Vibrating diaphragm pressure transducer
Vibrating diaphragm transducer for pressure measurements in wind tunnels - construction, sensitivity, stability, energy losses, and cost estimate
ENERGY LOSS↗
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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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Urban heat islands can influence the wind energy resource during heatwaves
Urban wind energy is critical for sustainable electricity generation in cities. However, little research has explored how the urban heat island (UHI) effect influences wind energy, particularly in heatwaves when energy demand surges. In this study, we examine wind energy distribution in the Boston–Providence metropolitan area during heatwaves, using Weather Research and Forecasting (WRF) model integrated with Building Energy Parameterization/Building Energy Model (BEP/BEM). Two scenarios, a realistic case and a hypothetical case without urban warmth, were compared to isolate UHI impacts. Results reveal that UHI induces a "wind energy loss zone" in this urban area, reducing wind power density (WPD) by 20–30 W/m 2 at 50–100 m, while suburban/rural areas exhibit a "wind energy gain zone," with WPD increases up to 40 W/m 2 at 150–200 m. These losses diminish with distance from urban centers and become negligible beyond main urban and suburban sprawl. Heatwave expands the urban "loss zone", while amplifying wind energy gains in suburban/rural areas, driven by stronger thermal gradients and weakened background winds that intensify air convergence in urban and urban-rural circulations, thereby exacerbating urban wind energy losses by 15–20 %. An analysis of 235 wind farms using turbine power curves reveals that built areas dependent on stand-alone or off-grid turbines face significant energy deficits during a heatwave. Wind energy drops by up to 25 %, while cooling-related building energy demand rises 30–40 % during a heatwave. These findings underscore the need for strategic urban wind energy planning to ensure reliable power during extreme heat.
Energy - Wind↗
Probing molecular vibrations by monochromated electron microscopy
Chemical bonds fundamentally determine molecular properties and are prevalently characterized by various spectroscopic means such as infrared and Raman spectroscopies. However, the spatial resolution of these conventional approaches is insufficient to reveal nanoscale features. Recently, monochromated electron energy-loss spectroscopy (EELS) in the transmission electron microscope achieved a groundbreaking energy resolution of a few millielectronvolts and enabled direct observation of molecular vibrational spectrum with unmatched spatial resolution. Vibrational EELS is widely applicable to both organic and inorganic matter in the solid state or liquid phase. In this study, we introduce recent advancements and key concepts of this method, compare with other spectroscopic techniques, and discuss future developments for potential applications in research fields centered on catalysts, polymers, and live cells.
Vibrational Spectroscopy↗
A Variable Pressure Multi-Pressure Rail System Design for Agricultural Applications
This paper presents a solution for reducing energy loss in the hydraulic control system of agricultural tractors and their implements. The solution is referred to as a multi-pressure rail (MPR) and provides power to the hydraulic functions following a pressure control logic, as opposed to the traditional flow control logic typical of hydraulic systems used in off-road vehicles. The proposed hydraulic control system allows for elimination of redundant flow control valves in the state-of-the-art system, which cause excessive throttling losses leading to poor overall energy efficiency. Related work on MPR technology targets construction vehicles, where the MPR solution can allow energy recovery during overrunning loads and better engine management. This paper alternatively addresses the case of agricultural applications where functions mostly operate under resistive load conditions with slow dynamics, which offers an opportunity to target throttle losses. For this purpose, the paper introduces a variable pressure control strategy to handle the instantaneous pressure at each rail. To develop both the controller and the hydraulic system architecture, a stationary test rig is conceived and used to validate a numerical simulation model of the MPR system and its control strategy. Particular focus is given to the dynamic behavior of the system during the switches of a function between different pressure rails, which needs to ensure reduced oscillations of the flow provided to each hydraulic function. Once validated, the simulation model is used to predict the energy savings of the MPR solution in an actual application: a 435 hp hydraulic tractor powering a 16-row planter, for which operating features during typical drive cycles were available to the authors. The results show up to 59% total power reduction at the pump shaft, corresponding to 89.8% system efficiency gain.
36 MATERIALS SCIENCE↗
Thermal Stability of Quasi-1D NbS 3 Nanoribbons and Their Transformation to 2D NbS 2 : Insights from in Situ Electron Microscopy and Spectroscopy
Here in situ electron microscopy imaging and spectroscopy enabled us to study the evolution of quasi-1D NbS 3 -IV nanoribbons with respect to morphology and chemical structure at temperatures between room temperature and 1000 °C. Scanning transmission electron microscopy (STEM) experiments included imaging in the secondary electron, (transmitted) bright field, and high-angle annular dark-field modes while operating in the low kV regime. The results showed that NbS 3 -IV samples transform dramatically from smooth nanoribbons into highly textured configurations featuring polyhedral divots and steps. Similar in situ heating experiments conducted with aberration-corrected STEM revealed that bilayers of NbS 3 -IV chains convert topotactically into aligned 2H-NbS 2 sheets upon loss of sulfur. Atomic resolution imaging, fast Fourier transform analysis, and electron energy loss spectroscopy confirmed these chemical changes, from which we propose an atomistic mechanism for the NbS 3 -IV → 2H-NbS 2 conversion.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Low‐Loss Tunable Infrared Plasmons in the High‐Mobility Perovskite (Ba,La)SnO 3
Abstract BaSnO 3 exhibits the highest carrier mobility among perovskite oxides, making it ideal for oxide electronics. Collective charge carrier oscillations known as plasmons are expected to arise in this material, thus providing a tool to control the nanoscale optical field for optoelectronics applications. Here, the existence of relatively long‐lived plasmons supported by high‐mobility charge carriers in La‐doped BaSnO 3 (BLSO) is demonstrated. By exploiting the high spatial and energy resolution of electron energy‐loss spectroscopy with a focused beam in a scanning transmission electron microscope, the dispersion, confinement ratio, and damping of infrared localized surface plasmons (LSPs) in BLSO nanoparticles are systematically investigated. It is found that LSPs in BLSO exhibit a high degree of spatial confinement compared to those sustained by noble metals and have relatively low losses and high quality factors with respect to other doped oxides. Further analysis clarifies the relation between plasmon damping and carrier mobility in BLSO. The results support the use of nanostructured degenerate semiconductors for plasmonic applications in the infrared region and establish a solid alternative to more traditional plasmonic materials.
36 MATERIALS SCIENCE↗
Electronic spectrum and ultraviolet optical properties of crystalline MgO.
Magnesium oxide single crystal electronic spectrum obtained from reflectance spectra, observing large plasma peak in energy loss function
ENERGY LOSS↗
Temperature of the thermosphere
The vertical temperature contrast for the thermosphere of Titan is estimated considering heating by absorption of solar energy, energy loss through infrared radiation by polyatomic molecules, and energy transfer by thermal conduction between the regions of energy deposition and loss. Current observational data suggest a CH4/H2 mixing ratio of approximately greater than 1, and a vertical temperature contrast smaller than 10 K. However, it is highly probable that H2 and CH4 are not in equilibrium in the thermosphere if there are large H2 escape rates.
Strobel, D. L.↗
Effect of a variable stator area on performance of a single-stage turbine suitable for air cooling. 2 - Stator detailed losses with 130 percent design area
Kinetic energy loss coefficients of stator blade row in open configuration
Bider, B.↗
Minimizing Selection Bias in Inclusive Jets in Heavy-Ion Collisions with Energy Correlators
The first-ever measurement of energy correlators within inclusive jets produced in heavy-ion collisions, revealed by the CMS Collaboration, shows a clear enhancement at large angles relative to the proton-proton (p-p) baseline. However, interpreting this enhancement is complicated due to selection bias from energy loss, which also distorts the energy correlator heavy-ion to p-p ratio in the hadronization region, hindering our understanding of parton/hadron dynamics in a colored medium. In this Letter, we introduce a new ratio of energy correlator observables that removes the leading effects of selection bias from the two-point energy correlator spectrum (E2C). PYTHIA and HERWIG simulations show that the impact of selection bias in the E2C is reduced by an order of magnitude, while sensitivity to any other medium modifications is retained. This quantity can be obtained directly from the experimental measurements presented by CMS, as illustrated in an accompanying note [C. Andres and J. Holguin, arXiv:2409.07526].
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Data for "Plasmon-driven exciton formation in a non-equilibrium Fermi liquid"
This repository contains source data for key plots presented in the manuscript "Plasmon-driven exciton formation in a non-equilibrium Fermi liquid." Experimental data that was analyzed in Igor Pro 8 are presented as the .pxp files used to generate individual sub-plots. Electronic spectral function calculations are provided as .txt files, in which consecutive rows refer to the meshgrid x coordinate, y coordinate, spectral function (and, where relevant, axis-projected local angular momentum). We additionally include the Wannier model and DFT-obtained bulk band structure on which the Wannier model was based. Files are named as the number of the figure in the manuscript to which they correspond, with additional details included where necessary. Details of file names: 2a_DOS_Lxz_Ek_KGM_40layer_xnum_800kpt_tot.txt: Density of states, xz-axis projected local orbital angular momentum, for 800 points along the K-Gamma-M path, for a 40-layer model. 2c_composite_y.pxp: ARPES (angle-resolved photoemission spectroscopy) spectra along the ky axis, including both a scan near the Fermi level and a scan at high kinetic energies. 2d_LCP_RCP_diff_Sect_20K.pxp: difference between ARPES constant energy cuts at T=20 K at E0 + 0.23 eV taken with left- and right-circularly polarized photons. The polarization-integrated intensity at the constant energy cut is also included. 2e_DOS_L45_E11pt79_m0pt25to0pt25_xnum_800kpt_tot.txt: Density of states, xz-projected local orbital angular momentum, and corresponding k-points in two dimensions from ab-initio electronic structure calculations for a constant-energy cut. 3a_[x]_[y]ps: ARPES cut under excitation at a fluence of x uJ/cm2, measured y ps after photoexcitation. Measurements were performed at 9 K. 3b_[x]: Energy distribution curves under excitation at a fluence x uJ/cm2 at selected delay times after photoexcitation. 4a_ImSigma_vs_temperature.pxp: Imaginary self energy (extracted from ARPES linewidths) at different energies above E0 for selected lattice temperatures. 4b_EELS_lowE.pxp: Electron energy loss spectrum over a low energy range 5b_diff_55m15.pxp: Difference between momentum-integrated Tr-ARPES traces at 55 uJ/cm2 and 15 uJ/cm2 photoexcitation. Time-dependent intensity at each energy level has been normalized to a maximum of 1 for each individual fluence prior to subtraction. 5d_invtau_at_EX_vs_fluence.pxp: decay rate at a specified energy EX for different excitation fluences, from single exponential fits. NOTE: Analyses based on the Wannier model presented here should cite both the associated Article and this dataset. For all other files in the repository, citing the dataset alone is sufficient.
Acharya, Rishi [University of Illinois] (ORCID:000↗
Joule heating in bad and slow metals
Heat supplied to a metal is absorbed by the electrons and then transferred to the lattice. In conventional metals energy is released to the lattice by phonons emitted from the Lindhard continuum. However in a 'bad' metal, with short mean free path, the low energy Lindhard continuum is destroyed. To describe energy transfer to the lattice in these cases we obtain a general Kubo formula for the energy relaxation rate in terms of the electronic density spectral weight \text{lm} \, G^R_{nn}(\omega_{k},k) lm G n n R ( ω k , k ) evaluated on the phonon dispersion \omega_k ω k . We apply our Kubo formula to the high temperature Hubbard model, using recent data from quantum Monte Carlo and experiments in ultracold atoms to characterize \text{lm} \, G^R_{nn}(\omega_{k},k) lm G n n R ( ω k , k ) . We furthermore use recent data from electron energy-loss spectroscopy to estimate the energy relaxation rate of the cuprate strange metal to a high energy optical phonon. As a second, distinct, application of our formalism we consider 'slow' metals. These are defined to have Fermi velocity less than the sound velocity, so that particle-hole pairs are kinematically unable to emit phonons. We obtain an expression for the energy relaxation rate of a slow metal in terms of the optical conductivity.
36 MATERIALS SCIENCE↗
Radio-emitting electrons and cosmic ray confinement
Evidence from radio data obtained at frequencies of 10 to 8000 MHz for steepening of the observed background-radio-continuum spectra in the directions of the galactic Anticenter (A) and Halo Minimum (H) is used to deduce quantitative information on the variation of the magnetic field with distance from the galactic plane. The radio data are analyzed in the framework of the cosmic-ray diffusion model developed by Bulanov and Dogel (1975), and some inferences are drawn regarding the injection spectrum of cosmic-ray electrons as well as their propagation in the Galaxy. The results indicate that: (1) radio-spectrum steepening is centered around 200 MHz in the direction of H and around 330 MHz in the direction of A, implying a lower mean magnetic field toward H and supporting the existence of a radio halo; (2) an injection electron spectrum with a single power law up to the lowest energies cannot explain the radio observations satisfactorily in terms of the diffusion model; and (3) the observed spectral steepening can be satisfactorily understood as being due partly to the deviation from a power-law injection spectrum below a few GeV and partly to the first break arising from electron energy losses in approximately the same energy region.
Badhwar, G. D.↗
Coronal heating by stochastic magnetic pumping
Recent observational data cast serious doubt on the widely held view that the Sun's corona is heated by traveling waves (acoustic or magnetohydrodynamic). It is proposed that the energy responsible for heating the corona is derived from the free energy of the coronal magnetic field derived from motion of the 'feet' of magnetic field lines in the photosphere. Stochastic motion of the feet of magnetic field lines leads, on the average, to a linear increase of magnetic free energy with time. This rate of energy input is calculated for a simple model of a single thin flux tube. The model appears to agree well with observational data if the magnetic flux originates in small regions of high magnetic field strength. On combining this energy input with estimates of energy loss by radiation and of energy redistribution by thermal conduction, we obtain scaling laws for density and temperature in terms of length and coronal magnetic field strength.
Sturrock, P. A.↗
Deceleration of the solar wind in the Earth foreshock region: ISEE 2 and IMP 8 observations
The deceleration of the solar wind in the region of the interplanetary space filled by ions backstreaming from the Earth bow shock was studied using a two spacecraft technique. This deceleration, which is correlated with the "diffuse" but not with the "reflected" ion population, depends on the solar wind bulk velocity: at low velocities (below 300 km/sec) the velocity decrease is about 5 km/sec, while at higher velocities (above 400 km/sec) the decrease may be as large as 30 km/sec. Along with this deceleration, the solar wind undergoes a deflection of about 1 deg away from the direction of the Earth bow shock. The energy balance shows that the kinetic energy loss far exceeds the thermal energy which is possibly gained by the solar wind, therefore, at least part of this energy must go into waves and/or into the backstreaming ions.
Bonifazi, C.↗
Deceleration of the solar wind in the earth's foreshock region - Isee 2 and Imp 8 observations
The deceleration of the solar wind in the region of the interplanetary space filled by ions backstreaming from the earth's bow shock and associated waves is studied using a two-spacecraft technique. This deceleration depends on the solar wind bulk velocity; at low velocities (below 300 km/s) the velocity decrease is about 5 km/s, while at higher velocities (above 400 km/s) the decrease may be as large as 30 km/s. The energy balance shows that the kinetic energy loss far exceeds the thermal energy which is possibly gained by the solar wind; therefore at least part of this energy must go into waves and/or into the backstreaming ions.
Bonifazi, C.↗
Coronal heating by stochastic magnetic pumping
Recent observational data cast serious doubt on the widely held view that the sun's corona is heated by traveling waves (acoustic or magnetohydrodynamic). It is here proposed that the energy responsible for heating the corona is derived from the free energy of the coronal magnetic field derived from motion of the 'feet' of magnetic field lines in the photosphere. Stochastic motion of the feet of magnetic field lines leads, on the average, to a linear increase of magnetic free energy with time. This rate of energy input is calculated for a simple model of a single thin flux tube. The model appears to agree well with observational data if the magnetic flux originates in small regions of high magnetic field strength as proposed by Tarbell et al. (1979). On combining this energy input with estimates of energy loss by radiation and of energy redistribution by thermal conduction, scaling laws are obtained for density and temperature in terms of length and coronal magnetic field strength.
Sturrock, P. A.↗
A brief outline of the development of cosmic ray modulation theory.
Cosmic ray modulation by solar wind fields noting transit time, energy loss and time variations
SOLAR WIND↗