Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “ice”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Analysis of Hot-Wire Probe Ice Water Content Measurements in High Ice Water Content Conditions

During the 2022 High Ice Water Content (HIWC) Flight Campaign, ice water content (IWC) measurements were made at various locations on the NASA DC-8 Airborne Science Laboratory using the Isokinetic Probe Version 2 (IKP2), Ice Crystal Detectors (ICD), and Robust Probe. Correlations of a wing mounted ICD to IKP2 were made to determine the collision/retention efficiency of the ICD total water content (TWC) element in glaciated conditions. Similarly, correlations of a nose mounted ICD near the pitot probes were made to the IKP2 and to the wing-mounted ICD to estimate the ice concentration factor near the DC-8 pitot probes. Results from the 2022 flight campaign were compared to results from the HIWC RADAR II flight campaign in 2018. There was an apparent reduction in the ICD TWC collision/retention efficiency during the 2022 flight campaign. Although reasons for this discrepancy were explored, more analyses are needed to fully understand the causes. However, it was concluded that an estimated ice concentration factor at the nose of 2.5 was consistent between the two flight campaigns. Additionally, a correlation model was developed to relate measurements from a Nose ICD to freestream IWC as measured by the IKP2 to support IWC measurements from the 2022 Convective Processes Experiment - Cabo Verde (CPEX-CV) flight campaign.

Icing↗
NASA NTRSDate not supplied

Analysis of Hot-Wire Probe Ice Water Content Measurements in High Ice Water Content Conditions

During the 2022 High Ice Water Content (HIWC) Flight Campaign, ice water content (IWC) measurements were made at various locations on the NASA DC-8 Airborne Science Laboratory using the Isokinetic Probe Version 2 (IKP2), Ice Crystal Detectors (ICD), and Robust Probe. Correlations of a wing mounted ICD to IKP2 were made to determine the collision/retention efficiency of the ICD total water content (TWC) element in glaciated conditions. Similarly, correlations of a nose mounted ICD near the pitot probes were made to the IKP2 and to the wing-mounted ICD to estimate the ice concentration factor near the DC-8 pitot probes. Results from the 2022 flight campaign were compared to results from the HIWC RADAR II flight campaign in 2018. There was an apparent reduction in the ICD TWC collision/retention efficiency during the 2022 flight campaign. Although reasons for this discrepancy were explored, more analyses are needed to fully understand the causes. However, it was concluded that an estimated ice concentration factor at the nose of 2.5 was consistent between the two flight campaigns. Additionally, a correlation model was developed to relate measurements from a Nose ICD to freestream IWC as measured by the IKP2 to support IWC measurements from the 2022 Convective Processes Experiment - Cabo Verde (CPEX-CV) flight campaign.

Icing↗
DOE OSTI2017

Validation of sea ice models using an uncertainty-based distance metric for multiple model variables: NEW METRIC FOR SEA ICE MODEL VALIDATION

Here, we implement a variance-based distance metric (D n ) to objectively assess skill of sea ice models when multiple output variables or uncertainties in both model predictions and observations need to be considered. The metric compares observations and model data pairs on common spatial and temporal grids improving upon highly aggregated metrics (e.g., total sea ice extent or volume) by capturing the spatial character of model skill. The D n metric is a gamma-distributed statistic that is more general than the χ 2 statistic commonly used to assess model fit, which requires the assumption that the model is unbiased and can only incorporate observational error in the analysis. The D n statistic does not assume that the model is unbiased, and allows the incorporation of multiple observational data sets for the same variable and simultaneously for different variables, along with different types of variances that can characterize uncertainties in both observations and the model. This approach represents a step to establish a systematic framework for probabilistic validation of sea ice models. The methodology is also useful for model tuning by using the D n metric as a cost function and incorporating model parametric uncertainty as part of a scheme to optimize model functionality. We apply this approach to evaluate different configurations of the standalone Los Alamos sea ice model (CICE) encompassing the parametric uncertainty in the model, and to find new sets of model configurations that produce better agreement than previous configurations between model and observational estimates of sea ice concentration and thickness.

58 GEOSCIENCES↗
DOE OSTI2015

THE EFFECT OF BROADBAND SOFT X-RAYS IN SO{sub 2}-CONTAINING ICES: IMPLICATIONS ON THE PHOTOCHEMISTRY OF ICES TOWARD YOUNG STELLAR OBJECTS

We investigate the effects produced mainly by broadband soft X-rays up to 2 keV (plus fast (∼keV) photoelectrons and low-energy (∼eV) induced secondary electrons) in the ice mixtures containing H{sub 2}O:CO{sub 2}:NH{sub 3}:SO{sub 2} (10:1:1:1) at two different temperatures (50 and 90 K). The experiments are an attempt to simulate the photochemical processes induced by energetic photons in SO{sub 2}-containing ices present in cold environments in the ices surrounding young stellar objects (YSO) and in molecular clouds in the vicinity of star-forming regions, which are largely illuminated by soft X-rays. The measurements were performed using a high-vacuum portable chamber from the Laboratório de Astroquímica e Astrobiologia (LASA/UNIVAP) coupled to the spherical grating monochromator beamline at the Brazilian Synchrotron Light Source (LNLS) in Campinas, Brazil. In situ analyses were performed by a Fourier transform infrared spectrometer. Sample processing revealed the formation of several organic molecules, including nitriles, acids, and other compounds such as H{sub 2}O{sub 2}, H{sub 3}O{sup +}, SO{sub 3}, CO, and OCN{sup −}. The dissociation cross section of parental species was on the order of (2–7) × 10{sup −18} cm{sup 2}. The ice temperature does not seem to affect the stability of SO{sub 2} in the presence of X-rays. Formation cross sections of new species produced were also determined. Molecular half-lives at ices toward YSOs due to the presence of incoming soft X-rays were estimated. The low values obtained employing two different models of the radiation field of YSOs (TW Hydra and typical T-Tauri star) reinforce that soft X-rays are indeed a very efficient source of molecular dissociation in such environments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

ICE CHEMISTRY ON OUTER SOLAR SYSTEM BODIES: ELECTRON RADIOLYSIS OF N{sub 2}-, CH{sub 4}-, AND CO-CONTAINING ICES

Radiation processing of the surface ices of outer Solar System bodies may be an important process for the production of complex chemical species. The refractory materials resulting from radiation processing of known ices are thought to impart to them a red or brown color, as perceived in the visible spectral region. In this work, we analyzed the refractory materials produced from the 1.2-keV electron bombardment of low-temperature N{sub 2}-, CH{sub 4}-, and CO-containing ices (100:1:1), which simulates the radiation from the secondary electrons produced by cosmic ray bombardment of the surface ices of Pluto. Despite starting with extremely simple ices dominated by N{sub 2}, electron irradiation processing results in the production of refractory material with complex oxygen- and nitrogen-bearing organic molecules. These refractory materials were studied at room temperature using multiple analytical techniques including Fourier-transform infrared spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy, and gas chromatography coupled with mass spectrometry (GC-MS). Infrared spectra of the refractory material suggest the presence of alcohols, carboxylic acids, ketones, aldehydes, amines, and nitriles. XANES spectra of the material indicate the presence of carboxyl groups, amides, urea, and nitriles, and are thus consistent with the IR data. Atomic abundance ratios for the bulk composition of these residues from XANES analysis show that the organic residues are extremely N-rich, having ratios of N/C ∼ 0.9 and O/C ∼ 0.2. Finally, GC-MS data reveal that the residues contain urea as well as numerous carboxylic acids, some of which are of interest for prebiotic and biological chemistries.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1954

Effect of Ice Formations on Section Drag of Swept NACA 63A-009 Airfoil with Partical-span Leading-edge Slat for Various Modes of Thermal Ice Protection

Studies were made to determine the effect of ice formations on the section drag of a 6.9-foot-chord 36 degree swept NACA 63A-009 airfoil with partial-span leading-edge slat. In general, the icing of a thin swept airfoil will result in greater aerodynamic penalties than for a thick unswept airfoil. Glaze-ice formations at the leading edge of the airfoil caused large increases in section drag even at liquid-water content of 0.39 gram per cubic meter. The use of an ice-free parting strip in the stagnation region caused a negligible change in drag compared with a completely unheated airfoil. Cyclic de-icing when properly applied caused the drag to decrease almost to the bare-airfoil drag value.

PROTUBERANCES - BODIES↗
NASA NTRS2018

Icing Simulation Research Supporting the Ice-Accretion Testing of Large-Scale Swept-Wing Models

The work summarized in this report is a continuation of NASA's Large-Scale, Swept-Wing Test Articles Fabrication; Research and Test Support for NASA IRT contract (NNC10BA05 -NNC14TA36T) performed by Boeing under the NASA Research and Technology for Aerospace Propulsion Systems (RTAPS) contract. In the study conducted under RTAPS, a series of icing tests in the Icing Research Tunnel (IRT) have been conducted to characterize ice formations on large-scale swept wings representative of modern commercial transport airplanes. The outcome of that campaign was a large database of ice-accretion geometries that can be used for subsequent aerodynamic evaluation in other experimental facilities and for validation of ice-accretion prediction codes.

Aerodynamics↗
NASA NTRS2012

The Annual Glaciohydrology Cycle in the Ablation Zone of the Greenland Ice Sheet: Part 2. Observed and Modeled Ice Flow

Ice velocities observed in 2005/06 at three GPS stations along the Sermeq Avannarleq flowline, West Greenland, are used to characterize an observed annual velocity cycle. We attempt to reproduce this annual ice velocity cycle using a 1-D ice-flow model with longitudinal stresses coupled to a 1-D hydrology model that governs an empirical basal sliding rule. Seasonal basal sliding velocity is parameterized as a perturbation of prescribed winter sliding velocity that is proportional to the rate of change of glacier water storage. The coupled model reproduces the broad features of the annual basal sliding cycle observed along this flowline, namely a summer speed-up event followed by a fall slowdown event. We also evaluate the hypothesis that the observed annual velocity cycle is due to the annual calving cycle at the terminus. We demonstrate that the ice acceleration due to a catastrophic calving event takes an order of magnitude longer to reach CU/ETH ('Swiss') Camp (46km upstream of the terminus) than is observed. The seasonal acceleration observed at Swiss Camp is therefore unlikely to be the result of velocity perturbations propagated upstream via longitudinal coupling. Instead we interpret this velocity cycle to reflect the local history of glacier water balance.

ice flow↗
NASA NTRS2015

Ice Crystal Icing Engine Testing in the NASA Glenn Research Center's Propulsion Systems Laboratory (PSL): Altitude Investigation

The National Aeronautics and Space Administration conducted a full scale ice crystal icing turbofan engine test in the NASA Glenn Research Centers Propulsion Systems Laboratory (PSL) Facility in February 2013. Honeywell Engines supplied the test article, an obsolete, unmodified Lycoming ALF502-R5 turbofan engine serial number LF01 that experienced an un-commanded loss of thrust event while operating at certain high altitude ice crystal icing conditions. These known conditions were duplicated in the PSL for this testing.

Turbofan Engine Icing Testing↗
NASA NTRS2017

Plans and Preliminary Results of Fundamental Studies of Ice Crystal Icing Physics in the NASA Propulsion Systems Laboratory

This paper describes plans and preliminary results for using the NASA Propulsion Systems Lab (PSL) to experimentally study the fundamental physics of ice-crystal ice accretion. NASA is evaluating whether this facility, in addition to full-engine and motor-driven-rig tests, can be used for more fundamental ice-accretion studies that simulate the different mixed-phase icing conditions along the core flow passage of a turbo-fan engine compressor. The data from such fundamental accretion tests will be used to help develop and validate models of the accretion process. This paper presents data from some preliminary testing performed in May 2015 which examined how a mixed-phase cloud could be generated at PSL using evaporative cooling in a warmer-than-freezing environment.

Ice-Crystal Ice Accretion↗
NASA NTRS2016

Plans and Preliminary Results of Fundamental Studies of Ice Crystal Icing Physics in the NASA Propulsion Systems Laboratory

This presentation accompanies the paper titled Plans and Preliminary Results of Fundamental Studies of Ice Crystal Icing Physics in the NASA Propulsion Systems Laboratory. NASA is evaluating whether PSL, in addition to full-engine and motor-driven-rig tests, can be used for more fundamental ice-accretion studies that simulate the different mixed-phase icing conditions along the core flow passage of a turbo-fan engine compressor. The data from such fundamental accretion tests will be used to help develop and validate models of the accretion process. This presentation (and accompanying paper) presents data from some preliminary testing performed in May 2015 which examined how a mixed-phase cloud could be generated at PSL using evaporative cooling in a warmer-than-freezing environment.

Ice-Crystal Ice Accretion↗
DOE OSTI2015

Quantifying sensitivities of ice crystal number and sources of ice crystal number variability in CAM 5.1 using the adjoint of a physically based cirrus formation parameterization

Abstract We present the adjoint of a cirrus formation parameterization that computes the sensitivity of ice crystal number concentration to updraft velocity, aerosol, and ice deposition coefficient. The adjoint is driven by simulations from the National Center for Atmospheric Research Community Atmosphere Model version 5.1 CAM 5.1 to understand the sensitivity of formed ice crystal number concentration to 13 variables and quantify which contribute to its variability. Sensitivities of formed ice crystal number concentration to updraft velocity, sulfate number, and is sufficient but sulfate number concentration is low, indicating a sulfate‐limited regime. Outside of the tropics, competition between homogeneous and heterogeneous nucleation may shift annually averaged sensitivities to higher magnitudes, when infrequent strong updrafts shift crystal production away from purely heterogeneous nucleation. Outside the tropics, updraft velocity is responsible for approximately 52.70% of the ice crystal number variability. In the tropics, sulfate number concentration and updraft jointly control variability in formed crystal number concentration. Insoluble aerosol species play a secondary, but still important, role in influencing the variability in crystal concentrations, with coarse‐mode dust being the largest contributor at nearly 50% in certain regions. On a global scale, more than 95% of the temporal variability in crystal number concentration can be described by temperature, updraft velocity, sulfate number, and coarse‐mode dust number concentration.

Sheyko, B. A.↗
DOE OSTI2020

Seismic Anisotropy of Temperate Ice in Polar Ice Sheets

Here we present a series of simple shear numerical simulations of dynamic recrystallization of two-phase nonlinear viscous materials that represent temperate ice. First, we investigate the effect of the presence of water on the resulting microstructures and, second, how water influences on P wave (V p ) and fast S wave (V s ) velocities. Regardless the water percentage, all simulations evolve from a random fabric to a vertical single maximum. For a purely solid aggregate, the highest V p quickly aligns with the maximum c-axis orientation. At the same time, the maximum c-axis development reduces V s in this orientation. When water is present, the developed maximum c-axis orientation is less intense, which results in lower V p and V s . At high percentage of water, V p does not align with the maximum c-axis orientation. If the bulk modulus of ice is assumed for the water phase (i.e., implying that water is at high pressure), we find a remarkable decrease of V s while V p remains close to the value for purely solid ice. These results suggest that the decrease in V s observed at the base of the ice sheets could be explained by the presence of water at elevated pressure, which would reside in isolated pockets at grain triple junctions. Under these conditions water would not favor sliding between ice grains. However, if we consider that deformation dominates over recrystallization, water pockets get continuously stretched, allowing water films to be located at grain boundaries. This configuration would modify and even overprint the maximum c-axis-dependent orientation and the magnitude of seismic anisotropy.

58 GEOSCIENCES↗
DOE OSTI2022

Uncertainty in Reconstructing Paleo‐Elevation of the Antarctic Ice Sheet From Temperature‐Sensitive Ice Core Records

Paleotemperature reconstructions from ice cores are mixed signals of changes in climate and ice‐surface elevation. A common, temperature‐based paleoaltimetry method suggests these signals can be disentangled by comparing two proxy locations with similar climates. The difference between the records is assumed to be due to elevation, which is estimated by scaling the temperature difference by a lapse rate. We investigate the uncertainty associated with this approach using a case study of the Antarctic Ice Sheet during the Last Glacial Maximum. From an ensemble of climate simulations, we extract modeled temperatures at locations of real ice cores. We find uncertainty on the order of hundreds of meters that results from spatial heterogeneity in non‐adiabatic temperature change, which itself stems in part from elevation‐induced atmospheric circulation change. Our findings suggest that caution is needed when interpreting temperature‐based paleoaltimetry results for ice sheets.

58 GEOSCIENCES↗
DOE OSTI2023

Use of Shallow Ice Core Measurements to Evaluate and Constrain 1980–1990 Global Reanalyses of Ice Sheet Precipitation Rates

Abstract Sea‐level rise (SLR) projections by Earth System Models (ESMs) depend on ice sheet surface mass balances. Accurate, global atmosphere reanalyses would be ideal for providing equilibrated ice sheet model initial conditions in fully coupled ESM simulations. Here we present the first evaluation of 1980–1990 global reanalysis precipitation over Greenland and Antarctica that uses independent observations of net accumulation rates derived from shallow ice cores. Precipitation distributions from both the European Centre for Medium‐Range Weather Forecast's Reanalysis (ERA5) and the Modern‐Era Retrospective Analysis for Research and Applications (MERRA‐2) are highly correlated with contemporaneous co‐located net accumulation rates from Greenland ( r 2 > 0.95) and West Antarctica ( r 2 > 0.7). Three other commonly used reanalyses (WFDE5, CRUNCEP, and GSWP3) exhibit significantly weaker correlations on one or both ice sheets. Our findings imply that ESMs should use ERA5 or MERRA‐2 in data‐forced simulations to validate ice sheet model dynamics and precondition firn for SLR projections.

Schneider, Adam↗
DOE OSTI2025

Ice sculpting: An artificial spin ice Tutorial on controlling microstate and geometry for magnonics and neuromorphic computing

Artificial spin ice, arrays of strongly interacting nanomagnets, are complex magnetic systems with many emergent properties, rich microstate spaces, intrinsic physical memory, high-frequency dynamics in the GHz range, and compatibility with a broad range of measurement approaches. This Tutorial article aims to provide the foundational knowledge needed to understand, design, develop, and improve the dynamic properties of artificial spin ice. Special emphasis is placed on introducing the theory of micromagnetics, which describes the complex dynamics within these systems, along with their design, fabrication methods, and standard measurement and control techniques. The article begins with a review of the historical background, introducing the underlying physical phenomena and interactions that govern artificial spin ice. We then explore the standard experimental techniques used to prepare the microstate space of the nanomagnetic array and to characterize magnetization dynamics, both in artificial spin ice and more broadly in ferromagnetic materials. Finally, we introduce the basics of neuromorphic computing applied to the case of artificial spin ice systems with a goal to help researchers new to the field grasp these exciting new developments.

Sultana, Rawnak [Univ. of Delaware, Newark, DE (Un↗
DOE OSTI2021

Enhancing the formation of ionic defects to study the ice Ih/XI transition with molecular dynamics simulations

Ice Ih, the common form of ice in the biosphere, contains proton disorder. Its proton-ordered counterpart, ice XI, is thermodynamically stable below 72 K. However, the formation of ice XI is kinetically hindered, and experimentally it is obtained by doping with KOH. Doping creates ionic defects that promote the migration of protons and the associated change in proton configuration. In this article, we mimic the effect of doping with a bias potential that enhances the formation of ionic defects in molecular dynamics simulations. The recombination of the ions thus formed proceeds through fast migration of the hydroxide along hydrogen bond loops, providing a physical and expedite way to change the proton configuration. Here, a key ingredient of this approach is a machine learning potential trained with density functional theory data and capable of modelling molecular dissociation. We exemplify the usefulness of this idea by studying the order-disorder transition using an appropriate order parameter that distinguishes the proton environments in ice Ih and XI. We calculate the changes in free energy, enthalpy, and entropy associated with the transition. Our estimated entropy agrees with experiment within the error bars of the calculation.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗