Role Of Nitrogen Research Articles

Insight into the role of nitrogen in N-doped ordered mesoporous carbons for the spontaneous non-covalent attachment and electrografting of redox-active materials.

The role of nitrogen functional groups in nitrogen-doped ordered mesoporous carbons (OMCs) toward the spontaneous non-covalent and electrografting was investigated using two home-made ionic liquid-derived ordered mesoporous carbons having different nitrogen concentrations (guanine-rich ionic liquid-derived ordered mesoporous carbon (GIOMC) and ionic liquid-derived ordered mesoporous carbon (IOMC)). The carbonaceous materials were fabricated by the carbonization of a mixture of ionic liquid (1-methyl-3-phenethyl-1H-imidazolium hydrogen sulfate) as a carbon source using SBA-15 as a hard template. Guanine was used during the carbonization of GIOMC as a nitrogen source. The electrode was modified with either GIOMC or IOMC followed by electrochemical surface functionalization with a few electro-active precursors as redox-active molecular models bearing different substituents and electronic properties. The high surface coverage of 5.6(±0.3) × 10-9 mol cm-2 for 4,4-biphenol was obtained for the GIOMC-modified electrode. We seek to explain whether the nitrogen content could indeed exert a dramatic impact on loading electroactive species on the electrode surface. The non-covalent anchoring studies indicated that at higher pH values the loading of electro-active moieties was significantly influenced by the content of nitrogen on the employed OMCs. The adsorption capacity (mg g-1) of the OMCs was studied for catechol as a typical electro-active species in the range of 0.050-0.165 mg ml-1. The adsorption capacity of 0.11 mg g-1 catechol was 42(±4) and 26(±3) mg g-1 for GIOMC and IOMC, respectively. In addition, our observations revealed that electro-grafting efficiency via diazonium ion was restricted by the protonation of nitrogen in the reaction media. Further, the fabricated redox-active/N-doped OMC electrodes showed sensitivity to pH, which was accompanied by either a Nernstian shift of the redox peak potentials (60(±3) mV per pH) in the pH range of 2-13 in the buffer solutions or variations of the redox peak currents (9.7(±0.3) μA per pH) in the pH range of 1-5.5 in the unbuffered situations. The resulting electrodes as voltammetric pH probes showed a simple response to pH in both buffer and unbuffered solutions. In addition, we introduced the fabricated electrode as a zero-gap generator/collector electrode system using a single electrode to recognize proton-dependent electron transfer from the proton-independent electrode process by detecting pH changes quite close to the surface of the electrode. The detailed descriptions are outlined.

Predicting ecosystem productivity based on plant community traits.

With the rapid accumulation of plant trait data, major opportunities have arisen for the integration of these data into predicting ecosystem primary productivity across a range of spatial extents. Traditionally, traits have been used to explain physiological productivity at cell, organ, or plant scales, but scaling up to the ecosystem scale has remained challenging. Here, we show the need to combine measures of community-level traits and environmental factors to predict ecosystem productivity at landscape or biogeographic scales. We show how theory can extend the production ecology equation to enormous potential for integrating traits into ecological models that estimate productivity-related ecosystem functions across ecological scales and to anticipate the response of terrestrial ecosystems to global change.

The Role of Nitrogen in Inducing Salt Stress Tolerance in Crocus sativus L.: Assessment Based on Plant Growth and Ions Distribution in Leaves

The role of nitrogen (N) in inducing salt stress tolerance in plants is not well understood, and the question is more complicated in saffron (Crocus sativus L.), which is sensitive to both nitrogen rates and salinity. The present study was conducted to investigate the effects of different N (0, 50 and 150 kg ha−1) supplies on saffron growth and ions concentration in shoots under several salt stress levels (0, 3, 6 and 9 dS m−1). Salinity negatively affected plant growth assessed by leaves number, leaves length, shoot dry weight, corms number and corms weight. Moreover, there was a clear direct correlation between higher salinity value and less plant growth. Different effects due to salinity and nitrogen were evident in terms of the number and length of leaves during the growing season from day 60 after first irrigation (DAF) and achieved a peak after 90 DAF. Salt stress also affected the ions balance, as Na+, Cl− and Ca2+ were enhanced and K+ was reduced, thereby damaging the plants. Nitrogen partially mitigated the negative impacts of salinity on plant growth and ions balance, although this compensatory effect was observed when nitrogen supply was set at 50 kg N ha−1. For example, in 2019–2020, the losses in shoot dry weight due to 9 dS m−1 salinity amounted to 47%, 44% and 54%, at 0, 50 and 100 kg N ha−1 respectively, thus indicating a less negative effect of salinity at 50 kg N ha−1. Moreover, at 100 kg N ha−1 the negative effect of salinity was stronger for six and nine dS m−1. Our findings suggested that the optimum N supply (50 kg N ha−1) strengthened the plant under non-saline and moderately saline (6 dS m−1) conditions, and consequently improved salt tolerance.

Nutrients and not temperature are the key drivers for cyanobacterial biomass in the Americas

Cyanobacterial blooms imperil the use of freshwater around the globe and present challenges for water management. Studies have suggested that blooms are trigged by high temperatures and nutrient concentrations. While the roles of nitrogen and phosphorus have long been debated, cyanobacterial dominance in phytoplankton has widely been associated with climate warming. However, studies at large geographical scales, covering diverse climate regions and lake depths, are still needed to clarify the drivers of cyanobacterial success. Here, we analyzed data from 464 lakes covering a 14,000 km north-south gradient in the Americas and three lake depth categories. We show that there were no clear trends in cyanobacterial biomass (as biovolume) along latitude or climate gradients, with the exception of lower biomass in polar climates. Phosphorus was the primary resource explaining cyanobacterial biomass in the Americas, while nitrogen was also significant but particularly relevant in very shallow lakes (< 3 m depth). Despite the assessed climatic gradient water temperature was only weakly related to cyanobacterial biomass, suggesting it is overemphasized in current discussions. Depth was critical for predicting cyanobacterial biomass, and shallow lakes proved more vulnerable to eutrophication. Among other variables analyzed, only pH was significantly related to cyanobacteria biomass, likely due to a biologically mediated positive feedback under high nutrient conditions. Solutions toward managing harmful cyanobacteria should thus consider lake morphometric characteristics and emphasize nutrient control, independently of temperature gradients, since local factors are more critical – and more amenable to controls – than global external forces.

Composition–structure–property relationships of transparent Ca–Al–Si–O–N oxynitride glasses: The roles of nitrogen and aluminum

AbstractWe explore the formation and composition–structure–property correlations of transparent Ca–Al–Si–O–N glasses, which were prepared by a standard melt‐quenching technique using AlN as the nitrogen source and incorporating up to 8 at.% of N. Their measured physical properties of density, molar volume, compactness, refractive index, and hardness—along with the Young, shear, and bulk elastic moduli—depended roughly linearly on the N content. These effects are attributed primarily to the improved glass‐network cross‐linking from N compared to O, rather than the formation of higher‐coordination AlO5and AlO6groups, where27Al magic‐angle‐spinning nuclear magnetic resonance experimentation revealed that aluminum is predominately present in tetrahedral coordination as AlO4units. Yet, several physical properties, such as the refractive index along with the bulk, shear, and Young's elastic moduli, increase concomitantly with the Al content of the glass. We discuss the incompletely understood mechanical–property boosting role of Al as observed both herein and in previous reports on oxynitride glasses, moreover suggesting glass‐composition domains that are likely to offer optimal mechanical properties.

Role of nitrogen (N) in plant growth, photosynthesis pigments, and N use efficiency: A review

Role of nitrogen (N) in plant growth, photosynthesis pigments, and N use efficiency: A review

Role of nitrogen (N) in plant growth, photosynthesis pigments, and N use efficiency: A review

Role of nitrogen (N) in plant growth, photosynthesis pigments, and N use efficiency: A review

Roles of Nitrogen on TWIP in Advanced Austenitic Stainless Steels

The influence of nitrogen on the mechanical properties of two high Ni containing advanced austenitic stainless steels with low stacking fault energies is investigated. The results show that increase of nitrogen content greatly increases both strength and elongation of the steel at the same time. At the cryogenic temperature, the steels show a twin induced plasticity behavior. Ab initio calculations indicate that the increase of nitrogen slightly increases the stacking fault energy and consequently the critical shear stress for twin initiation in the steel. However, addition of nitrogen significantly increases the flow stress. This leads to a smaller critical strain for twin initiation and promotes deformation twinning in the high nitrogen steel. This is confirmed by the microstructure investigation. Deformation in steels is a competitive process between slip and twinning. Dislocation slip is dominant at low strain range, but formation of stacking fault and twinning become important in the later stages of deformation. At cryogenic temperature, it is mainly deformation twinning. The influence of nitrogen addition on magnetic property and its effect on deformation twinning are also discussed. The present study increases the understanding for the development of high‐performance and low‐cost advanced austenitic stainless steels.

Role of Nitrogen and Yttrium Contents in Manufacturing (Cr, Y)Nx Film Nanostructures.

The high-power impulse magnetron sputtering (HiPIMS) technique was applied to deposit multilayer-like (Cr, Y)Nx coatings on AISI 304L stainless steel, using pendular substrate oscillation and a Cr-Y target and varying the nitrogen flow rate from 10 to 50 sccm. The microstructure, mechanical and tribological properties were investigated by scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, instrumented nano-hardness, and wear tests. The columnar grain structure became highly segmented and nanosized due to pendular substrate oscillation and the addition of yttrium. The deposition rate increased continuously with the growing nitrogen flow rate. The increase in nitrogen flow from 10 to 50 sccm increased the hardness of the coatings (Cr, Y)Nx, with a maximum hardness value of 32.7 GPa for the coating (Cr, Y)Nx with a nitrogen flow of 50 sccm, which greatly surpasses the hardness of CrN films with multilayer-like (Cr, Y)Nx coatings architecture. The best mechanical and tribological performance was achieved for a nitrogen flow rate of 50 sccm. This was enabled by more elevated compressive stresses and impact energies of the impinging ions during film growth, owing to an increase of HiPIMS peak voltage with a rising N2/Ar ratio.

N–TiO2 crystal seeds incorporated in amorphous matrix for enhanced solar hydrogen generation: Experimental & first-principles analysis

We present here a combined study on the photoelectrochemical activity of highly active Nitrogen doped titanium dioxide thin-film using experiments and First principle density (DFT) based calculation. Hybridization of N 2p with O 2p and localized valence band upshifting leads to the reduction in band-gap of N–TiO2. To validate theoretical findings, the role of nitrogen in TiO2 is revisited with a focus on partial crystallinity. The best-case photoelectrode, nanostructured partially crystalline nitrogen-doped titanium dioxide (PCNDTO) offered photocurrent density of 24.3 mA/cm2 at 1 V versus saturated calomel electrode (SCE). The absence of well-defined peaks and long-range order in XRD pattern and Raman spectrum respectively suggests partially crystallinity. High-resolution transmission electron microscopy (HR-TEM) images confirm the presence of TiO2 crystals in the amorphous matrix. High photoelectrochemical response can be attributed to the abundance of hydroxyl groups, high electrochemical active surface area, reduced charge transfer resistance, and reduced charge carrier recombination rate.

Nitrogen‐Rich Carbonaceous Materials for Advanced Oxygen Electrocatalysis: Synthesis, Characterization, and Activity of Nitrogen Sites

AbstractNitrogen‐doped carbons are among the fastest‐growing class of materials used for oxygen electrocatalysis, namely, the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), thanks to their low cost, environmental friendliness, excellent electrical conductivity, and scalable synthesis. The perspective of replacing precious metal‐based electrocatalysts with nitrogen‐doped carbon is highly desirable for reducing costs in energy conversion and storage systems. In this review, the role of nitrogen and N‐induced structural defects on the enhanced performance of N‐doped carbon electrocatalysts toward the OER and the ORR as well as their applications for energy conversion and storage technologies is summarized. The synthesis of N‐doped carbon electrocatalysts and the characterization of their nitrogen functional groups and active sites for the conversion of oxygen are also reviewed. The electrocatalytic performance of the main types of N‐doped carbon materials for OER/ORR electrocatalysis are then discussed. Finally, major challenges and future opportunities of N‐doped carbons as advanced oxygen electrocatalysts are highlighted.

A Study of the Effect of Alloying Elements and Temperature on Nitrogen Solubility in Industrial Stainless Steelmaking

The role of nitrogen varies in different stainless steels from a harmful impurity to a valuable alloying element. Therefore, the strict control of nitrogen content is a very important issue in the steel making process. Better understanding about the thermodynamics of nitrogen solubility is the basis for this control. The aim of this study was to determine whether the nitrogen solubility at atmospheric pressure at any given composition and temperature in an Argon Oxygen Decarburization (AOD) converter could be reliably predicted. This was done by comparing different equations for nitrogen solubility to industrial measurements of several different steel grades with a wide range of compositions and temperatures. The test set consisted of 100 heats to ensure reproducibility and sufficient variability. The focus was on examining the effect of the main alloying elements (Cr, Ni, Mo, Mn) and temperature on nitrogen solubility. Nitrogen solubility is increased most by the chromium content, followed by manganese and molybdenum, whereas nickel decreases the solubility. The interaction effect of an alloying element on nitrogen declines at increasing temperatures, resulting in a negative temperature dependence, i.e., the maximum nitrogen solubility is obtained near the liquidus temperature. The study showed that most of the examined thermodynamic equations predicted the nitrogen solubility quite well in common stainless steels and even in high alloyed steels. On the other hand, clear discrepancies were observed for steels with a high manganese content as well as with strongly deviating temperatures. Therefore, based on the present measurements and the literature data, a new equation was developed for predicting the solubility of nitrogen in a wide range of stainless steels. This equation can be coupled with the existing process models to control the AOD process.

Role of Nitrogen and Spacing on Growth and Yield of Summer Groundnut (Arachis hypogaea L.)

The effect of nitrogen and spacing on summer groundnut traits like growth and yield was studied through an experiment performed in 2021 KVK Farm of SHUATS,Prayagraj (U.P) The experiment had 9 different treatments, replicated thrice in a Randomized control design. The treatments encompassed three different levels of nitrogen soil application and three different plant spacings. The outcome of the study revealed that in treatment (T3) the grouping of 30 kg/ha nitrogen + 20 cm × 10 cm spacing resulted in maximum plant height (52.27cm) and in treatment (T6) the usage of 30 kg/ha nitrogen + 25 cm × 10 cm layout resulted in a significant root nodules per plant (39.57) and dry weight (38.00 g). Treatment (T2) showed a maximum crop growth rate (31.44 g/m2/day) in the combination of 25 kg/ha nitrogen + 20 cm × 10 cm arrangement and 20-40 DAS interval. Furthermore, treatment (T6) had a maximum pods per plant (30.80), seed capitulate (2355.6 kg/ha), and haulm yield (3402.3 kg/ha) with 30 kg/ha nitrogen + 25 cm × 10 cm while treatment (T1) obtained maximum harvest index (42.32%) with the use of 20 kg/ha nitrogen + 20 cm × 10 cm.

Role of Nitrogen containing heterocyclic compounds in Acyl co-A carboxylase carboxyltransferase: Docking with dynamic simulation studies

Role of Nitrogen containing heterocyclic compounds in Acyl co-A carboxylase carboxyltransferase: Docking with dynamic simulation studies

The role of nitrogen and sulfur dual coordination of cobalt in Co-N4−xSx/C single atom catalysts in the oxygen reduction reaction

Single-atom catalysts have been considered as potential candidates for fuel cell applications due to their good oxygen reduction reaction (ORR) activity. In this study, Co-N3S/C revealed a lower overpotential pathway for ORR activity in acidic solution in a fuel cell.

The 6.2 μm PAH Feature and the Role of Nitrogen: Revisited

Abstract This study revisits the role that nitrogen inclusion in polycyclic aromatic hydrocarbons (PAHs; those with nitrogen inclusion, PANHs) plays in their infrared (IR) spectral properties. We present spectra of pure PAHs, PANHs, and protonated PANHs, computed using density functional theory and basis sets that treat polarization. We investigate trends in peak position and relative intensities as a function of nitrogen position, charge, and geometry. We use Spitzer-IRS spectral map data of the northwest photodissociation region of NGC 7023 and a database-fitting approach, using exclusively the PA(N)H spectra computed in this paper, to assess their IR contribution to the cosmic PAH emission. We find that, by including the treatment of polarization, pure PAH cations can account for the class A 6.2 μm PAH emission, with the 6.2 μm band position being dependent on the molecular geometry. PANH cations are required to reproduce the most blueshifted 6.2 μm bands observed in class A sources, albeit PANH cations come with strong 11.0 μm emission. Blind database fits demonstrate that the restriction imposed by the 11.0 μm emission in the astronomical spectra limits the contribution of PANH cations and the fits have to use neutral PANHs to avoid inflating the 11.0 μm feature even further. By assuming that all of the 11.0 μm emission is due to PANHs, we derive an upper limit for the contribution of PANH cations to the astronomical 6.2 μm PAH band of ∼12%. The fits further show hydrogenated PANHs significantly contributing in NGC 7023's more benign region, supporting the view that shielded environments could sustain protonated PA(N)Hs.

The reduction in water volume favors filamentous cyanobacteria and heterocyst production in semiarid tropical reservoirs without the influence of the N:P ratio

Predictions of more frequent and intense toxic cyanobacterial blooms in the future arise due to the synergistic effects of eutrophication combined with climate change. Thus, the intensification of dry conditions in arid and semiarid areas promotes a reduction in the water level of aquatic ecosystems and favors the growth of cyanobacteria. Among these conditions, there is a lack of consensus on the role of nitrogen (N) or phosphorus (P) limitation, particularly when cyanobacterial communities are dominated by N-fixing taxa. The present study evaluated the effects of water volume reduction on cyanobacterial abundance and heterocyst production in semiarid tropical reservoirs during a period of prolonged drought. Physicochemical variables and the phytoplankton community were analyzed, and a structural equation model was built to identify the variables that explain the heterocystous cyanobacteria and heterocysts. The reduction in water volume increased the cyanobacterial biomass due to the increase in the biomass of heterocystous filamentous cyanobacteria associated with higher production of heterocysts. Heterocysts were correlated with an increase in the trophic status, low light availability and high salinity maintained under the lower volume conditions. In addition, contrary to expectations, heterocysts were not correlated with the N:P ratio, which suggests that in the tropics, N fixation does not necessarily occur when the N:P ratio is low, and N is limiting. These results indicate the potential for dominance of heterocystous filamentous cyanobacteria in future climate change scenarios, and therefore, we recommend that bloom mitigation strategies prioritize the reduction of N and P associated with the control of variables that favor heterocystous filamentous (i.e., light and salinity). We also recommend including cyanotoxin analysis in the relationship with lowering the water level to determine whether cell-bound toxin production and the associated risk to aquatic biota and humans are increased in the dry period.

Role of Nitrogen and Sulphur Fertilization for Sustaining the Growth, Physiology and Defence of Brassica juncea L. (Indian Mustard) Plants Exposed to Enhanced CO2 Concentration

Role of Nitrogen and Sulphur Fertilization for Sustaining the Growth, Physiology and Defence of Brassica juncea L. (Indian Mustard) Plants Exposed to Enhanced CO2 Concentration

Is nitrogen in ammonia an elusive electron accepting pnicogen in a predominantly phosphorus bonded PCl3:NH3 dimer?

The unlikely role of nitrogen in NH3as an electron accepting pnicogenhas been observed experimentally using matrix isolation infrared spectroscopy and computationally. Nitrogen hosts twin H-N…Cl pnicogen bonds, which enhance the stabilization of a dominantly Cl-P…N phosphorus bondedPCl3-NH3heterodimer.The Cl-P…N phosphorus bond is proven to operate via the prominent σ-holes of phosphorus whilst the H-N…Cl pnicogen bonds appear to be driven by dispersion. The possibility of nitrogen in NH3, a popular Lewis base, acting as an electron acceptor, reveals a thus far unexpected scenario: pnicogen bonds operating even in theabsence of σ/π-holes.

Substitution of ZA with organic fertilizer on monoculture red ginger

This research was aimed to get the role of nitrogen and the role of substitution synthetic nitrogen with organic nitrogen on red ginger cultivation. The research was conducted from March to September 2020 at Wonorejo, Jatiyoso, Karanganyar. The research was carried out using randomized complete block design (RCBD) with 1 factor, 4 treatments, and 6 repetitions namely P0 (Control), P1 (0.3 ton ha-1 ZA), P2 (0.15 ton ha-1 ZA + 1.99 ton ha-1 organic fertilizer), and P3 (3.98 ton ha-1 organic fertilizer). The data will be analyzed using analysis of variance and continued with a DMRT level of 5% if there is a significant difference. The result showed that the substitution of ZA (Zwavelzure Ammonium) fertilizer with organic fertilizer increased the yield of red ginger cultivation. The use of organic fertilizer with 3.98 ton ha-1 increased the number of leaves, the number of saplings, fresh and dry strawweight, fresh and stored rhizomes weight, and the length of rhizomes..