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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Structural relaxation of water during rapid cooling from ambient temperatures

Experiments investigating the properties of deeply supercooled liquid water are needed to develop a comprehensive understanding of water’s anomalous properties. One approach involves transiently heating nanoscale water films into the supercooled region for several nanoseconds at a time and then interrogating the water films after they have quenched to cryogenic temperatures. To relate the results obtained with this approach to other experiments and simulations on supercooled water, it is important to understand how closely the quenched structure tracks the (metastable) equilibrium structure of water as a function of the transient heating temperature. A key step involves quantifying the extent to which water that is transiently heated to ambient temperatures [hyperquenched water (HQW)] subsequently relaxes toward the structure of low-density amorphous (LDA) ice as it cools. We analyzed the infrared reflection–absorption spectra of LDA, HQW, and crystalline ice films to determine their complex indices of refraction. With this information, we estimate that HQW retains ~50%–60% of a structural motif characteristic of water at high temperatures with the balance comprised of a low-temperature motif. This result, along with results from x-ray diffraction experiments on water and amorphous ices, allows one to quantify the fraction of the high-temperature motif at approximately zero pressure as a function of temperature from 150 to 350 K.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Silicon implantation and annealing in β -Ga 2 O 3 : Role of ambient, temperature, and time

Optimizing thermal anneals of Si-implanted β-Ga 2 O 3 is critical for low resistance contacts and selective area doping. Here we report the impact of annealing ambient, temperature, and time on the activation of room temperature ion-implanted Si in β-Ga 2 O 3 at concentrations from 5 × 10 18 to 1 × 10 20 cm −3 , demonstrating full activation (>80% activation, mobilities >70 cm 2 /V s) with contact resistances below 0.29 Ω mm. Homoepitaxial β-Ga 2 O 3 films, grown by plasma-assisted molecular beam epitaxy on Fe-doped (010) substrates, were implanted at multiple energies to yield 100 nm box profiles of 5 × 10 18 , 5 × 10 19, and 1 × 10 20 cm −3 . Anneals were performed in an ultra-high vacuum-compatible quartz furnace at 1 bar with well-controlled gas compositions. To maintain β-Ga 2 O 3 stability, p O2 must be greater than 10 −9 bar. Anneals up to p O2 = 1 bar achieve full activation at 5 × 10 18 cm −3, while 5 × 10 19 cm −3 must be annealed with p O2 ≤ 10 −4 bar, and 1 × 10 20 cm −3 requires p O2 < 10 −6 bar. Water vapor prevents activation and must be maintained below 10 −8 bar. Activation is achieved for anneal temperatures as low as 850 °C with mobility increasing with anneal temperatures up to 1050 °C, though Si diffusion has been reported above 950 °C. At 950 °C, activation is maximized between 5 and 20 min with longer times resulting in decreased carrier activation (over-annealing). This over-annealing is significant for concentrations above 5 × 10 19 cm −3 and occurs rapidly at 1 × 10 20 cm −3 . Rutherford backscattering spectrometry (channeling) suggests that damage recovery is seeded from remnant aligned β-Ga 2 O 3 that remains after implantation; this conclusion is also supported by scanning transmission electron microscopy showing retention of the β-phase with inclusions that resemble the γ-phase.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

Carboxylic Group Rotation and Lattice Expansion in a Co 2 (Pyrazine-2,3-Dicarboxylate) 2 (4,4'-Bipyridine) Porous Coordination Polymer Induced by CO 2 Adsorption at Ambient Temperature

Here, a Co 2 (pzdc) 2 (bpy)(H 2 O) m (pzdc: pyrazine-2,3dicarboxylate; bpy: 4,4'-bipyridine) porous coordination polymer (PCP) was studied for CO 2 uptake and concomitant structural changes at ambient temperature. Extended structural characterization included evaluation of lattice parameter changes upon CO 2 adsorption and in situ synchrotron X-ray powder diffraction data. The PCP effective pore size increased by ~2% with gas uptake over the pressure range of 1-50 atm, allowing the adsorption capacity to double. Furthermore, the hysteretic behaviors seen during CO 2 adsorption at moderate pressures are commensurate with the structural changes from synchrotron data. The adsorption and hysteresis occur with rotation of the linking carboxylate groups, and yet only minor changes in unit cell volume (ΔV ≈ 6 Å 3 ) are observed. This contrasts the findings for [Cu 2 (pzdc) 2 (bpy)] n , where a combination of pillar bpy rotations and significant lattice expansion (ΔV ≈ 68 Å(3)) takes place upon hysteretic adsorption of CO 2 . In situ high-temperature X-ray diffraction revealed that the Co(II)-based material has good thermal stability up to ca. 200° C. Finally, the CO 2 uptake also appears to be at a physisorption level, with adsorbent-adsorbate interactions that are ca. 30% stronger than what has been reported for CO 2 adsorption onto [Cu 2 (pzdc) 2 (bpy)] n .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Shock initiation of cyclotol (75/25) at both ambient temperature and 70 °C

Here, six shock initiation experiments have been carried out to study the shock sensitivity and develop the unreacted Hugoniot for the Cyclotol composition 75/25 %wt RDX/TNT. The experiments were carried out both at ambient temperature, and elevated to 70 °C, close to the TNT melt temperature of 80 °C. Two sets of three experiments were fired at nominal pressures of 4.1, 6.0 and 7.7 GPa. Comparison has been made to the previously studied (80/20 %wt RDX/TNT) composition and analysis shows that the five percent decrease in RDX content has resulted in a significant increase in shock sensitivity. The increase in initial temperature has yielded an unexpectedly small increase in shock sensitivity, particularly relative to the effects of the compositional change. Wave profiles will be presented, along with a discussion of the unreacted Hugoniot and relative sensitivities presented in the Pop plot.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Developing A New NG Super-Absorbent Polymer (NG-SAP) for a Practical NG Storage System with Low Pressure, Ambient Temperature, and High Energy Density

This R&D project proposed a systematical study to develop a new class of NG super-absorbent polymer (NG-SAP) with the objective to achieve similar CNG volumetric storage level ~250 cm 3 -STP/cm 3 and fast sorption-desorption kinetics at ambient temperature but lower operational pressure (<100 bar). We suggested two consecutive research phases, including (i) a systematical investigation of various polymer systems to identify the suitable classes that can exhibit methane (C1) binding energy in the range of 20-25 kJ/mol and then (ii) focusing on the potential class polymers to identify the specific structure and morphology that can achieve the project objective.In first research phase (1st year), the major tasks included design and synthesis of several representative polymers with various structure attributes, examining their molecular structures, pore morphology, and BET surface area as the prepared samples, and then studying their C1 binding energy and sorption capacity.

03 NATURAL GAS↗
DOE OSTI2022

Cooperative allostery and structural dynamics of streptavidin at cryogenic- and ambient-temperature

Multimeric protein assemblies are abundant in nature. Streptavidin is an attractive protein that provides a paradigm system to investigate the intra- and intermolecular interactions of multimeric protein complexes. Also, it offers a versatile tool for biotechnological applications. Here, we present two apo-streptavidin structures, the first one is an ambient temperature Serial Femtosecond X-ray crystal (Apo-SFX) structure at 1.7 Å resolution and the second one is a cryogenic crystal structure (Apo-Cryo) at 1.1 Å resolution. These structures are mostly in agreement with previous structural data. Combined with computational analysis, these structures provide invaluable information about structural dynamics of apo streptavidin. Collectively, these data further reveal a novel cooperative allostery of streptavidin which binds to substrate via water molecules that provide a polar interaction network and mimics the substrate biotin which displays one of the strongest affinities found in nature.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

Autonomous Aerosol and Plasma Co‐Jet Printing of Metallic Devices at Ambient Temperature

Abstract Additive manufacturing of metallic materials holds the potential to revolutionize the fabrication of functional devices unattainable via traditional methods. Despite recent advancements, printing metallic materials typically requires thermal processing at elevated temperatures to form dense structures with desired properties, which presents a major challenge for direct printing and integration with temperature‐sensitive materials. Herein, a unique co‐jet printing (CJP) method is reported integrating an aerosol jet and a non‐thermal, atmospheric pressure plasma jet to enable concurrent aerosol deposition of metal nanoparticle inks and in situ sintering at ambient temperature. A machine learning algorithm is integrated with the CJP to perform real‐time defect detection and autonomous correction, enhancing the yield of printed films with high electrical conductivity from 44% to 94%. Concurrent printing and sintering eliminate the need for post‐printing processing, reducing the overall manufacturing time by multiple folds depending on product size. CJP enables direct printing of functional devices on a variety of temperature‐sensitive materials including biological materials. Direct printing of hydration sensors on living plant leaves is demonstrated for long‐duration monitoring of hydration level in the plant. The versatile CJP method opens tremendous opportunities to harmoniously integrate abiotic and biotic materials for emerging applications in wearable/implantable devices and biohybrid systems.

Du, Yipu [Department of Aerospace and Mechanical E↗
DOE OSTI2021

Iron-activated persulfate oxidation degrades aqueous Perfluorooctanoic acid (PFOA) at ambient temperature

Perfluorooctanoic acid (PFOA, C 8 HF 15 O 2 ) is an industrial surfactant that is highly resistant to natural breakdown processes such as those mediated by heat, hydrolysis, photolysis, and biodegradation. Many efforts have been developed to breakdown PFOA to less harmful species due to its widespread human exposure and potential toxicity. However, these methods require high temperature or specialized equipment with serious disadvantages of high energy cost for long-term use. For this paper, we investigated the effectiveness of PFOA degradation by ferrous iron-activated persulfate oxidation (IAPO) under various aqueous geochemical conditions. Approximately 64% of PFOA (initial concentration = 1.64 μmol L –1 ) was degraded after 4 h under illuminated anoxic conditions at ambient temperature. This degradation rate and magnitude support the potential use of IAPO as a novel inexpensive and environmentally friendly method to remediate PFOA in soil and groundwater.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Constructing Crown Ether-Based Supramolecular Adhesives with Ambient-Temperature Applicable and Durable Adhesion

Supramolecular adhesives are attracting considerable attentions owing to their dynamic and reversible bonding, while the complex curing conditions and poor performance under extreme conditions severely restrict their applicability. Herein, a series of tetra-crown ether-terminated polyethylene glycol (TCE-PEG) adhesives are presented in which plenty of supramolecular interactions, including Van der Waals, hydrogen bonding, π–π staking, metal coordination, and electrostatic ones, provide strong adhesion on multiple types of substrates. Highly relevant for practical applications, ultra-strong adhesivity of TCE-PEG can be achieved without requiring additional ultraviolet radiation, heat, or chemical treatment at ambient temperature. It also exhibits durable adhesive behavior, excellent underwater stability, and low-temperature tolerance. Especially, by incorporating ionic polymer fragments of polyethyleneimine hydrochloride, additional hydrogen bonding between secondary amines and crown ether rings can be induced to enhance the lap-shear strength to 7.21 MPa due to the formation of supramolecular cross-linked network. Finally, this work pioneers a rather unique supramolecular approach for easily formed, ultra-strong crown-ether-based adhesives bearing great potential for applications in critical environments of limited heat source and unallowed solvent usage.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Metal-Organic Frameworks (MOFs) Containing Frustrated Lewis Pairs (FLP) for H 2 Storage at Ambient Temperature

This final technical report summarizes the key accomplishments of the HyMarc Seedling project to develop new materials based on metal-organic framework (MOF) incorporated with frustrated Lewis pairs (FLP) termed as FLP@MOF, as next-generation of hydrogen storage sorbent that can meet or exceed DOE’s 2025 performance target of hydrogen storage gravimetric density of 5.5 wt.% and volumetric density of 0.040 kg H 2 /L. The project was carried out by the PI Shengqian Ma at the University of North Texas (UNT) along with Argonne National Laboratory (ANL) to develop FLP@MOF systems that exhibit high hydrogen storage capacity at ambient temperature under pressure <100 bar, as well as to obtain improved fundamental understanding of hydrogen adsorption mechanism in FLP@MOF system.

08 HYDROGEN↗
DOE OSTI2022

Ambient-temperature liquid jet targets for high-repetition-rate HED discovery science

High-power lasers can generate energetic particle beams and astrophysically relevant pressure and temperature states in the high-energy-density (HED) regime. Recently-commissioned high-repetition-rate (HRR) laser drivers are capable of producing these conditions at rates exceeding 1 Hz. However, experimental output from these systems is often limited by the difficulty of designing targets that match these repetition rates. To overcome this challenge, we have developed tungsten microfluidic nozzles, which produce a continuously replenishing jet that operates at flow speeds of approximately 10 m/s and can sustain shot frequencies up to 1 kHz. The ambient-temperature planar liquid jets produced by these nozzles can have thicknesses ranging from hundreds of nanometers to tens of micrometers. In this work, we illustrate the operational principle of the microfluidic nozzle and describe its implementation in a vacuum environment. Further, we provide evidence of successful laser-driven ion acceleration using this target and discuss the prospect of optimizing the ion acceleration performance through an in situ jet thickness scan. Future applications for the jet throughout HED science include shock compression and studies of strongly heated nonequilibrium plasmas. When fielded in concert with HRR-compatible laser, diagnostic, and active feedback technology, this target will facilitate advanced automated studies in HRR HED science, including machine learning-based optimization and high-dimensional statistical analysis.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Vapor detection and vapor pressure measurements of fentanyl and fentanyl hydrochloride salt at ambient temperatures

There is a need for non-contact, real-time vapor detection of drugs to combat illicit transportation and help curb the opioid epidemic. The low-volatility of drugs, like fentanyl, makes room temperature vapor detection of illicit drugs challenging, but feasible by atmospheric flow tube-mass spectrometry (AFT-MS). AFT-MS is a non-contact vapor detection approach capable of ultra-trace detection of drugs, including fentanyl and its analogs at low parts-per-quadrillion (ppqv) levels. The determination of vapor pressure values of fentanyl is necessary to understand potential vapor concentrations that may be available for detection. In this paper, vapor pressures of fentanyl free base and fentanyl hydrochloride salt (a common form of the illicit drug) were measured as a function of temperature at or near ambient conditions using the transpiration (gas saturation) method and AFT-MS. Based on our measurements, the vapor pressure of fentanyl at 25 °C is 9.0 × 10-14 atm (90 ppqv), and the vapor pressure of fentanyl hydrochloride at 25 °C is 1.8 x 10-17 atm (0.018 ppqv). We also demonstrate non-contact, real-time vapor detection of fentanyl. Preconcentration of vapors can further extend the detection capabilities. The collection, desorption, and detection of fentanyl vapors at ambient conditions was demonstrated for sampling times of seconds to an hour resulting in increased signal. AFT-MS is a viable detection method of fentanyl and other drugs for screening of packages and cargo.

atmospheric flow tube-mass spectrometry (AFT-MS), ↗
DOE OSTI2026

Catalytic Ambient Temperature Dinitrogen Conversion to a Bis(silyl)amine by Mononuclear Group 4 Aryloxide Complexes

The homogeneous conversion of ambient dinitrogen to amine products via the N2 reduction reaction (N2RR) remains a prized yet challenging feat for d-block complexes and is scarcely reported for f-block complexes. New, mononuclear TiIV and ZrIV aryloxide complexes Ti(DP)2 (1Ti), Zr(DP)2 (1Zr), and DP = [2-(OC6H2-2-tBu,4-Me)2CHPh] produce up to 51 eq. and up to 7.0 eq. of HN(SiMe3)2 per Ti/Zr, from N2, K0, weak acid, and chlorotrimethylsilane. Complex 1Ti exhibits more than double the activity toward N2-silylation of any previously reported Ti N2RR catalyst and can also catalyze the formation of up to 19 eq. of NH3, a new feature in early metal N2RR chemistry. The mononuclear 1Zr is the most active Zr catalyst for N2-silylation to date. [KSm(DP)2(THF)3] (1Sm), the mononuclear analogue of our previously reported dinuclear A-Sm complex, displays only stoichiometric N2-silylation due to its vulnerability to deleterious side reactions. DFT calculations confirm the catalysis can proceed via a monomeric Ti complex with a terminally bound, activated N2, agreeing with experimental 1H DOSY NMR measurements; the N-H bond is formed first, directing the catalyst selectivity. The isolable reduction product [K3(THF)Ti(DP)(DP-)(N2)] is also an active catalyst, and an intermediate in the calculated cycle.

Hernandez, Matthew↗
DOE OSTI2026

Tussock tundra surface temperatures, ambient air and incoming photosynthetically active radiation measured at the NGEE Arctic Council site, 2021 - 2023

This dataset contains temperature measurements carried out along two fiber optics cables/lines (150 m each) laid out along the ground at the Next Generation Ecosystem Experiment (NGEE) Arctic site near Council, Alaska. The lines traverse an heterogeneous part of the tussock tundra site including thermokarst features and lichen dominated sections of the tundra. Measurements were done using a Sensornet Oryx DTS, a Distributed Temperature sensor that was installed in September 2021 and taken down in August 2023. The sensor was powered by solar power with data being collected every 30 minutes at 1 m resolution. In addition to these measurements air temperature and incoming photosynthetically active radiation (PAR) are provided. These measurements are co-located with the NGEE Arctic Council eddy flux and meteorological station (AmeriFlux ID US-NGC). Included are six *.csv files (four data files and two reporting format files) and two *.kml files. The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research. The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska. Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

Air temperature↗
DOE OSTI2021

Benzene Ring Knitting Achieved by Ambient-Temperature Dehalogenation via Mechanochemical Ullmann-Type Reductive Coupling

The current approaches capable of affording conjugated porous networks (CPNs) still rely on solution-based coupling reactions promoted by noble metal complexes or Lewis acids, on-surface polymerization conducted in ultrahigh-vacuum environment at very high temperatures (>200 °C), or mechanochemical Scholl-type reactions limited to electron-rich substrates. To develop simple and scalable approaches capable of making CPNs under neat and ambient conditions, herein, a novel and complementary method to the current oxidative Scholl coupling processes is demonstrated to afford CPNs via direct aromatic ring knitting promoted by mechanochemical Ullmann-type reactions. The key to this strategy lies in the dehalogenation of aromatic halides in the presence of Mg involving the formation of Grignard reagent intermediates. Products (Ph-CPN-1) obtained via direct C-C bond formation between 1,2,4,5-tetrabromobenzene (TBB) monomer feature high surface areas together with mesoporous architecture. The versatility of this approach is confirmed by the successful construction of various CPNs via knitting of the corresponding aromatic rings (e.g., pyrene and triphenylene), and even highly crystalline graphite product was obtained. The CPNs exhibit good electrochemical performance as the anode material in lithium-ion batteries (LIBs). Overall, this approach expands the frontiers of CPN synthesis and provides new opportunities to their scalable applications.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Photo-DAC: Light-Driven Ambient-Temperature Direct Air Capture by a Photobase

Direct air capture (DAC) may reduce atmospheric CO 2 concentrations to preindustrial levels, yet the high energies and temperatures involved in current DAC technologies hinder large-scale deployment. In the case of aqueous-based CO 2 absorbents, a large energetic penalty is associated with heating and boiling off water, as required for thermally driven solvent regeneration. This could be avoided via photochemically driven pH swings involving photoacids or photobases, and harnessing abundant and renewable solar energy, though efficient solvent regeneration and recycling in a realistic multicycle DAC process remains challenging. Herein, we report a photochemically driven DAC process (photo-DAC) in which atmospheric CO 2 capture by an aqueous glycylglycine (GlyGly) solution is enabled through a pH swing by a pyridine-substituted diiminoguanidine (PyDIG) photobase. Upon irradiation with UV light, the PyDIG photobase undergoes photoisomerization from the E,E to the Z,Z isomer, corresponding to a pK a increase of 2.8 units that activates GlyGly for DAC through deprotonation. After the GlyGly/PyDIG solvent is saturated with atmospheric carbon dioxide, leaving it in the dark under ambient conditions leads to the isomerization of PyDIG from the Z,Z back to the E,E isomer, which is accompanied by a pH drop and CO 2 release. To demonstrate the recyclability of the GlyGly/PyDIG solvent, we have completed six consecutive DAC cycles, with a measured average cyclic capacity in the range of 0.21–0.26 mol CO 2 per mol of GlyGly/PyDIG. These results open the prospect for energy-efficient DAC cycles completed entirely at ambient conditions, thereby avoiding the significant energy penalties associated with heating and boiling aqueous solvents.

Einkauf, Jeffrey D. [Oak Ridge National Laboratory↗
DOE OSTI2021

Impact of Oxygen Non-Stoichiometry on Near-Ambient Temperature Ionic Mobility in Polaronic Mixed-Ionic-Electronic Conducting Thin Films

Enhanced ionic mobility in mixed ionic and electronic conducting solids contributes to improved performance of memristive memory, energy storage and conversion, and catalytic devices. Ionic mobility can be significantly depressed at reduced temperatures, for example, due to defect association and therefore needs to be monitored. Measurements of ionic transport in mixed conductors, however, proves to be difficult due to dominant electronic conductivity. This study examines the impact of different levels of quenched-in oxygen deficiency on the oxygen vacancy mobility near room temperature as measured by a novel dynamic current-voltage analysis. A Pr 0.1 Ce 0.9 O 2-δ film was grown by pulsed laser deposition and subsequently annealed, from 400-600° C, in various oxygen partial pressures to modify its oxygen vacancy concentration while minimizing microstructural growth and cation segregation. To monitor changes in film non-stoichiometry, we leverage the existence of an optical absorption center, related to the oxidation state of Pr ions in Pr0.1Ce0.9O2-δ. The oxygen vacancy migration enthalpy was found to exhibit a small increase from 0.73± 0.04 to 0.79 ± 0.02 eV with increasing oxygen deficiency, while the pre-factor was found to increase by a factor of 135. Here, a nearly 13-fold increase in ionic mobility at 60 °C for increases in oxygen non-stoichiometry from 0.032 ± 0.001 to 0.042± 0.001 was thereby detected. Raman spectroscopy was employed to rule out changes in strain as the primary cause for the significant change in mobility. Several factors potentially contributing to the large pre-factor changes are examined and discussed. Insights into how ionic defect concentration can markedly impact ionic mobility should help in elucidating the origins of variations seen in nanoionic devices.

36 MATERIALS SCIENCE↗