Ammonium Nitrate Solution Research Articles

OBTAINING, PROPERTIES AND GROWTH-STIMULATING ACTIVITY OF GRANULAR NITROGEN-CONTAINING ORGANO-MINERAL FERTILIZERS BASED ON ASPEN SAWDUST

A method for preparation of nitrogen-containing fertilizers based on aspen sawdust, including their impregnation with a water solution of ammonium nitrate and subsequent granulation, is proposed. The resulting fertilizers contain 15.42–16.07 wt.% nitrogen. The physicochemical properties of sawdust and fertilizers based on them are studied. It was shown that the pre-treatment of aspen sawdust by 1.0 wt.%. water solution of NaOH leads to the development of their porous structure, a decrease in the content of phenolic substances and makes it possible to obtain denser fertilizer granules. As a result of a field test on growing wheat of the Krasnoyarskaya 12 variety, a growth-stimulating effect of nitrogen-containing granular fertilizers based on aspen sawdust was revealed - the crop yield increased by 0.4–0.9 t/ha compared to the unfertilized background. A more effective effect on the yield of wheat of granulated nitrogen-containing fertilizer based on sawdust after their treatment with 1.0 wt.% water NaOH solution was established – according to this indicator, the achieved effect is 0.5 t/ha more compared to fertilizer based on the original aspen sawdust.

Electromass Transfer in the System "Cation Exchange Membrane-Ammonium Nitrate Solution".

The paper describes an experimental study and the mathematical simulation of the electromembrane transfer of cations of weak electrolytes (namely, ammonium ions), hindered by hydrolysis reactions taking place in the surface layers of the cation exchange membrane. Using the finite element method, we found a solution to the corresponding diffusion-kinetic electrodialysis problem in potentiostatic mode. Based on the experimental data and the results of theoretical simulation, we analyzed the effect of hydrolysis on the concentration polarization of the electromembrane system and the transport characteristics of ions, and suggested a mechanism of transfer of the components of the ammonium nitrate solution through the cation exchange membrane.

The influence of zeolite X ion-exchangeable forms and impregnation with copper nitrate on the adsorption of phosphate ions from aqueous solutions

Removal of phosphate ions from aqueous environment has become a global concern. Adsorption is one of the most efficient methods for removal of various pollutants. In this study, zeolite NaX derived from fly ash was modified by simple ion exchange with ammonium nitrate solution to obtain ammonium form (NH4X) and calcinated to proton form (HX) of zeolite X. The obtained materials were investigated as potential adsorbents of phosphate ions from aqueous solutions to find out the effect of zeolite form on adsorption capacity. Furthermore, zeolites NaX and NH4X were impregnated with copper nitrate solution and calcinated at 550 °C to obtain materials with Cu content of 3 wt% to simulate the potential utility of spent catalysts. The obtained results indicated that parent zeolite NaX has rather weak affinity towards phosphate ions — 4.38 mg (PO43−) g−1, only. The ammonium and proton forms of zeolite X showed significantly improved adsorption capacities of 12.09 and 35.33 mg (PO43−) g−1, respectively, implying the positive effect of ion exchange on removal of phosphate ions from aqueous solutions. Impregnated zeolites exhibited sufficient adsorption capacities of 11.86 and 26.53 mg (PO43−) g−1 for 3%Cu@NaX and 3%Cu@HX, respectively. However, no synergic effect of impregnation and zeolite form was observed due to partial pore blockage after preparation of zeolite 3%Cu@HX. To gain a deeper knowledge about the adsorption mechanisms, selected samples were subjected to kinetic adsorption studies and XPS measurements.

Batchwise Leaching of Calcium from Demolished Concrete Fines in an Aqueous Ammonium Nitrate Solution: Part 1 Experimental Study

In this work, the dissolution step of the indirect mineral carbonation process was investigated; first, a process-relevant thermodynamic framework is introduced, and then, an extensive experimental campaign with aqueous ammonium nitrate (AN) as the solvent is presented. Steady-state experiments after 24 h of leaching under different solvent concentrations and cement dosing were studied, confirming the applicability of the developed thermodynamic framework and its mathematical description. Afterward, batch experiments were performed to study the kinetic leaching behavior from different particle sizes, at different temperatures, and under a variety of industrially relevant conditions. Smaller particles release more calcium faster than larger particles as their calcium content is higher, and they have more specific surface available and less intraparticle diffusion limitations. Between temperatures of 5 and 35 °C, a 20% increase in dissolution performance was observed, which is due to an increase in reaction kinetics and/or diffusivity. Experiments under industrially relevant conditions reveal that increasing both the AN concentration and the solid to liquid ratio increases the amount of calcium in solution but has contradicting effects on extraction efficiency. For the typical conditions of a solid to liquid ratio of 0.2 and an AN concentration of 0.5 M, about 32% of the available calcium was leached after 20 min, resulting in a calcium concentration of 0.065 M; thereafter, this leaching process slows down sharply. The knowledge developed in this work forms a solid foundation for future modeling and scaling up of the indirect mineral carbonation process.

Triaxial direct shear property and permeability change of interface between high-performance concrete and claystone with water injection and chemical leaching

The mechanical properties and permeability change of the interface between barrier rock and concrete are essential to the load-carrying capacity and sealing performance evaluation of radioactive waste repository. This paper is devoted to investigating the mechanical property and permeability change of the concrete-claystone interface during the triaxial direct shear process in the context of repository tunnels. The cemented interface was firstly characterized by a high-resolution optical microscope. With the help of the triaxial test system and a self-designed direct shear device, a series of triaxial direct shear tests with water injection was carried out to study the hydromechanical characteristics and permeability change of the interface during shear at different confining pressures. The permeability evolution and shear strength of the interface under the influence of chemical dissolution were also investigated. The results show that the shear strength of the interface samples decreased by 21.8% due to water injection and decreased by 35.5% due to chemical leaching at the confining pressure of 12 MPa concerning its natural dry state. The permeability of the interface decreases at the beginning and then increases slightly when subjected to chemical leaching by ammonium nitrate solution. The results are beneficial to the safety evaluation of the claystone-hosted repository.

Inorganic Nitrogen-Containing Aerosol Deposition Caused "Excessive Photosynthesis" of Herbs, Resulting in Increased Nitrogen Demand.

The amount of atmospheric nitrogen-containing aerosols has increased dramatically due to the globally rising levels of nitrogen from fertilization and atmospheric deposition. Although the balance of carbon and nitrogen in plants is a crucial component of physiological and biochemical indexes and plays a key role in adaptive regulation, our understanding of how nitrogen-containing aerosols affect this remains limited; in particular, regarding the associated mechanisms. Using a fumigation particle generator, we generated ammonium nitrate solution (in four concentrations of 0, 15, 30, 60 kg N hm−2 year−1) into droplets, in 90% of which the diameters were less than 2.5 μm, in the range of 0.35–4 μm, and fumigated Iris germanica L. and Portulaca grandiflora Hook. for 30 days in April and August. We found that the weight percentage of nitrogen in the upper epidermis, mesophyll tissue, and bulk of leaves decreased significantly with the N addition rate, which caused a decrease of carbon:nitrogen ratio, due to the enhanced net photosynthetic rate. Compared with Portulaca grandiflora Hook., Iris germanica L. responded more significantly to the disturbance of N addition, resulting in a decrease in the weight percentage of nitrogen in the roots, due to a lower nitrogen use efficiency. In addition, the superoxide dismutase activity of the two plants was inhibited with a higher concentration of nitrogen sol; a reduction of superoxide dismutase activity in plants means that the resistance of plants to various environmental stresses is reduced, and this decrease in superoxide dismutase activity may be related to ROS signaling. The results suggest that inorganic nitrogen-containing aerosols caused excessive stress to plants, especially for Iris germanica L.

Modeling of a Continuous Carbonation Reactor for CaCO3 Precipitation

To stop global warming well below 2°C, a rapid decarbonization of our economy, including the industrial sector is required—reaching net-zero GHG emissions in 2050. CO2 mineralization processes, capturing CO2 from industrial point sources and trapping it as carbonate minerals, have the potential to store climate-relevant amounts of CO2. To get there, the potential processes have to be designed and developed, with the help of a process model that can support the process scale-up and optimization. In this work, a process model describing a gas-liquid-solid continuous cristallizer for CO2 absorption into an aqueous ammonium nitrate solution and CaCO3 precipitation has been developed. It consists of the relevant material balances, of a speciation model, and a population balance equation. While several of the model parameters can be obtained from the literature, a few have been estimated by fitting a comprehensive set of experimental data presented earlier. In particular, the process quantities used for parameter estimation are the CO2 mass transfer rate, the calcium carbonate crystallization rate, and the average particle size of the CaCO3 product crystals. The accuracy of the model, particularly in reproducing mass transfer rates and average particle sizes, has been assessed. Interestingly, it has been shown that the dominating mechanism for crystal formation is primary rather than secondary nucleation. The validated model has been used to explore the effect of the different operating conditions on various key performance indicators so as to gain a deeper insight into the process performance and potential. It has been shown that the CO2 absorption efficiency is mainly affected by the feed stoichiometry and the gas feed rate, whereas the CO2 capture and precipitation efficiency are controlled by the liquid phase composition and the residence time; increasing the calcium concentration in the feed is obviously one way to improve the efficiency. Moreover, we could show that the particle size tends to increase with calcium concentration and to decrease with liquid feed rate and supersaturation of the solution.

Leaf Scorching following Foliar Fertilization of Wheat with Urea or Urea–Ammonium Nitrate Is Caused by Ammonium Toxicity

Foliar fertilization is a potential tool to increase the use-efficiency of nitrogen (N) fertilizers. However, whilst leaf scorching has frequently been reported, the underlying physiological processes are not clear. In the present work, we investigate the intensity of leaf scorching as affected by the balance between ammonium assimilation and accumulation. Leaves were sprayed with urea–ammonium nitrate (UAN) solution without surfactant or applied liquid droplets of urea in different N concentrations with surfactant. UAN solutions without surfactant containing >10% N caused leaf scorching already after 24 h and the severity increased with the N concentration. The same pattern was observed 3 days after the application of urea solutions containing >4% N together with surfactant. The scorching was accompanied by a massive increase in foliar and apoplastic ammonium (NH4+) concentration. Moreover, the activity of glutamine synthetase (GS), most pronouncedly that of the chloroplastic isoform (GS2), decreased a few hours after the application of high N-concentrations. Along with this, the concentration of glutamate—the substrate for GS—decreased. We conclude that leaf scorching is promoted by NH4+ accumulation due to a limitation in N assimilation capacity.

EPIZOOTOLOGICALLY SIGNIFICANT HELMINTH INFECTIONS IN GOATS IN THE PLAIN BELT OF DAGESTAN

The paper presents the results of the studies on the main helminth infections of goats performed in the plain belt of Dagestan. Materials on this issue are published for the first time. In 2000–2020, 120 goats of different ages were examined during their lifetime and post mortem according to seasons of the year. The study was performed by methods of complete helminthological dissection per K. I. Skrjabin and a flotation method with a saturated ammonium nitrate solution according to G. A. Kotelnikov, V. M. Khrenov and Berman-Orlov. Goats in the plain belt were infected with 33 helminth species with the prevalence of infection (IP) of 1.0– 60.0% and the infection intensity (II) of 1–2360 specimens. Epizootologically significant were fascioliasis, dicroceliasis, monieziasis, echinococcosis, chabertiosis, bunostomiasis, trichostrongylosis, haemonchosis, nematodirosis, dictyocaulosis and protostrongylidosis. The goats were infected by causative agents of these helminths with the IP of 15.6–60.0% and the II of 25–2360 specimens. Goats catch the above helminth infections annually showing mixed infections where the number of pathogens varies from 5 to 14 species. Goats in lowland Dagestan were infected with 33 helminth species. Epizootologically significant were fascioliasis, dicroceliasis, monieziasis, echinococcosis, chabertiosis, bunostomiasis, trichostrongylosis, haemonchosis, nematodirosis and dictyocaulosis. Helminthiasis was recorded in mixed infections where the number of pathogens varies from 5 to 14 species.

Processing of Metallic Bismuth and Production of Bismuth Compounds

This paper demonstrates the efficiency of dissolving metallic bismuth in 7 mol/L nitric acid in the presence of 325–558 g/L ammonium nitrate to produce nitric acid solutions. Thus, solutions with 415–450 g/L bismuth can be obtained while the transition of nitrogen oxides in the gas phase can be decreased from 66 to 0.01 % and more. The obtained solutions were treated by bismuth precipitation in the first stage. Thus, the solutions with the following composition: [Bi6O4(OH)4](NO3)6·H2O – were 10 times diluted with water at the temperature of 60±3 oC, then they were rinsed with water resulting in the following compound: [Bi6O5(OH)3](NO3)5·3H2O. The product was then dried at 100 oC and baked at 630±30 oC into high-purity oxides. Bismuth was precipitated from the mother and wash liquors by adding a 2.5 mol/L ammonium carbonate solution at 55 oC until рН = 1 was reached. The precipitate was rinsed with water, dried and baked resulting in the production of chemically pure bismuth oxides. It is shown that the following oxohydroxo nitrates: [Bi6O4(OH)4](NO3)6·H2O and [Bi6O5(OH)3](NO3)5·3H2O – produced as a result of metallic bismuth processing can be used as precursors of high-purity bismuth compounds when interacting with acidic or alkaline solutions. Based on the results of the conducted study, an eco-friendly process was developed for Ви1 grade metallic bismuth containing at least 98% of bismuth. The process involves dissolving bismuth in nitric acid in the presence of ammonium nitrate, processing of bismuth-containing solution by water-alkali hydrolysis. At the water hydrolysis stage, 81.8 % of bismuth is recovered as high-purity bismuth oxides. At the same time, 15.1 % of bismuth is recovered as chemically pure bismuth oxides when hydrolysis is conducted with an ammonium carbonate solution at рН = 1. Due to final precipitation of bismuth from the solution at рН = 3 in the form of oxohydroxo nitrate and that of lead, silver and copper at рН = 8 while sending bismuth oxohydroxo nitrate and the ammonium nitrate solution to the metallic bismuth dissolution stage, a minimum 99.9 % of bismuth, as well as the ammonium nitrate solution, can be utilized at the metallic bismuth processing stage. The transition of nitrogen oxides in the gas phase during metallic bismuth dissolution does not exceed 0.01 %.

Mixed gastrointestinal strongylatosis and anoplocephalatosis of sheep in the context of the vertical zonality of Dagestan

The purpose of the research is to study mixed infections of gastrointestinal strongylates and Anoplocephala sp. in sheep in the context of the vertical zonality of Dagestan.Materials and methods. In 2000-2020, 360 collections of the digestive tract of sheep and 600 fecal samples were studied in the plain, foothill, and mountain belts of Dagestan. The material was analyzed in young animals up to 1 year old, animals from 1 year to 2 years old, and animals over three years old. The study was performed in all four seasons. The work used methods of full helminthological dissection according to K. I. Skrjabin, sequential washing of feces with a saturated ammonium nitrate solution according to G. A. Kotelnikov, V. M. Khrenov and Berman-Orlov, as well as larvae cultivation in a thermostat.Results and discussion. Mixed helminth infections were recorded in sheep in all natural and climatic zones of Dagestan. The greatest species diversity, high rates of infection prevalence (IP 15.0–43.3%) and infection intensity (II 16–3860 sp.) were observed at gastrointestinal Strongylata and Anoplocephalata infections in the plain belt. Of the pathogens in the plain and foothill belts, mixed infections were dominated by Chabertia, Bunostoma, Trichostrongylidae, Haemonchus, and Nematodirus; and from Anoplocephala – moniezia. The IP and II rates were significantly lower, 25–8.3% and 43–32 sp., respectively, in the mountain belt at an altitude of over 2500 m above the sea level. Lambs in the first year of age were infected with Chabertia, Bunostoma (B. trigonocephalum), Trichostrongylidae (T. axei and T. vitrinus), Haemonchus and Nematodirus (N. spathiger) in the plain and foothill belts. In the second year of age, sheep older than three years were infected with T. axei, T. capricola, T. vitrinus, T. colubriformis, O. ostertagi, O. circumcincta, O. occidentalis, O. antipini, O. leptospicularis, C. punctata, C. oncophora, N. filicollis and N. abnormalis with IP of 2.5–8.3% and II of 1–11 sp., in addition to the dominant species. We recorded M. expansa, M. benedeni, T. giardia and A. centripunctata (IP 2.5–30.0%, and II 1–48 sp.). In the mountain belt over 2500 m above the sea level, lambs were infected with Ch. ovina, B. trigonocephalum, T. axei, H. contortus, N. spathiger (IP 8.3–11.6%, II 3–32 sp.) and M. expansa (IP 2.5–5.0%, II 1–29 sp.). Young animals in the second year of age and sheep over three years old had mixed infections with the species as indicated in lambs (IP 3.5–8.3%, II 3–29 sp.).

Recovery of ammonium nitrate solution from urine wastewater via novel free nitrous acid (FNA)-mediated two-stage processes

Nitrogen (N) recovery from urine wastewater has been an important route to overcome intensive energy consumption in the conventional N-removal process. Hereby, this study reports a new process for recovering N in the form of ammonium nitrate (AN, i.e. NH4NO3), a common, stabilized type of fertilizer in agriculture. The process is achieved through two-stage biological–chemical reactions by using free nitrous acid (FNA) as an intermediate. In the first stage, a biological reactor was operated for 170 days, with ammonium-rich human urine wastewater as influent and gradually increased influent ammonium loading rates. Then a closed chemical reactor was designed to generate AN from the effluent of the biological reactor. Experimental results demonstrate that the two-stage biological-chemical process is technically and economically viable. Comprehensive modelling analyses show that FNA is the key to maintain stable partial nitritation in the biological reactor, and also critically affects the reaction rate of the chemical nitrite oxidation. pH adjustment of the bioreactor effluent is needed to increase an FNA concentration up to 250 mg HNO2-N/L in the biological reactor effluent. As such, chemical nitrite oxidation can reach a substantially high rate, i.e. at 15 kg N/(m3·d), compared with the nitrite production rate of ∼0.5 kg N/(m3·d) achieved in the biological reactor. This result also indicates that the biological stage is a rate-limiting step in the overall process. Overall, the proposed FNA-based approach provides a promising option for nitrogen recovery from urine wastewater.

Biodiversity of gastrointestinal strongylates in sheep on pastures of different ecological types in lowland Dagestan

The purpose of the research is to study biodiversity of gastrointestinal strongylates in sheep grazing on pastures of different ecological types in lowland Dagestan.Materials and methods. In 2004–2020, biodiversity was studied of gastrointestinal strongylates in sheep on lowland wet, steppe, saline, semi-desert, and shrub pastures in lowland Dagestan. In total, 360 collections of gastrointestinal tract were dissected and 500 fecal samples from sheep were examined. The studies were performed in all seasons by age groups: lambs, young animals from one to two years old and sheep from three years old and older. The work used methods of complete helminthological dissection according to K. I. Skrjabin, sequential washing, flotation with a saturated ammonium nitrate solution according to G. A. Kotelnikov and V. M. Khrenov, and larvae cultivation in a thermostat.Results and discussion. The biodiversity of gastrointestinal strongylates in sheep in lowland Dagestan was represented by 31 species, including the genus Chabertia, 1 species, 2 genus Bunostomum species, 3 genus Oesophagostomum species, 5 genus Trichostrongylus species, 6 genus Ostertagia species, 1 genus Maramastrongylus species, 2 genus Marschallagia species, 1 genus Haemonchus species, 3 genus Cooperia species, and 7 genus Nematodirus species. The Strongylata prevalence (the IP) in sheep was 100% with the infection intensity (the II) of 1–3860 parasites. The prevalence of infection with individual species varied as follows: 1.6% with M. schikobalovi, 44.1% with B. trigonocephalum with the II of 1 specimen of O. columbianum and 3860 specimens of H. contortus. The biodiversity was dominated by Ch. ovina, B. trigonocephalum, T. axei, T. capricola, T. colubriformis, T. skrjabini, T. vitrinus, H. contortus, N. filicollis, N. helvetianus and N. spathiger in terms of the prevalence. The IP of 1.6–10.0% and the II of 1–23 specimens were recorded in B. phlebotomum, and in species Oesophagostomum, Ostertagia, Maramastrongylus, Marschallagia, Cooperia, N. oiratianus, N. abnormalis, N. dogeli and N. andreevi. Rich species diversity and high rates of the prevalence (17.5–44.1%) and intensity of infection (1–3860 specimens) were observed in strongylates on lowland wet and plain steppe pastures.

Acidity and Stability of Brønsted Acid Sites in Green Clinoptilolite Catalysts and Catalytic Performance in the Etherification of Glycerol

Natural zeolite clinoptilolite CLIN with a framework ratio of Si/Al ≥ 4 containing mainly potassium and calcium ions in its internal channel system was used as a starting material. The acidic HCLIN catalysts were prepared under soft conditions avoiding the use of environmental less-benign mineral acids. The starting material was ion exchanged using a 0.2 M aqueous ammonium nitrate solution at a temperature 80 °C for 2 h. The obtained NH4CLIN was converted into the acid HCLIN catalyst by calcination at 300–600 °C. The obtained samples were characterized by XRD, FTIR, SEM/TEM, AAS, and EDX element mapping. The state of aluminium and silicon was studied by 27Al- and 29SiMAS NMR spectroscopy. The textural properties of the catalysts were investigated by nitrogen adsorption and desorption measurements. The Brønsted acidity of the HCLIN catalysts was studied by temperature-programmed decomposition of the exchanged ammonium ions releasing ammonia as well as 1H MAS NMR, {1H–27Al} Trapdor, and {1H–27Al} Redor experiments. The strongly agglomerated samples were crystalline and thermally stable up to >500 °C. Although a part of the clinoptilolite framework is maintained up to 600 °C, a loss of crystallinity is already observed starting from 450 °C. The specific surface areas of the starting CLIN and ammonium exchanged NH4CLIN are low with ca. 26 m2/g. The pores are nearly blocked by the exchangeable cations located in the zeolite pores. The thermal decomposition of the ammonium ions by calcination at 400 °C causes an opening of the pore entrances and a markable increase in the specific micropore area and micropore volume to ca. 163 m2/g and 0.07 cm3/g, respectively. It decreases with further rising calcination temperature indicating some structural loss. The catalysts show a broad distribution of Brønsted acid sites (BS) ranging from weak to strong sites as indicated the thermal decomposition of exchanged ammonium ions (TPDA). The ammonium ion decomposition leaving BS, i.e., H+ located at Al–O–Si framework bridges, starts at ≥250 °C. A part of the Brønsted sites is lost after calcination specifically at 500 °C. It is related to the formation of penta-coordinated aluminium at the expense of tetrahedral framework aluminium. The Brønsted sites are partially recreated after repeated ammonium ion exchange. The catalytic performance of the acidic HCLIN catalysts was tested in the etherification of glycerol as a green renewable resource with different C1-C4 alcohols. The catalysts are highly active in the etherification of glycerol, especially with alcohols containing the branched, tertiary alkyl groups. Highest activity is observed with the soft activated catalyst HCLIN300 (300 °C, temperature holding time: 1 min). A total of 78% conversion of glycerol to mono and di ether were achieved with tert-butanol at 140 °C after 4 h of reaction. The mono- and di-ether selectivity were 75% and 25%, respectively. The catalyst can be reused.

Optimising the root traits of summer maize to improve nutrient uptake and utilisation through rational application of urea ammonium nitrate solution

The production of summer maize is greatly affected by nitrogen (N) sources through regulating root growth and distribution. Four N treatments in the field experiment were designed as UAN (urea ammonium nitrate solution was applied under traditional side-dressing method), urea (urea was applied under traditional side-dressing method), UWFI (UAN was applied underwater and fertiliser integration technology) and CK (no N applied). The results showed that the root length density, surface area density and volume of DH605 (mid-late hybrid) and DH518 (mid-early hybrid) under UWFI were higher than other treatments, especially in shallow layers. The root absorption area of each soil layer under N application treatments varied with the growth stage. The grain yield and the accumulations of N, P and K in the shoots showed the trend of UWFI > UAN > urea > CK. Compared with UAN and urea, the nitrogen agronomic efficiency of UWFI treatment increased by 40.5~78.6%, and the nitrogen partial factor productivity increased by 4.75~7.61%. Consequently, rational application of UAN would improve root traits, nutrient uptake and utilisation, and yield of summer maize.

Increasing grain yield, nitrogen use efficiency of summer maize and reducing greenhouse gas emissions by applying urea ammonium nitrate solution

AbstractThe contradiction between the high grain yield of summer maize (Zea mays L.) and greenhouse gas (GHG) emissions in the field can be resolved by selecting effective nitrogen (N) sources and fertilization methods. In this study, two fertilization methods were used: (a) urea ammonium nitrate solution (UAN) and urea (210 kg ha–1 nitrogen applied) were applied by farmers' traditional fertilization method; and (b) fertigation of four UAN application rates: CK (no N applied), AF1 (126 kg N ha–1), AF2 (168 kg N ha–1), AF3 (210 kg N ha–1). The results showed that both hybrids (DH518 and DH605) applied UAN under the traditional fertilization method increased grain yield by 2.4 and 1.8% and enhanced nitrogen use efficiency (NUE) by 25.1 and 9.9%, respectively, compared with urea. While under fertigation treatment, the grain yield increased by 7.6 and 6.6%, and the NUE increased by 23.2 and 12.4%. Grain yield increased with the increase of UAN application, and the NUE showed a trend of rising first and then falling under fertigation treatment. Both the cumulative N2O emissions and N2O emission factor showed an increasing trend as well. An application rate of UAN at 168 kg N ha–1 (AF2) resulted in a NUE that was 49% higher than urea. Compared with urea, the global warming potential (GWP) and greenhouse gas intensity (GHGI) of AF2 were reduced by 29.5% and 31.2%, respectively. These indicated that optimizing the application rate of UAN through fertigation would achieve better summer maize yield and environmental benefits.

Novel Sensitizing Agent Formulation for Bulk Emulsion Explosives with Improved Energetic Parameters.

Bulk emulsion explosives, although they are very convenient and safe to use, also have disadvantages, with the main one being the relatively low power in relation to cartridged emulsion explosives or classic nitroesters (e.g., dynamites). Therefore, materials of this type currently have only limited use. In addition, these materials are characterized by the variability of blasting parameters over time from loading into the blasthole, which is closely dependent on the utilised mining method of the mine, which makes it difficult to precisely control the fragmentation. The industry is trying to respond to the demand for bulk emulsion explosives with increased energy and improved parameter stability, but so far it has not been possible to do so in a safe and effective way. Methods of improving blasting parameters mainly rely on additives to oxidant solutions during production, which creates additional risks at the production stage, as it involves handling hot and concentrated ammonium nitrate solutions, for which there are known cases of uncontrolled decomposition of such solutions, even leading to an explosion. This paper presents a method of improving the thermodynamic parameters and the stability of the sensitization reaction without the need for changes in the oxidant solution.

Трансформация изопропанола с использованием гибридных цеолитсодержащих систем типа H-ZSM-5 и H-Beta

The continuous depletion of hydrocarbon sources contributes to a wide study of the use of biorenewable raw materials to obtain synthetic hydrocarbons from them. Isopropyl alcohol is traditionally produced by chemical hydration of propylene, however, with the development of biotechnology, broad prospects have opened for its production by fermentation of glucose-containing substrates obtained from agricultural and forestry waste. This way, isopropyl alcohol can also be considered as a bio-renewable raw material and it can be widely used for the production of chemical synthesis products, including hydrocarbons. One of the possible ways of processing isopropyl alcohol is the catalytic transformation of alcohols on zeolites and zeotypes of various natures with the formation of hydrocarbons. Currently, zeolite H-ZSM-5 and zeotype SAPO-34 are the most frequently used catalysts for the transformation of alcohols into hydrocarbons, however, their rapid deactivation due to the formation of a carbon residue remains an unresolved problem. The formation of core-shell structures with H-ZSM-5 zeolite in center and an outer shell consist of H-Beta zeolite with large pores can reduce the deactivation of zeolite because of increase in reagents diffusion rate. In this article is devoted to synthesis of ZSM-5/Beta sample with a core-shell structure, as well as a study of its catalytic and physicochemical properties. To form the H-ZSM-5 zeolite, a colloidal solution of tetrapropylammonium hydroxide, a colloidal solution of silicon oxide, aluminum oxide, sodium hydroxide of distilled water was used. The colloidal solution was placed in an autoclave, heated to 140 °C and kept at this temperature for 48 hours, after which the crystals formed were centrifuged, washed with distilled water and kept in a 1M solution of ammonium nitrate for a day. Then, to form the H-Beta layer, H-ZSM-5 was suspended in a colloidal solution consisting of tetraethylammonium hydroxide, tetraethylammonium chloride, a colloidal solution of silicon oxide, sodium hydroxide, sodium chloride and distilled water. The suspension was placed in an autoclave and kept at a temperature of 140 °C for 48 hours, followed by centrifugation, washing in distilled water, suspended in a 1M solution of ammonium nitrate, with repeated washing with distilled water, drying and calcining at 600 °C. Testing of the synthesized of H-ZSM-5/Beta zeolite sample showed a significant decrease in the rate of deactivation compared to the synthesized sample of H-ZSM-5; it is also necessary to note a slight increase in the fraction of liquid hydrocarbons for the sample H-ZSM-5/Beta.

Interactions between hydrated cement pastes and aggressive ammonium: experimental batches characterization

Agricultural and food industries concrete facilities face chemically aggressive conditions that can damage their microstructure and reduce their lifespan. They are particularly exposed to ammonium-rich environments from natural microbial activity. The poorly crystalline mineralogy of hydrated cement pastes, the compositional variability of the phases and their reactivity make the geochemical behaviour of such materials difficult to investigate and predict over both large periods of time and wide variety of chemical compositions. This work aims (i) to assess the stability of the cement phases involved in ammonium-rich conditions as well as to identify the alteration products, and (ii) to understand the mechanisms and intensity of alteration. To do this, experiments were carried out both on OPC paste powder and on monolithic OPC pastes, degraded by an ammonium nitrate solution in semi-batch conditions. The powder was gradually added to the aggressive solution while the monoliths were immersed for 16 weeks in regularly renewed solution. The pH and the concentration of the chemical elements in solution were monitored over the experiments. The microstructural, chemical and mineralogical changes of the samples were analysed by scanning electron microscopy, electron probe micro-analysis and X-Ray diffraction and showed phenomena of dissolution, leaching and carbonation.

Single-side polypyrrole coated conductive and flexible polyurethane films.

In this study, single-side polypyrrole (PPy) coated conductive stretchable polyurethane (PU) / PPy composite films were synthesized by chemical oxidative method in the acetonitrile (ACN)/H2O interface as a new alternative to two-side coated PU films which have already reported in the literature. One surface of the PU film was contacted with aqueous Py solution and the other surface with cerium ammonium nitrate (CAN) solution in ACN, so that only one surface of the film was coated with PPy and the resulting composite was named PU/PPy (PUP). This composite was characterized by four-point probe conductivity measurement, Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) measurements, and mechanical testing. The thickness of PPy coating was determined as 16 μm, by using polarized microscope imagines of crosssection of film. Tg value of the composite was obtained as -60.38 °C and the highest conductivity of PPy coated side of PU was obtained as 3.5 × 10-4 S cm-1, while the back side of PU film was still insulator.