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We report O2 broadening coefficients for rovibrational transitions in the nu3 band of ozone for temperatures between 165 and 280 K. We assumed a power-law dependence of the temperature for these coefficients, with a temperature exponent n. For the 25 transitions we measured, the average value of gamma-0 is 0.071/cm/atm and the average for n is 0.67.
Temperature effects on self diffusion coefficients of gaseous ammonia
We explored a series of highly uniform magnetic nanoparticles (MNPs) with a core-shell nanoarchitecture prepared by an efficient solvothermal approach. In our study, we focused on the water dispersion of MNPs based on two different CoFe 2 O 4 core sizes and the chemical nature of the shell (MnFe 2 O 4 and spinel iron oxide). We performed an uncommon systematic investigation of the time and temperature evolution of the adiabatic heat release at different frequencies of the alternating magnetic field (AMF). Our systematic study elucidates the nontrivial variations in the heating efficiency of core-shell MNPs concerning their structural, magnetic, and morphological properties. In addition, we identified anomalies in the temperature and frequency dependencies of the specific power absorption (SPA). We conclude that after the initial heating phase, the heat release is governed by the competition of the Brown and Néel mechanism. In addition, we demonstrated that a rational parameter sufficiently mirroring the heating ability is the mean magnetic moment per MNP. Our study, thus, paves the road to fine control of the AMF-induced heating by MNPs with fine-tuned structural, chemical, and magnetic parameters. Importantly, we claim that the nontrivial variations of the SPA with the temperature must be considered, e.g., in the emerging concept of MF-assisted catalysis, where the temperature profile influences the undergoing chemical reactions.
The coefficient for recombination of O4(+) ions with electrons has been measured as a function of Te by analyzing electron- and ion-density decays in microwave-generated afterglow plasmas in neon-oxygen mixtures. Te values in the afterglow were elevated above those of the neutral species and ions by continuous application of microwave power. The data analysis included effects on the Te arising from inelastic collisions of electrons with the minority oxygen molecules and spatial nonuniformities of Te due to the spatially nonuniform microwave heating field. Over the temperature range Te = 143-5500 K the recombination coefficients were found to have a Te exp -z dependence, with z = 0.48 + 0.1 or - 0.05. While the values of the recombination coefficients for this dimer ion are an order of magnitude larger than those of the monomer ions, the temperature dependence is close to the Te exp -0.5 dependence predicted and often observed for diatomic ions.
While high-resolution cross-correlation spectroscopy (HRCCS) techniques have proven effective at characterizing the atmospheres of transiting and nontransiting hot Jupiters, the limitations of these techniques are not well understood. We present a series of simulations of one HRCCS technique, which combines the cross-correlation functions from multiple epochs, to place temperature and contrast limits on the accessible exoplanet population for the first time. We find that planets approximately Saturn-sized and larger within ∼0.2 au of a Sun-like star are likely to be detectable with current instrumentation in the L band, a significant expansion compared with the previously studied population. Cooler (T {sub eq} ≤ 1000 K) exoplanets are more detectable than suggested by their photometric contrast alone as a result of chemical changes that increase spectroscopic contrast. The L-band CH{sub 4} spectrum of cooler exoplanets enables robust constraints on the atmospheric C/O ratio at T {sub eq} ∼ 900 K, which have proven difficult to obtain for hot Jupiters. These results suggest that the multi-epoch approach to HRCCS can detect and characterize exoplanet atmospheres throughout the inner regions of Sun-like systems with existing high-resolution spectrographs. We find that many epochs of modest signal-to-noise ratio (S/N{sub epoch} ∼ 1500) yield the clearest detections and constraints on C/O, emphasizing the need for high-precision near-infrared telluric correction with short integration times.
Nanometer size grains, solid solution strengthening, low temperatures, and a high density of nanotwins can provide significant strengthening to a material. Nevertheless, under loading the microstructure may evolve altering the effect of grain size, twin density, etc. on this strengthening. In some cases, these effects can be coupled as in detwinning, which is a mechanism for cryogenic grain growth. Here, in this work, a series of copper nanotwinned columnar grains are solid solution alloyed with aluminum and subject to ambient and cryogenic (–196 °C) environments during mechanical indentation, with the influence of alloying on the detwinning evolution studied. Under indentation, at a lower aluminum solute content (2 at.%), the columnar grains bent corresponding to a loss of twins. At a higher aluminum solute content (8 at.%), the grains shear and retain the nanotwins. Atomistic-scale simulations reveal an increase in the incoherent twin boundary velocity with decreasing temperature, but this boundary velocity is reduced with increasing alloy solute content. The coupling of solid solution strengthening and nanotwin stabilization is then used to explain the microstructural stability as a function of indentation at different temperature conditions.
Temperature effect on microyield points in prestrained magnesium single crystals
Temperature effect on microstrain points in prestrained magnesium single crystals
Temperature effects on irradiation cross linking of linear polyethylene
Temperature effects on long wavelength photon frequency and linewidth in diamond, using Raman scattering techniques
The correction for temperature response of optical radiometers implies access to their working temperature (i.e., either the internal or ambient one with the radiometers in thermal equilibrium). With specific reference to a class of widely used hyperspectral radiometers lacking a thermistor to measure the internal temperature, this work investigated the potential for operational corrections relying on the ambient temperature derived from the radiometer dark digital counts. With the objective to keep within approximately 1% the uncertainty for radiometric corrections in the 400–800-nm spectral range, findings showed the applicability of the method for ambient temperatures higher than approximately 30°C. The alternative use of an ambient temperature proxy, determined from the air temperature incremented by a few degrees Celsius, was shown a valid solution to constrain the uncertainty of radiometric corrections to within 1% over the entire 0°–40°C interval.
Frequency Domain Reflectometry (FDR) has attracted significant attention for use in nuclear power plants (NPPs) for non-destructive cable health monitoring. However, cable aging detection using FDR faces challenges due to its high sensitivity to environmental factors such as temperature, vibrations, proximity to other cables, and so on. This work aims to evaluate the influence of measurement temperature on the FDR reflected signal in a low voltage cable undergoing accelerated thermal aging. A 100 ft long multi-core low-voltage unshielded power cable insulated with flame retardant ethylene propylene rubber (FR-EPR) and covered by a chloro-polyethylene (CPE) jacket was selected for this study. The cable was energized during aging by a 480 VAC 3-phase motor, and a 30 ft mid-section of this cable was routed through an air circulating oven held at 140 °C for up to an effective aging time of 62 days. FDR measurements were taken periodically with the oven on (at 140 °C) and with the oven off (at 22 °C). A comparative analysis of data collected at both temperatures showed that the FDR response was strongly dependent on measurement temperature. FDR measurements at ambient temperature showed large peaks corresponding to impedance changes in the aged section of the cable after 3 days of aging. These peaks continued to rise steadily with increasing aging time. However, for measurements taken at 140 °C, slowly rising peaks in the oven region (aged section) were observed only after a lead time of 23 days of aging. This work highlights the importance of measurement temperature on the performance of FDR as a condition monitoring tool for aging cables.
Parallel-tempering molecular dynamics simulations reveal the temperature- and size-dependent shapes of Cu nanocrystals.
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A method and system for determining temperature are provided. The method comprises using an x-ray source to irradiate a sample of a material with x-rays. Photon fluorescence produced by the sample in response to the x-ray irradiation is detected by a number of photon detectors. Based on the detected fluorescence a temperature of the sample is determined according to a predetermined relationship between photon fluorescence and temperature for the material.
The temperature correlation of the relative coalignment between the fine-pointing sun sensor and fixed-head star trackers measured on the Solar Maximum Mission (SMM) is analyzed. An overview of the SMM, including mission history and configuration, is given. Possible causes of the misalignment variation are discussed, with focus placed on spacecraft bending due to solar-radiation pressure, electronic or mechanical changes in the sensors, uncertainty in the attitude solutions, and mounting-plate expansion and contraction due to thermal effects. Yaw misalignment variation from the temperature profile is assessed, and suggestions for spacecraft operations are presented, involving methods to incorporate flight measurements of the temperature-versus-alignment function and its variance in operational procedures and the spacecraft structure temperatures in the attitude telemetry record.
Laboratory measurements of the relative absorption cross sections of ozone at temperatures 195, 228, and 295 K have been made throughout the 185 to 254 nm wavelength region. The absolute absorption cross sections at the same temperatures have been measured at several discrete wavelengths in the 185 to 250 nm region. The absolute cross sections of ozone have been used to put the relative cross sections on a firm absolute basis throughout the 185 to 255 nm region. These recalibrated cross sections are slightly lower than those of Molina and Molina (1986), but the differences are within a few percent and would not be significant in atmospheric applications.
Time-dependent, predictive simulations were performed with the 1.5D tokamak integrated modeling code TRANSP on a large set of well-analyzed, high performing discharges from the National Spherical Torus Experiment (NSTX) in order to evaluate how well modern reduced transport models can reproduce experimentally observed temperature profiles in spherical tokamaks. Overall, it is found that simulations using the Multi-Mode Model (MMM) more consistently agree with the NSTX observations than those using the Trapped Gyro-Landau Fluid (TGLF) model, despite TGLF requiring orders of magnitude greater computational cost. When considering all examined discharges, MMM has median overpredictions of electron temperature (T e ) and ion temperature (T i ) profiles of 28% and 27%, respectively, relative to the experiment. TGLF overpredicts T e by 46%, with much larger variance than MMM, and underpredicts T i by 25%. As the ratio of kinetic to magnetic field pressure (β) is increased across NSTX discharges, TGLF predicts lower T e and significant flattening of the T i profile, conflicting with NSTX observations. When using an electrostatic version of TGLF, both T e and T i are substantially overpredicted, underscoring the importance of electromagnetic turbulence in the high β spherical tokamak regime. Additionally, calculations with neural net surrogate models for TGLF were performed outside of TRANSP with a time slice flux matching transport solver, finding better agreement with experiment than the TRANSP simulations, highlighting the impact of different transport solvers and simulation techniques. Furthermore, the reasonable agreement with experiment of temperature profiles predicted by MMM motivates a more detailed examination of the sensitivities of the TRANSP simulations with MMM to different NSTX plasma regimes in a companion paper (Lestz et al Plasma Phys. Control. Fusion 67 105030), in preparation for self-consistent, time-dependent predictive modeling of NSTX-U scenarios.