Nitrogen Research Articles

Response of Microbiological Properties to Short-term Nitrogen Addition in Perennial Alpine Cultivated Grassland

Removing nitrogen limitation is necessary to increase plant productivity in alpine grasslands. A short-term nitrogen addition experiment was conducted to understand the effects of nitrogen addition on the soil physicochemical properties and microbial community structure of perennial alpine cultivated grassland in the region around Qinghai Lake. From June to August 2022, four N application gradients （T0： 0 kg·hm-2·a-1, T1： 22.5 kg·hm-2·a-1, T2： 45 kg·hm-2·a-1, T3： 67.5 kg·hm-2·a-1） were set up in a four-age perennial cultivated grassland, and soil samples were collected from the 0-20 cm soil layer. The soil physical and chemical properties and microbial community structure were determined under the different treatments. The results showed that soil water content （SWC）, soil organic carbon （SOC）, ammonium nitrogen （NH4+-N）, nitrate nitrogen （NO3--N）, available nitrogen （AN）, available phosphorus （AP）, total phosphorus （TP）, total nitrogen （TN）, and total carbon （TC） tended to increase with the increase in nitrogen application level and the T3 treatment significantly decreased the soil pH. Nitrogen addition did not significantly alter the Alpha diversity of soil microbial communities and different levels of nitrogen application affected the structure of soil microbial communities to different degrees. The T1 and T2 treatments increased the number of soil bacteria and fungi and T3 treatment decreased the number of soil bacteria and fungi. Nitrogen addition increased the relative abundance of the dominant flora of Actinobacteriota, Zygomycota, Blastococcus, and Gibberella and decreased the relative abundance of the dominant flora of Proteobacteria, Bacteroidota, Sphingomonas, and Claroideoglomus. RDA analysis showed that SOC and soil electrical conductivity （EC） were the key soil physicochemical factors affecting changes in soil bacterial communities, and soil pH was the main factor affecting the distribution of soil fungal communities. Collectively, 67.5 kg·hm-2·a-1 may be the optimal level of N application to improve the soil environment of perennial alpine cultivated grasslands.

Cooperative Catalysis in Stereoselective O- and N-Glycosylations with Glycosyl Trichloroacetimidates Mediated by Singly Protonated Phenanthrolinium Salt and Trichloroacetamide.

The development of small-molecule catalysts that can effectively activate both reacting partners simultaneously represents a pivotal pursuit in advancing the field of stereoselective glycosylation reactions. We report herein the development of the singly protonated form of readily available phenanthroline as an effective cooperative catalyst that facilitates the coupling of a wide variety of aliphatic alcohols, phenols, and aromatic amines with α-glycosyl trichloroacetimidate donors. The glycosylation reaction likely proceeds via an SN2-like mechanism, generating β-selective glycoside products. The developed protocol provides access to O- and N-glycosides in good yields with excellent levels of β-selectivity and enables late-stage functionalization of O- and N-glycosides via cross-coupling reactions. Importantly, this method exhibits excellent β-selectivity that is unattainable through a C2-O-acyl neighboring group participation strategy, especially in the case of glycosyl donors already containing a C2 heteroatom or sugar unit. Kinetic studies demonstrate that the byproduct trichloroacetamide group plays a previously undiscovered pivotal role in influencing the reactivity and selectivity of the reaction. A proposed mechanism involving simultaneous activation of the glycosyl donor and acceptor by the singly protonated phenanthrolinium salt catalyst with the assistance of the trichloroacetamide group is supported by kinetic analysis and preliminary computational studies. This cooperative catalysis process involves four consecutive hydrogen bond interactions. The first interaction occurs between the carbonyl oxygen of the trichloroacetamide group and the hydroxyl group of alcohol nucleophile (C═O···HO). The second involves the trichloroacetamide-NH2 forming a hydrogen bond with the nitrogen atom of the phenanthroline (NH···N). The third involves the donor trichloroacetimidate (═NH) engaging in a hydrogen bond interaction with the phenanthrolinium-NH (NH···N═H). Lastly, the protonated trichloroacetimidate-NH2 forms a hydrogen bond with the fluorine atom of the tetrafluoroborate ion.

Biodegradation of various edible oils and fat by Staphylococcus petrasii sub sp. jettensis VSJK R1 for application in bioremediation of lipid rich restaurant wastewater.

The disposal of fat, oil, and grease (FOG) pollutants from various sources, including restaurants, food processing facilities, and domestic kitchens, poses significant challenges to wastewater treatment systems. In this study, we isolated and characterized a novel bacterial strain. The result of 16S rRNA gene and phylogenetic analysis showed that the isolate was Staphylococcus petrasii sub sp. jettensis and named as VSJK R1 (Fig. S1). It was tested for its biodegradation potential of FOG contaminants. Our investigation revealed that Staphylococcus petrasii sub sp. jettensis VSJK R1 effectively degraded a variety of edible oils, including soybean, sunflower, cottonseed, palm, groundnut, and butter, with notable efficiency. Optimization studies were conducted to determine the optimal conditions for biodegradation, including the effects of nitrogen, carbon, phosphorus, pH, temperature, and salt concentration. Results indicated that organic nitrogen sources and glucose as carbon source significantly enhanced biodegradation rates, while the addition of phosphorus further improved degradation efficiency within specific concentration ranges. Moreover, the optimal pH for biodegradation was found to be neutral, with temperature ranging between 22°C and 45°C favoring microbial activity. Remarkably, Staphylococcus petrasii sub sp. jettensis VSJK R1 exhibited resilience to high salt concentrations, making it suitable for treatment of wastewater with elevated salt content. Additionally, comparative studies with other microbial strains underscored the unique biodegradation capabilities of Staphylococcus petrasii sub sp. jettensis VSJK R1, particularly in degrading various edible oils. The results suggest promising applications of this novel isolate in bioremediation efforts targeting FOG pollutants in wastewater treatment plants and grease traps. Future research may focus on scaling up the bioremediation process and field testing the efficacy of Staphylococcus petrasii sub sp. jettensis VSJK R1 in real-world wastewater treatment scenarios.

Effect of mulching and organic manure on maize yield, water, and nitrogen use efficiency in the Loess Plateau of China

Current agricultural practices prioritize intensive food production, often at the expense of environmental sustainability. This approach results in greenhouse gas emissions and groundwater pollution due to over-fertilization. In contrast, organic agriculture promotes a more efficient use of non-renewable energy, improves soil quality, and reduces ecological damage. However, the effects of mulching and organic manure on maize yield, water use efficiency (WUE), and nitrogen use efficiency (NUE) in China’s Loess Plateau have not been sufficiently researched. In 2017 and 2018, an experiment utilizing a randomized complete block design with two factors (two mulching levels × three organic nitrogen application rates) was conducted. The water content of the upper soil layer was found to be 12.6% to 19.4% higher than that of the subsoil layer. Across all soil depths and years, the soil nitrate-N content in mulched treatments was 10% to 31.8% greater than in non-mulched treatments with varying organic nitrogen rates. Additionally, mulching resulted in an increase in grain yield of 9.4% in 2017 and 8.9% in 2018 compared to non-mulched treatments. A significant interaction was observed between mulching and organic nitrogen application rate concerning WUE, alongside a negative correlation between WUE and NUE. These findings suggest that the application of 270 kg N ha−1 of sheep manure in conjunction with mulching is a highly recommended practice for the Loess Plateau, thereby supporting sustainable agricultural strategies.

A text-based, generative deep learning model for soil reflectance spectrum simulation in the solar range (400–2499 nm)

Soil spectral reflectance is a necessary input for land surface and radiative transfer models, and can be used to infer soil properties. Numerous soil reflectance inversion models have been developed based on mechanistic approaches, each with their own limitations. Mechanistic models based on radiative transfer theory are usually based on only a few input soil properties, whereas data-driven approaches are limited by high non-uniformity of available published datasets that severely limits the amount of data usable for model calibration. To address these limitations, a fully data-driven soil optics generative model (SOGM) for simulation of soil reflectance spectra from soil property inputs was developed based on the denoising diffusion probabilistic model (DDPM). The model was trained on an extensive dataset comprising nearly 180,000 soil spectra-property set pairs from 17 published datasets. The model generates soil reflectance spectra from text-based inputs describing soil properties and their values rather than only numerical values and labels in binary vector format, which means the model can handle variable formats for property reporting. Because the model is generative, it can simulate reasonable output spectra based on an incomplete set of available input properties, which becomes more reliable as the input property set becomes more complete. Two additional sub-models were also built to complement the SOGM: a spectral padding model that can fill in the gaps for spectra shorter than the target solar range (400 to 2499 nm), and a wet soil spectra model that can estimate the effects of water content on soil reflectance spectra given the dry spectrum predicted by the SOGM. It can also be easily integrated with other soil–plant radiation models used for remote sensing research such as PROSAIL and Helios 3D plant modeling software. The testing results of the SOGM on new datasets not included in model training demonstrated that the model can generate reasonable soil reflectance spectra based on available property inputs. Results also show soil clay/sand/silt fraction, organic carbon content, nitrogen content, and iron content tended to be important properties for spectra simulation. Inclusion of some trace minerals like nickel as model inputs decreased model performance because of their low concentrations and large propensity for ground-truth measurement error.

Recent Progress in Isolating and Purifying Amide Alkaloids from their Natural Habitats: A Review

: Alkaloids are nitrogen-containing chemical compounds found in nature. Many alkaloids are heterocyclic in nature. They are nitrogen-based organic compounds with the nitrogen atoms enclosed in a heterocyclic ring. The chemical "pro alkaloid" is derived from the alkyl amines in it. Many ancient people, long before the advent of organic chemistry, recognized that many of these substances have measurable effects on the body's physiological functions. Alkaloids are a type of natural substances that are classified as secondary metabolites. Many different types of organisms create alkaloids, which are a class of natural products. Alkaloids showed antifungal, local anesthetic, anti-inflammatory, anticancer, analgesic, neuropharmacologic, antimicrobial, and many other activities. Amines, as opposed to alkaloids, are the more common classification for naturally occurring compounds that contain nitrogen in the exocyclic position (such as mescaline, serotonin, and dopamine). An amide molecule has a nitrogen atom that is chemically bound to a carbon atom in the carbonyl group. The -oic acid ending of the corresponding carboxylic acid is converted to -amide to form the correct nomenclature for an amide. This article offers an overview of numerous techniques for extracting, separating, and purifying alkaloids for use in natural medicine.

Involvement of CN Sites in Solvothermally Engineered Metal-Free Carbon Material From Weed Lantana camara for the Detection of Mercury Ions: Experimental and DFT Insights.

Embarking on a journey to decipher the role of active sites in the detection and removal of toxic mercury(II) ions from polluted water, the surface of thermally engineered biomass derived carbon matrix NC-180 was customized with nitrogen atoms. The HR-TEM and XRD analyses revealed the amorphous nature of Lantana camara derived carbon material with small spherical flakes embedded in it. XPS analysis indicated the presence of pyrrolic, pyridinic, and graphitic N atoms, which was further confirmed by FT-IR analysis. The material shows quenching effect in presence of Hg2+ ions resulting in the "turn off" effect with a detection limit of 7.2 nM. The activity of NC-180 was recovered through "turn on" effect in the presence of L-cysteine. Furthermore, the mystery of binding of mercury(II) ions with N-sites is clarified through its comparison with other materials bearing sulfur and oxygen functional groups designated as AC-180, SC-180, and NSC-180. The conclusive evidence for efficient binding of nitrogen sites in NC-180 with mercury(II) ions is derived from various analyses, including 1H-NMR, FT-IR, XPS, and density functional theory. Notably, sustainability is achieved through utilization of toxic weed L. camara for the preparation of this selective carbon material for detection and adsorption of mercury(II) ions.

Multi-functional spin-caloritronic device based on co-doped zigzag silicene nanoribbon heterojunction

The discovery of graphene has sparked significant interest in two-dimensional (2D) materials within the research community. Graphene’s discovery has led to the exploration of several 2D-materials with varied properties. Silicene, a silicon-based analogue of graphene, is one of the newer 2D-materials. Silicene is a promising material for electronic applications and novel fields like spintronics. In this study, we propose a spin-caloritronic device based on zigzag silicene nanoribbons (ZSiNRs). The device features a heterojunction between two ZSiNRs, one of which is doped with boron (B) and nitrogen (N) atoms. The ZSiNRs’ edges are terminated with hydrogen (H) atoms for both the nanoribbons in the heterojunction. We utilize the density functional theory (DFT) combined with non-equilibrium Green’s function (NEGF) to investigate the thermal-spin transport properties of this device under the influence of a thermal gradient. Notably, the device operates without any external bias, with spin transport driven solely by the thermal gradient. We find that a thermal colossal magnetoresistance (CMR) effect may be produced by modulating thermally generated spin currents by changing the magnetic configuration. Furthermore, the proposed device has superior transport properties, displaying phenomena including the spin-Seebeck diode effect (SSD), spin filtering effect (SFE), and spin-Seebeck effect (SSE). These characteristics position the proposed device as a strong candidate for multi-functional spin-caloritronic applications.

Effects of Alternate Wetting and Drying Irrigation on Methane and Nitrous Oxide Emissions From Rice Fields: A Meta-Analysis.

Reducing water input and promoting water productivity in rice field under alternate wetting and drying irrigation (AWD), instead of continuous flooding (CF), are vital due to increasing irrigation water scarcity. However, it is also important to understand how methane (CH4) and nitrous oxide (N2O) emissions and global warming potential ( of CH4 and N2O) respond to AWD under the influence of various factors. Here, we conducted a meta-analysis to investigate the impact of AWD on CH4 and N2O emissions and , and its modification by climate conditions, soil properties, and management practices. Overall, compared to CF, AWD significantly reduced CH4 emissions by 51.6% and by 46.9%, while increased N2O emissions by 44.0%. The effect of AWD on CH4 emissions was significantly modified by soil drying level, the number of drying events, mean annual precipitation (MAP), soil organic carbon content (SOC), growth cycle, and nitrogen fertilizer (N) application. Regarding N2O emissions, mean annual temperature (MAT), elevation, soil texture, and soil pH had significant impacts on the AWD effect. Consequently, the under AWD was altered by soil drying level, soil pH, and growth cycle. Additionally, we found that MAP or MAT can be used to accurately assess the changes of global or national CH4 and N2O emissions under mild AWD. Moreover, increasing SOC, but not N application, is a potential strategy to further reduce CH4 emissions under (mild) AWD, since no difference was found between application of 60-120 and > 120 kg N ha-1. Furthermore, the soil pH can serve as an indicator to assess the reduction of under (mild) AWD as indicated by a significant linear correlation between them. These findings can provide valuable data support for accurate evaluation of non-CO2 greenhouse gas emissions reduction in rice fields under large-scale promotion of AWD in the future.

Bioavailability of dissolved organic matter (DOM) derived from seaweed Gracilaria lemaneiformis meditated by microorganisms

Seaweed Gracilaria lemaneiformis, a significant oceanic primary producer, releases substantial dissolved organic matter (DOM) during growth and decay, potentially impacting coastal organic carbon reservoirs and microbial communities. This study aimed to investigate the bioavailability of Gracilaria-derived DOM and its interactions with microbial communities. Laboratory experiments introduced Gracilaria-derived DOM into natural seawater, tracking variations in DOM composition, microbial structure, and eight extracellular enzyme activities over 168 h. The results indicated a rapid breakdown of dissolved organic carbon, nitrogen, and phosphorus, representing 48 % to 90 % of their total concentrations within 168 h, highlighting the high DOM bioavailability. Tryptophan substances were identified as the primary components of Gracilaria-derived DOM, being highly labile and utilized by microorganisms. Within the initial 0–12 h of DOM influx, Proteobacteria significantly increased and dominated in bacterial community, while after 48 h, as DOM decomposed, Desulfobacterota became the dominant group. The labile DOM stimulated bacteria, particularly Proteobacteria, to release substantial extracellular enzymes that peaked within the first 12 h. Subsequent substrate depletion led to decreased enzyme activities. Positive correlations were observed among bacterial abundance, enzyme activities, and tryptophan substances, emphasizing the intricate interplay among microbial communities, labile DOM, and extracellular enzymes. This study underscores the high bioavailability of Gracilaria-derived DOM and its interactions with microbial communities in nearshore environments.

Comprehensive analysis of water and sediment from holy water body ‘Pokhri’ reveals presence of biomolecules that may educe skin, gastroenterological and neurological dysfunction

‘Pokhri mai’ refers to the natural pond amidst the hilly forest slopes of the Buxa tiger reserve (BTR) nearby Jayanti considered to be sacred by the local ethnic groups serving as the prime source of water for wild animals and occasionally by neighbouring inhabitants. However, the water body is designated to be noxious by a group of native people with no scientific validation. This paper focuses to explore its toxicity status and allied environmental concerns through Pokhri water and sediment sample analysis through physicochemical assessment, in vitro antioxidant assay, microbiological investigation followed by AAS, GC–MS and in silico study. pH of soil and water samples were found to be quite high (>6.8) with organic matter, carbon and available nitrogen content being 1.5308 ± 0.28 %, 0.89 ± 0.17 % and 0.072 ± 0.34 % respectively. Profuse microbial growths were observed in both sediment and water samples with consortia obtained exhibiting tolerance against a range of antifungals and antibiotics. Inhibition zone was absent for sediment consortium whereas consortium of water samples portrayed susceptibility against various heavy metals viz. Cu2+, Pb2+, Zn2+, Fe3+ and Al3+ salts with corresponding AAS quantified values of sediment samples being 133, 223.3, 86.8, 1449 and 481.5 ppm. A summative of 18 metabolites were identified by GC–MS in Pokhri lake sediment among which 13 (occupying 96.35 % peak area) were investigated to be potentially toxic with 2,4-Di-tert-butylphenol (53.38 %) as the major compound. Biomolecular characterization, ADMET test and molecular docking study with dermal, gastrointestinal and neural peptides exhibiting high binding affinity scores (ranging between −2.6 to −8.3 kcal/mol) further affirmed the toxicity attributes of the GC–MS deciphered molecules. The findings clearly justifies the local ‘myth’ of Pokhri water to be deleterious with prospective dermatotoxic, neurotoxic and being evident of gastrointestinal toxicity emphasizing ecological risk to the environment, wildlife and microflora of the adjoining forests.

Rapid Adaption but Genetic Diversity Loss of a Globally Distributed Diatom in the Warmer Ocean.

Studies have demonstrated that marine phytoplankton can adapt to the warmer environment. However, the underlying mechanisms remain largely unknown. Here, we quantified the capacity of a globally distributed marine diatom Skeletonema dohrnii, for rapid evolution under the moderate (24°C) and severe (28°C) warming scenarios. Whole-genome resequencing analysis revealed that the evolutionary adaptation of S. dohrnii to moderate warming was slow (i.e., 700 generations), whereas it was rapid (i.e., 300 generations) under severe warming but suffered a substantial loss of genetic diversity within the population. Genes associated with energy production and lipid metabolism evolved rapidly, particularly under severe warming, suggesting their vital roles in thermal adaptation. Proteomic results also showed the enhanced expression of proteins involved in energy production and lipid metabolism, especially under severe warming. Furthermore, particulate organic carbon and nitrogen production was greatly enhanced in the moderate warming-selected population but increased insignificantly in the severe warming-selected population, indicating more rapid adaptation driven by severe warming. Our results provide molecular insights into the rapid but limited evolution of thermal adaptation in marine diatoms and highlight energy production and lipid metabolism as the most important adaptive strategy. Future warming will affect genetic diversity and population dynamics of diatoms in the ocean.

Studies of the Novel Bioactive Acridine‐1,3‐thiazolidin‐4‐one Derivatives With Human Serum Albumin Using Fluorescence Spectroscopy and Molecular Modelling

ABSTRACTIn this study, we employ spectroscopic, thermodynamic and molecular docking approaches to identify the mechanism by which thiazolidinone derivatives 4a–4d bind with human serum albumin. It has been suggested that the affinity of the interaction of derivatives 4a–4d with HSA is within the optimal range necessary for the transportation and distribution of compounds within the organism. The binding constant values for the derivative/HSA complexes were found to be 0.03–5.87 × 105 M−1. Both ΔH0 and ΔS0 values were negative, which indicates that binding occurs mainly through van der Waals forces and hydrogen bonding. The negative values calculated for ΔG0 indicate that the binding of derivatives 4a–4d with HSA is a spontaneous process. Our study also reveals that derivatives 4a–4d bind to the subdomain IB (Site III) of HSA and that this binding alters the conformation and thermodynamic stability of HSA. Molecular docking simulations suggest that the main binding forces are van der Waals interactions, hydrophobic interactions and hydrogen bonds. The studied compounds showed weak DPPH‐scavenging activity at all of the tested concentrations. The results suggest that compound 4b with a phenyl substituent at the nitrogen atom of the 1,3‐thiazolidin‐4‐one moiety can be considered the most potent antioxidant in the series.

Excellent tensile strengthening and corrosion resistance of M50 bearing steels by plasma torch surface nitrogen atoms injection

Excellent tensile strengthening and corrosion resistance of M50 bearing steels by plasma torch surface nitrogen atoms injection

The Coordination Bond Reinforced FeOCl/C3N4 Heterostructure for Photocatalytic Degradation of Persistent Organic Pollutants

Persistent organic pollutants (POPs) present a substantial environmental challenge due to their enduring nature and adverse effects on human health. The exploration of photocatalysts featuring abundant active sites and appropriate band structures represents a promising approach for harnessing solar energy in photo-self-Fenton reactions for pollutant oxidation. In this investigation, a two-dimensional S-scheme FeOCl/C3N4 heterostructure was fabricated for the degradation of POPs. The coordination between dangling nitrogen atoms in C3N4 and Fe3+ in FeOCl established a novel pathway for the transfer of photogenerated electrons, thereby prolonging their lifespan by mitigating recombination events. Assessment of the photocatalytic performance using 4-chlorophenol (4-CP) as a model pollutant revealed a 5.4-fold and 40-fold enhancement in degradation rate over FeOCl/C3N4 compared to individual catalysts. Notably, nearly complete mineralization rates were achievable with FeOCl/C3N4, underscoring its robustness. Mechanistic investigations delineated hydroxyl radicals (•OH) as the primary active species responsible for pollutant degradation.

N,N-Disubstituted 4-Sulfamoylbenzoic Acid Derivatives as Inhibitors of Cytosolic Phospholipase A2α: Synthesis, Aqueous Solubility, and Activity in a Vesicle and a Whole Blood Assay.

Cytosolic phospholipase A2α (cPLA2α) is the key enzyme that initiates the arachidonic acid cascade through which pro-inflammatory lipid mediators can be formed. Therefore, cPLA2α is considered an interesting target for the development of anti-inflammatory drugs. Although several effective inhibitors of the enzyme have been developed, none of them has yet reached clinical application. Recently, we have prepared new 4-sulfamoylbenzoic acid derivatives based on a cPLA2α inhibitor found in a ligand-based virtual screening. The most effective of these compounds were now subjected to further variations in which the substitution pattern on the sulfamoyl nitrogen atom was changed.. The new compounds were tested in vitro in a vesicle assay for cPLA2α inhibition as well as for their water solubility, metabolic stability, and selectivity towards related enzymes. In addition, they were evaluated ex vivo in a whole blood assay in which metabolites of the arachidonic acid cascade formed after activation of cPLA2α were quantified using a combined online dilution/ online solid phase extraction HPLC-MS method. Inhibitors with submicromolar inhibitory in vitro potency were found with favourable water solubility and selectivity. However, their efficacy did not match that of the highly effective, known, structurally related cPLA2α inhibitor giripladib, which was also tested as a reference. One advantage of some of the new compounds compared to giripladib was their significantly improved water solubility. When analyzing the substances in the ex vivo whole blood assay, it was found that the obtained inhibition data correlated better with the in vivo results when the phorbol ester 12-Otetradecanoylphorbol- 13-acetate was used for activation of the enzyme in the blood cells instead of the calcium ionophore A23187. New compounds with good activity towards cPLA2α and reasonable physicochemical properties were identified. Overall, the results obtained could be helpful in the development of clinically applicable inhibitors of this enzyme.

Effect of AP and AN on the combustion and injection performance of Al-H2O gelled propellant

Aluminum-water propellants (Al-H2O propellants), representing a novel class of solid propellants, demonstrate the merits of cost efficiency and reduced feature signal characteristics. However, the conventional formulations of Al-H2O propellants are hampered by the generation of substantial condensed residues. In our investigation, we explored the incorporation of oxidizers into the Al-H2O propellant grain, aiming to enhance combustion and injection performance. Employing a multifaceted experimental approach, we conducted thermal gravimetric analysis, laser ignition experiments, and ignition tests within a lab-scale solid rocket motor (SRM) firing to systematically examine the effects of varying content of ammonium perchlorate (AP) and ammonium nitrate (AN) on the combustion and injection performance of Al-H2O propellants. Our findings indicated that integrating AP and AN at a mass fraction of 3 % each notably curtailed ignition delay time by approximately 67 % and 90 %, respectively, and concurrently decreased burning rates by approximately 50 % and 58 %. Significantly, it has been observed that a composition incorporating a 5 % mass fraction of AP enhances the combustion efficiency of the Al-H2O propellant system by approximately 2 %. Conversely, the integration of a 5 % mass fraction of AN into the same propellant matrix results in an augmentation of the injection efficiency by an estimated 47 %. Empirical evidence validating the augmentative impacts of AP and AN on the performance of Al-H2O propellants has been substantiated through a series of motor hot firing experiments. Furthermore, the combustion behavior of Al-H2O propellants has been elucidated through an analysis of the combustion physical mechanism of Al particles. The thermal decomposition of AP yields a substantial volume of oxidizing gases, which effectively accelerates the combustion rate of the Al particles, subsequently leading to an enhancement in the overall combustion efficiency of the propellant. Conversely, the decomposition of AN results in an increased production of nitrogen gas, thereby augmenting the velocity of gas flow and, consequently, elevating the injection efficiency of the propellant. This finding holds promise for guiding the developmental trajectory of Al-H2O propellants and refining the design parameters of propulsion systems.

Forms, Importance and Sources of Dissolved Organic Nitrogen (DON) in the Environment: A Review

Forms, Importance and Sources of Dissolved Organic Nitrogen (DON) in the Environment: A Review

Investigation of nitrogen conversion in ditch-treated greywater: Contributions of biochar and aeration

This study aimed to assess the contribution of different combinations of uninterrupted aeration and tidal flow modes, as well as shallow and deep biochar landfill methods, to nitrogen removal pathways in ditches. Compared to natural ditches, the addition of biochar and aeration resulted in higher water pollution removal rates, lower Greenhouse Gas (GHG) emissions, and reduced sediment leaching. The nitrogen mass balance revealed that Total Nitrogen removal efficiency of each ditch group was 25.33% for CA-C, 43.75% for DBT-C, 49.08% for UBT-C, 30.75% for DBA-C, and 45.16% for UBA-C. Compared to the control group (CA-C), the tidal flow group with deep biochar landfill (DBT-C)demonstrated the highest efficiency in total nitrogen removal. To elucidate the fate of nitrogen elements, potential transformation processes of unexplained nitrogen were explored. The primary outflow pathway of nitrogen pollution in ditches is through liquids. The nitrogen composition in the liquid of each ditch indicated that for shallow biochar configurations (UBT-C/UBA-C), denitrification might be the main factor limiting TN removal efficiency. In contrast, for deep biochar configurations (DBT-C/DBA-C), hydrolysis and nitrification of organic nitrogen were identified as limiting factors, with tidal flow alleviating these limitations. Overall, the combination of shallow biochar and tidal flow aeration in a ditch is the most effective method for removing rural greywater, providing valuable insights for the development of design parameters in greywater removal systems.

A Review on The Nitrogen Laser

Abstract: A nitrogen laser is a type of gas laser that uses molecular nitrogen as its gain medium to operate in the ultraviolet (UV) spectrum. First created in 1963, nitrogen lasers were first put to use in commerce in 1972. A nitrogen laser is a type of gas laser that uses molecular nitrogen as its gain medium to operate in the ultraviolet (UV) spectrum. First created in 1963, nitrogen lasers were first put to use in commerce in 1972.Applications for nitrogen lasers can be found in physics, chemistry, and medical research. The principle of operation for nitrogen lasers is a quick electrical discharge through nitrogen gas. Liquid nitrogen or a gas cylinder might be used to supply the nitrogen gas. The UV-wavelength laser light has a short pulse width and a high intensity. The principle of operation for nitrogen lasers is a rapid electrical discharge via nitrogen gas. Liquid nitrogen or a gas cylinder might be used to supply the nitrogen gas. The laser light has a short pulse width, high intensity, and is released into the ultraviolet spectrum. Electricity is used by the nitrogen laser to excite the nitrogen. The electrons in the laser strike the nitrogen atoms in the air when an electric spark passes through a spark gap, stimulating them into a metastable condition. A photon with a wavelength of 337 nm causes stimulated emission and the creation of a laser state in the excited nitrogen atoms. Electricity is used by the nitrogen laser to excite the nitrogen. The nitrogen atoms in the air are excited into a metastable condition when an electric spark passes through a spark gap in the laser. A photon with a wavelength of 337 nm causes stimulated emission and the creation of a laser state in the excited nitrogen atoms. [22]