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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Importance of gas heating in capacitively coupled radiofrequency plasma-assisted synthesis of carbon nanomaterials

In pursuit of diamond nanoparticles, a capacitively-coupled radio frequency flow-through plasma reactor was operated with methane-argon gas mixtures. Signatures of the final product obtained microscopically and spectroscopically indicated that the product was an amorphous form of graphite. This result was consistent irrespective of combinations of the macroscopic reactor settings. To explain the observed synthesis output, measurements of C 2 and gas properties were carried out by laser-induced fluorescence and optical emission spectroscopy. Strikingly, the results indicated a strong gas temperature gradient of 100 K per mm from the center of the reactor to the wall. Based on additional plasma imaging, a model of hot constricted region (filamentation region) was then formulated. It illustrated that, while the hot constricted region was present, the bulk of the gas was not hot enough to facilitate diamond sp 3 formation: characterized by much lower reaction rates, when compared to sp 2 , sp 3 formation kinetics are expected to become exponentially slow. This result was further confirmed by experiments under identical conditions but with a H 2 /CH 4 mixture, where no output material was detected: if graphitic sp 2 formation was expected as the main output material from the methane feedstock, atomic hydrogen would then be expected to etch it away in situ, such that the net production of that sp 2 -hybridized solid material is nearly a zero. Finally, the crucial importance of gas heating was corroborated by replacing RF with microwave source whereby facile sp 3 production was attained with H 2 /CH 4 gas mixture.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Droplet-Gas Interactions in Nanoelectrospray Multiphase Flow

Electrospray (ES) is production of a charged droplet plume that transits from an electrically biased supply capillary to a counter electrode under the influence of an electric field. Drag interactions with the surrounding gas decelerate the droplets while transferring the momentum from droplets to accelerate the surrounding gas, resulting in an induced gas flow. This work seeks to characterize the structure of the resulting gas jet and identify the key mechanisms defining the flow structure. The phenomenon of gas jets produced by momentum transfer from nano-electrospray (nES) plumes is explored with schlieren visualization, thermal anemometry, and numerical simulations. Schlieren visualization experiments provide information on the flow structure in support of simulation predictions, and the hot thermistor anemometry measurements of gas velocities outside the spray demonstrate quantitatively validated simulation results. The study reveals the formation of a moderately high velocity coaxial gas jet within the nES plume and provides insight into the overall flow structure of the induced flow. The multiphase electrohydrodynamic simulations enable numerical experimentation to explore the fundamental physics of coupled droplet-gas transport and the resulting flow structure. The simulations, confirmed by the experiments, reveal gas jetting induced by nES with a narrow (sub hundred micrometers in diameter) core originating from the nES liquid-jet breakup region and a surrounding larger-in-extent zone (several hundred micrometers in diameter) of lower velocity gas flow within the electrospray plume. This behavior is due to nES ejecting a stream of droplets from the tip of a narrow liquid cone-jet, where the combined effect of many small droplets transferring momentum to a confined region of gas yields a narrow but high-velocity gas stream. Furthermore, the micro-jets produced by nES have practical utility for mass spectrometry, 3D printing and fabrication, and thermal management.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2025

Hot-spot model for inertial confinement fusion implosions with an applied magnetic field

Imposing a magnetic field on inertial confinement fusion implosions magnetizes the electrons in the compressed fuel; this suppresses thermal losses, which increases temperature and fusion yield. Indirect-drive experiments at the National Ignition Facility with 12 and 26 T applied magnetic fields demonstrate up to 40% increase in temperature, 3× increase in fusion yield, and indicate that magnetization alters the radial temperature profile [Moody et al., Phys. Rev. Lett. 129, 195002 (2022); Lahmann et al., APS DPP (2022)]. In this work, we develop a semi-analytic hot-spot model, which accounts for the two-dimensional (2D) Braginskii anisotropic heat flow due to an applied axial magnetic field. First, we show that hot-spot magnetization alters the radial temperature profile, increasing the central peakedness, which is most pronounced for moderately magnetized implosions (with 8–14 T applied field), compared to both unmagnetized (with no applied field) and highly magnetized (with 26 T or higher applied field) implosions. This model explains the trend in the experimental data, which finds a similarly altered temperature profile in the 12 T experiment. Next, we derive the hot-spot model for gas-filled (Symcap) implosions, accounting for the effects of magnetization on the thermal conduction and in changing the radial temperature (and density) profiles. Using this model, we compute predicted central temperature amplification and yield enhancement scaling with the applied magnetic field. The central temperature fits the experimental data accurately, and the discrepancy in the yield suggests a systematic (independent of applied field) degradation, such as mix, and additional degradation in the reference unmagnetized shot, such as reduced laser drive, increased implosion asymmetry, or the magnetic field suppressing ablator mixing into the hot-spot.

Alpha particles↗
DOE OSTI2022

The Toughness of High-Strength Steel Weld Metals

Low-temperature phase transformation (LTPT) welding consumables are a new class of welding wires developed to mitigate hydrogen-induced cracking in the welding of high-strength steels without preheating or postweld heat treatment. LTPT weld metals have a high strength, but their toughness needs further investigation. LTPT weld metals predominately contain a martensite microstructure, which is necessary to achieve high strength; however, martensitic weld metals containing oxide inclusions have relatively poor toughness. For this study, three welding processes — gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), and hot wire GTAW — were investigated. Optical microscopy, scanning electron microscopes, and transmission electron microscopes were employed for characterization. The role of the shielding gas in the formation of oxide inclusions in LTPT weld metals was investigated. The formation of oxide inclusions in the weld metals was related to the CO 2 in the shielding gas. When 100% Ar or a pure inert shielding gas mixture was used for all three welding processes, oxide inclusions were greatly reduced, and the weld metal toughness improved considerably, matching the base metal toughness. The mechanism by which inclusions promote fracture propagation in the weld metal was proposed.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Formation of Magnetically Truncated Accretion Disks in 3D Radiation-transport Two-temperature GRMHD Simulations

Multiwavelength observations suggest that the accretion disk in the hard and intermediate states of X-ray binaries (XRBs) and active galactic nucleus transitions from a cold, thin disk at large distances into a hot, thick flow close to the black hole (BH). However, the formation, structure, and dynamics of such truncated disks are poorly constrained due to the complexity of the thermodynamic, magnetic, and radiative processes involved. We present the first radiation-transport two-temperature general relativistic magnetohydrodynamic (GRMHD) simulations of truncated disks radiating at ~35% of the Eddington luminosity with and without large-scale poloidal magnetic flux. We demonstrate that when a geometrically thin accretion disk is threaded by large-scale net poloidal magnetic flux, it self-consistently transitions at small radii into a two-phase medium of cold gas clumps floating through a hot, magnetically dominated corona. This transition occurs at a well-defined truncation radius determined by the distance out to which the disk is saturated with magnetic flux. The average ion and electron temperatures in the semiopaque corona reach, respectively, $T_i$ ≳ 10 10 K and $T_e$ ≳ 5 × 10 8 K. The system produces radiation, powerful collimated jets, and broader winds at the total energy efficiency exceeding 90%, the highest ever energy extraction efficiency from a spinning BH by a radiatively efficient flow in a GRMHD simulation. This is consistent with jetted ejections observed during XRB outbursts. The two-phase medium may naturally lead to broadened iron line emission observed in the hard state.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Field Testing of Self-Healing Metallic Coatings for Internal Corrosion Protection of Natural Gas Pipelines

Internal corrosion occurs in natural gas pipelines primarily due to the presence of water, carbon dioxide, and hydrogen sulfide. Internal corrosion can eventually result in leakage, cracks, and rupture of the pipeline. The objective of this work is to mitigate internal corrosion in steel pipelines transporting natural gas using cold spray coatings. The corrosion behavior of carbon steel coated with self-healing zinc chromium (ZnCr) and zinc niobium (ZnNb) cold spray coatings was investigated in a natural gas environment. For comparison purposes, hot-dip galvanized steel (HDGS) was tested under the same conditions as cold spray coatings. The field test was performed at the NW Natural gas storage facility in Mist, Oregon. The field test was conducted in a 6-inch diameter pipe transporting wet natural gas out of an underground storage well at 500 psi and 4.4 °C. The coupons were tested for 15 and 32 days under stagnant and flow conditions, respectively. Weight loss method was used to measure the corrosion rate of metallic coatings. Post-corrosion surface characterization was performed on the specimen using a scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS). Crystalline phases were determined by X-ray diffraction (XRD). The field-test results confirmed that the metallic coatings provided corrosion protection of carbon steel exposed to wet natural gas under stagnant and flow conditions. The formation of the ZnCO 3 layer on top of ZnNb and ZnCr coatings led to passivation of the coatings which helps to reduce the self-corrosion. These layers form a barrier for diffusion of corrosive species to the surface.

03 NATURAL GAS↗
DOE OSTI2023

Development and testing of residential micro-CHP powered by opposed piston engine (CRADA Final Report)

A micro–combined heat and power (mCHP) prototype powered by innovative opposed piston engine technology was developed to simultaneously provide electricity and heat to residential or light commercial buildings. The mCHP prototype targeted at residential applications includes an opposed-piston four-stroke (OP4S) engine, generator, rectifier, inverter, battery energy storage system, 52 gal water tank, and application accessories for hot water supply and space heating. The OP4S engine can use renewable or regular natural gas, as well as hydrogen, to generate mechanical power and waste heat in form of hot coolant and exhaust gas simultaneously. The waste heat is recovered and stored in the water tank and can be used as a regular hot water supply and/or for space heating application. The tests show that the mCHP prototype enabled power outputs in the range of 3.2 –7.4 kW with up to 26.4% of AC electricity efficiency and up to 93.1% of the overall mCHP efficiency under stoichiometric combustion modes λ=~1.0. The mCHP was also run under lean combustion mode conditions at λ=~1.3. The lean mode operation enables more than 30% improvement in electrical energy efficiency. The maximum AC efficiency of the lean combustion mode attained was 35.2%, with the engine efficiency is approaching 40%. The exceptional electrical efficiency breaks the typical upper boundary of 30% for ICE-based mCHP. The engine exhaust temperatures in the lean modes are substantially less than in the stoichiometric modes. Moreover, the lean cases achieve high overall mCHP efficiencies: the overall mCHP efficiencies are all greater than 93%. Considering the mCHP prototype can achieve low-cost, flexible matching of thermal and electrical loads through reducing the complexity of distribution and installation, and high efficiency the novel technology will promote mCHP acceptance in the US residential and light commercial markets.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

Geothermal Play Fairway Analysis for Low-Temperature Resources in the Denver Basin

This dataset is part of an effort to highlight the advantages of incorporating low-temperature (< 150 C) geothermal resource evaluation into the implementation of combined heat and power (CHP), and geothermal direct use (GDU) technologies (e.g., space heating and/or cooling). For this Denver Basin example, resource favorability maps were created to identify potentially favorable areas for further geothermal exploration and are provided here. Favorability was based on three types of data: (1) geologic, (2) economic, and (3) risk. This raw data is also provided below. Geologic data include bottom-hole temperatures (BHT) from oil and gas wells, water co-production volumes from oil and gas wells, well groundwater levels, hot spring locations, temperatures, and chemistries, faults, and earthquakes. Economic feasibility data include population, thermal energy demand, infrastructure, and roads. Risk data (which includes data on excluded areas) include flood plains, protected lands (e.g. wildlife conservation areas, national parks). The included report describes this project in detail, covering workflows, relevant datasets, Python code, and both common and composite maps used to create low-temperature geothermal resource favorability maps for the Denver Basin, which extends across Colorado, Nebraska, and Wyoming. The figures in this report include: maps of the original datasets; maps of transformed data and derived parameters (such as the geothermal gradient or thermal conductivity); results of uncertainty analyses; results of data completeness (using the GeoRePORT tool); examples of the data combination and processing (using the geoPFA Python library, which is introduced in the attached report); favorability maps for each criteria; and a final combined favorability map. This project is designed to facilitate future deployment of CHP and GDU by providing data, tools, and a workflow applicable to low-temperature geothermal resources in sedimentary basins.

15 GEOTHERMAL ENERGY↗
DOE OSTI2024

ORNL Campus Sustainability and Decarbonization using Waste Heat Recovery from the Oak Ridge Leadership Computing Facility’s High-Performance Computing Data Center

Heat pumps are a clean and efficient technology that can be powered by renewable electricity to transfer heat using a refrigerant from one place to another by different heat sources, making buildings clean and environmentally friendly. With the support of the ORNL Laboratory Modernization Division, this project explored and evaluated an innovative solution that uses water-water cost-effective midtemperature heat pump (MTHP) technology to leverage the low-grade waste heat from ORNL Frontier and the data center to deliver 85°C hot water, which replaces hot steam generated using natural gas combustion boilers for water heating or space heating in the buildings of ORNL campus. Two scenarios were studied. In the first scenario, which considered the 5600-5700-5800 complex only, Carrier’s commercial 1,000 kW MTHP technology achieves more than 6,640 MWh/year energy savings, an emission reduction of 858 TCO2e/year CO2, and a payback time of 4.85 years. In the second scenario, which considered the 5600-5700-5800 complex and Buildings 5100, 5200, and 5300, the CO2 emission reduction is 1,483 TCO2e/year, the operating cost savings are $0.21 million annually, and the payback time is 3.74 years. Additionally, a comprehensive HP ShowCase Tool was developed for evaluating the optimal solution to improve sustainability and decarbonization of the buildings on the ORNL campus. The tool is an Excel-based tool integrated with VBA (Visual Basic for Applications) coding. The tool includes collected ORNL campus building information and an MTHP library, which comprises collected commercial and ORNL-defined MTHPs. The tool was used to evaluate the sustainability and decarbonization of the ORNL campus. The tool can be widely used or referenced for heat pump solutions and building decarbonization renovation strategies to modernize ORNL facilities and energy use–intensive equipment to enable efficient, sustainable, and resilient operations in the future.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

NitroNet: Smart System to Quantify Nitrous Oxide Emissions

Agricultural croplands are the largest anthropogenic source of nitrous oxide (N 2 O), the third most important greenhouse gas. Emissions are characterized by “hot spots” and “hot moments”, meaning emissions are highly heterogeneous in space and time. Emissions are driven by nitrification and denitrification processes which depend upon complex factors such as soil characteristics (type, compaction, pH, moisture, topography), management practices (fertilizer type and application, tillage, crop type, field history, irrigation), biogeochemistry (organic carbon, microbial composition), and meteorology (precipitation, temperature, and wind). For these reasons, quantifying cropland emissions by either measurements or modeling is extremely challenging with large uncertainties.

09 BIOMASS FUELS↗
DOE OSTI2024

Specification of FIPD Fission Gas Chemistry Data

The current FIPD library contains two main sets of fission gas chemistry data. The first set is data collected during the Integral Fast Reactor (IFR) program from 1984 to 1994, using a gas mass spectrometry system located in the Analytical Laboratory (AL) at Argonne National Laboratory-West (Argonne-West). Throughout this period, numerous fission gas release and chemistry datasets were gathered from a variety of metallic fuel pins. The fission gas was sampled by the Gas Assay, Sample and Recharge (GASR) System in the Hot Fuel Examination Facility (HFEF) and transferred to the AL to perform gas composition and isotopic abundance analysis. The second set is data collected after the IFR program. The fission gas samples were also collected by the GASR system at the HFEF, but analyzed using a similar gas mass spectrometer located in Pacific Northwest National Laboratory (PNNL). Many fuel pins irradiated in Experimental Breeder Reactor II (EBR-II) and the Fast Flux Test Facility (FFTF) were measured, including the fuel pins for the MFF series of experiments, designed to qualify metal fuel for use as driver fuel in the FFTF and X496 experiment. For either set of data, fission gas was sampled with the gas sampling line in GASR using sample bottles after the capsule/element volume has been determined and the system is still full of radioactive gas. The sample bottles were then transferred to the sample packaging cylinder or an approved storage location pending transfer to the AL or prepared for shipment to another laboratory (such as PNNL) for analysis of the collected gas as directed on the GASR data form, other approved form. The receiving laboratories (AL or PNNL) required their Analytical Service Request form to be completed prior to sample transfer. Typical sample transfer processes were initiated at HFEF by the principal or process engineer. The laboratories performing the analyses (AL or PNNL) use the sample bottle numbers as well as a sample number produced by the respective laboratory. HFEF and the responsible experimenter tracked the sample using the analysis number, the gas bottle number, and the fuel pin number.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2023

Experimental Characterization of an Additively Manufactured Inconel 718 Heat Exchanger for High-Temperature Applications

This work presents the experimental results of a novel, air-to-air, additively manufactured manifold-microchannel heat exchanger with straight fins on both sides. The heat exchanger was made of Inconel 718 using a direct metal laser sintering technique. The overall core size of the heat exchanger was 94 mm × 87.6 mm × 94.4 mm, with a fin thickness of 0.220 mm on both the hot and cold sides. The heat exchanger was tested with pressurized nitrogen gas at 300 °C and 340 kPa for the hot side, while air at an ambient condition was used for the cold side. An overall heat transfer of 276 W/m2K was obtained for Reynolds number values of 132 and 79 for the cold and hot sides, respectively. A gravimetric heat transfer density (Q/m∆T) of 4.7–6.7 W/kgK and a volumetric heat transfer density (Q/V∆T) of 6.9–9.8 kW/m3K were recorded for this heat exchanger with a coefficient of performance value that varied from 42 to 52 over the operating conditions studied here. The experimental pressure drop results were within 10% of the numerical values, while the corresponding heat transfer results were within 17% of the numerical results, mainly due to imperfections in the fabrication process. Despite this penalty, the performance of the tested heat exchanger was superior to the conventional plate-fin heat exchangers: more than 60% of improvements in both gravimetric and volumetric heat transfer densities were recorded for the entire range of experimental data.

42 ENGINEERING↗
DOE OSTI2025

Processes in Salt Repositories for Radioactive Waste Disposal

This document summarizes the key processes (thermal, hydrological, mechanical, and chemical; THMC) impacting the features of a deep geological repository for radioactive waste in salt. Some processes are natural and on-going whether the repository is there or not, and other processes are driven by the perturbation associated with the repository. The features considered here include both engineered and natural components of the repository system. The engineered barrier system (EBS) in a salt repository is quite different from those implemented for a repository in clay or crystalline rocks, because it is comprised mostly of granular salt and salt-compatible cements, rather than bentonite. When compared to other rocks (i.e., silicates), salt has unique properties that make it an excellent potential host rock. Openings and fractures in salt creep closed readily. Salt has high thermal conductivity, which can reduce peak temperatures. Additionally, far away from the excavations the porosity of salt is unconnected, which leads to essentially zero advective or diffusive transport. The small amount of hypersaline brine occurring in salt minimizes microbial activity, reduces colloid-assisted transport, and eliminates in-package criticality (i.e., chloride is a neutron poison). At the end of the report, we present a brief outline for a potential salt repository, including considerations avoided in previous repository disposal concepts. We propose considering higher-temperature processes in future disposal concepts, rather than trying to minimize the thermal perturbation of the repository. Since hot salt is drier, a dry repository would limit corrosion, gas generation, and solute transport. Openings and fractures creep shut faster in hot salt. Therefore, higher temperatures could be seen as beneficial, rather than something to minimize, through increased spacing between waste packages (increasing repository costs).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Experimental observations of shock-wave-induced bubble collapse and hot-spot formation in nitromethane liquid explosive

We studied the collapse of individual helium gas bubbles in the homogeneous explosive nitromethane (NM) to investigate effects of hot-spot formation on the detonation process. A bubble was injected into a NM sample, and a shock wave from an explosive detonator compressed the bubble, creating a localized hot spot. We measured shock and detonation wave speeds with optical velocimetry, and we used a high-speed camera to image the shock propagation and the pre- and post-bubble collapse processes. An infrared camera image showed the residual radiance temperature distribution after the bubble collapse, and an optical fiber pyrometer measured the time-resolved thermal radiance. We measured the optical spectra of light emitted from detonating NM without a bubble and from a collapsing bubble in shocked, undetonated NM. We estimated temperatures of the detonation fronts and of the hot spots formed by bubble collapse. To study the incipient detonation process, we performed all bubble collapse experiments at pressures below the threshold for creating a sustained detonation. Where the bubble collapsed, we observed an opaque, thermally emissive region believed to be chemical reaction products. Chemical reactions in NM can be produced with lower shock pressures (~1 GPa) when a helium bubble is present than without a bubble (~10 GPa). We used hydrodynamic modeling to predict shock wave propagation, extent of chemical reaction, and subsequent temperature rise from the collapsing bubble. Simulations using a temperature-dependent Arrhenius burn model gave much better results than reactive burn models that depend only on pressure and density.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2024

“Max-tech FHR”: What is the maximum technically achievable water delivery capacity from a single 120 V plug?

Electrifying water heating will require affordable, direct drop-in replacements for existing gas water heaters that meet consumer expectations for hot water delivery. For many replacement scenarios, affordability requires a replacement option with like-for-like physical product dimensions, and existing consumer expectations presume a large delivery capacity from a small water heater. This work explores the technical potential for hot water delivery capacity for a heat pump water heater (HPWH) powered from a common 120 V plug. Delivery capability in this work is quantified by two metrics: the First Hour Rating (FHR) defined in the Code of Federal Regulations, and a real-world draw profile that resulted in hot water runout during field studies of 120 V HPWHs. The work focuses on the common “tall-and-slim” gas water heater product category, with external product dimensions of 20 inch diameter and 60 inch height. Using a simulation model in DOE/ORNL Heat Pump Design Model, validated by experimental baseline testing of a commercially available 120 V HPWH model, several measures were evaluated to maximize the delivery capacity of a 120 V HPWH. The 120 V HPWH was constrained by 1) external product dimensions of 20 in diameter and 60 inch height, 2) electrical power of 1.5 kW (85% of the available power from a dedicated 120 V, 15 A circuit), and 3) commercially-available components. The measures implemented included a large compressor, a pumped loop with plate heat exchanger to maximize tank stratification, enlarged heat exchangers, and relatively thin insulation to maximize the water storage volume.

Gluesenkamp, Kyle↗
DOE OSTI2020

Structure factors of the unitary gas under supernova conditions

Here, we compute with lattice field theory the vector and axial static structure factors of the unitary gas for arbitrary temperature above the superfluid transition and for fugacities 0.1 < $\mathcal{z}$ < 1.0 . Using the lattice formulation, we calculate beyond the validity of the virial expansion, a commonly used technique in many-body physics. We find qualitative differences in the behavior of the structure factors at high fugacity compared to the predictions of the virial expansion. Due to the large scattering length of neutrons, we expect the unitary gas structure factors to approximate the structure factors of hot neutron gases, and we therefore expect our calculations to be useful in supernova simulations, where neutron gas structure factors are needed to compute in-medium neutrino-neutron scattering rates.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Vibrational spectroscopy of shock compressed condensed phase nitrous oxide: Frequency shifts in the ν 1 mode

Over many years, we have published vibrational spectra of molecular materials at extreme pressure and temperature obtained using shock compression and coherent Raman spectroscopy methods. For diatomic molecules, we were able to extract vibrational temperatures from the intensities of spectrally resolved vibrational hot bands. Larger molecules in the condensed phase suffer band broadening effects that obscure the vibrational hot bands as the anharmonicities are typically smaller than the widths of the bands. This inability to resolve the hot bands inhibits the extraction of vibrational temperature and the measurement of the vibrational frequency of the fundamental. Here, we use a hot band model based on gas-phase anharmonic coupling coefficients to fit coherent anti-Stokes Raman spectra of the ν 1 vibrational mode of shock compressed condensed phase N 2 O with shock pressures and temperatures estimated from literature equations of state and compare to fits from a model using a single Gaussian peak. We report the resulting vibrational frequency shifts with shock pressure.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Life cycle greenhouse gas emissions of ethanol produced via fermentation of sugars derived from shrub willow (Salix ssp.) hot water extraction in the Northeast United States

Abstract Background The amount of carbon dioxide in the atmosphere has been on the rise for more than a century. Bioenergy crops are seen by the Intergovernmental Panel on Climate Change as an essential part of the solution to addressing climate change. To understand the potential impact of shrub willow ( Salix spp . ) crop in the northeast United States, effective and transparent life cycle assessment of these systems needs to occur. Results Here we show, ethanol produced from the fermentation of sugars from hot water extract of willow grown on cropland can sequester 0.012 ± 0.003 kg CO 2eq MJ −1 for a supply system incorporating summer harvest and storage. Despite decreases in soil organic carbon when willow is instead grown on grassland, the produced fuel still can provide significant climate benefits compared to gasoline. Conclusions Shrub willow converted to ethanol can be a carbon negative source of transportation fuel when the electricity and heat required for the conversion process are generated from renewable biomass. The sequestration of carbon in the belowground portion of the plants is essential for the negative GHG balance for cropland and low GHG emissions in grassland.

10 SYNTHETIC FUELS↗