development hub for the region’s energy technology innovation industry. The building houses basic research facilities and business development in an incubator format. In addition, the TBEIC performs community outreach and education initiatives in advanced and sustainable energy. The building is linked to a back warehouse which will eventually be used as a build-out for energy laboratory facilities. The projects research component investigated shrouded wind turbines, and specifically the “Windcube” which was renamed the “Wind Sphere” during the course of the project. There was a specific focus on the development in the theory of shrouded wind turbines. The goal of this work was to increase the potential efficiency of wind turbines by improving the lift and drag characteristics. The work included computational modeling, scale models and full-sized design and construction of a test turbine. The full-sized turbine was built on the YSU campus as a grid-tie system that supplies the YSU research facility. Electrical power meters and weather monitors were installed to record the power generated and aid in continued study. In addition, an education/outreach component to help elicit creative engineering and design from amongst area students, faculty, entrepreneurs, and small business in the energy related fields was performed.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Small-scale test program to develop a more efficient swivel nozzle thrust deflector for V/STOL lift/cruise engines

The installed performance degradation of a swivel nozzle thrust deflector system obtained during increased vectoring angles of a large-scale test program was investigated and improved. Small-scale models were used to generate performance data for analyzing selected swivel nozzle configurations. A single-swivel nozzle design model with five different nozzle configurations and a twin-swivel nozzle design model, scaled to 0.15 size of the large-scale test hardware, were statically tested at low exhaust pressure ratios of 1.4, 1.3, 1.2, and 1.1 and vectored at four nozzle positions from 0 deg cruise through 90 deg vertical used for the VTOL mode.

Schlundt, D. W.↗