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During summer, ammonia emissions in Southeast Asia influence air pollution and cloud formation. Convective transport by the South Asian monsoon carries these pollutant air masses into the upper troposphere and lower stratosphere (UTLS), where they accumulate under anticyclonic flow conditions. This air mass accumulation is thought to contribute to particle formation and the development of the Asian Tropopause Aerosol Layer (ATAL). Despite the known influence of ammonia and particulate ammonium on air pollution, a comprehensive understanding of the ATAL is lacking. In this modelling study, the influence of ammonia on particle formation is assessed with emphasis on the ATAL. We use the EMAC chemistry-climate model, incorporating new particle formation parameterisations derived from experiments at the CERN CLOUD chamber. Our diurnal cycle analysis confirms that new particle formation mainly occurs during daylight, with a 10-fold enhancement in rate. This increase is prominent in the South Asian monsoon UTLS, where deep convection introduces high ammonia levels from the boundary layer, compared to a baseline scenario without ammonia. Our model simulations reveal that this ammonia-driven particle formation and growth contributes to an increase of up to 80% in cloud condensation nuclei (CCN) concentrations at cloud-forming heights in the South Asian monsoon region. We find that ammonia profoundly influences the aerosol mass and composition in the ATAL through particle growth, as indicated by an order of magnitude increase in nitrate levels linked to ammonia emissions. However, the effect of ammonia-driven new particle formation on aerosol mass in the ATAL is relatively small. Ammonia emissions enhance the regional aerosol optical depth (AOD) for shortwave solar radiation by up to 70%. We conclude that ammonia has a pronounced effect on the ATAL development, composition, the regional AOD, and CCN concentrations. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of oxygen concentration on ammonia combustion, the effect of oxygen concentration on ammonia combustion and its mechanism were systematically investigated by using the ReaxFF molecular dynamics simulations and density functional theory (DFT) calculations. The results show that different oxygen concentrations significantly affect the concentration of reactants, free radicals, intermediates and products in the ammonia combustion process. High oxygen concentration significantly increases the concentration of free radicals, which effectively promotes the ammonia reaction. However, more free radicals such as ·H and ·OH are produced in the early stage of the reactions, which react with ·NH 2 radicals. It promotes the production of the intermediates HNO and indirectly inhibits the production of the intermediates N 2 H 4 and N 2 H 2. It promotes the production of NO X. The results of the DFT calculations show that the relative Gibbs free energy barrier of the reaction of ·OH with NH 3 is low at 1.00 kcal/mol, so the increase in ·OH concentration greatly facilitates the reaction of NH 3. These results not only identify the intrinsic effect of oxygen concentration on ammonia combustion and its mechanisms, but also provide some theoretical guidance for the study of efficient and clean ammonia utilization. • NH 3 combustion with different O 2 numbers was studied by ReaxFF MD simulations. • The main chain reactions of NH 3 combustion were studied by DFT calculations. • The effect of O 2 concentration on NH 3 combustion was studied by DFT calculations. • High oxygen concentration promotes the NH 3 combustion. • High oxygen concentration promotes the production of NO X of NH 3 combustion. [ABSTRACT FROM AUTHOR]

The reduction of nitrogen oxides (NOx), critical pollutants from stationary to mobile sources, mainly relies on the selective catalytic reduction (NH3-SCR) method, employing ammonia to reduce NOx into nitrogen and water. However, conventional catalysts, while effective, pose both environmental and operational challenges. This study investigates ceria-zirconia-supported molybdenum-based catalysts, exploring the effects of zirconium doping and different catalyst synthesis techniques, i.e., co-precipitation and impregnation. The catalytic performance of the differently prepared samples was significantly influenced by the molybdenum incorporation method and the zirconium content within the ceria-zirconia support. Co-precipitation at higher temperatures resulted in catalysts with better structural attributes but slightly lower catalytic activity compared to those prepared via impregnation. Optimal NOx reduction (close to 100%) was observed at a 15 mol% zirconium doping level when using the impregnation method. [ABSTRACT FROM AUTHOR]

Performance of available air-source heat pumps (ASHP) for buildings is extremely influenced by the outdoor air temperature (OAT). When OAT falls below –20 °C, especially in subarctic climate, most commercially available ASHPs lose their defined functionality. To address this issue, a novel cascade heat pump (CHP) is proposed that utilizes two natural (with zero global warming index) refrigerants: ammonia, aka R717, as the low stage (LS) refrigerant, and water, aka R718, as the high stage (HS) working fluid. The proposed system is equipped with two rotary vane compressors for LS and HS. To desuperheat the compressor discharge temperatures and increase the HS heating capacity, liquid refrigerant is injected into the chamber of both LS and HS compressors. The wet compression is thermodynamically modeled and validated against experimental data available in the literature. Optimum design parameters such as the maximum allowable temperatures during compression and the minimum vapor quality after injection are obtained where the COP is maximized. Total exergy destruction, number/location of injectors and the injected amounts are also investigated. The proposed CHP can deliver 6.35 kW heating load at 50 °C with a COP of 1.985 when OAT is –40 °C. From a broader perspective, the proposed CHP not only proves its efficacy in extremely cold subarctic climates but also emerges as a pivotal player in addressing the global warming issue. This is accomplished through a dual approach to decarbonization—firstly, by electrifying heating processes and secondly, by substituting phased-out refrigerants with environmentally friendly natural alternatives. [ABSTRACT FROM AUTHOR]

In South Korea, environmental complaints related to livestock odors continue to increase, and various efforts are underway to overcome them. An objective of this study is to monitor indoor concentrations of ammonia and sulfur-based odorous substances emitted from laying hen houses in South Korea through on-site visits for one year to understand their temporal emission patterns. The highest concentration was found in ammonia (NH3), at 6.92 ppmv, followed by hydrogen sulfide (H2S), at 8.98 ppbv. The concentrations of methyl mercaptan (CH3SH), dimethyl sulfide (DMS), and dimethyldisulfide (DMDS) ranged from sub ppbv to 10 ppbv. In general, there was no consistent concentration distribution of ammonia and sulfur-based odorous substances in laying hen houses between those with forced ventilation and natural ventilation. Regarding the seasonal distribution of odorous compounds, their concentrations in winter season (December to February) when the ventilation rate in laying hen houses decreased were generally higher than those in the summer season (June to August) when the ventilation rate in poultry buildings was relatively high, which is applied to properly maintain the thermal environment in laying hen houses. The limitation of this study is that unexpected conditions such as clearance of laying hen houses, chicken shipments, and disorders of exhaust fans were not controlled for intentionally due to on-site investigations. [ABSTRACT FROM AUTHOR]

Current understanding of the ammonia distribution in Jupiter's atmosphere is provided by observations from major ground‐based facilities and spacecraft, and analyzed with sophisticated retrieval models that recover high fidelity information, but are limited in spatial and temporal coverage. Here we show that the ammonia abundance in Jupiter's upper troposphere, which tracks the overturning atmospheric circulation, can be simply, but reliably determined from continuum‐divided ammonia and methane absorption‐band images made with a moderate‐sized Schmidt‐Cassegrain telescope (SCT). In 2020–2021, Jupiter was imaged in the 647‐nm ammonia absorption band and adjacent continuum bands with a 0.28‐m SCT, demonstrating that the spatially resolved ammonia optical depth could be determined with such a telescope. In 2022–2023, a 619 nm methane‐band filter was added to provide a constant reference against which to correct the ammonia abundances (column‐averaged mole fraction) for cloud opacity variations. These 0.28‐m SCT results are compared with observations from: (a) the MUSE instrument on ESO's Very Large Telescope (b) the TEXES mid‐infrared spectrometer used on NASA's InfraRed Telescope Facility; and (c) the Gemini telescopes, and are shown to provide reliable maps of ammonia abundance. Meridional and longitudinal features are examined, including the Equatorial Zone (EZ) ammonia enhancement, the North Equatorial Belt depletion, depletion above the Great Red Spot, and longitudinal enhancements in the northern EZ. This work demonstrates meaningful ammonia monitoring can be achieved with small telescopes that can complement spacecraft and major ground‐based facility observations. Plain Language Summary: On Jupiter, ammonia—in addition to water—forms clouds, precipitates, and evaporates. The main clouds we see are commonly thought to be made of ammonia ice, with "coloring agents" that provide sometimes vivid hues. Where ammonia is and is not provides a powerful tracer of weather processes on Jupiter, making it important for understanding the planet and others like it. Most measurements of ammonia are made using large astronomical facilities or spacecraft. However, because of competition for observing time at large telescope facilities and the limited views of spacecraft, professional observations may only occur a few times a year or only cover part of Jupiter. We show here that useful measurements of ammonia can be made with small telescopes and equipment available to many amateur astronomers. By comparing images that show absorption due to ammonia and methane gases, we can determine the variation in the amount of ammonia in and above Jupiter's clouds. We have compared our small telescope measurements with those from large professional telescopes and found similar results on the distribution of ammonia. Our observation method means that non‐professional observers can fill observational gaps and provide context for professional observing campaigns. Key Points: Ground‐based, narrow‐band imaging with a small telescope reveals spatially resolved ammonia abundance in Jupiter's upper troposphereValues from disk‐averages, meridional profiles, and two‐dimensional maps compare favorably with large instrument resultsSmall observatory observations can offer frequent observations to provide context and continuity for professional research programs [ABSTRACT FROM AUTHOR]

Dairy slurry could be a significant source of nitrogen (N) for plants, but mismanagement can lead to atmospheric ammonia losses or nitrate leaching into groundwater. To make the use of dairy slurry efficient and reasonable, the loss of N pollution to the environment should be reduced. We used repacked lysimeters to comprehensively determine ammonia emission and N leaching losses in an alfalfa–soil system. The application of dairy slurry had no significant effect on alfalfa yield at the same rate of N application in comparison to chemical fertilizer, and adding humic acids significantly increased yield by about 12%. However, the application of dairy slurry increased the ammonia emission rate significantly, leading to an increase in the cumulative amount of ammonia emission, while the addition of humic acids reduced the ammonia emissions by 11%. Chemical fertilizer and dairy slurry application significantly increased nitrate leaching compared to the control treatment, while the addition of humic acids can significantly reduce ammonium N leaching. Dairy slurry was proven to be as effective as chemical N fertilizer in achieving the optimum biomass, and adding humic acids can significantly reduce N loss to the atmosphere and groundwater. This study showed the possibility of replacing chemical fertilizer with dairy slurry in alfalfa production and the advantages of humic acids' addition to alfalfa to maintain production yield and improve environmental friendliness. [ABSTRACT FROM AUTHOR]

The conversion of atmospheric nitrogen (N2) into ammonia (NH3), known as nitrogen fixation, plays a crucial role in sustaining life on Earth, facing innovation with electrocatalytic and photocatalytic methods. These approaches promise gentler conversions from atmospheric nitrogen to ammonia, diverging from the energy‐intensive Haber‐Bosch process, which requires complex plant infrastructure. Vitality lies in eco‐friendly, cost‐effective, and energy‐efficient pathways. The challenge is that electrocatalysts and photocatalysts for nitrogen reduction have shown low Faraday efficiency, hampered by hydrogen evolution. This work delves into recent strides in electro/photo‐catalytic nitrogen fixation/reduction, deciphering mechanisms, catalysts, and prospects. By unveiling the core principles steering these processes, it dissects efficiency drivers. Experimental and theoretical studies, ranging from density functional calculations/simulations to machine learning‐based catalyst screening, mark the path toward highly efficient catalysts, including single/multi‐atom catalysts embedded in 2D materials. The journey explores diverse catalysts, assessing their performance, spotlighting emerging nanomaterials, heterostructures, and co‐catalyst techniques. Perspectives on future directions and potential applications of electro/photo‐catalytic nitrogen fixation/reduction are offered, by emphasizing their role in sustainable nitrogen management and their implications for global agriculture and environmental sustainability. [ABSTRACT FROM AUTHOR]

Ammonia, being a carbon-free fuel, is garnering increasing attention in the combustion community. However, its application is still impeded by its limited stability range and significantly NOx emissions. This study delves into the impact of primary and overall equivalence ratios (ϕ pri and ϕ ovr) on emissions production in ammonia–hydrogen co-firing flames, utilizing a two-stage swirling model gas turbine combustor. The emissions concentration is measured using Fourier Transform Infrared Spectroscopy (FTIR). The physical and chemical processes influencing emissions production are comprehensively analyzed through a combination of Large Eddy Simulation (LES) and Flamelet-Generated Manifold (FGM) method. The reliability of the simulation is validated by the experimental data, showing a good capability in predicting the combustion. Results indicate that the two-stage combustion strategy exhibits significantly controlling effects on NOx and unburned NH 3 emission. The NO emission exhibits a non-monotonic variation with ϕ pri , reaching its lowest value at ϕ pri ≈ 1.2. Further analysis shows that ϕ pri plays a crucial role in determining the temperature and OH concentration in the primary combustion zone, thereby influencing NOx production in this area. When the primary zone is operated at lean condition, the reduction on NO in secondary zone is primarily attributed to dilution effect by the secondary air. In contrast, when ϕ pri > 1, the concentrations of the main emissions in secondary zone are dominated by chemical effects. In this scenario, unburned NH 3 and H 2 from the primary zone are consumed, resulting in a substantial production of NO in the secondary combustion zone. Additionally, with an increase in ϕ pri , the secondary NO production also increases. The ϕ ovr exhibits two considerable effects. On one hand, an increase in ϕ ovr results in a higher local equivalence ratio in the secondary zone, thereby promoting local NOx production. Simultaneously, the elevated flame temperature enhances the consumption of N 2 O. On the other hand, the rise in ϕ ovr results in a reduction in vortex scale and residence time in the secondary combustion zone, leading to a decrease in local NO production. • The NOx mitigation of NH 3 /H 2 /air co-firing flames have been achieved through the secondary staged air. • The proposed LES-FGM method was validated adequate predicting the flow field and emission characters. • The impact of primary and overall equivalence ratio on emissions have been revealed in-depth. • The optimal operating condition for emission control in the current combustor has been proposed. [ABSTRACT FROM AUTHOR]

Artificial ammonia synthesis via the Haber‐Bosch process is environmentally problematic due to the high energy consumption and corresponding CO2 ${_2 }$ emissions, produced during the reaction and before hand in hydrogen production upon methane steam reforming. Photocatalytic nitrogen fixation as a greener alternative to the conventional Haber‐Bosch process enables us to perform nitrogen reduction reaction (NRR) under mild conditions, harnessing light as the energy source. Herein, we systematically review first‐principles calculations used to determine the electronic/optical properties of photocatalysts, N2 adsorption and to expound possible NRR mechanisms. The most commonly studied photocatalysts for nitrogen fixation are usually modified with dopants, defects, co‐catalysts and Z‐scheme heterojunctions to prevent charge carrier recombination, improve charge separation efficiency and adjust a band gap to for utilizing a broader light spectrum. Most studies at the atomistic level of modeling are grounded upon density functional theory (DFT) calculations, wholly foregoing excitation effects paramount in photocatalysis. Hence, there is a dire need to consider methods beyond DFT to study the excited state properties more accurately. Furthermore, a few studies have been examined, which include higher level kinetics and macroscale simulations. Ultimately, we show there is still ample room for improvement with regard to first principles calculations and their integration in multiscale models. [ABSTRACT FROM AUTHOR]

Hydrogen-bonded interactions of organic acids play crucial role in many chemical and biochemical processes vital for life's maintenance. They are important as well in the context of secondary aerosol formation in the atmosphere. In the present work, we study the nature of hydrogen-bonded acid–base interactions present in the binary clusters of vanillic acid, a natural phenolic compound found in various plants and also observed in Amazonian aerosol, with common atmospheric bases such as ammonia and methylamines (mono-, di-, and tri-methylamine). Detailed and systematic quantum-chemical DFT calculations have been performed to analyze the structural, energetic, electrical, and spectroscopic properties of the clusters. The presence of strong intermolecular hydrogen-bonds and large binding electronic energies indicates that vanillic acid interacts strongly with atmospheric molecules. Scattering intensities of radiation (Rayleigh activities) are found to increase with cluster formation. The changes in binding free energy and enthalpy of formation of the vanillic acid-ammonia/amine binary clusters at lower temperatures demonstrate increased thermodynamical stability. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) from animal feeding operations (AFOs) is an important source of reactive nitrogen in the US, but despite its ramifications for air quality and ecosystem health, its near‐source evolution remains understudied. To this end, Phase I of the Transport and Transformation of Ammonia (TRANS2Am) field campaign was conducted in the northeastern Colorado Front Range in summer 2021 and characterized atmospheric composition downwind of AFOs during 10 research flights. Airborne measurements of NH3, nitric acid (HNO3), and a suite of water‐soluble aerosol species collected onboard the University of Wyoming King Air research aircraft present an opportunity to investigate the sensitivity of particulate matter (PM) formation to AFO emissions. We couple the observations with thermodynamic modeling to predict the seasonality of ammonium nitrate (NH4NO3) formation. We find that during TRANS2Am northeastern Colorado is consistently in the NH3‐rich and HNO3‐limited NH4NO3 formation regime. Further investigation using the Extended Aerosol Inorganics Model reveals that summertime temperatures (mean: 23°C) of northeastern Colorado, especially near the surface, inhibit NH4NO3 formation despite high NH3 concentrations (max: ≤114 ppbv). Finally, we model spring/autumn and winter conditions to explore the seasonality of NH4NO3 formation and find that cooler temperatures could support substantially more NH4NO3 formation. Whereas NH4NO3 only exceeds 1 μg m−3 ∼10% of the time in summer, modeled NH4NO3 would exceed 1 μg m−3 61% (88%) of the time in spring/autumn (winter), with a 10°C (20°C) temperature decrease relative to the campaign. Plain Language Summary: Animal feeding operations (AFO; i.e., feedlots for large‐scale meat/dairy production) emit large amounts of ammonia into the atmosphere. Gas‐phase ammonia can change into aerosol‐phase ammonium (i.e., gas‐aerosol partitioning) and contribute to particulate matter air pollution. In this study, we try to understand whether ammonia emitted from AFOs is forming aerosols, and if so, what mechanisms are governing the gas‐aerosol transfer between ammonia and ammonium. To do so, we flew a research aircraft downwind of several AFOs in northeastern Colorado in summer 2021 and measured a suite of gases and aerosols (and temperature and relative humidity). We measured high amounts of ammonia gas and low amounts of ammonium aerosols, so the observations alone only indicate that ammonia from AFOs likely is not a significant source of summertime PM2.5. We then put our observations into an aerosol thermodynamic model and learned that summertime northeastern Colorado is too hot and dry to favor aerosol formation despite high amounts of ammonia. We also make some approximations of spring/autumn and winter conditions in the model and learn that the cooler temperatures could potentially support substantial PM2.5 formation. This means that ammonia from AFOs could be a significant source of wintertime PM2.5 pollution in Northeastern Colorado. Key Points: Ammonium nitrate formation in summertime over northeastern Colorado is ammonia‐rich and nitrate‐limitedObservations and model analyses indicate that <300 m agl, ammonium nitrate is usually <1 μg m−3 and inhibited by warmer temperaturesCooler temperatures during spring/autumn and winter in northeastern Colorado are predicted to support substantial NH4NO3 formation [ABSTRACT FROM AUTHOR]

The variability of the shortwave radiative fluxes at the surface and top of atmosphere (TOA) is examined in a pre‐industrial modeling setup using the Pacific Decadal Oscillation (PDO) as a possible pacemaker of atmospheric decadal‐scale variability. Within models from the Coupled Model Intercomparison Project—Phase 6, downwelling shortwave radiation at the surface, the net shortwave fluxes at the surface and TOA, as well as cloud radiative effects show remarkably similar patterns associated with the PDO. Through ensemble simulations designed with a pure PDO pattern in the North Pacific only, we show that the PDO relates to about 20%–40% of the unforced year‐to‐year variability of these shortwave fluxes over the Northern Hemispheric continents. The sea surface temperature imprint on shortwave‐flux variability over land is larger for spatially aggregated time series as compared to smaller areas, due to the blurring effect of small‐scale atmospheric noise. The surface and TOA radiative flux anomalies associated with the PDO index range of [−1.64; 1.64] are estimated to reach up to ±6 Wm−2 for North America, ∓3 Wm−2 for India and ±2 Wm−2 for Europe. We hypothesize that the redistribution of clouds in response to a North Pacific PDO anomaly can impact the South Pacific and North Atlantic SSTs. Plain Language Summary: We investigate how solar radiation at Earth's surface and the top of the atmosphere, which are mainly controlled by cloudiness, can vary over decades as a response to a horseshoe pattern typical for the North Pacific sea surface temperatures (SSTs)—the Pacific Decadal Oscillation (PDO). We use idealized climate model simulations to show that about a third of the year‐to‐year changes in solar radiation over the Northern Hemispheric continents are related to this phenomenon. These changes are more noticeable when looking at large areas rather than small ones, as high frequency smaller scale atmospheric variations can obscure the bigger picture. By keeping the PDO fixed to a constant negative value, implying below average cold sea surface temperatures off the western coast of North America and warmer than average temperatures toward Japan, we show that North America and Europe exhibit a reduction in cloudiness, while clouds increase in India. The same with an opposite sign is true for a positive PDO anomaly. These changes in cloud patterns might further affect SSTs in the South Pacific and North Atlantic oceans. Key Points: The Pacific Decadal Oscillation (PDO) is a prominent pacemaker for variability, accounting for about 1/3 of the shortwave flux year‐to‐year variability over NH continentsA negative PDO anomaly leads to a reduction in atmospheric shortwave reflectivity (clouds) in North America and Europe and an increase in IndiaThe redistribution of clouds in response to a North Pacific PDO anomaly might influence SSTs in the South Pacific and North Atlantic [ABSTRACT FROM AUTHOR]

The In-O-Mo bond-modulated In 2 O 3 /Bi 2 MoO 6 S-scheme heterostructure was synthesized using the static electron assembly method. At the heterostructure interface, the formation of In-O-Mo bonds serves as an essential pathway for rapid carrier transfer/transport, resulting in carrier-oriented accumulation and significantly improving PNRR performance. [Display omitted] • In 2 O 3 /Bi 2 MoO 6 photocatalysts were synthesized using a mild electrostatic assembly method. • The formation of In-O-Mo bond at the heterogeneous interface was critical for rapid charge-carrier transportation and carrier oriented accumulation. • The carrier-oriented accumulation of carriers can trigger PNRR and OER half-reactions, facilitating efficient photocatalytic N 2 -to-NH 3 conversion. • 3 % In/BMO-based S-scheme heterostructure realized a nitrogen fixation rate of 150.9 μmol·g cat −1·h−1, demonstrating a significant performance improvement. Photocatalytic nitrogen fixation presents an eco-friendly approach to converting atmospheric nitrogen into ammonia (NH 3), but the process faces challenges due to rapid interface charge recombination. Here, we report an innovative charge transfer and oriented accumulation strategy using an In-O-Mo bond-modulated S-scheme heterostructure composed of In 2 O 3 /Bi 2 MoO 6 (In/BMO) synthesized using a simple electrostatic assembly. The unique interfacial arrangement with optimal photocatalyst configuration (3 % In/BMO) enabled enhanced photogenerated electron separation and transfer, leading to a remarkable nitrogen fixation rate of approximately 150.9 μmol·g cat −1·h−1 under visible light irradiation. The performance of the photocatalyst was 9-fold and 27-fold higher than that of its pristine components, Bi 2 MoO 6 and In 2 O 3 , respectively. The experimental and theoretical evaluation deemed interfacial In-O-Mo bonds crucial for rapid transfer and charge-oriented accumulation. Whereas the generated internal electric field drove the spatial separation and transfer of photo-generated electrons and holes, significantly enhancing the photocatalytic N 2 -to-NH 3 conversion efficiency. The proposed work lays the foundation for designing S-scheme heterostructures with highly efficient interfacial bonds, offering a promising avenue for substantial improvements in photocatalytic nitrogen fixation. [ABSTRACT FROM AUTHOR]

Despite long-standing interest in the biogeochemistry of the Santa Barbara Basin (SBB), there are no direct rate measurements of different nitrogen transformation processes. We investigated benthic nitrogen cycling using in situ incubations with 15 NO 3- addition and quantified the rates of total nitrate (NO 3-) uptake, denitrification, anaerobic ammonia oxidation (anammox), N 2 O production, and dissimilatory nitrate reduction to ammonia (DNRA). Denitrification was the dominant NO 3- reduction process, while anammox contributed 0 %–27 % to total NO 3- reduction. DNRA accounted for less than half of NO 3- reduction except at the deepest station at the center of the SBB where NO 3- concentration was lowest. NO 3- availability and sediment total organic carbon content appeared to be two key controls on the relative importance of DNRA. The increasing importance of fixed N retention via DNRA relative to fixed N loss as NO 3- deficit intensifies suggests a negative feedback loop that potentially contributes to stabilizing the fixed N budget in the SBB. Nitrous oxide (N 2 O) production as a fraction of total NO 3- reduction ranged from 0.2 % to 1.5 %, which was higher than previous reports from nearby borderland basins. A large fraction of NO 3- uptake was unaccounted for by NO 3- reduction processes, suggesting that intracellular storage may play an important role. Our results indicate that the SBB acts as a strong sink for fixed nitrogen and potentially a net source of N 2 O to the water column. [ABSTRACT FROM AUTHOR]

Ba-based perovskite oxides rich in oxygen vacancies (OVs) are anticipated to possess robust electron-donating capabilities and other favourable properties, rendering them a promising support for Ru catalysts in NH 3 synthesis. Herein, a glucose-urea deep eutectic solvent calcinating method was developed to synthesize an OV-rich BaTiO 3 (BTO-H) support for Ru catalysts. The BTO-H-supported Ru (Ru/BTO-H) catalyst achieves an impressive NH 3 synthesis rate of 5133 μmol g cat –1 h−1 (256.7 mmol g R u –1 h−1) at 400 °C and 0.1 MPa, surpassing the performance of Ru catalysts supported on OV-poor BTO supports and other supported Ru catalysts. Physical characterizations and kinetic experiments reveal the multifaceted influence of OVs on enhancing the catalytic performance of Ru/BTO-H in NH 3 synthesis. OVs serve as electron donors to Ru catalyst, facilitating the activation and dissociation of N 2. Simultaneously, OVs act as hydrogen acceptors from the Ru surface, mitigating hydrogen poisoning effects. Additionally, OVs stimulate the formation of surface hydrides, not only providing active sites for N 2 activation but also bestowing an electron-donating effect on the supported Ru catalyst. The combined positive effects of OVs establish BTO-H as an outstanding support for Ru catalysts in NH 3 synthesis. • A glucose-urea DES calcinating method was used to synthesize BaTiO 3 (BTO) support. • BTO support had rich oxygen vacancies and large specific surface area (70 m2 g−1). • Oxygen vacancies in BTO support played multiple roles in NH 3 synthesis. • BTO-supported Ru catalyst exhibited an NH 3 synthesis rate of 5133 μmol g-1 cat h−1. [ABSTRACT FROM AUTHOR]

Micro-tubular ceramic electrochemical reactors have attracted significant interest due to their high packing density, large electrode specific surface area, and long triple phase boundaries (TPBs). In this work, a micro-tubular proton-conducting ceramic electrochemical reactor (MT-PCER) with a unique microstructure is facilely constructed for ammonia synthesis at atmospheric pressure. BaCe 0.7 Zr 0.1 Y 0.2 O 3-δ (BCZY as the electrolyte)/Ni–BaCe 0.7 Zr 0.1 Y 0.2 O 3-δ (Ni-BCZY as the catalytic cathode) dual-layer hollow fibers with open finger-like pores on the inner surface are first fabricated using a modified co-spinning/co-sintering process to form a basic MT-PCER. Fe-based catalyst was then coated into these open finger-like pores in Ni-BCZY layer as an additional catalytic cathode of the MT-PCER. The unique open finger-like pores structure of the basic MT-PCER decreases the mass transfer resistance and also provides space for loading additional catalysts, contributing towards the higher catalytic performance of the MT-PCER. However, the Faradaic efficiency for ammonia formation remained low, indicating that the cathode catalyst required further improvement. This fabrication technique provides a flexible method to adjust the cathode catalysts to optimize the catalytic performance of the MT-PCERs. NH 3 production via the upgraded micro-tubular proton-conducting ceramic electrochemical reactor (MT-PCER) at atmospheric pressure. [Display omitted] • MT-PCER is prepared by a one-step co-spinning/co-sintering method. • The microstructure of MT-PCER is redesigned into a new morphology. • The new MT-PCER facilitates mass transfer and provides space for catalyst loading. • It provides a flexible method to adjust the cathode catalysts of MT-PCER. [ABSTRACT FROM AUTHOR]

The transport of hydrogen in used natural gas pipelines is a strategic key element of a pan-European hydrogen infrastructure. At the same time, accurate knowledge of the hydrogen quality is essential in order to be able to address a wide application range. Therefore, an experimental investigation was carried out to find out which contaminants enter into the hydrogen from the used natural gas pipelines. Pipeline elements from the high pressure gas grid of Austria were exposed to hydrogen. Steel pipelines built between 1960 and 2018, which were operated with odorised and pure natural gas, were examined. The hydrogen was analysed according to requirements of ISO14687: 2019 Grade D measurement standard. The results show that based on age, odorization and sediments, different contimenants are introduced. Odorants, hydrocarbons but also sulphur compounds, ammonia and halogenated hydrogen compounds were identified. Sediments are identified as the main source of impurities. However, the concentrations of the introduced contaminants were low (6 nmol/mol to 10 μmol/mol). Quality monitoring with a wide range of detection options for different components (sulphur, halogenated compounds, hydrocarbons, ammonia and atmospheric components) is crucial for real operation. The authors deduce that a Grade A hydrogen quality can be safely achieved in real operation. • Adequate hydrogen quality can be achieved in used natural gas pipes. • Grade A would be reached safely in normal operation of the sampled pipelines. • Detection of odorants from natural gas operations can be confirmed. • Sediments in the pipe are found to be the main source of contamination. • Newer pipes without solid deposits hardly carry any detectable impurities in hydrogen. [ABSTRACT FROM AUTHOR]

Simple Summary: Soybean meal is one of the main high-quality protein feedstuffs and deficient in China, and the sustainability of the beef cattle industry is facing more and more challenges. It is essential to seek efficient alternative N sources to ensure a steady increase in beef production. The in vitro and in vivo experiments were conducted to test if dietary isobutyramide and slow-release urea could benefit animal performance, rumen fermentation, nutrient digestibility, and blood parameters and develop a new strategy for substituting soybean meal in beef cattle. We suggest the optimal strategy is the isonitrogenous substitution of soybean meal with 0.3% slow-release urea and 0.6% isobutyramide of the diet. Two experiments were conducted to investigate the effects of isobutyramide (IBA) and slow-release urea (SRU) as substitutes for soybean meal (SBM) in the finishing diet of beef cattle. The completely randomized design in vitro experiment with five treatments, i.e., control, 0.9% SRU group, 0.6% SRU + 0.3% IBA group (SRU-I), 0.3% SRU + 0.6% IBA group (IBA-S), 0.9% IBA group was conducted. The results showed that the IBA-S and IBA increased (p ≤ 0.05) substrate disappearance of dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF), total gas, and total volatile fatty acids (TVFA). The SRU group had the highest (p < 0.01) crude protein disappearance and ammonia nitrogen concentration, but the IBA contrarily decreased (p < 0.01) them compared with the control. Inclusion of IBA increased isobutyrate concentrations (p = 0.01) with the highest value for the IBA group. Then, an 84-day replicate 4 × 4 Latin square design with 8 Angus steers and four treatments, i.e., control, SRU, SRU-I, IBA-S was performed. The results showed that the treatments did not affect DM intake (p > 0.05) but tended (p = 0.09) to increase average daily gain. The inclusion of IBA increased (p < 0.05) the apparent digestibility of DM, organic matter, NDF, ADF, TVFA, and microbial crude protein with the highest values for the IBA-S group. The IBA-contained groups also increased (p ≤ 0.01) isobutyrate concentration, activities of carboxymethyl cellulase and xylanase, and the relative abundance of Butyrivibrio fibrisolvens with the highest values for the IBA-S group. The SRU had no effect on animal growth and nutrient apparent digestibility. In conclusion, IBA was developed as a new substitute for SBM in the finishing diet of beef cattle, and the optimal strategy was the isonitrogenous substitution of SBM with 0.3% SRU and 0.6% IBA of the diet. [ABSTRACT FROM AUTHOR]

While ammonia (NH 3) and hydrogen (H 2) are promising carbon-free fuels, there are significant challenges presented by their combustion properties. Blending them can help mitigate some of these issues; however, the fundamental behaviors of these blends need to be well understood. A constant volume combustion chamber (CVCC) is used to study the emissions of nitrogen oxides (NO, NO 2 , N 2 O), laminar burning velocity (LBV), and intrinsic instabilities for H 2 -NH 3 blends across a wide range of equivalence ratios (Φ = 0.5 to 1.5) and volume fractions of H 2 in the blends (0% to 50%). Measurements of LBV are consistent with existing data where available. The largest NO x and N 2 O emissions are found at lean conditions and decrease significantly for rich mixtures. NO x emissions tend to increase with H 2 fractions in fuel for lean mixtures. Intrinsic instabilities are more prominent at lean conditions and heavily influenced by the amount of H 2 in the blend. [Display omitted] • NO x production peaks at Φ =0.7, increases with H 2 content for lean mixtures. • N 2 O production peaks at lowest Φ , no significant variation with H 2 content. • Higher H 2 content results in earlier and more pronounced flame wrinkling. • LBV and emissions data extends available range for mechanism validation. [ABSTRACT FROM AUTHOR]

The concentration of ammonia (NH3) and the temperature of the air surrounding the rabbit habitat in the farm condition basic health processes such as breathing and feeding. The indoor climate in a rabbit farm is largely conditioned by the ventilation system (air conditioning). The objective of this study was to build a numerical model based on computational fluid dynamics (CFD) in order to evaluate, by numerical simulations, the air dynamics of a rustic farm. After the validation of the computational model, the thermal gradient and ammonia concentration were analyzed under three wind incidence angles (0°, 45°, and 90° with respect to the horizontal Z axis of the facility). The results of the simulations showed that, in the area occupied by the rabbits (AOR), the concentration of ammonia with respect to the source was reduced by 37.3% in the most favorable case (wind direction at 45°), and 21.2% in the least favorable case (wind direction at 0°), and the indoor temperature presented a maximum difference of 2 °C with respect to the outside temperature. Climate control is a more expensive cost in rabbit farm exploitation; dynamics modulation can serve as an auxiliary tool for reducing health risks in rabbits. The use of models based on fluid dynamics allowed us to understand the efficiency of the ventilation system, which must be increased to reduce the found temperature gradient. Through numerical simulation it will be possible to find alternatives to increase the ventilation rate. [ABSTRACT FROM AUTHOR]

Wurtzite-type aluminum nitride (AlN) thin films exhibiting high thermal conductivity, large grain size, and low surface roughness are desired for both bulk acoustic wave and surface acoustic wave resonators. In this work, we use ammonia (NH3) assisted reactive sputter deposition of AlN to significantly improve these properties. The study shows a systematic change in the structural, thermal, and morphological properties of AlN grown in nitrogen (N2) and N2 + NH3 atmosphere. The study demonstrates that NH3 assisted AlN sputtering facilitates 2D growth. In addition, the study presents a growth model relating the 2D growth to improve the mobility of aluminum (Al) and nitrogen (N) ad-atoms in NH3 atmosphere. Consequently, the thermal conductivity and roughness improve by ≈ 76%, and ≈ 35%, while the grain size increases by ≈ 78%. [ABSTRACT FROM AUTHOR]

The estimation of material performance plays a crucial role in practical life, enabling the rational allocation of time and resources while enhancing the practical application of materials. Therefore, this study investigates the analytical and predictive capabilities of five machine learning (ML) algorithms (the Random Forest algorithm – RF, the Adaboost algorithm – AB, the Gradient Boosting algorithm – GB, the Extra Trees algorithm – ET and linear models – LM) for comprehensive performance parameters of wood ceramics (ammonia nitrogen adsorption quantity - Q , open porosity - P , burn-off , and hardness). In the analysis of model prediction capabilities, five key statistical parameters (Root Mean Square Error - RMSE , Mean Square Error - MSE , Coefficient of Correlation - R , Determination Coefficient - R 2 , and Mean Absolute Relative Error - MARE) were calculated. The results indicate the following: (1) Among various ML models, the GB model exhibits the most superior performance with an R 2 ≥ 0.9594. (2) However, in predicting the four performance parameters of wood ceramics, the AB model with an R 2 ranging from 0.0078 to 0.45, indicating notably poor predictive capabilities. Despite integrating the Support Vector Regression (SVR) module, no enhancement in predictive accuracy was observed. (3) While forecasting the four performance parameters of wood ceramics, the LM model demonstrates predictive accuracy relatively akin to that of the RF and ET models among the ML models. (4) Though the feature importance scores vary across distinct input variable models, there is a consistent trend of change. (5) Variables B and D exhibit some level of correlation with other variables. In summary, the results of this study suggest that, for the analysis and prediction of wood ceramic performance, the GB model among the five regression models demonstrates outstanding simulation performance. [ABSTRACT FROM AUTHOR]

The hydrogen carrier ammonia is considered a prominent carbon-free alternative fuel. This paper examines the impact of flue gas recirculation (FR) on combustion instability and emission behavior of premixed CH 4 /NH 3 /air swirl flame at different equivalence ratios (Φ) and ammonia mole fractions (χ NH 3 ). Experimental results show that FR is beneficial to suppressing the self-excited pulsating pressure and pulsating heat release rate of CH 4 /NH 3 /air flame, and the pulsating frequency decreases monotonically with the increase of FR. Under fuel-lean and stoichiometric conditions, FR is beneficial to suppressing NOx formation but will increase CO and NH 3 emissions. Under fuel-rich conditions, FR reduces CO emissions but increases NOx emissions. The NO emissions obtained from the chemical reactor network simulation are in qualitative agreement with the experimental results. The results show that the elementary reactions related to HNO and NHi radicals play a crucial role in the influence of FR on NO formation. • Flue gas recirculation (FR) suppresses combustion instability of CH 4 /NH 3 /air flame. • FR decreases NOx emission but increases CO emission under non-rich conditions. • FR increases NOx emission but decreases CO emission under fuel-rich conditions. • Chemical reactor network reveals the main reactions of FR affecting NO formation. [ABSTRACT FROM AUTHOR]

The low flame speed and NO x emissions of ammonia are the key to affecting combustion temperature, stability, flame structure, and pollutant control, limiting its application in power generation devices. This study proposes oxy-ammonia combustion (oxygen content in oxidant = 100%, NH 3 /O 2 combustion) as a novel method for significantly enhancing ammonia combustion. A method for measuring the laminar flame speed using the NH* distribution of the Bunsen burner flame is proposed, and the measured data is close to the constant volume combustion bomb. 21 kinetic models were collected and optimized after comparison with the experimental data of constant volume combustion bombs, and results show that Han et al.'s model has higher prediction accuracy for NH 3 /O 2 flames. The preheating temperature was relevant to gas turbine combustors (298.15–500 K), and the equivalence ratio ranged from 0.7 to 1.6. At this extreme condition (oxygen content in oxidant = 100%), the results show that the maximum laminar flame speed reaches 1.25 m/s at ambient pressure and temperature, which is approximately 18 times that of NH 3 /air combustion, mainly due to the increased reaction rates of OH, H, O and NH 2 radicals in the reaction zone (primary ammonia decomposition and H/O radical pool). The NO emission of NH 3 /O 2 combustion at stoichiometric conditions is about 7216 ppmv@15%O 2 , 1.5 and 13 times that of NH 3 /air and CH 4 /air combustion, respectively. NO production and consumption may follow the N 2 O and NNH mechanism, and HNO is an important precursor for NO formation. Increasing the preheating temperature has less effect on the reaction pathway directions in the reaction network of nitrogen conversion but affects the path flux significantly. [Display omitted] • Oxy-fuel combustion enhances the ammonia combustion to "m/s" level. • Active radical pools and ammonia primary decomposition determine flame speeds. • N 2 O–NNH mechanism dominates nitric oxide production and consumption. • Preheating and fuel-lean conditions promote ammonia primary decomposition. • HNO is the dominant precursor of nitric oxide and competes with NH radicals. [ABSTRACT FROM AUTHOR]

An enhanced formation of brown carbon (BrC) with a non-negligible warming effect at the tropopause has recently been found. However, its formation mechanism is unclear. Here we report a BrC formation process that happens during air mass upward transport by conducting simultaneously a 4-hour time resolution of measurement on atmospheric BrC at the mountain foot (MF, 400 m a.s.l.) and mountainside (MS, 1120 m a.s.l.) of Mt. Hua, China in 2016 summer. Our results showed that the daytime light-absorption (Abs365nm) of BrC at MS is approximately 60 % lower than that at MF due to a dilution effect caused by the planetary boundary layer expansion, but the daytime light-absorption of BrC relative to black carbon at MS is about 30 % higher than that at MF, suggesting a significant formation of secondary BrC in the lifting process of air mass from MF to MS. Such a secondary formation accounted for >50 % of BrC at MS but only 27 % of BrC at MF. Moreover, N:C elemental ratio of the daytime BrC was 15 % higher at MS than that at MF, mainly due to an aerosol aqueous phase formation of water-soluble organic nitrogen (WSON) compounds. Stable nitrogen isotope composition further indicated that such light-absorbing WSON compounds were produced from the aerosol aqueous-phase reaction of carbonyls with NH4+. Our work for the first time revealed that ammonia-induced aerosol aqueous reactions can significantly promote BrC formation during the air mass lifting process, which is probably responsible for an enhanced light absorption of BrC in the upper troposphere. [ABSTRACT FROM AUTHOR]

To improve the compatibility and flame retardance of kaolinite (Kaol) in polymeric materials, ammonium dihydrogen phosphate (ADP) was intercalated into kaolinite to obtain a novel intercalated kaolinite (K‐ADP) for enhancing thermal stability, flame retardance, smoke suppression, and mechanical performance of epoxy resins (EPs). The results show that the presence of K‐ADP exerts a more positive effect on reducing the heat release and smoke generation of EPs than the same addition of Kaol. Condensed phase analysis shows that EP/K‐ADP composite generates more aromatic cross‐links in the condensed phase to reinforce the compactness and intumescence of char compared to EP/Kaol composite. Especially, 5 wt% K‐ADP confers a 43.7% reduction in peak heat release rate value and a 36.3% reduction in peak smoke production rate value to EP. Toxic gases analysis shows that K‐ADP conduces to inhibiting the release of combustible gases including isocyanates and aromatic volatiles, and generating incombustible gases including ammonia and carbon dioxide to reduce the intensity of EP combustion. The mechanical test shows that K‐ADP imparts less adverse impact on mechanical behavior to EP composites than Kaol due to the good dispersion and compatibility between K‐ADP with EP matrix. [ABSTRACT FROM AUTHOR]

The use of ammonia and hydrogen as fuels to decarbonise the heavy transport industry has attracted worldwide attention. In this work, a swirl-enhanced combustion test rig has been built to investigate the combustion and emission characteristics of non-premixed ammonia/hydrogen flames. The blowoff limits were first examined to ensure that a range of stable flames could be achieved. Emissions containing nitric oxide (N O) , nitrous oxide (N O 2) , ammonia slip (N H 3) and unburnt hydrogen (H 2) were then measured with a variety of global equivalence ratios, hydrogen blending ratios, inlet gas temperature, swirl numbers and combustion chamber insulation conditions. The structure of non-premixed ammonia/hydrogen flames and the relationship between excited hydroxyl radicals (O H *) and N O emission were revealed using O H * chemiluminescence profiles. The stable non-premixed ammonia/hydrogen flames were achieved when the hydrogen blending ratio was greater than 20 %. The optimal emission performance was achieved under stoichiometric conditions, as determined by combustion efficiency. The insulation conditions of the combustor wall played a key role in the emission results, as significant growth of N O and N O 2 as well as a reduction of ammonia slip were found. Although a lower swirl number improved the flame stability range, the increases in N O and N O 2 emissions were observed. • Non-premixed ammonia/hydrogen swirl-enhanced combustion was tested. • Optimal emission control at stoichiometric conditions. • Higher hydrogen ratios, inlet temperature, and lower swirl numbers expand blowoff limits. • O H * intensity aligns with N O emissions when the same swirler was used. [ABSTRACT FROM AUTHOR]

The close-coupled selective catalytic reduction (cc-SCR) catalyst is an effective technology to reduce tailpipe NOx emission during cold start. This paper investigated the optimal ammonia storage under steady and transient state in the cc-SCR. The study showed that a trade-off between NOx conversion efficiency and ammonia slip is observed on the pareto solutions under steady state, and the optimal ammonia storage is calculated with ammonia slip less than 10 µL/L based on the China Ⅵ emission legislation. The rapid temperature increase will lead to severe ammonia slip in the transient test cycle. A simplified 0-D calculation method on ammonia slip under transient state is proposed based on kinetic model of ammonia adsorption and desorption. In addition, the effect of ammonia storage, catalyst temperature and temperature increasing rate on ammonia slip are analyzed. The optimal ammonia storage is calculated with maximum ammonia slip less than 100 µL/L according to the oxidation efficiency of ammonia slip catalyst (ASC) downstream cc-SCR. It was found that the optimal ammonia storage under transient state is much lower than that under steady state in cc-SCR at lower temperature, and a phase diagram is established to analyze the influence of temperature and temperature increasing rate on optimal ammonia storage. [ABSTRACT FROM AUTHOR]

Turbidity has been one of the most typical problems in urban rivers, accompanied by eutrophication. Though the colloid is a nonnegligible factor associated with turbidity and nutrient enrichment in urban rivers, the characteristics of nitrogen enrichment and bacterial communities of colloids under different turbidity conditions of urban rivers have not been well understood. In this study, colloids of low and high molecular weights (LMW, 30 kDa–0.2 μm, and HMW, 0.2–1 μm) were separately collected from the bulk water (<1 μm) of several typical urban rivers in China. Since the colloidal concentration presented the significantly highest correlation with turbidity, colloidal characteristics were further explored under three turbidity gradients with two cutoffs of 10 and 30 NTU. Results showed that colloidal organic matter in medium and high turbidity rivers was mainly sourced from the release of endogenous plankton and the proportion of colloidal organic carbon in dissolved organic carbon increased from 33% to 38% with increased turbidity. Colloidal ammonia nitrogen in medium turbidity accounted for the highest proportion (an average of 60%) in bulk water, which could be explained by the significantly positive correlation of colloidal ester groups and ammonia nitrogen (R2 = 0.47). Bulk water, HMW, and LMW colloids presented different dominant bacterial genera and LMW colloids also contained three unique dominant filterable genera: Flavobacterium, Acinetobacter, and Limnohabitans. LMW colloidal filterable bacteria under medium and high turbidities presented the greatest potential for dissimilatory nitrate reduction to ammonium, which might further enhance the enrichment of ammonia nitrogen in colloids. This study provides a primary understanding of the characteristics of colloids and colloidal bacterial communities in urban rivers from the perspective of turbidity and puts a new insight on the remediation of rivers under medium turbidity. [ABSTRACT FROM AUTHOR]

New particle formation (NPF) in the free troposphere (FT) is thought to be a significant source of particles over the oceans. The entrainment of particles initially formed in the marine FT is further suspected to be a major contributor to cloud condensation nuclei (CCN) number concentrations in the marine boundary layer (BL). Yet, little is known about the process and, more broadly, about the composition of the marine FT, which remains poorly explored due to access difficulties. Here we report measurements performed in April 2018 at the Maïdo Observatory with a nitrate-based chemical ionization atmospheric pressure interface time-of-flight mass spectrometer, which have allowed the first molecular-level characterization of the remote marine FT composition. A number of molecules and clusters were identified and classified into nine groups according to their chemical composition; among the identified species, the groups containing methanesulfonic acid (MSA) and C2 amines show signals that are on average significantly higher when the site is under conditions representative of the marine FT (compared to the BL). The correlation analysis revealed apparent connections between the signals of the identified compounds and several variables concurrently measured at the site (under FT conditions) or related to air mass history, suggesting that oxalic acid, malonic acid, and observed C2 amines could be of terrestrial origin, with, in addition, a possible marine source for oxalic acid and amines, while iodic acid, sulfur species, and maleic acid have a dominant marine origin. Identification of FT conditions at the site was based on the analysis of the standard deviation of the wind direction; this parameter, which can easily be derived from continuous measurements at the site, is shown in the first part of the study to be a relevant tracer when compared to predictions from the Meso-NH atmospheric model. Similar to other high-altitude sites, FT conditions are mainly encountered at night at Maïdo; therefore, the link to NPF could not be established, and further research is needed to assess the composition of precursors to nanoparticle formation in the marine FT. [ABSTRACT FROM AUTHOR]

In this study, natural clinoptilolite was treated with HCl, HNO3, and C2H2O4 at various concentrations (0.1, 0.5, and 1.0 M) at different temperatures (60, 70, and 80 °C) and treatment times (2, 3, and 4 h). The hydrogen adsorption capacity of natural clinoptilolite increased from 0.446 to 3.255 mmol/g after treating with 0.5 M HNO3 at 80 °C for 2 h. The correlation of the newly produced textural and structural properties with hydrogen adsorption ability is explained by characterizing the modified clinoptilolites using X-ray fluorescence (XRF), X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, and temperature programmed desorption of ammonia (NH3-TPD) measurements. The results show that the hydrogen adsorption capacity of modified clinoptilolites is associated with both the quantity and strength of the strong acid sites, in addition to the enhanced surface area and micropore volume. The hydrogen adsorption data for natural and acid-treated clinoptilolite samples at 77 K obeyed the Freundlich isotherm model. [ABSTRACT FROM AUTHOR]

Atmospheric ammonia (NH3) is a chemically active trace gas that plays an important role in the atmospheric environment and climate change. Satellite remote sensing is a powerful technique to monitor NH3 concentration based on the absorption lines of NH3 in the thermal infrared region. In this study, we establish a retrieval algorithm to derive the NH3 column from the Hyperspectral Infrared Atmospheric Sounder (HIRAS) onboard the Chinese FengYun (FY)-3D satellite and present the first atmospheric NH3 column global map observed by the HIRAS instrument. The HIRAS observations can well capture NH3 hotspots around the world, e.g., India, West Africa, and East China, where large NH3 emissions exist. The HIRAS NH3 columns are also compared to the space-based Infrared Atmospheric Sounding Interferometer (IASI) measurements, and we find that the two instruments observe a consistent NH3 global distribution, with correlation coefficient (R) values of 0.28–0.73. Finally, some remaining issues about the HIRAS NH3 retrieval are discussed. [ABSTRACT FROM AUTHOR]

As an important irritant trace gas in the atmosphere, ammonia (NH3) significantly impacts human health and environment. Bottom-up emission inventories are widely used to estimate ammonia emissions and their geographical distributions over China. However, high uncertainties are still associated with emission inventories due to inaccurate emission factors used. The Differential Evolution (DE) algorithm is a population-based stochastic optimization algorithm used to solve complicated optimization problems. We quantify NH3 emissions and lifetime from Infrared Atmospheric Sounding Interferometer (IASI) NH3 observations together with MERRA-2 wind fields based on the DE algorithm. Two inland cities, Urumchi and Golmud in China, are chosen to study of the NH3 emissions based on the distributions of NH3 total columns and wind fields. The NH3 emissions rate estimated is about 5.84 × 10−11 and 4.19 × 10−11 kg·m−2s−1 in Urumchi and in the Golmud area from May to September from 2008 to 2023, respectively. The lifetime of NH3 estimated in the two areas is 4.31 and 9.19 h, respectively. We compare the NH3 emissions and lifetime estimated in this study with the values in other studies, and the results show the reliability of the method used. This work is one of few quantitative studies of NH3 emissions from cities using satellite observations in China. [ABSTRACT FROM AUTHOR]

The interaction of plants and soil bacteria rhizobia leads to the formation of root nodule symbiosis. The intracellular form of rhizobia, the symbiosomes, are able to perform the nitrogen fixation by converting atmospheric dinitrogen into ammonia, which is available for plants. The symbiosis involves the resource sharing between two partners, but this exchange does not include equivalence, which can lead to resource scarcity and stress responses of one of the partners. In this review, we analyze the possible involvement of the autophagy pathway in the process of the maintenance of the nitrogen-fixing bacteria intracellular colony and the changes in the endomembrane system of the host cell. According to in silico expression analysis, ATG genes of all groups were expressed in the root nodule, and the expression was developmental zone dependent. The analysis of expression of genes involved in the response to carbon or nitrogen deficiency has shown a suboptimal access to sugars and nitrogen in the nodule tissue. The upregulation of several ER stress genes was also detected. Hence, the root nodule cells are under heavy bacterial infection, carbon deprivation, and insufficient nitrogen supply, making nodule cells prone to autophagy. We speculate that the membrane formation around the intracellular rhizobia may be quite similar to the phagophore formation, and the induction of autophagy and ER stress are essential to the success of this process. [ABSTRACT FROM AUTHOR]

[Display omitted] • The CeCoMnO x spinel-type catalyst prepared using oxalic acid precipitant has a more favorable physicochemical structure for NO conversion than that prepared using alkaline precipitant. • 400 °C is the optimum calcination temperature for oxalic acid precipitated CeCoMnO x spinel for NH 3 -SCR reaction. • The oxalic acid precipitated CeCoMnO x calcined at 400 °C has nearly 100 % NO conversion at 100–200 °C at GHSV = 15,000 mL·g−1·h−1. • An interface-enhanced redox macrocycle mechanism incorporating acid cycling is proposed for oxalic acid precipitated CeCoMnO x catalysts. CeCoMnO x spinel-type catalysts for the selective catalytic reduction of NO using NH 3 (NH 3 -SCR) are usually prepared by alkaline co-precipitation. In this paper, a series of CeCoMnO x spinel-type catalysts with different calcination temperatures were prepared by acidic oxalate co-precipitation. The physicochemical structures and NH 3 -SCR activities of the CeCoMnO x spinel-type catalysts prepared by oxalate co-precipitation and conventional ammonia co-precipitation were systematically compared. The results show that the CeCoMnO x spinel-type catalysts prepared by the oxalate precipitation method (CeCoMnO x -C) have larger specific surface area, more mesopores and surface active sites, stronger redox properties and adsorption activation properties than those prepared by the traditional ammonia co-precipitation method at 400 °C (CeCoMnO x -N-400), and thus CeCoMnO x -C have better low-temperature NH 3 -SCR performance. At the same calcination temperature of 400 °C, the NO conversion of CeCoMnO x -C-400 exceeds 89 % and approaches 100 % within the reaction temperature of 100–125 °C, which is 14.8 %-2.5 % higher than that of CeCoMnO x -N-400 at 100–125 °C. In addition, the enhanced redox and acid cycle matching mechanisms on the CeCoMnO x -C surface, as well as the enhanced monoadsorption Eley-Rideal (E-R) and double adsorption Langmuir-Hinshelwood (L-H) reaction mechanisms, are also derived from XPS and in situ DRIFTS characterization. [ABSTRACT FROM AUTHOR]

The growth and sustainable development of humanity is heavily dependent upon molecular nitrogen (N2) fixation. Herein we discover ambient catalyst-free disproportionation of N2 by water plasma which occurs via the distinctive HONH-HNOH+• intermediate to yield economically valuable nitroxyl (HNO) and hydroxylamine (NH2OH) products. Calculations suggest that the reaction is prompted by the coordination of electronically excited N2 with water dimer radical cation, (H2O)2+•, in its two-center-three-electron configuration. The reaction products are collected in a 76-needle array discharge reactor with product yields of 1.14 μg cm–2 h–1 for NH2OH and 0.37 μg cm–2 h–1 for HNO. Potential applications of these compounds are demonstrated to make ammonia (for NH2OH), as well as to chemically react and convert cysteine, and serve as a neuroprotective agent (for HNO). The conversion of N2 into HNO and NH2OH by water plasma could offer great profitability and reduction of polluting emissions, thus giving an entirely look and perspectives to the problem of green N2 fixation. The growth and sustainable development of humanity is heavily dependent upon N2 fixation. Herein, authors developed an ambient catalyst-free disproportionation of N2 by water plasma to yield economically valuable nitroxyl and hydroxylamine products. [ABSTRACT FROM AUTHOR]

Simple Summary: This study assesses the risk of ammonia exposure in broiler chicken production and correlates these risks with health issues, utilizing machine learning techniques. Two broiler breeds, fast-growing (Ross®, 42 days) and slow growing (Hubbard®, 63 days), were studied at different densities. Slow-growing birds had a fixed density of 32 kg/m2, while fast-growing ones were housed at low (16 kg/m2) and high (32 kg/m2) densities. The high concentration of atmospheric ammonia has been associated with a greater occurrence of bird health problems, such as pododermatitis, visual impairment and mucosal lesions compared to birds stocked in controlled environments with low concentrations of atmospheric ammonia. A total of 1250 birds were used, and classification algorithms (decision tree, SMO, Naive Bayes, and Multilayer Perceptron) were applied to predict ammonia risk levels. The analysis involved data selection, pre-processing, transformation, mining, and interpretation of results. The Multilayer Perceptron proved the most effective in predicting exposure risk. The Spearman's correlation coefficient indicated a strong correlation between high ammonia concentrations and higher incidences of injuries in the birds that were evaluated. This research highlights the importance of managing ammonia levels in broiler production to mitigate health risks for both fast- and slow-growing breeds. The study aimed to forecast ammonia exposure risk in broiler chicken production, correlating it with health injuries using machine learning. Two chicken breeds, fast-growing (Ross®) and slow-growing (Hubbard®), were compared at different densities. Slow-growing birds had a constant density of 32 kg m−2, while fast-growing birds had low (16 kg m−2) and high (32 kg m−2) densities. Initial feeding was uniform, but nutritional demands led to varied diets later. Environmental data underwent selection, pre-processing, transformation, mining, analysis, and interpretation. Classification algorithms (decision tree, SMO, Naive Bayes, and Multilayer Perceptron) were employed for predicting ammonia risk (10–14 pmm, Moderate risk). Cross-validation was used for model parameterization. The Spearman correlation coefficient assessed the link between predicted ammonia risk and health injuries, such as pododermatitis, vision/affected, and mucosal injuries. These injuries encompassed trachea, bronchi, lungs, eyes, paws, and other issues. The Multilayer Perceptron model emerged as the best predictor, exceeding 98% accuracy in forecasting injuries caused by ammonia. The correlation coefficient demonstrated a strong association between elevated ammonia risks and chicken injuries. Birds exposed to higher ammonia concentrations exhibited a more robust correlation. In conclusion, the study effectively used machine learning to predict ammonia exposure risk and correlated it with health injuries in broiler chickens. The Multilayer Perceptron model demonstrated superior accuracy in forecasting injuries related to ammonia (10–14 pmm, Moderate risk). The findings underscored the significant association between increased ammonia exposure risks and the incidence of health injuries in broiler chicken production, shedding light on the importance of managing ammonia levels for bird welfare. [ABSTRACT FROM AUTHOR]

The inhibitory action of Schiff base complexes of 3d metals against the urease enzyme is well explored in the scientific community. However, the ability of such complexes in mimicking active metallobiosites of urease enzymes, possessing ureolytic behavior, still remains unexplored. With this aim firstly, two Zn(II)-complexes (PPR-HMB-Zn and PZ-HMB-Zn) have been developed from two different Schiff base ligands (HL1 = 2-((E)-(2-(piperidin-1-yl)ethylimino)methyl)-5-methylphenol and HL2 = 2-((E)-(2-(piperizin-1-yl)ethylimino)methyl)-5-methylphenol) and structurally characterized using single crystal XRD. The hydrolytic enzymatic activity of both complexes was demonstrated by the gradual increase in the absorption maxima at 425 nm for the formation of the p-nitrophenolate ion from catalytic hydrolysis mediated by the Zn(II) complexes with a disodium salt of p-nitrophenyl phosphate as a model substrate. Associated kinetic parameters, pH dependency and a relevant hydrolysis mechanism have also been explored. After confirming the hydrolytic ability, the complexes were exploited to mimic the hydrolytic activity of Jack bean urease that catalytically hydrolyses urea into ammonia and CO2. The change in the pH of the solution owing to the formation of ammonia under the complex catalysed hydrolytic action of urea has been monitored spectrophotometrically using the pH dependent structural change of phenol red. The amount of ammonia has been quantified using the Nessler's reagent spectrophotometric method. The ureolytic reaction mechanism has been investigated using density functional theory (DFT) calculations using the B3LYP and TPSSH methods for the systematic calculation of the interaction energy. In contrast to PZ-HMB-Zn, PPR-HMB-Zn functions more effectively as a catalyst due to the existence of a lattice-occluded water molecule in its crystal structure and the protonation of the non-terminal N to attract urea by H-bonding, which was further confirmed by AIM analysis. [ABSTRACT FROM AUTHOR]

Nitrogen deposition is an important means of exogenous nitrogen input in reservoir water. Agricultural activities around the reservoir lead to a sharp increase in the concentration of ammonia in the atmosphere, which poses a threat to the reservoir water body. Clarifying the contribution of agricultural ammonia release to atmospheric NH x (gaseous NH 3 and particulate NH 4 +), in the reservoir area can provide a theoretical foundation for local reactive nitrogen control. We collected atmospheric NH 3 and NH 4 + samples during the agricultural periods and analyzed the isotopic characteristics of atmospheric NH x and the contribution rates of different ammonia sources in the Xichuan area of the Danjiangkou Reservoir. The results showed that the initial δ15N values of NH 3 (–30.0‰ to –7.2‰) and particulate NH 4 +(–33‰ to +4.9‰ for finer and coarser particles, respectively) are different, and their contribution ratios from dissimilar ammonia sources are also different, among which NH 4 + is more susceptible to meteorological factors. However, since the atmospheric NH x in the Xichuan area is mainly gaseous NH 3 , the final sources of atmospheric ammonia nitrogen source depend on gaseous NH 3. Agricultural sources (59%-74%) were the main NH 3 sources in this area. Among them, the fertilizer use emission was dominant; it had the highest contribution rate in summer during the agricultural period and a more prominent impact in areas with less human interference. Reasonable regulation of the application of high-ammonia releasing fertilizer, especially during the agricultural period in summer, is an effective way to reduce the threat of atmospheric ammonia to water health. [Display omitted] [ABSTRACT FROM AUTHOR]

This work investigates the effect of chemical structural positioning of different functional groups in 29 amines covering primary, secondary and tertiary alkanolamines as well as multi-alkylamines and cyclic amines on both amine degradation and ammonia (NH3) emissions during post-combustion amine-based carbon dioxide capture. The results helped to elucidate possible relationships between degradation and emissions as related to the chemical structure of the amine. The results showed that longer alkyl chain lengths in multi-alkylamines caused a more drastic decrease in both degradation and NH3 emissions followed by secondary alkanolamines. The decrease in those activities for primary and tertiary alkanolamines as well as cyclic amines was low and more so for NH3 emissions. In contrast, the increase in hydroxyl groups in secondary alkanolamines caused a drastic increase in degradation and NH3 emissions. On the other hand, having more hydroxyl groups in sterically hindered primary and tertiary alkanolamines caused a more drastic decrease in degradation and a smaller decrease in NH3 emissions due to the steric hindrance within their structure. An increase in the number of amino groups in an amine caused an increase in both degradation and NH3 emission rates because these provided the reactive sites for the formation of free radicals. This effect was not as large in alkyl-cyclic amines as in multi-alkylamines due to the ability of the former to resist oxidative degradation. Furthermore, branched alkyl groups between amino and hydroxyl groups more drastically increased both the degradation and NH3 emission activities than branched alkyl groups located at the nitrogen atom. [ABSTRACT FROM AUTHOR]

Reducing the environmental issues brought on by nutrients especially nitrogen pollution and loss is important. Owing to its unique composition and physico-chemical characteristics, biomass-derived biochar exhibits varying degrees of adsorption and interception for all types of soil nutrients. Thus, a novel way to improve nutrient absorption in the soil is to include biomass derived biochar into it. Various biomass-derived biochar from locally available biobased substances was synthesized through low-cost portable charring kiln. It has been quantified the influence of four biobased substances and three pyrolysis temperature on different morphomineralogical characteristics of biochar for utilizing as low-cost sorbent to manage nutrient adsorption and retention capacity. The morphomineralogical characteristics were principally manipulated by feedstocks rather than pyrolysis temperature. Higher porosity and surface area of biomass-derived biochar illustrated its soil structural modification and nutrient retention capacity along with their utilization for adsorbents. With increase in pyrolysis temperature, the adsorption capacity of biochar for NH4+-N and NO3−-N was gradually weakened and gradually enhanced respectively. The adsorption process of ammonia nitrogen and nitrate nitrogen conformed to the Langmuir model and the fitted KL value was less than 1 indicating that the adsorption process was uniform monolayer adsorption and the adsorption of biochar was favorable adsorption. With increase in biochar application rate the leaching of NO3−-N decreased having higher at 2.5 t ha−1 application rate followed by 5 t ha−1 and lower at 7.5 t ha−1. In packed soil column, the NH4+-N in leachate was maximum in T7 (18.6), followed by T4 (17.9), T13 (17.3) and minimum in T10 (17.2) at same application rate of manures and biochar. Finally, results also revealed that packed soil column performed better as compared with intact soil column to retain soil nutrient and hence, leaching potential of nutrient was less in packed column than intact soil column. In conclusion, biomass-derived biochar can enhance the amount of nutrient that is absorbed into the soil while decreasing the loss of nutrient from the soil in the form of ammonia and nitrate. To sum up, biomass-derived biochar can increase the adsorption amount of the nitrogen and reduce the loss of ammonia nitrogen and nitrate nitrogen in the soil, thus retaining the nitrogen. [ABSTRACT FROM AUTHOR]

Wastewater containing high concentrations of ammonium-nitrogen (NH4+-N) is considered a major concern because its untreated discharge has a variety of adverse effects on the environment and human health. Adsorption using biochars is an easy and cost-effective wastewater treatment method. However, aquatic plants such as water hyacinth for biochar feedstock are considered unsuitable for adsorbent use due to limited NH4+-N adsorption capacity. In this study, biochar made from water hyacinth was modified with potassium hydroxide (KOH) and hydrogen peroxide (H2O2) to obtain highly efficient adsorbent. This study aimed to enhance NH4+-N adsorption capacity by KOH- and H2O2-treatments and identify NH4+-N adsorption mechanism of the modified biochars derived from water hyacinth. The NH4+-N adsorption of all biochars was dependent on the initial solution pH increasing from pH 2 to 4, then relatively constant from pH 4 to 8. Pseudo-second-order model and Langmuir model were found to be the best fit for NH4+-N adsorption data. The maximum NH4+-N adsorption capacity of biochars increased about 8 times (17.1 mg g−1) and 10 times (21.5 mg g−1) after KOH- and H2O2-modification, respectively, compared to pristine biochar (2.14 mg g−1). The main NH4+-N adsorption mechanisms were suggested as cation exchange for both biochars particularly KOH-modified biochar, and hydrogen bonding by oxygen-containing surface functional groups for H2O2-modified biochar. This study suggested that aquatic plant-based biochar, which has been considered difficult to use, had potential as a promising alternative adsorbent for removing NH4+-N from wastewater through modification. [ABSTRACT FROM AUTHOR]

Fuel recirculation is a system configuration designed to improve the fuel utilization of fuel cells by recirculating the unreacted fuels at the outlet to the fuel inflow stream. In this study, fuel recirculation of a solid oxide fuel cell (SOFC) operated with ammonia is investigated. Recirculation operation results in a notable elevation of nitrogen content within the cell, originating from the decomposition of ammonia within the cell and subsequently reintroduced into the inflow stream. Therefore, the fuel flow rate needs to be increased to maintain the fuel utilization level the same as the base operation, which is an ammonia-fueled operation without recirculation. A multiscale model of an SOFC stack is used to compare the base operation and saturated level of the recirculation operation cases based on their polarization curves and distributions of ammonia, hydrogen, current density, temperature, first principal stress, and nitriding in the fuel electrode. The results show that overall stack performance, as reflected in the polarization curves, remains comparable between the base and recirculation operation cases. The power densities exhibit a difference of less than 2% between the base and recirculation operation cases. Moreover, it is indicated that the recirculation operation cases lead to more uniform hydrogen and current density distributions, lower temperature gradients, and lower thermal stresses. The results demonstrate that the recirculation operation cases lead to a reduction of up to 38% in the maximum tensile stresses within the fuel support layer. Nevertheless, these recirculation operation cases also induce nitriding across a larger portion of the active area. But as shown here this is a challenge that can effectively be addressed by applying nickel coatings to the inlet headers. • Overall stack performance remains comparable for the base and AOR operation cases. • AOR operation results in more uniform hydrogen and current density distributions. • AOR operation decreases temperature gradients, reducing thermal stresses. • AOR operation increases nitriding across a broader portion of the active area. • Mitigation of nitriding is achievable through nickel coatings over inlet headers. [ABSTRACT FROM AUTHOR]

Combustion is the cornerstone for generating energy in various sectors and applications. The predominance of hydrocarbons combustion causes several environmental and human health issues. The ever-increasing demand for decarbonization of combustion technologies in order to reduce or eliminate undesirable emissions has created a major challenge, putting tremendous pressure on the international research community to develop alternative fuels. Ammonia has recently been explored as a promising carbon-free fuel and a great alternative to hydrocarbon fuels to achieve zero-carbon emissions. However, despite its advantages over hydrogen, ammonia combustion has some drawbacks including low burning velocity, flame stability, and high NOx emissions. This review begins with energy and environmental issues before moving on to hydrogen and ammonia as promising potential solutions, their advantages and drawbacks, and ammonia combustion kinetics. It summarises the principles of chemical kinetics of both ammonia combustion and NOx reduction coupled with the chemistry, kinetic mechanisms and impact of plasma on ammonia combustion. The effects of plasma on ammonia combustion and NOx reduction are also discussed, with a comparison of NOx reduction mechanisms and plasma approach. Finally, the review discusses the perspectives and challenges of using plasma in ammonia combustion. [Display omitted] • Plasma assisted ammonia combustion. • Advantages and drawbacks of ammonia combustion with kinetics. • NOx reduction coupled kinetics and impacts of plasma on ammonia combustion. • Perspectives and challenges of plasma ammonia combustion technologies. [ABSTRACT FROM AUTHOR]

The addition of renewable fuel to hydrocarbon fuel mitigated the carbon monoxide, carbon dioxide and soot particle emissions of internal combustion engines. A comparative study of the ammonia and hydrogen effect on combustion and emission characteristics of n-hexadecane flames was executed at various flame conditions. The results showed that alternative fuels had a stronger impact on peak temperature at diffusion flame conditions rather than at premixed flame conditions. The premixed flame released carbon monoxide emission lower than the diffusion flames with/without additional fuels. The carbon monoxide emissions decreased highly with ammonia enrichment instead of hydrogen. At premixed and coflow diffusion flame conditions, the ammonia highly reduced carbon dioxide emission compared to hydrogen. Hydrogen addition reduced the nitrogen oxide emission, whereas it was increased by ammonia. The soot particle number density was reduced highly by hydrogen addition instead of ammonia at the premixed flow flame and diffusion coflow flame conditions. The impact of hydrogen on the reduction of soot mass concentration emissions was greater than that of ammonia at all combustion conditions. It is suggested that H 2 ≥ 70% should be mixed in n-hexadecane fuel because a higher burning velocity can be achieved with a higher emission reduction. A reduction in the emission of carbon-related species can be realized with a small reduction in burning velocity at NH 3 < 70%. • Comparative study of H 2 and NH 3 impact on n-Hexadecane flame. • Premixed flow flame and diffusion counterflow and coflow flames studied. • Combustion species along with PAH and NOx species were discussed. • Soot surface equations along with Moss-Brookes model were used. • Results suggest H 2 ≥ 70% and NH 3 ≤ 70% should be used in n-Hexadecane fuel. [ABSTRACT FROM AUTHOR]

The manuscript presents the new insight into temperature effect on the adsorption and adsorption kinetics of cationic guar gum (CGG) on the halloysite surface (NH). The polymer/clay mineral hybrid materials and stability of the CGG/NH suspensions were analyzed using the following methods: UV-Vis, FT-IR, XRD, SEM-EDX, nitrogen adsorption/desorption, CHN and electrokinetic potential measurements. According to the results the increase of temperature increases both the adsorption of CGG on NH and stability of the CGG/NH suspensions. Thus CGG can effectively stabilize the NH suspensions at higher temperatures. The textural properties of the obtained hybrid materials were also strongly influenced by temperature. It was also observed that the CGG adsorption on NH is spontaneous, endothermic and thermodynamically privileged (ΔG° 15 C= -12.90 kJ/mol; ΔG° 25 C= -14.03 kJ/mol; ΔG° 35 C =−16.34 kJ/mol; ΔH° 15–30 C =37.15 kJ/mol; ΔS° 15–35 C =0.17 kJ/mol). The mechanism of this process can be regarded as a physisorption. The adsorption kinetics was adjusted to the multi-exponential equation. The presented results have a great application potential in wastewater or water treatment processes. [Display omitted] • Increase of temperature improves adsorption of cationic guar gum on halloysite. • Increase of temperature improves stability of the cationic guar gum/halloysite suspensions. • Cationic guar gum stabilizes the halloysite suspensions via electrosteric interactions. • The adsorption of cationic guar gum on halloysite is spontaneous and thermodynamically privileged. • The adsorption of cationic guar gum on halloysite is a physisorption, endothermic process. [ABSTRACT FROM AUTHOR]

Adsorption heat storage holds great promise for solar energy applications. The development of new adsorbent materials is currently the research focus in this area. The present work designs several activated carbon models with different functional groups, including -OH, -NH2, -COOH, and -SO3H, and explores the influence of functional groups' categories and numbers on the water adsorption capacity of the activated carbon using the GCMC method. The adsorption mechanism between functional groups and water molecules is analyzed using density functional theory. The results show that the functional groups could significantly improve the water adsorption capacity of activated carbon due to the hydrogen bond between functional groups and water molecules. In the scope of this paper, under low pressure, the activated carbon with -SO3H exhibits the best adsorption capacity, followed by the activated carbon with -COOH. Under low and medium pressure, increasing the number of -SO3H functional groups could increase the water adsorption capacity; however, when the pressure is high, increasing the functional group numbers might decrease the water adsorption capacity. As the temperature increases, the water adsorption capacity of activated carbons decreases, and the activated carbon with -SO3H is proven to have excellent application prospects in heat energy storage. [ABSTRACT FROM AUTHOR]

Ammonia is a significant precursor of PM 2.5 particles and thus contributes to poor air quality in many regions. Furthermore, ammonia concentrations are rising due to the increase of large-scale, intensive agricultural activities, which are often accompanied by greater use of fertilizers and concentrated animal feedlots. Ammonia is highly reactive and thus highly variable and difficult to measure. Satellite-based instruments, such as the Atmospheric Infrared Sounder (AIRS) and the Cross-Track Infrared Sounder (CrIS), have been shown to provide much greater temporal and spatial coverage of ammonia distribution and variability than is possible with in situ networks or aircraft campaigns, but the validation of these data is limited. Here we evaluate MUSES (multi-spectra, multi-species, multi-sensors) ammonia retrievals from AIRS and CrIS against ammonia measurements from aircraft in the California Central Valley and in the Colorado Front Range. These are small datasets taken over high-source regions under very different conditions: winter in California and summer in Colorado. Direct comparisons of the surface values of the retrieved profiles are biased very low in California (∼ 40 ppbv) and slightly high in Colorado (∼ 4 ppbv). This bias appears to be primarily due to smoothing error, since applying the instrument operator effectively reduces the bias to zero; even after the smoothing error is accounted for, the average uncertainty at the surface is in the 20 %–30 % range. We also compare 3 years of CrIS ammonia against an in situ network in the Magic Valley in Idaho We show that CrIS ammonia captures both the seasonal signal and the spatial variability in the Magic Valley, although it is biased low here also. In summary, this analysis substantially adds to the validation record but also points to the need for more validation under many different conditions and at higher altitudes. [ABSTRACT FROM AUTHOR]