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Initial experimental data set from the NETL ammonia combustion project being performed under the Advanced Turbines Multi-Year-Research-Plan. Release 1.0 includes fundamental measurements performed in the Pittsburgh Fundamental Combustion Laboratory between 2023-2024.
Streamer and glow plasma phases have been modeled at two thermochemical states of an ammonia-air flame: fresh reactants and burnt products. A new AMReX-based solver has been verified against benchmarks in the literature and has been used to perform these simulations. A Helmholtz-equation based photoionization model with parameters accounting for the presence of NH3 in air has been coupled with the solver to accurately model the streamer propagation phase. A detailed plasma kinetics mechanism has been compiled and used to predict the evolution of electrons, excited states, ions, and radicals during streamer propagation and glow formation. The propagation velocity of streamers was found increase by almost two-fold when the mixture was changed from the fresh reactants to the burnt products. Moreover, vibrational excitation was found to be limited to the streamer body, whereas ionization predominantly occurred at the streamer head, as is expected. Finally, the differences in the pathways of O and H radical production during the streamer propagation and glow phases have been briefly discussed.
We present an overview of the first data release (DR1) and first-look science from the Green Bank Ammonia Survey (GAS). GAS is a Large Program at the Green Bank Telescope to map all Gould Belt star-forming regions with A{sub V}≳7 mag visible from the northern hemisphere in emission from NH{sub 3} and other key molecular tracers. This first release includes the data for four regions in the Gould Belt clouds: B18 in Taurus, NGC 1333 in Perseus, L1688 in Ophiuchus, and Orion A North in Orion. We compare the NH{sub 3} emission to dust continuum emission from Herschel and find that the two tracers correspond closely. We find that NH{sub 3} is present in over 60% of the lines of sight with A{sub V}≳7 mag in three of the four DR1 regions, in agreement with expectations from previous observations. The sole exception is B18, where NH{sub 3} is detected toward ∼40% of the lines of sight with A{sub V}≳7 mag. Moreover, we find that the NH{sub 3} emission is generally extended beyond the typical 0.1 pc length scales of dense cores. We produce maps of the gas kinematics, temperature, and NH{sub 3} column densities through forward modeling of the hyperfine structure of the NH{sub 3} (1, 1) and (2, 2) lines. We show that the NH{sub 3} velocity dispersion, σ{sub v}, and gas kinetic temperature, T {sub K}, vary systematically between the regions included in this release, with an increase in both the mean value and the spread of σ{sub v} and T {sub K} with increasing star formation activity. The data presented in this paper are publicly available (https://dataverse.harvard.edu/dataverse/GAS-DR1).
We use data on gas temperature and velocity dispersion from the Green Bank Ammonia Survey and core masses and sizes from the James Clerk Maxwell Telescope Gould Belt Survey to estimate the virial states of dense cores within the Orion A molecular cloud. Surprisingly, we find that almost none of the dense cores are sufficiently massive to be bound when considering only the balance between self-gravity and the thermal and non-thermal motions present in the dense gas. Including the additional pressure binding imposed by the weight of the ambient molecular cloud material and additional smaller pressure terms, however, suggests that most of the dense cores are pressure-confined.
We present the results of Very Large Array NH{sub 3} (J,K)=(1,1) and (2,2) observations of the HH 111/HH 121 protostellar system. HH 111, with a spectacular collimated optical jet, is one of the most well-known Herbig–Haro objects. We report the detection of a new source, NH{sub 3}–S, in the vicinity of HH 111/HH 121 (∼0.03 pc from the HH 111 jet source) in two epochs of the ammonia observations. This constitutes the first detection of this source, in a region that has been thoroughly covered previously by both continuum and spectral line interferometric observations. We study the kinematic and physical properties of HH 111 and the newly discovered NH{sub 3}–S. We also use HCO{sup +} and HCN (J=4−3) data obtained with the James Clerk Maxwell Telescope and archival Atacama Large Millimeter/submillimeter Array {sup 13}CO, {sup 12}CO, and C{sup 18}O (J=2−1), N{sub 2}D{sup +} (J=3−2), and {sup 13}CS (J=5−4) data to gain insight into the nature of NH{sub 3}–S. The chemical structure of NH{sub 3}–S shows evidence for “selective freeze-out,” an inherent characteristic of dense cold cores. The inner part of NH{sub 3}–S shows subsonic nonthermal velocity dispersions indicating a “coherent core,” while they increase in the direction of the jets. Archival near- to far-infrared data show no indication of any embedded source in NH{sub 3}–S. The properties of NH{sub 3}–S and its location in the infrared dark cloud suggest that it is a starless core located in a turbulent medium, with the turbulence induced by Herbig–Haro jets and associated outflows. More data are needed to fully understand the physical and chemical properties of NH{sub 3}–S and if/how its evolution is affected by nearby jets.
Rocket engine starting with mixed oxides of nitrogen and liquid ammonia by flow-line additives
Injection techniques for 200-pound thrust ammonia- oxygen rocket engine
Injector evaluation in 2400-pound-thrust rocket engine using liquid oxygen and liquid ammonia
Ammonia reactions with CH radicals, investigating quantitative aspects of hydrogen cyanide formation by mass spectrometry
Determination of lethal concentrations of ammonia, and aftereffects to mice of such doses in air mixture
Forced convection and nucleate boiling heat transfer characteristics of liquid ammonia
The radio Signal form the Galileo probe to the orbiter experienced attenuation due to ammonia in Jupiter's atmosphere during the probe descent.
The radio signal from the Galileo prove to the orbiter experienced attenuation due to ammonia in Jupiter's atmosphere during the probe descent.
The Tropospheric Emission Spectrometer (TES) on the EOS Aura satellite makes global measurements of infrared radiances which are used to derive profiles of species such as O3, CO, H2O, HDO and CH4 as routine standard products. In addition, TES has a variety of special modes that provide denser spatial mapping over a limited geographical area. A continuous-coverage mode (called ''transect'', about 460 km long) has now been used to detect additional molecules indicative of regional air pollution. On 10 July 2007 at about 05:37 UTC (13:24 LMST) TES conducted such a transect observation over the Beijing area in northeast China. Examination of the residual spectral radiances following the retrieval of the TES standard products revealed surprisingly strong features attributable to enhanced concentrations of ammonia (NH3) and methanol (CH3OH), well above the normal background levels. This is the first time that these molecules have been detected in space-based nadir viewing measurements that penetrate into the lower atmosphere.
Satellite ammonia (NH 3 ) observations provide unprecedented insights into NH3 emissions, spatiotemporal variabilities and trends, but validation with in situ measurements remains lacking. Here, total columns from the Infrared Atmospheric Sounding Interferometer (IASI) were intercompared to boundary layer NH 3 profiles derived from aircraft- and surface-based measurements primarily in Colorado, USA, in the summer of 2014. IASI-NH 3 version 3 near real-time data set compared well to in situ derived columns (windows ±15 km around centroid, ±1 h around overpass time) with a correlation of 0.58, a slope of 0.78 ± 0.14 and an intercept of 2.1 × 10 15 ±1.5 × 10 15 molecules cm −2 . Agreement degrades at larger spatiotemporal windows, consistent with the short atmospheric lifetime of NH 3 . We also examined IASI version 3R data, which relies on temperature retrievals from the ERA Reanalysis, and a third product generated using aircraft-measured temperature profiles. The overall agreement improves slightly for both cases, and neither is biased within their combined measurement errors. Thus, spatiotemporal averaging of IASI over large windows can be used to reduce retrieval noise. Nonetheless, sampling artifacts of airborne NH 3 instruments result in significant uncertainties of the in situ-derived columns. For example, large validation differences exist between ascent and descent profiles, and the assumptions of the free tropospheric NH 3 profiles used above the aircraft ceiling significantly impact the validation. Because short-lived species like NH 3 largely reside within the boundary layer with complex vertical structures, more comprehensive validation is needed across a wide range of environments. More accurate and widespread in situ NH 3 data sets are therefore required for improved validations of satellite products.
Emissions of trace gases and particles from fires have a major impact on climate, visibility, air quality, and public health. Biomass burning emissions include reactive nitrogen gases, among which ammonia (NH3) plays a prominent role. NH3 is a short-lived gas that acts as precursor for secondary inorganic aerosols. This process is still poorly constrained in downwind fire plumes. In summer 2019, NASA and NOAA carried out the joint airborne FIREX-AQ (Fire Influence on Regional to global Environments and Air Quality) mission over the continental US to sample plumes from wildfires and agricultural fires. On board the NASA DC-8, we used a modified PTR-ToF-MS instrument for measuring NH3 in situ and at high time resolution. Over the course of the mission, we collected a large set of NH3 data in plumes emitted from fires differing in fuel type and burning stage. Herein, we will present the measured NH3 emissions ratios and factors, compare them with the literature, and investigate the dependence of NH3 emissions on fuel type and burning conditions.
General Electric Environmental Control Solutions (formerly Alstom Power Environmental Control Systems) set out to complete the Phase 1 award requirements for a Phase II renewal application for their project selected under DOE-FOA-0001190 “Small and Large Scale Pilots for Reducing the Cost of CO 2 Capture and Compression”. The project focus was to implement several improvement concepts utilizing membrane technology at the recipient’s Chilled Ammonia Process (CAP) CO 2 capture large-scale pilot plant. The goal was to lower the overall cost of technology. During the development of costs for the preliminary techno-economic assessment (TEA), it became clear that the capital and operating costs of this concept were not economically attractive. All work related to a Phase II renewal application at that point was halted as GE made the decision not to submit a Phase II renewal application. Discussions with DOE resulted in a path towards useful information produced from the design and cost work already completed on the project. With the reverse osmosis (RO) unit providing most of the cost issues, GE would provide a sensitivity analysis of the RO unit with respect to project cost. This information would be included with the Techno-Economic Analysis along with the Technology Gap Analysis.
This presentation provides an overview of increasing variable renewable electricity generation, its implications on the grid, the opportunity for load side grid support, H2@Scale, the potential need for seasonal electricity storage, and how ammonia production might fit into H2@Scale and its vision.