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DOE OSTI2021

Control approach for power modulation of end-use loads

Methods, apparatus, and systems are disclosed herein for power modulation control of power grids using end-use loads. At the beginning of a coordination period typically lasting a few minutes, a population of end-use loads (water heaters, air conditioners, plug-in electric vehicles, etc.) is interrogated for their willingness to participate in power modulation by undergoing state transitions from on to off, or off to on. Distribution system flexibilities are calculated from the sums of device powers within distribution systems. Area flexibilities are calculated from the sums of device powers within areas. Thresholds for various devices to change state in response to inter-area oscillation damping or frequency regulation are derived from these flexibilities. Two power functions are monitored in real-time and compared with the device thresholds to trigger state changes which then remain locked throughout the remainder of the coordination period, then the devices are released from the lockout state.

Lian, Jianming↗

DOE OSTI2021

Rapid measurement of RH-dependent aerosol hygroscopic growth using a humidity-controlled fast integrated mobility spectrometer (HFIMS)

Abstract. The ability of aerosol particles to uptake water (hygroscopic growth) is an important determinant of aerosol optical properties and radiative effects. Aerosol hygroscopic growth is traditionally measured by humidified tandem differential mobility analyzers (HTDMA), in which size-selected dry particles are exposed to elevated relative humidity (RH), and the size distribution of humidified particles is subsequently measured using a scanning mobility particle sizer. As a scanning mobility particle sizer can measure only one particle size at a time, HTDMA measurements are time consuming, and ambient measurements are often limited to a single RH level. Pinterich et al. (2017b) showed that fast measurements of aerosol hygroscopic growth are possible using a humidity-controlled fast integrated mobility spectrometer (HFIMS). In HFIMS, the size distribution of humidified particles is rapidly captured by a water-based fast integrated mobility spectrometer (WFIMS), leading to a factor of ∼10 increase in measurement time resolution. In this study we present a prototype HFIMS that extends fast hygroscopic growth measurements to a wide range of atmospherically relevant RH values, allowing for more comprehensive characterizations of aerosol hygroscopic growth. A dual-channel humidifier consisting of two humidity conditioners in parallel is employed such that aerosol RH can be quickly stepped among different RH levels by sampling from alternating conditioners. The measurement sequence is also optimized to minimize the transition time between different particle sizes. The HFIMS is capable of measuring aerosol hygroscopic growth of six particle diameters under five RH levels ranging from 20 % to 85 % (30 separate measurements) every 25 min. The performance of this HFIMS is characterized and validated using laboratory-generated ammonium sulfate aerosol standards. Measurements of ambient aerosols are shown to demonstrate the capability of HFIMS to capture the rapid evolution of aerosol hygroscopic growth and its dependence on both size and RH.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS1989

Sequentially evaporated thin Y-Ba-Co-O superconducting films on microwave substrates

The development of high T sub c superconducting thin films on various microwave substrates is of major interest in space electronic systems. Thin films of YBa2Cu3O(7-Delta) were formed on SrTiO3, MgO, ZrO2 coated Al2O3, and LaAlO3 substrates by multi-layer sequential evaporation and subsequent annealing in oxygen. The technique allows controlled deposition of Cu, BaF2 and Y layers, as well as the ZrO buffer layers, to achieve reproducibility for microwave circuit fabrication. The three layer structure of Cu/BaF2/Y is repeated a minimum of four times. The films were annealed in an ambient of oxygen bubbled through water at temperatures between 850 C and 900 C followed by slow cooling (-2 C/minute) to 450 C, a low temperature anneal, and slow cooling to room temperature. Annealing times ranged from 15 minutes to 5 hrs. at high temperature and 0 to 6 hr. at 450 C. Silver contacts for four probe electrical measurements were formed by evaporation followed with an anneal at 500 C. The films were characterized by resistance-temperature measurements, energy dispersive X-ray spectroscopy, X-ray diffraction, and scanning electron microscopy. Critical transition temperatures ranged from 30 K to 87 K as a function of the substrate, composition of the film, thicknesses of the layers, and annealing conditions. Microwave ring resonator circuits were also patterned on these MgO and LaAlO3 substrates.

Valco, G. J.↗

NASA NTRS2017

The Transiting Exocomets in the HD 172555 System

The Earth is thought to have formed dry, in a part of the Solar Nebula deficient in organic material, and to have acquired its organics and water through bombardment by minor bodies. Observations of this process in well-dated systems can provide insight into the probable origin and composition of the bombarding parent bodies. Transiting cometary activity has previously been reported in Ca II for the late-A member of the 241 Myr old Pictoris Moving Group member, HD 172555(Kiefer et al. 2014). We present HST STIS and COS spectra of HD 172555 demonstrating that the star has chromospheric emission and variable in falling gas features in transitions of silicon and carbon ions at times when no Fe II absorption is seen in the UV data, and no Ca II absorption is seen in contemporary optical spectra. The lack of CO absorption and stable gas absorption at the system velocity is consistent with the absence of a cold Kuiper belt analog (Riviere-Marichalar et al. 2012) in this system. The presence of infall in some species at one epoch and others at different epochs suggests that, like Pictoris, there may be more than one family of exocomets. If perturbed into star-grazing orbits by the same mechanism as for Pic, these data suggest that the wide planet frequency among A-early F stars in the PMG is at least 37.5, well above the frequency estimated for young moving groups independent of host star spectral type.

Pictoris Moving Group↗

DOE OSTI2022

Near-Quantitative Predictions of the First-Shell Coordination Structure of Hydrated First-Row Transition Metal Ions Using K-Edge X-ray Absorption Near-Edge Spectroscopy

Understanding the solvation structure of transition metal ions is important due to its broad impact on the kinetics, stability, and reactivity in a variety of applications in geochemistry, biochemistry, energy storage, and environmental chemistry. Using water as the common ligand, we study the X-ray absorption pre-edge and near-edge spectra at the K-edge of a near-complete series of hydrated first-row transition metal ions with d-orbital occupancy ranging from d 2 to d 10 . Starting with optimized structures that were derived from an explicit solvation treatment at the density functional theory (DFT) level, we then compute the pre-edge X-ray absorption spectra at the metal ion K-edge at the time dependent density functional theory (TDDFT) and restricted active-space second-order perturbation theory (RASPT2) levels of theory. TDDFT calculations provide accurate results for spectra that are dominated by single excitations, while significant improvements were obtained with RASPT2 calculations that correctly distinguish between singly and doubly excited states, where relevant, with quantitative accuracy compared with experiment. We analyze and assign the dierent pre-edge features for each metal ion in order to reveal the impact of the variations in the d orbital occupancy on the rst-shell coordination environment. For completeness, we also report the lowest energy ligand-field d-d transitions for all the transition metal aqua ions considered in this study using complete active space second order perturbation theory (CASPT2).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS2013

Infrared Transmission Spectroscopy of the Exoplanets HD 209458b and XO-1b Using the Wide Field Camera-3 on the Hubble Space Telescope

Exoplanetary transmission spectroscopy in the near-infrared using the Hubble Space Telescope (HST) NICMOS (Near Infrared Camera and Multi-Object Spectrometer) is currently ambiguous because different observational groups claim different results from the same data, depending on their analysis methodologies. Spatial scanning with HST/WFC3 (Wide Field Camera-3) provides an opportunity to resolve this ambiguity.We here report WFC3 spectroscopy of the giant planets HD 209458b and XO-1b in transit, using spatial scanning mode for maximum photon-collecting efficiency. We introduce an analysis technique that derives the exoplanetary transmission spectrum without the necessity of explicitly decorrelating instrumental effects, and achieves nearly photon-limited precision even at the high flux levels collected in spatial scan mode. Our errors are within 6 percent (XO-1) and 26 percent (HD 209458b) of the photon-limit at a resolving power of lambda divided by delta times lambda approximating 70, and are better than 0.01 percent per spectral channel. Both planets exhibit water absorption of approximately 200 ppm at the water peak near 1.38 m. Our result for XO-1b contradicts the much larger absorption derived from NICMOS spectroscopy. The weak water absorption we measure for HD209458b is reminiscent of the weakness of sodium absorption in the first transmission spectroscopy of an exoplanet atmosphere by Charbonneau et al. Model atmospheres having uniformly distributed extra opacity of 0.012 square centimeters per gram account approximately for both our water measurement and the sodium absorption. Our results for HD 209458b support the picture advocated by Pont et al. in which weak molecular absorptions are superposed on a transmission spectrum that is dominated by continuous opacity due to haze and or dust. However,the extra opacity needed for HD 209458b is grayer than for HD 189733b, with a weaker Rayleigh component.

planetary systems↗

DOE OSTI2024

Solar enhanced oxygen evolution reaction with transition metal telluride

The photo-enhanced electrocatalytic method of oxygen evolution reaction (OER) shows promise for enhancing the effectiveness of clear energy generation through water splitting by using renewable and sustainable source of energy. However, despite benefits of photoelectrocatalytic (PEC) water splitting, its uses are constrained by its low efficiency as a result of charge carrier recombination, a large overpotential, and sluggish reaction kinetics. Here, we illustrate that Nickel telluride (NiTe) synthesized by hydrothermal methods can function as an extremely effective photo-coupled electrochemical oxygen evolution reaction (POER) catalyst. In this study, NiTe was synthesized by hydrothermal method at 145°C within just an hour of reaction time. In dark conditions, the NiTe deposited on carbon cloth substrate shows a small oxygen evolution reaction overpotential (261 mV) at a current density of 10 mA cm –2 , a reduced Tafel slope (65.4 mV dec -1 ), and negligible activity decay after 12 h of chronoamperometry. By virtue of its enhanced photo response, excellent light harvesting ability, and increased interfacial kinetics of charge separation, the NiTe electrode under simulated solar illumination displays exceptional photoelectrochemical performance exhibiting overpotential of 165 mV at current density of 10 mA cm -2 , which is about 96 mV less than on dark conditions. In addition, Density Functional Theory investigations have been carried out on the NiTe surface, the results of which demonstrated a greater adsorption energy for intermediate -OH on the catalyst site. Since the -OH adsorption on the catalyst site correlates to catalyst activation, it indicates the facile electrocatalytic activity of NiTe owing to favorable catalyst activation. DFT calculations also revealed the facile charge density redistribution following intermediate -OH adsorption on the NiTe surface. This work demonstrates that arrays of NiTe elongated nanostructure are a promising option for both electrochemical and photoelectrocatalytic water oxidation and offers broad suggestions for developing effective PEC devices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Assessment of Precipitating Marine Stratocumulus Clouds in the E3SMv1 Atmosphere Model: A Case Study from the ARM MAGIC Field Campaign

This paper presents a process-oriented evaluation of precipitating stratocumulus and its transition to cumulus in version 1 of the Energy Exascale Earth System Model (E3SMv1) using comprehensive case-study observations from a field campaign of the Atmospheric Radiation Measurement program (ARM). The E3SMv1 single-column model (SCM) of the marine boundary layer and its low clouds and precipitation are compared to observations including subcloud drizzle retrievals from a combination of Doppler radar and lidar backscatter measurements. Additionally, the SCM is also compared to a large-eddy simulation (LES) of the same case. The combination of advanced remote sensing observations and LES is a powerful framework to evaluate the physical parameterizations of large-scale models. Given the observed large-scale environment, the E3SMv1 SCM realistically represents the evolution of clouds and boundary layer structure during the stratocumulus-to-cumulus transition. The model well simulates the liquid water path and its diurnal cycle in the stratocumulus period as well as the two-layer vertical thermodynamic structure and lower cloud fraction in the transition period. E3SMv1’s success in simulating the cloud in the stratocumulus period permitted examination of its precipitation processes. Here problems were identified with E3SMv1 producing an unrealistically small subcloud precipitation fraction, an unrealistic double peak in the vertical profiles of precipitation mass, and drizzle that evaporates too close to the surface. Further model diagnostics determined that these unrealistic characteristics resulted from an overly long microphysics time step and an unrealistic parameterization of the precipitation fraction. These results imply that careful consideration of these issues is needed in order to better simulate precipitation processes in marine stratocumulus.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2022

Decline in Seasonal Snow during a Projected 20-Year Dry Spell

Snowpack loss in midlatitude mountains is ubiquitously projected by Earth system models, though the magnitudes, persistence, and time horizons of decline vary. Using daily downscaled hydroclimate and snow projections, we examine changes in snow seasonality across the U.S. Pacific Southwest region during a simulated severe 20-year dry spell in the 21st century (2051–2070) developed as part of the 4th California Climate Change Assessment to provide a “stress test” for water resources. Across California’s mountains, substantial declines (30–100% loss) in median peak annual snow water equivalent accompany changes in snow seasonality throughout the region compared to the historic period. We find that 80% of historic seasonal snowpacks transition to ephemeral conditions. Subsetting empirical-statistical wildfire projections for California by snow seasonality transition regions indicates a two-to-four-fold increase in the area burned, consistent with recent observations of high elevation wildfires following extended drought conditions. By analyzing six of the major California snow-fed river systems, we demonstrate snowpack reductions and seasonality transitions result in concomitant declines in annual runoff (47–58% of historical values). The negative impacts to statewide water supply reliability by the projected dry spell will likely be magnified by changes in snowpack seasonality and increased wildfire activity.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2024

EPCAPE-PT-LANL Measurements: Gas Monitors

Coastal cities offer a unique environment for studying aerosol-cloud interactions and the effects of urban emissions on cloud properties. As part of the Eastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE), the Partitioning Thrust by Los Alamos National Laboratory (EPCAPE-PT-LANL) was conducted. Our campaign focused on measuring the optical and chemical properties of aerosols and their interactions within marine stratocumulus clouds in La Jolla, California. EPCAPE-PT-LANL enhances the primary goals of EPCAPE through innovative observations of vapor-phase transitions between aerosols and cloud droplets, the impact of black carbon on aerosol-cloud dynamics, and the effects of cloud processing on aerosol optical properties. Instrument: G2401 Gas Concentration Analyzer (Picarro) Data Notes: The Picarro G2401 gas concentration analyzer provides simultaneous, precise measurement of carbon monoxide (CO), carbon dioxide (CO2), methane (CH4) at parts-per-billion (ppb), and water (H2O) vapor at parts per-million (ppm) sensitivity with negligible drift for atmospheric science, air quality, and emissions quantification. Header: - CO[ppm]: Concentration of carbon monoxide (CO) measured at the time of sampling, expressed in parts per million (ppm). - CO2[ppm]: Concentration of carbon dioxide (CO2) measured at the time of sampling, expressed in parts per million (ppm). - CH4[ppm]: Concentration of methane (CH4) measured at the time of sampling, expressed in parts per million (ppm). - H2O[%]: Water vapor content in the air at the time of the measurement, expressed as a percentage

54 ENVIRONMENTAL SCIENCES↗

NASA NTRSDate not supplied

Florida Water Resources: Assessing Coastal Resiliency Across Florida's Aquatic Preserves Response To Hurricane Forces

Intensifying weather events, sea level rise, and extensive coastal development in Southwestern Florida are escalating the need for Florida’s mangrove conservation. These mangroves are imperative for coastline stabilization, habitat provision for native species, and water quality management. Our partner, the Florida Department of Environmental Protection (FDEP), Office of Resilience and Coastal Protection is tasked with monitoring and conserving the Charlotte Harbor, Estero Bay, Rookery Bay, and Pinellas County Aquatic Preserves. We developed the Growth, Resilience, and Optical Vegetation Evaluator (GROVE) Google Earth Engine toolset for partners to determine mangrove forest extent through time, analyze mangrove forest health, and collect several water quality parameters within the preserves from January 2002–August 2022. The toolset provides easily accessible data from Landsat 7 Enhanced Thematic Mapper Plus (ETM+), Landsat 8 Operational Land Imager (OLI), Landsat 9 Operational Land Imager 2 (OLI-2), and the Shuttle Radar Topography Mission (SRTM). Using training datasets of known mangrove forest locations, we also established a machine learning approach to create mangrove extent maps. Maps from all four preserves indicated migration of mangrove forests inland as the greatest areas of change were transitional zones. Additionally, normalized difference vegetation index (NDVI), normalized difference turbidity index (NDTI), and chlorophyll-a maps were generated for the partners. This project provides decision makers with a useful tool for understanding temporal changes in Florida’s aquatic preserves, identifying areas of ecological stress, and providing actionable data to make informed plans for mangrove preservation.

Samuel Perrello↗

NASA NTRS2022

Florida Water Resources: Assessing Coastal Resiliency Across Florida's Aquatic Preserves in Response to Hurricane Forces

Remote sensing↗

NASA NTRS2020

Direct Numerical Simulation of Fog Formation Within the Surface Layer

We investigate the effects of shear-driven turbulence on fog formation in the stably stratified surface layer, using recent direct numerical simulations (DNS) of dry and moist open-channel flows. A constant cooling rate applied at the ground mimics longwave radiative cooling, leading to either turbulent (weakly stable) or laminar (very stable) flows. The transition of the Obukhov, Ozmidov and buoyancy length scales are investigated for different cooling rates and Reynolds numbers. Compared to the dry case, the condensation of liquid water in the moist case supports slightly higher cooling rates before leading to turbulence collapse. In the very stable moist cases, runaway cooling leads to substantial condensation of liquid water close to the ground and fog (visibility less than 1 km) results over much of the domain. In the weakly stable cases, turbulent mixing narrowly yields visibilities of 1 km close to the ground over a similar time period. Despite the idealised nature of the system, the present results suggest that turbulence impedes, although will not necessarily inhibit, fog formation.

Teixeira, Joao↗

NASA NTRS2005

Measurement of hydraulic characteristics of porous media used to grow plants in microgravity

Understanding the effect of gravity on hydraulic properties of plant growth medium is essential for growing plants in space. The suitability of existing models to simulate hydraulic properties of porous medium is uncertain due to limited understanding of fundamental mechanisms controlling water and air transport in microgravity. The objective of this research was to characterize saturated and unsaturated hydraulic conductivity (K) of two particle-size distributions of baked ceramic aggregate using direct measurement techniques compatible with microgravity. Steady state (Method A) and instantaneous profile measurement (Method B) methods for K were used in a single experimental unit with horizontal flow through thin sections of porous medium providing an earth-based analog to microgravity. Comparison between methods was conducted using a crossover experimental design compatible with limited resources of space flight. Satiated (natural saturation) K ranged from 0.09 to 0.12 cm s-1 and 0.5 to >1 cm s-1 for 0.25- to 1- and 1- to 2-mm media, respectively. The K at the interaggregate/intraaggregate transition was approximately 10(-4) cm s-1 for both particle-size distributions. Significant differences in log(10)K due to method and porous medium were less than one order of magnitude and were attributed to variability in air entrapment. The van Genuchten/Mualem parametric models provided an adequate prediction of K of the interaggregate pore space, using residual water content for that pore space. The instantaneous profile method covers the range of water contents relevant to plant growth using fewer resources than Method A, all advantages for space flight where mass, volume, and astronaut time are limited.

NASA Center JSC↗

DOE OSTI2023

A High-Entropy Oxide as High-Activity Electrocatalyst for Water Oxidation

High-entropy materials are an emerging pathway in the development of high-activity (electro)catalysts because of the inherent tunability and coexistence of multiple potential active sites, which may lead to earth-abundant catalyst materials for energy-efficient electrochemical energy storage. In this report, we identify how the multication composition in high-entropy perovskite oxides (HEO) contributes to high catalytic activity for the oxygen evolution reaction (OER), i.e., the key kinetically limiting half-reaction in several electrochemical energy conversion technologies, including green hydrogen generation. We compare the activity of the (001) facet of LaCr 0.2 Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 O 3-δ with the parent compounds (single B-site in the ABO 3 perovskite). While the single B-site perovskites roughly follow the expected volcano-type activity trends, the HEO clearly outperforms all of its parent compounds with 17 to 680 times higher currents at a fixed overpotential. As all samples were grown as an epitaxial layer, our results indicate an intrinsic composition–function relationship, avoiding the effects of complex geometries or unknown surface composition. In-depth X-ray photoemission studies reveal a synergistic effect of simultaneous oxidation and reduction of different transition metal cations during the adsorption of reaction intermediates. The surprisingly high OER activity demonstrates that HEOs are a highly attractive, earth-abundant material class for high-activity OER electrocatalysts, possibly allowing the activity to be fine-tuned beyond the scaling limits of mono- or bimetallic oxides.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Azo–hydrazone tautomerism in organometallic complexes triggered by a -Re(CO) 3 (L) core: A spectroscopic and theoretical study

The spectroscopic properties and tautomeric behavior of five novel Rhenium (I) tricarbonyl complexes bearing an azo ligand are presented. The organic ligand is stable in solution as the hydrazone tautomer. It remains as hydrazone in different medium conditions (solvent, concentration, pH, etc.) without the formation of detectable amounts of the azo tautomer. However, the complexation of this ligand to the strong electron-withdrawing fragment -Re(CO) 3 X (X = Cl – , Br – ) causes tautomerism to appear in the organic moiety. Two well-defined regions in the electronic spectra for both tautomers were observed, allowing the azo/enol-keto/hydrazone equilibrium to be followed. TD-DFT calculations indicate that for the keto/hydrazone form, the main absorption band is attributed to an IL transition. In contrast, the azo/enol species shows a major contribution of the 1 MLCT (dπ(Re) → dπ*(NN)) transition. The tautomeric equilibrium is easily shifted using solvents with different dielectric constant and hydrogen bond donor/acceptor (HBD/HBA) abilities. Also, the tautomerization process is deeply influenced by the electronic properties of the axial ligand. Therefore, this behavior represents a different strategy for the design of novel materials with optical properties. Furthermore, tautomerism is affected by the concentration of complexes and the presence of water in solvents. Finally, the acid-base behavior of these compounds in a 50% v/v ethanol-buffer system showed that the azo/enol tautomer is stabilized in acidic media. At the same time, an increase of pH promotes tautomerization toward the keto/hydrazone, followed by forming the anionic form at pH > 8.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS1991

Theory and simulation of cometary shocks

In this paper, recent kinetic simulation studies of cometary bow shocks are reviewed. Cometary shocks are formed due to solar wind mass loading by water group cometary ions. This process is kinetic in nature and varies as a function of the angle between the solar wind flow velocity and the interplanetary magnetic field, as do the properties of cometary shocks. For perpendicular and parallel orientations, quasi-steady shocks with dissipation scales on the order of proton inertial length form. At oblique orientations, no steady shocks are formed; instead, the transition from supersonic to subsonic flow takes place through multiple shocklets (steepened magnetosonic waves) which are generated by the pickup ions via the resonant electromagnetic ion beam instability. This new, time dependent model of cometary bow shocks is further investigated using a large scale kinetic simulation and is compared to the observations at Comet Giacobini-Zinner.

Omidi, N.↗

DOE OSTI2020

Photoresponsive Structured Liquids Enabled by Molecular Recognition at Liquid–Liquid Interfaces

Using host-guest molecular recognition at the oil-water interface, a new type of photoresponsive nanoparticle surfactant (NPS) was designed and prepared to structure liquids. With the help of a polymeric surfactant, the interfacial host-guest interactions can be significantly enhanced, leading to the rapid formation and assembly of a NP monolayer and offering sufficient binding energy to hold the NPs in a jammed state. The assembly of the NPSs can be reversibly manipulated via a photoswitchable jamming-to-unjamming transition, endowing the interface as well as the macroscopic assemblies with responsiveness to the external trigger (photons). Finally, this study for the first time opens a pathway for the construction of multiresponsive, structured all-liquid systems by introducing host-guest chemistry, showing promising potential applications in encapsulation, delivery systems, and unique microfluidic devices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗