Amount Of Nitrogen Research Articles

Mitigation of ammonia volatilization from organic and inorganic nitrogen sources applied to soil using water hyacinth biochars

The recent global population explosion has increased people’s food demand. To meet this demand, huge amounts of nitrogen (N) fertilizer have been applied in the worldwide. However, ammonia (NH3) volatilization is one of the primary factors of N loss from soil after N application causing decrease crop N utilization efficiency and productivity. Incubation experiments were conducted on an acidic clayey soil with two different N sources (urea and anaerobic digestion effluent; ADE), two differently-produced biochars, and three biochar application rates (0%, 0.25%, and 1.0% w/w). Ammonia volatilization was lower from urea (14.0–23.5 mg N kg−1) and ADE (11.3–21.0 mg N kg−1) with biochar application than those without biochar (40.1 and 26.2 mg N kg−1 from urea and ADE alone, respectively). Biochar application significantly mitigated volatilization and reduction percentages for urea and ADE were 40%–64% and 18%–55%, respectively. 1.0% biochar application mitigated volatilization significantly compared to 0.25% application regardless of N source and biochar types. Possible mechanism for volatilization mitigation for urea and ADE were increased N immobilization by soil microorganisms and accelerated net nitrification rate due to increased soil nitrifying bacteria, respectively. Overall, our results clarified different mechanisms for N volatilization mitigation from different (inorganic vs. organic) N sources with biochar application.

Assessment of the surface water quality in high-altitude springs in the Sagarmatha (Everest) National Park, Nepal

This study's goal was to examine how the physico-chemical properties of high-altitude springs in eastern Nepal's Sagarmatha National Park and buffer zone changed annually over a period of three years (2008-2010). The majority of the sampling locations were chosen along the treks from Lukla to Everest Base Camp, Gokyo, and Imja valley. Chemical parameters, such as total nitrogen and total phosphorous, were studied in the ecology laboratory of Central Department of Botany, Tribhuvan University, while physical characteristics such as pH, temperature, total dissolved solids (TDS), and conductivity were assessed on the spot by water analyzer kit Although water quality standards still meets the WHO's and Nepal's standards for drinking water, the quality of the spring water is starting to deteriorate. On the main tourist treks, Changes in water quality metrics in water bodies have been observed. Each year, the values of total nitrogen (TN-NO3), total phosphorous (TP-PO4), and pH change, indicating a decline in the quality of the springs water bodies in the Sagarmatha National Park and Buffer Zone (SNPBZ). The values of TN-NO3 and TP-PO4 had significantly increased, indicating that human impact had also increased. Although the amount of total nitrogen in water samples was lower than the WHO limit, there has been an increase in nitrate-nitrogen as compared to past findings. Similar to this, it was discovered that the total phosphorus value increased both annually and in earlier reports. Therefore, sufficient care should be taken to stop future deterioration. The research produced a database for the current state of Nepal's highland springs, which may be used to manage the springs and research how human activity affects water quality.

Impacts on water quality of producing biogas on pig farms as a function of the associated agricultural practices

The aim of this study was to assess positive or negative impacts of anaerobic digestion (AD) on water quality using a systemic approach. To this end, we used the agro-hydrological model Topography-based Nitrogen Transfer and Transformation (TNT2), a spatially explicit model that simulates nitrogen and water flows at the watershed scale on a daily time step. Four scenarios were constructed and analyzed: a baseline before the introduction of AD (S0), AD with adjusted fertilization (S1), AD with unadjusted fertilization (S2), and agroecological AD (S3). The results showed that, when spreading practices were similar and an equivalent amount of effective nitrogen was applied, digested pig slurry generally had a predicted amount of nitrate leaching similar to that of undigested pig slurry. In addition, replacing catch crops with energy cover crops had little impact on water quality. Scenario S3 was the most favorable one for water quality and biogas production, but not for soil organic nitrogen storage and food and feed production. This study’s strength is its systemic approach, which considered both environmental and agronomic aspects to assess the scenarios.

Sunflower-nitrogen calibration based on the amount of mineral nitrogen in soil under rainfed conditions in thrace region

Sunflower is grown under both rainfed and irrigated conditions in all regions to meet the vegetable oil needs of Türkiye, however, in the Thrace region, it is the main rotation crop grown under rainfed conditions after wheat. This study was conducted in the Thrace Region between 2013 and 2016 in order to evaluate the parameters that can be used as an index for nitrogen fertilization recommendations for sunflower plant. For this purpose, organic matter and saturation were determined in soil samples taken from 0-20 cm depth before the experiment and ammonium and nitrate contents were determined in soil samples taken from 0-30 cm, 30-60 cm, and 60-90 cm depths. Within the scope of the study, 27 field trials were conducted over four years. Nitrogen levels of 0 (control), 3, 6, 9, and 12 kg da-1 were implemented in the trials conducted in a Latin square experimental design. In this study, log (279.9-y) = log279.9-0.090b1-0.117x Mitscherlich calibration equations were determined based on 0-30 cm ammonium+nitrate content in the soil.

Optimizing water and nitrogen management for saline wasteland improvement: A case study on Suaeda salsa

Cultivating Suaeda salsa (S. salsa) is a promising strategy for the improvement and development of saline wastelands. However, the absence of a scientifically reasonable water and fertilizer management system has long hindered the large-scale improvement and utilization of saline wastelands. Therefore, we performed field experiments for two consecutive years to investigate the effects of water-nitrogen coupling on biomass, forage quality, salt absorption capacity, soil improvement effect, and economic benefits of S. salsa. The optimal water and nitrogen dosages for multi-objective optimization were determined using multiple regression and spatial analysis methods. Three irrigation levels were established for the experiment based on 0.35 (W1), 0.50 (W2), and 0.65 (W3) of the local ETo (Where ETo denotes the reference evapotranspiration calculated based on the FAO-56 recommended by the Food and Agriculture Organization). The three nitrogen application levels were 150 (F1), 250 (F2), and 350 (F3) kg ha−1 in the complete combination design. At the same nitrogen application level, the biomass and economic benefits of the W3 irrigation level were the highest. However, the forage quality, salt absorption capacity, salt reduction, and water productivity at the W3 irrigation level were lower than those at the W2 irrigation level, and the water productivity at the W1 irrigation level was the highest. At the same irrigation level, when the nitrogen application level was F2, the biomass, forage quality, salt absorption, salt reduction, and net profit, all reached their maximum values, and water productivity was the highest at the F3 level. The optimal amount of water and nitrogen applied for each parameter was different, so it was impossible to obtain the highest biomass, forage quality, salt absorption, salt reduction, water productivity, and net profit at the same time. Therefore, multi-objective optimization was needed, the optimal irrigation volume range was 3350.11–3485.97 m3 ha−1, and the nitrogen application rate range was 273.49–326.66 kg ha−1. These findings provide a scientific basis for the large-scale cultivation of S. salsa in extreme arid region, which is helpful for the improvement and utilization of saline-alkali land.

Formulation of N-doped carbon with meso/microporous structure for supercapacitors through biotemplates

Developing carbon materials based on biomass for supercapacitors has enormous potential to address the pressing issues of resource waste and environmental contamination. Nevertheless, biomass-based supercapacitors confront two major challenges: limited pore structure and the absence of surface functional groups. In this research, urea (U) acted as the nitrogen dopant, eggshells (ES) as the biotemplate, and eucalyptus leaves (EL) as the primary raw material to produce N-doped hierarchical porous carbon via co-pyrolysis. The results demonstrated that ES0.25U1 possesses a large specific surface area (SSA) of 1742.59 m2.g−1 and an excellent meso/microporous structure. Furthermore, significant quantities of oxygen (25.22 %) and nitrogen (3.18 %) were detected in ES0.25U1. The ES0.25U1 exhibits a specific capacitance (Cs) of 349F.g−1 (0.5 A.g−1), and the symmetric supercapacitor constructed from it possesses an energy density of 7.57 Wh.kg−1 while maintaining a capacity retention rate of 92.57 % and a Coulombic efficiency of 98.76 % after 10,000 charging/discharging cycles. Moreover, a comprehensive exploration into the N-doping mechanism and the underlying principles governing the formation of meso/microporous architectures through the utilization of bio-templates has been undertaken. This work provides a robust theoretical framework for the rational design and fabrication of high-value bio-derived carbonaceous materials utilizing combinatorial strategies of biotemplates and heteroatom doping.

Efficient Biovalorization of Oil Palm Trunk Waste as a Low-Cost Nutrient Source for Bioethanol Production

This study aimed to efficiently utilize felled oil palm trunk (OPT) for bioethanol and lactic acid production. OPT was separated into two fractions: oil palm sap (OPS) and OPT fiber. OPS contained substantial amounts of sugars (38–40 g/L) and nitrogen (0.60–0.70 g/L), which can serve as a base medium for bioethanol production. As bioethanol production requires high sugar concentrations, OPS was concentrated, supplemented with OPT fiber, and used for bioethanol production through simultaneous saccharification and fermentation (SSF) by Saccharomyces cerevisiae. Repeated-batch SSF for five cycles efficiently utilized OPT fiber and achieved an average ethanol production of 35–42 g/L in each cycle. To increase the accessibility of the enzyme, OPT fiber was acid-pretreated prior to the SSF process. The combined use of acid-pretreated OPT slurry and concentrated OPS provided the maximum ethanol production of 49.63 ± 1.05 g/L. The fermented broth after ethanol recovery, containing mainly xylose, was used to produce lactic acid at a concentration of 18.85 ± 0.55 g/L. These strategies can greatly contribute to the zero-waste biorefinery of OPT and may also be applicable for the efficient biovalorization of other similar agricultural wastes.

Quantification of nitrogen leaching losses by paddy cultivation under controlled and continual runoff conditions

In Asia, paddy is an important food crop that requires a high level of nitrogen, which is provided by straight chemical fertilizers that contribute a single nutrient, mainly urea. A study was conducted to quantify the leaching loss of nitrogen (as NO3--N) under two water management practices: controlled runoff and continual runoff in paddy cultivation at Low Country Intermediate Zone, Sri Lanka from 2015 to 2016 for four consecutive cropping seasons. Urea (N 46%) was applied as a sole source of Nitrogen at the rate of 225 kg ha-1. A randomized complete block design was employed with triplicates by two factors and two levels (cropping seasons; Yala, Maha, gradients; upper, lower). Lysimeters were arranged to collect leached water. The leachate from the study plots was collected weekly throughout the cropping period and the total amount of leached NO3--N for each cropping season was quantified. The leaching losses of NO3--N accounted under controlled runoff and continual runoff conditions were 8.6 kg ha-1 and 3.0 kg ha-1 respectively throughout the cropping period. It contributed to 8% and 3% of Nitrogen out of the total amount of applied N fertilizers in the same order. The water management practices and gradient effects were significant with respect to nitrogen leaching losses from paddy fields while cropping season had no effect on nitrogen leaching. A significant amount of nitrogen leaching losses could occur under the root zone, even though a controlled runoff situation posing possible threats of surface and groundwater pollution.

In Ukrainian

The CMs were obtained in argon in three stages: 1) heating (4 grad/min) to the specified temperature t in the range of 350–825 °С; 2) isothermal exposure 1 h; 3) cooling, washing from alkali and drying. Samples are denoted as CM(t). The CM yield (Y, %) and CMs elemental composition are determined. Based on low-temperature (77 K) nitrogen adsorption-desorption isotherms, integral and differential dependences of the specific surface area SDFT (m2/g) and pore volume V (cm3/g) on the average pore diameter (D, nm) were calculated by 2D-NLDFT-НS method (SAIEUS program). They were used to define volumes of ultramicropores (Vumi), supermicropores (Vsmi) and micropores (Vmi). The total pore volume V was calculated from the nitrogen amount adsorbed at a relative pressure p/p0 ~ 1.0. The S values of ultramicropores (Sumi), supermicropores (Ssmi) and micropores (Smi) were similarly determined. The CM yield was established to decrease linearly (R2 = 0.979) from 70.2 to 45.3 % with an increase in temperature from 350 to 825 °С. The carbon content decreases to a minimum value at 500 °С (72.6 %), and then increases to a maximum value (87.5 %) at 825 °С; the oxygen content changes antibatically. Two temperature regions were identified: region I (≤ 500 °С) of increasing the oxygen content due to reactions in which KOH acts as a donor of O atoms; region II (≥ 500 °C) of dominating the thermal destruction of functional groups (carboxyl, lactone, ester) with the release of CO and CO2, and condensation increasing the size of polyarenes of the CM secondary framework and formsng single Сar-Саr bonds between them. The CM(350) sample was found to contain only mesopores (D ≥ 10 nm) and macropores. An activation temperature increase to 400 °C initiates the additional formation of small-diameter micropores and mesopores. In samples CM(400) - CM(825), the main portion of newly formed pores falls on pores with D ≤ 5 nm. With increasing temperature, the micropores volume increases almost linearly (R2 = 0.992). The Vumi and Vsmi volumes increase up to 600 °C. At higher temperatures the ultramicropores volume decreases due to transforming ultramicropores (D ≤ 0.7 nm) into supermicropores (D = 0.7–2.0 nm). Portion of the ultramicropores volume changes with a maximum (23.9 %) in the CM(600) sample. The SBET specific surface area linearly (R2 = 0.992) increases with temperature up to 1729 m2/g. The SDFT values are close to SBET, but noticeably lower (1514–1530 m2/g) for CM(785)-CM(825). The micropores specific surface area increases to 1415 m2/g, and ultramicropore surface Sumi changes extremely with a maximum (526 m2/g) for the CM(600) sample, which should be expected based on the temperature dependence of the Vumi parameter. The decrease in Sumi values after the maximum is compensated by an increase in the supermicropore surface. Such an effect - the redistribution of pores by size in the microporous range (D ≤ 2 nm) with an increase in the alkaline activation temperature is not described in the literature. The portion of the micropores surface is dominant (92.6–97.0 %) in samples prepared at t ≥ 450 °C. The portion of the ultramicropore surface is maximum (56.3 %) in CM(500). Pores are revealed that do not form at all at 450–750 °C. These are supermicropores (D = 0.96–2.00 nm) and mesopores of small diameters (D = 2.0–2.82 nm). This effect was assumed to be due to the properties of the CM supramolecular framework, which is formed from polyarene fragments of the initial and activated coals having polyarenes with diameters of the same order (1.68–2.54 nm).

Examining the dual effect of copper nanoparticles and nitrogen doping on Cu@N-TiO2

Abstract The study of six compositions of Cu@N-TiO2 with different amounts of copper and nitrogen synthesized using a sol–gel method is reported. X-ray diffraction patterns and Raman spectra indicated the formation of a single anatase TiO2 phase in all materials without evidence of secondary phases including copper or nitrogen. Electron microscopy images showed a homogeneous distribution of the copper particles around a TiO2 matrix, just as that the insertion of nitrogen did not have a significant effect on the morphology of the particles. X-ray photoelectron spectroscopy analysis confirmed that nitrogen was inserted in the atomic arrangement of titanium dioxide, while copper was presented mainly as metallic element on the TiO2 surface. Characterization of the optical properties and photoactivity test confirm that band gap strongly depends on the copper and nitrogen content phenomenon attributed to the combined presence of modifiers over the TiO2 surface and the promotion of a plasmonic effect, which displaced the absorption UV bands to higher wavelengths with respect to un-doped TiO2. The catalytic test performed using rhodamine-B as probe molecule, confirm that TiCuN2 and TiCuN3 samples exhibit the best decomposition percentages of 38 and 36 % respectively. Such results confirm the surface plasmon resonance effect associated to Cu particles on the TiO2 as main cause in the increase in current along synthesized samples and the use of cyclic voltammetry technique to identify these effects between 0.0 and 1.5 V.

Co-pyrolysis of algae and lignocellulosic biomass in molten salts to produce N-doped carbon for supercapacitor application

Conventional pyrolysis strategies present challenges in maintaining the nitrogen fraction and improving the electrical conductivity of the product carbon at the same time. Co-pyrolysis of algae and lignocellulosic biomass with different temperature-controlled procedures in molten Na2CO3–K2CO3 is innovatively proposed to produce N-doped capacitive carbon. Results show that interactions between algae and bamboo in the presence of molten salt incorporate more nitrogen species into the carbon matrix and increase carbon yield. Co-pyrolysis with an optimal switching temperature of two-stage pyrolysis improves the nitrogen amount in carbon and the carbon yield by up to 108.7 % and 34.7 %, respectively. Through diffusion and infiltration, the liquid molten carbonates increase the contact area between the salt molecules and the carbon matrix, resulting in superior and uniform capacitive carbon. The resulting carbon shows a high specific capacitance of 306.2 F/g at 0.25 A/g with a cycling stability of 91.3 % after 5000 cycles, due to its hierarchical porous structure, high specific surface area (1326.58 m2/g) and abundant pyridine-N/pyrrolidine-N (81 %). Therefore, applying co-pyrolysis in molten carbonates with two-stage pyrolysis to produce high-yield N-doped carbon for supercapacitor application is proved to be promising.

Impacts of organic farming on the nitrogen balance in agricultural land of OECD countries: Evidence from panel ARDL approach

AbstractThe growing concern for health and the environment among individuals is anticipated to boost the demand for organic foods. However, there is a research gap in expanding field experiment results for the impact of organic farming to the real world. This study examines the causal relationship between nitrogen balance, organic farming area, agricultural land, and Gross Domestic Product per capita in 18 Organisation for Economic Co‐operation and Development countries from 2000 to 2019. By employing panel Autoregressive Distributed Lag, we found that a 1% increase in organic farming areas is associated with a 0.054% decrease in nitrogen balance in the long run. However, we found that the nitrogen balance increased by 0.392% and 0.487% with 1% expansion of agricultural farmland and economic development in the long run, respectively. Our findings will help policymakers develop or implement soil health management practices to reduce and maintain the amount of nitrogen in the environment. In addition, environmentally friendly raising livestock practices might be another consideration to improve nitrogen balance in livestock‐intensive countries. Finally, expanding agricultural land may not be an appropriate way to solve the problems of soil and underground water contamination.

Enhancing crop production and carbon sequestration of wheat in arid areas by green manure with reduced nitrogen fertilizer

Green manure with appropriate amount of chemical nitrogen fertilizer can increase crop yield, but also aggravate soil carbon emissions. However, it is unclear whether incorporation of green manure into the cropping pattern with reduced nitrogen amount can alleviate this situation and enhance carbon sequestration potential. So, a field experiment with split-plot design was set up in 2018 of northwest China, and studied the effects of nitrogen reduction on crop productivity, carbon emissions, and carbon sequestration potential in 2021–2023. The main plots were two cropping patterns, including multiple cropped green manure after wheat harvest (W-G) and fallow after wheat harvest (W). Three nitrogen application levels formed the split-plots, including local conventional nitrogen amount (N3, 180 kg ha−1), nitrogen amount reduced by 15% (N2, 153 kg ha−1) and 30% (N3, 126 kg ha−1). The results showed that W-G increased grain yield of wheat and energy yield of wheat multiple cropped green manure pattern. The multiple cropped green manure after wheat harvest with local conventional nitrogen amount reduced by 15% (W-GN2) had the significant increasing-effect, and increased grain yield of wheat by 9.6% and increased total energy yields by 39.3% compared to fallow after wheat harvest with local conventional nitrogen amount (W–N3). Relative to W–N3, W-GN2 did not significantly increase carbon emissions of wheat season, and increased total carbon emissions of cropping pattern by 11.1%. Compared to multiple cropped green manure after wheat harvest with local conventional nitrogen amount (W-GN3), W-GN2 decreased carbon emissions by 5.8% in wheat season and decreased by 3.9% in the whole cropping pattern. Therefore, W-GN2 gained high carbon emission efficiency based on grain yield, and were 9.9% and 11.2% higher than W–N3 and W-GN3, respectively. In addition, W-GN2 enhanced soil total nitrogen, carbon, and organic carbon contents, compared with W–N3, thus increasing soil carbon sequestration potential index (net primary productivity/carbon emissions). We conclude that multiple cropped leguminous green manure after wheat harvest with local conventional nitrogen amount reduced by 15% can enhance crop productivity and carbon sequestration potential of farmland in arid areas.

Post-heading accumulation of nonstructural carbohydrates and nitrogen in rice (Oryza sativa L.) roots

ContextRoots are plant organs that absorb nutrients and water. While roots serve as sink organs for nutrients in perennial and woody plant species, the dynamics of nutrient accumulation in roots for annual plant species, particularly in crop species like Oryza sativa L. (rice), are not well understood. Japanese rice cultivars bred for whole-crop silage exhibit large aboveground biomass and a notably small number of spikelets. This sink-source imbalance leads to the accumulation of non-structural carbohydrates (NSC) in stems after heading. Research questionIt is hypothesized that rice cultivars with substantial aboveground biomass might also develop significant belowground biomass. Consequently, the sink-source imbalance may result in NSC accumulation in roots. This study aims to test two hypotheses: firstly, that newly developed small-panicle rice cultivars accumulate NSC in roots post-heading, and secondly, that this post-heading NSC accumulation in roots can be influenced by cultural practices affecting spikelet number per panicle. MethodsTwo small-panicle cultivars, Tachisuzuka and Tachiayaka, and two large-panicle cultivars, Kusanohoshi and Hoshiaoba, were grown using different methods of three cultural practices: nitrogen application, transplanting season, and planting density. Measurements of dry matter, NSC (starch and sugars), and nitrogen in each plant part (panicle, leaf, stem, and roots) were taken over time after heading. The spikelet number per panicle was also counted. ResultsPost-heading, the small-panicle cultivars exhibited NSC accumulation in roots, a phenomenon not observed in the large-panicle cultivars. Although the three cultural practices altered the spikelet number per panicle and thus the sink capacity of the small-panicle cultivars, root NSC accumulation remained unaffected. Additionally, nitrogen weight per unit field area increased with increases in root weight in the small-panicle cultivars. ConclusionsThe imbalance in the sink-source relationship is likely responsible for the post-heading NSC accumulation in roots observed in small-panicle cultivars. However, the lack of root response in NSC accumulation to changes in panicle sink capacity suggests other mechanisms might be involved in root NSC accumulation. Notably, significant amounts of NSC and nitrogen remain in the roots of small-panicle cultivars after harvest. ImplicationsThe accumulation of NSC and nitrogen in roots post-heading could potentially enhance crop growth in subsequent years.

Growth and fatty acid profile of Nannochloropsis oceanica cultivated on nano-filtered whey permeate

Nano-filtered whey permeate (WP), a major by-product of dairy industry, is produced by membrane filtration of whey. The oleaginous microalga Nannochloropsis oceanica was successfully cultivated on WP without salinity and nutrient amendments. Growth, cell characteristics, and fatty acid profile of the cultures were analyzed using microscopy, flow cytometry, and GC analysis. WP was nitrogen limited, comprising primarily protein as a nitrogen source and only small amounts of free inorganic nitrogen (in the form of nitrate). Nannochloropsis oceanica (and associated bacteria) efficiently removed nitrate (100%), protein (87%), and phosphate (74%) from the whey permeate. Microscopic and flow cytometric analysis revealed diverse size distributions in whey permeate cultures, with significant cell aggregation attributed to low-salinity acclimatization and nitrogen limitation. Autofluorescence analysis revealed reduced photosynthetic activity in whey permeate-grown cells, possibly as a consequence of heightened mixotrophic activities on carbon source in the medium. Low nitrogen availability in whey permeate resulted in biomass with a fatty acid profile enriched in saturated fatty acids. Despite this, a considerable level of the omega-3 polyunsaturated fatty acid (in the form of eicosapentanoic acid or EPA) was detected at ca. 16% of total fatty acids. Whey permeate proved beneficial for the growth of N. oceanica and yielded high concentrations of eicosapentaenoic acid in the extracted lipids for potential applications in the feed/food industries.

Optimal design of coolant jacket for cryogen transfer pipelines

AbstractCryogenic liquids such as liquid oxygen and liquid hydrogen are extensively used in many processes and manufacturing industries. In these industries, transferring cryogens via pipelines is a routine phenomenon. As the boiling points and latent heat of cryogens are low, excessive vaporization of these cryogens is innate. Therefore, ensuring that the cryogen reaches the utility in its liquid form is challenging. In the case of liquid hydrogen and liquid helium, the pipelines are jacketed with a high boiling cryogen like nitrogen. The idea is to dump most of the heat into cheap nitrogen to limit the loss of precious hydrogen or helium. From a heat inleak point, maximizing the amount of nitrogen in the jacket is advantageous by choosing large cross‐sectional areas. Also, larger flow cross sections would lower pressure drops and, therefore, lower pumping costs. However, such a choice would add to the mass of the pipeline. An increase in the mass of the pipeline increases the need for better structural support of the pipeline assembly. Therefore, the design of cryogen jackets for limiting heat inleak is a multi‐objective optimization problem. In this work, we model the heat leak into the hydrogen via the nitrogen jacket and the pressure drop of liquid nitrogen, and we find the mass of the pipeline assembly. Then, we optimize the design of nitrogen jackets fitted over hydrogen pipelines. We employ the evolutionary optimization technique, genetic algorithm (GA), to perform this optimization.cryogen; genetic algorithm; heat inleak; liquid hydrogen; optimization.

Fast, Efficient Tailoring Growth of Nanocrystalline Diamond Films by Fine-Tuning of Gas-Phase Composition Using Microwave Plasma Chemical Vapor Deposition.

Nanocrystalline diamond (NCD) films are attractive for many applications due to their smooth surfaces while holding the properties of diamond. However, their growth rate is generally low using common Ar/CH4 with or without H2 chemistry and strongly dependent on the overall growth conditions using microwave plasma chemical vapor deposition (MPCVD). In this work, incorporating a small amount of N2 and O2 additives into CH4/H2 chemistry offered a much higher growth rate of NCD films, which is promising for some applications. Several novel series of experiments were designed and conducted to tailor the growth features of NCD films by fine-tuning of the gas-phase compositions with different amounts of nitrogen and oxygen addition into CH4/H2 gas mixtures. The influence of growth parameters, such as the absolute amount and their relative ratios of O2 and N2 additives; substrate temperature, which was adjusted by two ways and inferred by simulation; and microwave power on NCD formation, was investigated. Short and long deposition runs were carried out to study surface structural evolution with time under identical growth conditions. The morphology, crystalline and optical quality, orientation, and texture of the NCD samples were characterized and analyzed. A variety of NCD films of high average growth rates ranging from 2.1 μm/h up to 6.7 μm/h were successfully achieved by slightly adjusting the O2/CH4 amounts from 6.25% to 18.75%, while that of N2 was kept constant. The results clearly show that the beneficial use of fine-tuning of gas-phase compositions offers a simple and effective way to tailor the growth characteristics and physical properties of NCD films for optimizing the growth conditions to envisage some specific applications.

MODIFICATION OF SODIUM HUMATE WITH ALUMINUM DIHYDROPHOSPHATE DEPENDING ON TIME AND THE RATIO OF SOLID AND LIQUID PHASES

Due to their high chemical activity, humic compounds participate in various reactions. A large number of functional groups opens up wide possibilities for the humic compounds chemical modification. Most studies on the modification of humic substances are focused on studying the structure of humic substances, as well as on the factors influencing the completeness of the release of one humic substances fraction. The purpose of the work is to study the patterns of modification processes of sodium humate with aluminum dihydrogen phosphate, to determine the composition and properties of the resulting organomineral composite materials. Methods. Chemical analysis, infrared spectroscopy, X-ray analysis. Results and discussion. The composition and properties of organo-mineral composite materials obtained by conversion of sodium humate with aluminum dihydrogen phosphate have been determined. With an increase in the S:L ratio from 1:0.5 to 1:1.5, the yield of humic compounds increases from 15.62 to 21.92%, and the amount of phosphorus and nitrogen, on the contrary, the S:L=1:1.5 decreases, that is, the amount of phosphorus decreases from 37.51 to 32.19%, and the amount of nitrogen decreases from 1.78 to 1.11%. This is due to the improvement of diffusion conditions by reducing the medium viscosity and increasing the rate of primary components interaction. And the reduction in the amount of nitrogen occurs due to a decrease in ammonia consumption due to the humic substances neutralizing ability. Conclusion. It has been shown that the conversion of humic compounds with aluminum dihydrogen phosphate leads to a change in its composition and properties; the resulting products are enriched with phosphorus and nitrogen, and have good physicochemical and physicomechanical properties. After the macromolecules of humic compounds modification with aluminum dihydrogen phosphate, the number of oxygen-containing functional groups increases as a result of which the ion-exchange, complexing, sorption, detoxification and growth-stimulating properties is observed.

Hybrid machine learning modeling of nitrogen removal from wastewater using gas-liquid-solid circulating fluidized bed riser

Municipal wastewater generally contains high amounts of nitrogen (N), approximately 23–28 mg/L of total Kjeldahl Nitrogen (TKN), which causes eutrophication and pollution of groundwater. This article reports the generation of empirical models for estimating the nitrogen removal efficacy of two outputs (NH4-N and NO3-N) from the anoxic riser of a highly efficient municipal wastewater treatment system involving a gas-liquid-solid circulating fluidized bed (GLSCFB) bioreactor. To identify the important variables and discard irrelevant ones, the ReliefF algorithm is applied initially. Out of 10 independent variables, this method indicates that only three, such as flow rate, total Kjeldahl Nitrogen (TKN), and downer effluent of NO3-N, are meaningful for anoxic nitrogen removal. Then, a hybrid Bayesian Optimization Algorithm and Support Vector Regression (BOA-SVR) is implemented, considering only the essential variables. In this regard, real-life laboratory data are utilized to develop the models. The BOA approach and k-fold cross-validation technique are explicitly applied to optimize the model's hyperparameters and avoid overfitting. The established models provided sufficiently accurate predictions via their comparisons to the experimental observations. Besides, the BOA-SVR model outperforms the classical multiple linear regression (MLR). The BOA-SVR models' forecasted results for both the predicted amount of NH4-N and NO3-N are favorably compared with the laboratory trials (R2> 99 %). A comprehensive evaluation is further conducted to validate the performance of this model by calculating the root mean square error, mean absolute percentage error, fractional bias, and computational efficiency. Gaussian white noise is used to add three distinct noise levels (20 %, 40 %, and 60 %) to the testing data to evaluate the model's robustness. Moreover, the plots of relative deviations and residuals were dispersed across the zero-reference line with moderate fluctuations. Sensitivity analysis indicated the relative importance of the three independent variables on the anoxic nitrogen removal in the order of influent TKN > downer effluent NO3-N >flowrate. Overall, the developed tool has substantial potential in modeling other convoluted processes.

Особенности накопления минеральных элементов и азота в ассимиляционном аппарате сосны обыкновенной

The research has been carried out in the Arkhangelsk forestry of the Arkhangelsk Region in a drained shrub-sphagnum pine forest. Census trees of medium diameter and height for the stand have been selected, from which samples of needles, both living and dying yellow ones, and shoots of different ages have been taken on model branches. Soil samples have also been taken from the 3 upper horizons. It has been established that most of all nitrogen and mineral elements accumulate in the living needles – 4.4 % on average, in the dying needles and shoots there are 37–40 % less. Among all the elements, nitrogen, potassium and calcium make up the largest proportion; while the rest of the chemical elements are several time less. In descending order of the share, they are arranged in the following sequence: magnesium, sulfur, phosphorus, manganese, silicon, iron and aluminum. The most important mineral elements are derived in significant quantities from the dying yellow needles. The content of sulfur, magnesium, phosphorus, manganese and iron decreases in them by 3.3, 2.1, 8.0, 1.5 and 1.4 times, respectively, compared to the living needles. Data on the presence of nitrogen and mineral elements in the soil horizons A0, T1 and T2 have been obtained. It has been established that some of the essential elements for the life of a tree are concentrated in the living needles in much larger quantities than in the soil: potassium, phosphorus, manganese and calcium – by 12.0, 4.0, 6.0 and 1.9, respectively. The yellow falling needles create a biological cycle of substances. The amount of nitrogen and ash constituents in these needles is proportional to their presence in the soil. In turn, the content of mineral elements in the shoots is close to their amount in the yellow falling needles, on the one hand, and on the other, depends on the age of the shoots. There is a steady trend of decreasing the content of nitrogen, potassium, phosphorus and sulfur with the age of the shoots.