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Evaporation of ammonia at the temperature and pressure of the surface of Venus will allow electronics' baseplate temperatures to remain at 120 C for limited time determined by the amount of ammonia.
The high altitude of Jupiter's Great Red Spot (GRS) may enhance the upward flux of gaseous ammonia (NH3 ) into the high troposphere, where NH3 molecules can be photodissociated and initiate a chain of chemical reactions with downwelling acetylene molecules (C2H2 ). These reactions, experimentally studied earlier by (Ferris and Ishikawa [1987] Nature 326, 777-778) and (Ferris and Ishikawa [1988] J. Amer. Chem. Soc. 110, 4306-4312), produce chromophores that absorb in the visible and ultraviolet regions. In this work we photolyzed mixtures of NH3 and C2H2 using ultraviolet radiation with a wavelength of 214 nm and measured the spectral transmission of the deposited films in the visible region (400-740 nm). From these transmission data we estimated the imaginary indices of refraction. Assuming that ammonia grains at the top of the GRS clouds are coated with this material, we performed layered sphere and radiative transfer calculations to predict GRS reflection spectra. Comparison of those results with observed and previously unreported Cassini visible spectra and with true-color images of the GRS show that the unknown GRS chromophore is spectrally consistent with the coupled NH3-C2H2 photochemical products produced in our laboratory experiments. Using high-resolution mass spectrometry and infrared spectroscopy we infer that the chromophore-containing residue is composed of aliphatic azine, azo, and diazo compounds.
Copper-water heat pipes are commonly used for thermal management of electronics systems on earth and aircraft, but have not been used in spacecraft thermal control applications to date, due to the satellite industry's requirement that any device or system be successfully tested in a microgravity environment prior to adoption. Recently, Advanced Cooling Technologies Inc., (ACT), NASA Marshall Space Flight Center, and the International Space Station office at NASA's Johnson Space Center demonstrated flight heritage in Low-Earth Orbit. The testing was conducted aboard the International Space Station (ISS) under the Advanced Passive Thermal eXperiment (APTx) project. The heat pipes were embedded in a high conductivity (HiK"TM") aluminum base plate and subject to a variety of thermal tests over a temperature range of -10 to 38 ºC for a ten-day period. Results showed excellent agreement with both predictions and ground tests. In addition, novel hybrid wick aluminum-ammonia heat pipes are developed to handle heat flux requirements for spacecraft thermal control applications. The 5-10 W/cm2 heat density limitation of aluminum-ammonia grooved heat pipes has been a fundamental limitation in the current design for space applications. The recently demonstrated 50 W/cm2 capability of the hybrid high heat flux heat pipes provides a realistic means of managing the high heat density anticipated for the next generation space designs.
Copper-water heat pipes are commonly used for thermal management of electronics systems on earth and aircraft, but have not been used in spacecraft thermal control applications to date, due to the satellite industry's requirement that any device or system be successfully tested in a microgravity environment prior to adoption. Recently, Advanced Cooling Technologies Inc., (ACT), NASA Marshall Space Flight Center, and the International Space Station office at NASA's Johnson Space Center demonstrated flight heritage in Low-Earth Orbit. The testing was conducted aboard the International Space Station (ISS) under the Advanced Passive Thermal eXperiment (APTx) project. The heat pipes were embedded in a high conductivity (HiK "TM") aluminum base plate and subject to a variety of thermal tests over a temperature range of -10 to 38 C for a ten-day period. Results showed excellent agreement with both predictions and ground tests. In addition, novel hybrid wick aluminum-ammonia heat pipes are developed to handle heat flux requirements for spacecraft thermal control applications. The 5-10 W/cm2 heat density limitation of aluminum-ammonia grooved heat pipes has been a fundamental limitation in the current design for space applications. The recently demonstrated 50W/cm2 capability of the hybrid high heat flux heat pipes provides a realistic means of managing the high heat density anticipated for the next generation space designs.
Results are presented on full-scale performance testing of vacuum-regenerable, carbon based sorbent monoliths for trace-contaminant (TC) removal integrated with the Rapid-Cycle Amine (RCA) swing bed for use in the Portable Life Support System (PLSS) during Extravehicular Activities (EVAs). The current state-of-art in TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is difficult to regenerate. The carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. Data on cyclic sorption-desorption of ammonia, which is a major TC of concern, were collected in a simulated PLSS ventilation loop which involved the RCA placed upstream of the Trace Contaminant Control System (TCCS). Results of testing involving pressure-swing operation of the integrated TCCS/RCA system indicate ammonia-removal efficiency exceeding 80% throughout multiple sorption-desorption cycles. This paper presents an overview of the TCCS research, the favorable results obtained, and provides insight into future work needed to further the technology development.
A system according to the principles of the present disclosure includes a storage estimation module and an air/fuel ratio control module. The storage estimation module estimates a first amount of ammonia stored in a first selective catalytic reduction (SCR) catalyst and estimates a second amount of ammonia stored in a second SCR catalyst. The air/fuel ratio control module controls an air/fuel ratio of an engine based on the first amount, the second amount, and a temperature of a substrate disposed in the second SCR catalyst.
There has been an increasing interest in the use of natural refrigerants in order to minimize the environmental impact of air conditioning and refrigeration equipment. This article is focused on the performance characterization of two widely accepted natural refrigerants; ammonia and propane for heat pump applications. Different cycle configurations including basic vapor compression cycle, cycle with liquid-line/suction-line heat exchanger and a two-stage flash economizer cycle have been analyzed for the performance evaluation of ammonia and propane in comparison to R-134a and R410A. The ultimate objective is to evaluate the performance of a heat pump utilizing natural refrigerants perform in relatively warm and cold climate with minimum environmental impact.
In one aspect, the disclosure relates to relates to heterogeneous catalysts useful for the synthesis of ammonia under microwave irradiation, processes for preparing the disclosed heterogeneous catalysts, and processes for synthesizing ammonia using the heterogeneous catalysts with microwave irradiation. In various aspects, the disclosed heterogeneous catalysts comprise: a metal selected from Group 7, Group 8, Group 9, Group 10, Group 11, or combinations thereof; a metal oxide support; and optionally a promoter material. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.
A method and system for membrane-assisted production of high purity concentrated dimethyl carbonate by the reaction of carbon dioxide and methanol is provided. Carbon dioxide is recovered from flue gas or other dilute streams from industrial processes by a membrane and subsequent conversion takes place to an intermediate methyl carbamate by reacting of carbon dioxide with ammonia and methanol. For high-purity carbon dioxide obtained by one of the carbon capture technologies or by a process (such as, for example, ethanol fermentation process) the membrane reactor is replaced with a catalytic reactor for direct conversion of carbon dioxide to methyl carbamate by reacting with ammonia and methanol. The methyl carbamate is further reacted with methanol for conversion to dimethyl carbonate. An integrated reactive distillation process using side reactors is used for facilitating the catalytic reaction in the subject method for producing high purity dimethyl carbonate.
The present invention discloses a series of ammonia decomposition catalysts, the method of making such catalysts and the use of such catalysts. The said catalysts are made of composite metal or metal alloys supported on composite oxides or nitrides as the catalyst supports. The catalysts are useful in ammonia decomposition at various temperatures and pressures, including temperatures below 500° C. and pressures up to 30 atm.
Ammonia gas is a potential uranium (U) remediation technique for the vadose zone at the Department of Energy's (DOE) Hanford Site in Washington State via pH manipulation. The objective of this work was to investigate U removal from the aqueous phase and mineral dissolution with either NaOH or NH{sub 4}OH in order to understand ammonia as a remediation technique for the vadose zone. Batch experiments were designed to investigate the fate of U and mineral dissolution upon treatment with either NaOH or NH{sub 4}OH. These experiments investigated mineral dissolution and U partitioning in the presence of pure minerals (quartz, kaolinite, illite, montmorillonite, muscovite) and sediments relevant to the Hanford site in either NaCl or synthetic groundwater formulated based on the Hanford site groundwater components. Analysis of mineral dissolution via measurement of major cations has demonstrated that there is a significant increase in dissolution of minerals with basic treatment and likely greater secondary precipitation for the NH{sub 4}OH as compared to NaOH treatment for clay minerals and Hanford sediments. (authors)
The present invention is directed to a method and system for enhancing the production of ammonia from gaseous hydrogen and nitrogen. Advantageously, the method and system does not emit carbon gases during production. The method and system enhances the production of ammonia compared to traditional Haber-Bosch reactions.
In this set of experiments, the focus is on developing a high entropy alloy catalyst to decompose ammonia into it two basic atomic elements; N2 and H2. 2𝑁𝐻3 ⇌ 𝑁2 + 3𝐻2 This must be done for the purpose of industrial release of ammonia into the atmosphere in a safer, healthier way. The goal behind this project was to create a catalyst with equal efficiency to ruthenium-based catalysts, which are the current industry standard. Using ruthenium at scale is cost prohibitive and is a hinderance to higher adoption of a hydrogen fuel economy.
This data set contains NH3 mixing ratios, net ecosystem NH3 exchange, and supporting information measured at a tall tower (KCMP, 244 meter) site near St. Paul, Minnesota, USA. The data include NH3 and H2O mixing ratios measured at the 100 meter level, as well as NH3 mixing ratio measured at the 56 meter level. Wind data was measured using a sonic anemometer at the 185 meter level. Also included in this data set are values of wet N and NH3 deposition from 2016 - 2018. This data was collected to improve understanding of the ammonia and reactive nitrogen budget for the region.Ammonia mixing ratios were filtered for periods when the NH3 analyzer measured anomalous (i.e. 10 mmol mol-1) water vapor mixing ratios based on comparison with the IRGA (LI7000). Further, we filtered out NH3 observations obtained during strongly condensing conditions. These periods were identified when the water vapor mixing ratio differences between the 100 m and 56 m levels were more negative than -0.5 mmol mol-1 (i.e. when the water vapor gradient was strong and directed toward the land surface). Finally, we filtered out NH3 fluxes when the atmosphere was strongly stable (i.e. when (z-d)/L exceeded a value of +4.5) and subject to decoupling from the surface fluxes. Approximately 35.1% of the hourly flux data were either missing due to instrument failure or filtered according to the above quality control procedures.
Abstract Nitrosospira briensis C-128 is an ammonia-oxidizing bacterium isolated from an acid agricultural soil. N. briensis C-128 was sequenced with PacBio RS technologies at the DOE-Joint Genome Institute through their Community Science Program (2010). The high-quality finished genome contains one chromosome of 3.21 Mb and no plasmids. We identified 3073 gene models, 3018 of which are protein coding. The two-way average nucleotide identity between the chromosomes of Nitrosospira multiformis ATCC 25196 and Nitrosospira briensis C-128 was found to be 77.2 %. Multiple copies of modules encoding chemolithotrophic metabolism were identified in their genomic context. The gene inventory supports chemolithotrophic metabolism with implications for function in soil environments.
This dataset contains measurements of gaseous ammonia (NH3(g)) at the S2 (Mt. Airy) site during the CoURAGE study from April to June 2025. This dataset includes 10-minute and 30-minute average NH3(g) concentrations in units of micrograms per cubic meter. Measurements are conducted with an AiRRmonia NH3 analyzer manufactured by RR Mechatronics. A data flag of -999 indicates missing data due to the instrument being offline (maintenance, calibration, etc.) while a data flag of -888 indicates measurements below the instrument LOD (LOD = 0.1 micrograms per cubic meter). The uncertainty of the measurements is 15%.
The electrochemical reduction of nitrates (NO 3 − ) enables a pathway for the carbon neutral synthesis of ammonia (NH 3 ), via the nitrate reduction reaction (NO 3 RR), which has been demonstrated at high selectivity. However, to make NH 3 synthesis cost-competitive with current technologies, high NH 3 partial current densities (j NH3 ) must be achieved to reduce the levelized cost of NH 3 . Here, the high NO 3 RR activity of Fe-based materials is leveraged to synthesize a novel active particle-active support system with Fe 2 O 3 nanoparticles supported on atomically dispersed Fe–N–C. The optimized 3×Fe 2 O 3 /Fe–N–C catalyst demonstrates an ultrahigh NO 3 RR activity, reaching a maximum j NH3 of 1.95 A cm −2 at a Faradaic efficiency (FE) for NH 3 of 100% and an NH 3 yield rate over 9 mmol hr −1 cm −2 . Operando XANES and post-mortem XPS reveal the importance of a pre-reduction activation step, reducing the surface Fe 2 O 3 (Fe 3+ ) to highly active Fe 0 sites, which are maintained during electrolysis. Durability studies demonstrate the robustness of both the Fe 2 O 3 particles and Fe–N x sites at highly cathodic potentials, maintaining a current of −1.3 A cm −2 over 24 hours. This work exhibits an effective and durable active particle-active support system enhancing the performance of the NO 3 RR, enabling industrially relevant current densities and near 100% selectivity.
Catalysts for the oxidation of NH 3 will be critical to utilize NH 3 as a large-scale energy carrier. Molecular complexes have not been shown to catalyze the oxidation of NH 3 to N 2 . We report Ru- catalyzed oxidation of ammonia to dinitrogen under ambient conditions using the molecular complex [Cp*Ru(P t Bu 2 N Ph 2 )( 15 NH 3 )][BAr F 4 ]. Mediating the cleavage of six N-H bonds and the formation of an N≡N bond was achieved by coupling H + and e - transfers as net hydrogen atom abstraction steps using the 2,4,6-tri- t ert-butylphenoxyl radical ( t Bu 3 ArO•) as the H atom acceptor. Employing an excess of t Bu 3 ArO• under 1 atm of NH 3 gas at 23 °C resulted in up to six turnovers. As a result, nitrogen isotopic ( 15 N) labeling studies provide mechanistic insights to confirm the N≡N bond forming step in the catalytic cycle.