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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 1,315 records · Page 73
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Higgs to b b ¯ from vector boson fusion for high-scale physics

Vector boson fusion is arguably the most direct collider probe of electroweak symmetry breaking. Typically, the signature includes two forward/backward jets with low transverse momenta with a scale that is set by the mass of the vector boson. For this reason, an upper cut is used when searching for vector boson fusion processes in the Standard Model. Alternatively, the upper cut on the forward jets can be removed and the high-momentum exchange region of vector boson fusion can be studied. This phase space region has sensitivity to new physics via higher dimensional operators and form factors. In this work, we study the high-momentum region of the vector boson fusion channel where the Higgs decays to b b ¯ . We show that, depending on the form of new physics, the limits on the new physics scale range from 0.5 to 1.8 TeV. Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2021

Regulatory Implications of Embedded Grid Energy Storage

Electricity is unique among commodities in that its supply chain was developed without a storage component. Every other resource commodity has the ability to store excess quantities built into its supply chain – in the form of granaries, warehouses, reservoirs, etc. This embedded storage creates a buffer for mismatches between supply and demand, stabilizing prices and protecting customers. Recent technological advances in cost-competitive energy storage technologies that are scalable and flexible have made the concept of embedded electrical storage feasible, but several regulatory questions remain. This paper summarizes energy regulatory structures in the U.S. and the implications that they would have for embedded storage on the electric grid. Regulatory challenges for embedded storage include the lack of underlying standards, inclusion in planning processes, ownership models, compensation, and metrics. Two possible pathways forward are explored: an incremental one including regulatory guidance regarding the evaluation of embedded storage in existing planning processes, and a complex one involving the revision of existing reliability standards or the development of a new standard specific to embedded storage.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2022

Adapting Technology Learning Curves for Prospective Techno-Economic and Life Cycle Assessments of Emerging Carbon Capture and Utilization Pathways

Comparisons of emerging carbon capture and utilization (CCU) technologies with equivalent incumbent technologies are necessary to support technology developers and to help policy-makers design appropriate long-term incentives to mitigate climate change through the deployment of CCU. In particular, early-stage CCU technologies must prove their economic viability and environmental reduction potential compared to already-deployed technologies. These comparisons can be misleading, as emerging technologies typically experience a drastic increase in performance and decrease in cost and greenhouse gas emissions as they develop from research to mass-market deployment due to various forms of learning. These changes complicate the interpretation of early techno-economic assessments (TEAs) and life cycle assessments (LCAs) of emerging CCU technologies. The effects of learning over time or cumulative production themselves can be quantitatively described using technology learning curves (TLCs). While learning curve approaches have been developed for various technologies, a harmonized methodology for using TLCs in TEA and LCA for CCU in particular is required. To address this, we describe a methodology that incorporates TLCs into TEA and LCA to forecast the environmental and economic performance of emerging CCU technologies. This methodology is based on both an evaluation of the state of the art of learning curve assessment and a literature review of TLC approaches developed in various manufacturing and energy generation sectors. Additionally, we demonstrate how to implement this methodology using a case study on a CO 2 mineralization pathway. Finally, commentary is provided on how researchers, technology developers, and LCA and TEA practitioners can advance the use of TLCs to allow for consistent, high-resolution modeling of technological learning for CCU going forward and enable holistic assessments and fairer comparisons with other climate technologies.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS1973

A new electric field effect in silicon solar cells.

The phenomenon of high-resistivity silicon solar cells manifesting high open-circuit voltages previously observed only for cells made from low-resistivity silicon is shown to be caused by the presence of a shallow diffused region at the back surface of the cell. The basic cell structure is either n+, p, p+ or p+, n, n+. The high open-circuit voltage arises from the injection and accumulation of excess majority carriers in the bulk upon illumination or application of forward bias to the structure. A working model for the cell, designated a back surface field (BSF) cell, is described, and recent developments are cited.

Mandelkorn, J.↗
NASA NTRS1974

Externally blown flap noise research

The Lewis Research Center cold-flow model externally blown flap (EBF) noise research test program is summarized. Both engine under-the-wing and over-the-wing EBF wing section configurations were studied. Ten large scale and nineteen small scale EBF models were tested. A limited number of forward airspeed effect and flap noise suppression tests were also run. The key results and conclusions drawn from the flap noise tests are summarized and discussed.

Dorsch, R. G.↗
NASA NTRS1974

Externally blown flap noise research

The Lewis Research Center cold-flow model externally blown flap (EBF) noise research test program is summarized. Both engine under-the-wing and over-the-wing EBF wing section configurations were studied. Ten large scale and nineteen small scale EBF models were tested. A limited number of forward airspeed effect and flap noise suppression tests were also run. The key results and conclusions drawn from the flap noise tests are summarized and discussed.

Dorsch, R. G.↗
NASA NTRS1976

Thermal analyses of the International Ultraviolet Explorer (IUE) scientific instrument using the NASTRAN thermal analyzer (NTA): A general purpose summary

The NTA Level 15.5.2/3, was used to provide non-linear steady-state (NLSS) and non-linear transient (NLTR) thermal predictions for the International Ultraviolet Explorer (IUE) Scientific Instrument (SI). NASTRAN structural models were used as the basis for the thermal models, which were produced by a straight forward conversion procedure. The accuracy of this technique was sub-sequently demonstrated by a comparison of NTA predicts with the results of a thermal vacuum test of the IUE Engineering Test Unit (ETU). Completion of these tasks was aided by the use of NTA subroutines.

Jackson, C. E., Jr.↗
NASA NTRS1977

Load and stability measurements on a soft-inplane rotor system incorporating elastomeric lead-lag dampers

An experimental investigation was conducted of the dynamic response and inplane stability associated with a new soft-inplane helicopter rotor. The unique feature of this rotor was the use of an internal elastomeric damper to restrain the blade inplane motion about the lead-lag hinge. The properties of the elastomer were selected to provide both a nominal first inplane frequency ratio of 0.65 and sufficient damping to eliminate the need for additional external damping sources to prevent ground resonance on a typical fuselage structure. For this investigation a 1/5-scale aeroelastic model was used to represent the rotor. The four-blade model had a diameter of 3.05 m (10 ft) and a solidity of 0.103. The first out-of-plane frequency ratio was 1.06. The model was tested in hover and in forward flight up to an advance ratio of 0.45. At each forward speed the rotor lift was varied up to simulated maneuver conditions. The measured rotor loads and response were within acceptable limits, and no adverse response qualities were observed. Moderate out-of-plane hub moments were measured, even for zero lift, to indicate the beneficial control power available for this design. Blade inplane stability testing indicated that the rotor system damping remained at moderate levels throughout the operating envelope.

Weller, W. H.↗
NASA NTRS1979

Low-speed wind-tunnel investigation of a large-scale VTOL lift-fan transport model

An investigation was conducted in the NASA-Ames 40 by 80 Foot Wind Tunnel to determine the aerodynamic characteristics of a large scale, VTOL, lift fan, jet transport model. The model had two lift fans at the forward portion of the fuselage, a lift fan at each wing tip, and two lift/cruise fans at the aft portion of the fuselage. All fans were driven by tip turbines using T-58 gas generators. Results were obtained for several lift fan, exit vane deflections and lift/cruise fan thrust deflections are zero sideslip. Three component longitudinal data are presented at several fan tip speed ratios. A limited amount of six component data were obtained with asymmetric vane settings. All of the data were obtained without a horizontal tail. Downwash angles at a typical tail location are also presented.

Aoyagi, K.↗
NASA NTRS1979

Wind-tunnel investigation of highly maneuverable supersonic V/STOL fighter

Results from the initial wind-tunnel test of a large-scale, highly maneuverable supersonic V/STOL fighter model in the Ames 40- by 80-foot wind tunnel are summarized. The STOL configuration which was tested combined upper surface blowing and spanwise blowing to improve the lift characteristics over a wide angle-of-attack range. A close-coupled canard was added to this configuration to create a highly maneuverable STOL aircraft. The 7.28 m (24 ft) span model was powered by two J-97 turbojet engines, each producing 9340 N (2200 lb) thrust at a pressure ratio of 2. With the nozzle flap and aileron set at 30 deg, the model produced lift coefficients greater than 4. The model was longitudinally unstable because of the forward canard position and because of the large body area of fuselage, strake, and nacelles forward of the center of gravity.

Falarski, M. D.↗
NASA NTRS1982

Dissipation of ionospheric irregularities by wave-particle and collisional interactions

The nonlinear dissipation of plasma irregularities aligned parallel to an ambient magnetic field is studied numerically using a model which employs both wave-particle and collisional diffusion. A wave-particle diffusion coefficient derived from a local theory of the universal drift instability is used. This coefficient is effective in regions of nonzero plasma gradients and produces triangular-shaped irregularities with spectra which vary as f to the -4th, where f is the spatial frequency. Collisional diffusion acts rapidly on the vertices of the irregularities to reduce their amplitude. The simultaneous action of the two dissipative processes is more efficient than collisions acting alone. In this model, wave-particle diffusion mimics the forward cascade process of wave-wave coupling.

Bernhardt, P. A.↗
NASA NTRS1982

Flight service evaluation of composite components on the Bell Helicopter model 206L: Design, fabrication and testing

The design, fabrication, and testing phases of a program to obtain long term flight service experience on representative helicopter airframe structural components operating in typical commercial environments are described. The aircraft chosen is the Bell Helicopter Model 206L. The structural components are the forward fairing, litter door, baggage door, and vertical fin. The advanced composite components were designed to replace the production parts in the field and were certified by the FAA to be operable through the full flight envelope of the 206L. A description of the fabrication process that was used for each of the components is given. Static failing load tests on all components were done. In addition fatigue tests were run on four specimens that simulated the attachment of the vertical fin to the helicopter's tail boom.

Zinberg, H.↗
NASA NTRS1984

Exploratory investigation of the aerodynamic characteristics of a biwing vehicle at Mach 20.3

Longitudinal and lateral-directional characteristics of a simple biwing configuration were determined over an angle-of-attack range from -3 deg to 50 deg. The body was comprised of a cylindrical section with an ogival forebody having an overall fineness ratio of 6.67. The delta wings had a 38.3 deg sweep angle and were geometrically similar in planform. The upper wing was located slightly forward relative to the lower wing. The model was tested in upright and inverted orientations including component buildups. This investigation was conducted in the 22-inch aerodynamics leg of the Langley Hypersonic Helium Tunnel Facility.

Bernot, P. T.↗
NASA NTRS1982

Evaluation of SRB phenolic TPS material made by an alternate vendor

Tests conducted to evaluate the adequacy of solid rocket booster (SRB) phenolic thermal protection system (TPS) material supplied by an alternate vendor chosen by United Space Boosters, Inc. (USBI), to replace the current phenolic TPS sections used thus far on the first four Shuttle flights. The phenolic TPS is applied mainly to the attach and kick rings of the solid rocket booster (SRB). Full-scale sectional models of both the attach and kick ring structure were made up with 0.0265 in. thick stainless steel thin skin covers with thermocouples on them to determine the heating rates. Such models were made up for both the forward and rear faces of the kick ring which has a different configuration on each side. The thin skins were replaced with the alternate phenolic TPS sections cut from flight hardware configuration phenolic parts as supplied by the new vendor. Two tests were performed for each configuration of the attach and kick rings and the samples were exposed to the flow for a duration that gave a heat load equivalent to that obtained in the series of runs made for the current line of phenolic TPS. The samples performed very well with no loss of any phenolic layers. The post-test samples looked better than those used to verify the current phenolic TPS.

Karu, Z. S.↗
NASA NTRS1987

An experimental and analytical investigation of stall effects on flap-lag stability in forward flight

Experiments have been performed with a 1.62 m diameter hingeless rotor in a wind tunnel to investigate flap-lag stability of isolated rotors in forward flight. The three-bladed rotor model closely approaches the simple theoretical concept of a hingeless rotor as a set of rigid, articulated flap-lag blades with offset and spring restrained flap and lag hinges. Lag regressing mode stability data was obtained for advance ratios as high as 0.55 for various combinations of collective pitch and shaft angle. The prediction includes quasi-steady stall effects on rotor trim and Floquet stability analyses. Correlation between data and prediction is presented and is compared with that of an earlier study based on a linear theory without stall effects. While the results with stall effects show marked differences from the linear theory results, the stall theory still falls short of adequate agreement with the experimental data.

Nagabhushanam, J.↗
NASA NTRS1989

Transonic aeroelasticity analysis for rotor blades

A numerical method is presented for calculating the unsteady transonic rotor flow with aeroelasticity effects. The blade structural dynamic equations based on beam theory were formulated by FEM and were solved in the time domain, instead of the frequency domain. For different combinations of precone, droop, and pitch, the correlations are very good in the first three flapping modes and the first twisting mode. However, the predicted frequencies are too high for the first lagging mode at high rotational speeds. This new structure code has been coupled into a transonic rotor flow code, TFAR2, to demonstrate the capability of treating elastic blades in transonic rotor flow calculations. The flow fields for a model-scale rotor in both hover and forward flight are calculated. Results show that the blade elasticity significantly affects the flow characteristics in forward flight.

Chow, Chuen-Yen↗
NASA NTRS1993

Detection of bearing failure in mechanical devices using neural networks

We present a novel time-domain method for the detection of faulty bearings that has direct applicability to monitoring the health of the turbo pumps on the Space Shuttle Main Engine. A feed-forward neural network was trained to detect modelled roller bearing faults on the basis of the periodicity of impact pulse trains. The network's performance was dependent upon the number of pulses in the network's input window and the signal-to-noise ratio of the input signal. To test the model's validity, we fit the model's parameters to an actual vibration signal generated by a faulty roller element bearing and applied the network trained on this model to detect faults in actual vibration data. When this network was tested on the actual vibration data, it correctly identified the vibration signal as a fault condition 76 percent of the time.

Burne, Richard A.↗