Articles de revues : « Nitrogen oxide decomposition »

1

Obalová, Lucie. « Catalytic Decomposition of N2O and NO ». Catalysts 11, n^o 6 (24 mai 2021) : 667. http://dx.doi.org/10.3390/catal11060667.

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McLarnon, C. R., et V. K. Mathur. « Nitrogen Oxide Decomposition by Barrier Discharge ». Industrial & ; Engineering Chemistry Research 39, n^o 8 (août 2000) : 2779–87. http://dx.doi.org/10.1021/ie990754q.

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POUR, V., et Z. SOBALIK. « ChemInform Abstract : Catalytic Decomposition of Nitrogen Oxide ». ChemInform 25, n^o 2 (19 août 2010) : no. http://dx.doi.org/10.1002/chin.199402303.

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Kulish, O. N., K. I. Zaporozhskiy, S. A. Kuzhevatov, M. N. Orlova, V. M. Senyavin et I. Sh Gleyzer. « Reducing the Formation of Secondary Pollutants in the Process of NonCatalytic Purification of Flue Gases from Nitrogen Oxides ». Ecology and Industry of Russia 24, n^o 7 (15 juillet 2020) : 8–11. http://dx.doi.org/10.18412/1816-0395-2020-7-8-11.

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The possibilities of the technology of non-catalytic reduction of nitrogen oxides (SNCR) to reduce the possible formation of secondary pollutants: ammonia, carbon monoxide and nitric oxide (I) are considered. The conditions for the process of reduction of nitrogen oxides by the thermal decomposition products of urea with a minimum formation of the above pollutants are determined.

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SWAMY, C. S., et J. CHRISTOPHER. « ChemInform Abstract : Decomposition of Nitrogen Oxide (N2O) on Perovskite-Related Oxides ». ChemInform 24, n^o 43 (20 août 2010) : no. http://dx.doi.org/10.1002/chin.199343274.

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Shukla, M. K., Balendra V. S. Chauhan, Sneha Verma et Atul Dhar. « Catalytic Direct Decomposition of NOx Using Non-Noble Metal Catalysts ». Solids 3, n^o 4 (2 décembre 2022) : 665–83. http://dx.doi.org/10.3390/solids3040041.

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Nitrogen oxides (NOx) gases, such as nitrous oxide (N2O), nitrogen oxide (NO), and nitrogen dioxide (NO2), are considered the most hazardous exhausts exhaled by industries and stationary and non-stationary application engines. Investigation of catalytic decomposition of NO has been carried out on copper ion exchanged with different bases, such as COK12, Nb2O5, Y-zeolite, and ZSM5. The catalytic decomposition of NO is widely accepted as an excellent method for the abatement of NO. However, the catalyst that achieves the highest reactivity in terms of NO decomposition is still a matter of research. The present paper aims to extend the research on the reactivity of non-noble metal-based catalysts using the direct decomposition method to remove NO from diesel engine exhaust. The reactivity of catalysts was observed in a quartz fixed bed reactor of 10 mm diameter placed in a furnace maintained at a temperature of 200 °C to 600 °C. The flow of NO was controlled by a mass flow controller, and the gas chromatography technique was used to observe the reactivity of the catalysts. Analysis showed that adding Cu to COK12, Nb2O5, Y-zeolite, and ZSM5 supports resulted in a rise in NO decomposition compared to stand-alone supports. Further experimental trials on the performance of Cu-ZSM5 at varying flow rates of NO showed that the NO decomposition activity of the catalyst was higher at lower flow rates of NO.

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Ongar, Bulbul, Hristo Beloev, Iliya Iliev, Assem Ibrasheva et Anara Yegzekova. « Numerical simulation of nitrogen oxide formation in dust furnaces ». EUREKA : Physics and Engineering, n^o 1 (10 janvier 2022) : 23–33. http://dx.doi.org/10.21303/2461-4262.2022.002102.

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Even though natural sources of air pollution account for over 50 % of sulphur compounds, 93 % of nitrogen oxide which are the most dangerous artificial anthropogenic sources of air pollution and primarily associated with the combustion of fossil fuel. Coal-fired thermal power plants and industrial fuel-burning plants that emit large quantities of nitrogen oxides (NО and NО2), solids (ash, dust, soot), as well as carbon oxides, aldehydes, organic acids into the atmosphere pollute the environment in majority. In the present work, a mathematical model and a scheme for calculating the formation of nitrogen oxide has been developed. Also, the dependence of the rate of release of fuel nitrogen from coal particles at the initial stage of gasification and content of volatiles has been obtained. The main regularities of the formation of NOx at the initial section of the flame in the ignition zone of the swirl burner flame during the combustion of Ekibastuz coal have been revealed. Modern environmental requirements for the modernization of existing and the creation of new heat and power facilities determine the exceptional relevance of the development of effective methods and constructions to reduce emissions of nitrogen oxides, sulfur oxides and ash to 200, 300, and 100 mg/nm3 at a=1.4. The dust consumption in all experiments was kept constant and amounted to 0.042 g/s, as well as with the results of calculating the thermal decomposition of the Ekibastuz coal dust, the recombination of atomic nitrogen into nitrogen molecules, and the kinetics of the formation of fuel nitric oxide. It was found that despite the presence of oxygen in Ekibastuz coal for gases Odaf=11.8 % in an inert atmosphere, nitrogen oxides are not formed

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Cvetanović, Sveta. « Overview of nitrogen oxide reactions during fossil fuel combustion in the atmosphere ». Safety Engineering 10, n^o 2 (2020) : 103–8. http://dx.doi.org/10.5937/se2002103c.

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This paper discusses the reactions of formation and decomposition of nitrogen oxides during fossil fuel combustion and in the atmosphere. Information about the chemical processes of pollutant formation and decomposition is the basis for the development of theoretical models of pollutant emissions. The information also provides a clearer picture about the primary factors influencing emissions. Nitrogen oxides are pollutants that damage human health, living and nonliving nature, and material property.

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Voitko, K. V., O. M. Bakalinska, Yu V. Goshovska, Yu I. Sementsov et M. T. Kartel. « Catalase-like properties of multilayer graphene oxides and their modified forms ». Surface 12(27) (30 décembre 2020) : 251–62. http://dx.doi.org/10.15407/surface.2020.12.251.

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The catalytic system, that mimets catalase enzyme such as “multilayer graphene oxide /peroxide molecule” in aqueous media was investigated. The main factors that influence on catalyst’s effectiveness were determining. The catalytic activity of as-synthesized multilayered graphene oxides, and their modified forms (oxidized and nitrogen doped) were investigated in the decomposition of hydrogen peroxides at room temperature and physiological pHs by measuring the volume of released gases. A phosphate buffer with a pH of 5 to 8 was chosen as the reaction medium. The original and modified samples were characterized using XPS, TPD-MS, Boehm titration analyses. The effect of surface chemistry on the catalytic reaction proceeding has been studied. It was found that catalysis on the graphene plane is determined by the presence of heteroatoms in their structure. The catalytic process takes place in the kinetic zone over the entire accessible surface of the samples. The active sites of the catalysts contain a large amount of both nitrogen and oxygen-containing functional groups. In addition, the surface of graphene oxide is hydrophilic, which enhances the catalytic reaction in an aqueous medium. It has been established that the rate of hydrogen peroxide decomposition by reduced graphene oxide samples is lower than for samples modified with oxygen and nitrogen. The catalase-like activity of graphene increases in alkaline pH up to 7.8. Studies have shown that samples of multilayer graphenes with a high content of functional groups can be an alternative to the catalase enzyme as a catalyst for the decomposition of hydrogen peroxide in physiological solutions.

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Frenzel, Nancy, Torsten Otremba, Reinhard Schomäcker, Thorsten Ressler et Martin Lerch. « Präparation und Charakterisierung von SiO2-geträgerten Zirconiumoxidnitriden mit hoher Oberfläche und Untersuchung ihrer katalytischen Aktivität bei der Ammoniakzersetzung / Synthesis, Characterization, and Catalytic Activity of Zirconium Oxide Nitrides Supported on High-surface SiO2 ». Zeitschrift für Naturforschung B 66, n^o 2 (1 février 2011) : 147–54. http://dx.doi.org/10.1515/znb-2011-0207.

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Zirconium oxide nitrides are active ammonia decomposition catalysts for the production of hydrogen. We present a route to zirconium oxide nitrides with high surface area. The precursor used consisted of a high-surface-area silica material coated with zirconium alkoxide. Subsequent hydrolysis and calcination resulted in ZrO2 supported on SiO2. The high surface area of the material could be maintained in the following ammonolysis procedure leading to the corresponding zirconium oxide nitride. In contrast to the as-prepared ZrO2, the zirconium oxide nitrides exhibited a significant catalytic activity in ammonia decomposition, but compared to an iron oxide-based reference material, the new oxide nitrides showed a rather low activity. Nevertheless, zirconium oxide nitrides constitute suitable model systems for elucidating the effect of nitrogen in the anion substructure on the activity and selectivity of oxide-based ammonia decomposition catalysts.

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Jayabal, Ezhilan, Rajesh Rajendiran et Venkatesan Rengarajan. « Study of Electronic and Magnetic Properties of Nitrogen Doped Graphene Oxide ». Advanced Materials Research 938 (juin 2014) : 97–102. http://dx.doi.org/10.4028/www.scientific.net/amr.938.97.

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The Nitrogen doped graphene oxide (NGO) was synthesized by doping N-atoms on graphene oxide (GO) sheet by using melamine which serves as the nitrogen source, through hydrothermal approach. The insertion of nitrogen atoms into the graphene oxide sheet was confirmed by FT-IR, EDS and Raman spectroscopic techniques. We also probed into the tuned dielectric and magnetic properties of NGO due to the decomposition of oxy functional groups of GO and the insertion of pyridinic, pyrrolic and graphitic type nitrogen atoms into the graphitic structure. The dielectric properties were measured by Broadband Dielectric Spectroscopy (BDS). The magnetic behaviour of the sample was demonstrated by Vibrational Scanning Magnetometer (VSM).

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Bahaj, Imane, Mohammed Kaddami et Mohamed Essahli. « Elaboration of the Al-Al3Ni Alloy Eutectic by a Carbothermal Process ». Scientific World Journal 2022 (26 octobre 2022) : 1–12. http://dx.doi.org/10.1155/2022/7764487.

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The present study develops an elaborate method of materials Al-Al3Ni by carbothermic reduction of nickel oxide from the decomposition of Ni(NO3)2.4H2O mixed with aluminum powder. This nitrate salt represents the source of nickel for an elaboration of these materials. The thermodynamic parameters adopted in the experimental study were defined based on the liquid-solid phase equilibrium diagram of the binary system Al-Ni and the Ellingham approach. Throughout this study, the metal Ni is elaborated by carbothermic reduction of nickel oxide resulting from nitrate salt decomposition at 900°C under a nitrogen atmosphere. The heat treatment at 900 °C of a mixture of nitrate salt with aluminum powder under an inert gas atmosphere leads to the formation of phases Al2O3, Al4C3, Al, and Ni. The annealing of these obtained phases during 1 h and under a nitrogen flow atmosphere at the temperature of 600°C allowed us to obtain the Al-Al3Ni alloy devoid of oxides. The characterization of these obtained solid phases was carried out by the XRD analysis, the SEM-EDS, the DTA, and the DSC.

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Brockwell, Jonathan L. « Prediction of decomposition limits for ethylene oxide-nitrogen vapor mixtures ». Plant/Operations Progress 9, n^o 2 (avril 1990) : 98–102. http://dx.doi.org/10.1002/prsb.720090208.

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Zhuang, Ting Ting, Jia Hui Xu, Jia Rong Xia, Yi Cao, Shi Lu Zhou, Ying Wang, Yuan Chun et Jian Hua Zhu. « New Development in Nanoporous Composites : Novel Functional Materials for Capturing Nitrosamines in Airstreams ». Journal of Nanomaterials 2006 (2006) : 1–9. http://dx.doi.org/10.1155/jnm/2006/54909.

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The latest progresses of the series of research on the trapper of nitrosamines are reported in this paper, involving the attempts to elevate the selective adsorption of zeolites through enhancing adsorbent-adsorbate interaction, in order to prepare the new functional nanoporous materials with high efficiency to eliminate the carcinogenic pollutants in environment and to protect public health. Incorporation of metal oxide such as copper oxide in NaY accelerated adsorption of volatile nitrosamines and anthracene, and moreover, coating zirconia onto the zeolite could dramatically suppress the release of nitrogen oxides in the decomposition ofN-nitrosopyrrolidine (NPYR) during temperature-programmed surface reaction (TPSR) process.

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Zheng, Min, Zuo Shan Wang et Qing Wang. « Synthesis of Nitrogen-Doped ZnO Nanocrystallites and its Novel Catalytic Activity on Ammonium Perchlorate ». Advanced Materials Research 236-238 (mai 2011) : 1665–69. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.1665.

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Nitrogen-doped zinc oxide (N-doped ZnO) nanocrystallites were synthesized via improved one-step combustion technique by using citric acid as additive. Scan electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to determine the grain size, shape, degree of nitrogen incorporation and nature of the resultant oxynitride chemical bonding. The catalytic performance of N-doped ZnO on the thermal decomposition of ammonium perchlorate (AP) was investigated by DSC-TG technique. The results show that the as-synthesized N-doped ZnO has uniform crystallite size about 20-30nm in diameter and 1.25%wt nitrogen incorporation, which forms into NO bonding region in ZnO crystal lattice. The nitrogen doping is accountable for the significant increase in catalytic activity on the thermal decomposition of AP versus the commercial nanometer ZnO and the thermal decomposition peak shifts 133°C downward when the content of N-doped ZnO in AP is 3%wt.

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Janoš, Pavel, Jakub Ederer et Marek Došek. « Some Environmentally Relevant Reactions of Cerium Oxide ». Nova Biotechnologica et Chimica 13, n^o 2 (1 décembre 2014) : 148–61. http://dx.doi.org/10.1515/nbec-2015-0005.

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Abstract Reactive forms of cerium oxide were prepared by a thermal decomposition of various precursors, namely carbonates, oxalates and citrates, commercially available nanocrystalline cerium oxide (nanoceria) was involved in the study for comparison. Scanning electron microscopy (SEM) and x-ray diffraction analysis (XRD) were used to examine the morphology and crystallinity of the samples, respectively, whereas the Brunauer-Emmett-Teller (BET) method of nitrogen adsorption was used to determine surface areas. Interactions of cerium oxide with some phosphorus-containing compounds were investigated. Some of the examined samples, especially those prepared by annealing from carbonate precursors, exhibited an outstanding ability to destroy highly toxic organophosphates, such as pesticides (parathion methyl), or nerve agents (soman, VX). There were identified some relations between the degradation efficiency of cerium oxides and their crystallinity. It was also shown that cerium oxide is able to destroy one of widely used flame retardants - triphenyl phosphate. A phosphatase-mimetic activity of various cerium oxides was examined with the aid of a standardized phosphatase test.

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Jang, Jum Suk, Eun Sun Kim, Hyun Gyu Kim, Sang Min Ji, Youngkwon Kim et Jae Sung Lee. « Nitrogen-doped titanium oxide microrods decorated with titanium oxide nanosheets for visible light photocatalysis ». Journal of Materials Research 25, n^o 6 (juin 2010) : 1096–104. http://dx.doi.org/10.1557/jmr.2010.0133.

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Nitrogen-doped titania with a unique two-level hierarchical structure and visible light photocatalytic activity is reported. Thus, nitrogen-doped titanium oxide microrods decorated with N-doped titanium oxide nanosheets were synthesized by a hydrothermal reaction in NH4OH and postcalcination. During the calcination, the in situ incorporation of nitrogen atoms of ammonium ion into titania lattice was accompanied by the structural evolution from titanate to anatase titania. The morphological and structural evolution was monitored by scanning electron microscopy (SEM), x-ray diffraction (XRD), thermogravimetric analysis/differential thermal analysis (TGA/DTA), Raman, Fourier transform infrared (FTIR), x-ray absorption near edge structure (XANES), x-ray photoelectron spectroscopy (XPS), and adsorption isotherms. The N-doping brought visible light absorption, and the material exhibited high photocatalytic activity in the decomposition of Orange II under visible light irradiation (λ ≥ 400 nm), especially when it was loaded with 1 wt% Pt as a cocatalyst.

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Jankowski, Antoni, et Mirosław Kowalski. « Alternative fuel in the combustion process of combustion engines ». Journal of KONBiN 48, n^o 1 (1 décembre 2018) : 55–81. http://dx.doi.org/10.2478/jok-2018-0047.

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Abstract The article analyses the impact of emulsified fuel, containing H2O2 hydrogen peroxide, on the emissions of nitrogen oxides and diesel engine smoke. The process of forming toxic components in exhaust gases of reciprocating engines during the engine operation, and the relationship that specifies the hydrogen peroxide decomposition process were presented. The research was carried out with the use of fuel containing 30%, 20% and 10% of hydrogen peroxide. The concentration courses of the nitric oxide (NO) and nitrogen oxides (NOx), as well as the (CO) carbon monoxide concentration and (S) engine smoke courses were shown separately for the external characteristics of the engine. Finally, the importance of knowledge related to the mechanisms of generation of toxic components in exhaust gases in the reciprocating engines was emphasised.

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Hamada, Hideaki, Yoshiaki Kintaichi, Motoi Sasaki et Takehiko Ito. « Silver-promoted Cobalt Oxide Catalysts for Direct Decomposition of Nitrogen Monoxide ». Chemistry Letters 19, n^o 7 (juillet 1990) : 1069–70. http://dx.doi.org/10.1246/cl.1990.1069.

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Van Pham, Viet, Hong-Huy Tran, Thao Kim Truong et Thi Minh Cao. « Tin dioxide nanomaterial-based photocatalysts for nitrogen oxide oxidation : a review ». Beilstein Journal of Nanotechnology 13 (21 janvier 2022) : 96–113. http://dx.doi.org/10.3762/bjnano.13.7.

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Semiconducting SnO2 photocatalyst nanomaterials are extensively used in energy and environmental research because of their outstanding physical and chemical properties. In recent years, nitrogen oxide (NOx) pollutants have received particular attention from the scientific community. The photocatalytic NOx oxidation will be an important contribution to mitigate climate change in the future. Existing review papers mainly focus on applying SnO2 materials for photocatalytic oxidation of pollutants in the water, while studies on the decomposition of gas pollutants are still being developed. In addition, previous studies have shown that the photocatalytic activity regarding NOx decomposition of SnO2 and other materials depends on many factors, such as physical structure and band energies, surface and defect states, and morphology. Recent studies have been focused on the modification of properties of SnO2 to increase the photocatalytic efficiency of SnO2, including bandgap engineering, defect regulation, surface engineering, heterojunction construction, and using co-catalysts, which will be thoroughly highlighted in this review.

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Shen, Yuesong, Chengliang Li, Yilong Tang et Shemin Zhu. « Calcination conditions and stability of supported Ni4La oxide for catalytic decomposition of N2O ». RSC Advances 5, n^o 17 (2015) : 13212–19. http://dx.doi.org/10.1039/c4ra13455a.

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Orlik, S. N., V. A. Ostapyuk, T. M. Pidruchna et V. L. Struzhko. « Direct Decomposition of Nitrogen(I) Oxide on Iron-Containing Zeolite, Zirconium Oxide, and Mixed Catalysts ». Theoretical and Experimental Chemistry 40, n^o 3 (mai 2004) : 177–80. http://dx.doi.org/10.1023/b:thec.0000036214.13353.45.

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Nguyen, Ba-Son, Yuan-Kai Xiao, Chun-Yan Shih, Van-Can Nguyen, Wei-Yang Chou et Hsisheng Teng. « Electronic structure manipulation of graphene dots for effective hydrogen evolution from photocatalytic water decomposition ». Nanoscale 10, n^o 22 (2018) : 10721–30. http://dx.doi.org/10.1039/c8nr02441c.

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Andrievskaya, N. V., O. A. Andrievskiy, M. D. Kuznetsov, T. S. Legotkina, V. S. Nikulin, S. A. Storozhev, Y. N. Khizhnyakov et A. A. Yuzhakov. « Neuro-Fuzzy Harmful Substances Control of Aircraft Gas Turbine Engine ». Mekhatronika, Avtomatizatsiya, Upravlenie 21, n^o 6 (4 juin 2020) : 348–55. http://dx.doi.org/10.17587/mau.21.348-355.

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One of the directions of aviation development is solving environmental problems, which excludes the emission of harmful substances into the atmosphere (nitric oxide, carbon monoxide) during the operation of an aircraft gas turbine engine (GTE) [1]. At low temperatures, oxygen and nitrogen are inert gases. At temperatures of 1100... 1600 K, oxides are formed, where nitrogen takes a valence of one to five. At temperatures above 1600 K, their atomic decomposition occurs. At temperatures in the range of 1100—1600 K, a reduction in NOx is possible with good mixing and a sufficient length of the combustion chamber, which determines the burning time of gases. If the combustion process is interrupted due to the poor operation of the automation, either vibro-combustion (atomic decomposition of NOx oxide) occurs at a temperature of 1600 K or flame failure occurs at 1100 K. Improving the process of converting the chemical energy of fuel and converting it into mechanical energy under conditions of uncertainty (variable caloric content of kerosene, changes in environmental parameters, wear of control equipment) is possible using neuro-fuzzy control of aviation gas turbine engine emissions into the environment. The control signal will be the fuel consumption in the diffusion manifold. In this case, fuel consumption in homogeneous reservoirs will vary evenly, provided that the total amount of fuel remains constant for the engine under consideration (the thrust should not change in the mode). A dynamic model of a neuro-fuzzy fuel consumption regulator by a diffusion collector has been developed. The method of obtaining training samples " % GT" = f (MNOx) for constructing the neural part of the regulator is presented. The desired " triangular" region of MNOx location (the integral of emission of nitrogen oxide emissions) is determined, on the basis of which control algorithms " with economy" and " without economy" of the MNOx integral are proposed.

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Roberts, James M. « Comment on “Isotopic evidence for dominant secondary production of HONO in near-ground wildfire plumes” by Chai et al. (2021) ». Atmospheric Chemistry and Physics 21, n^o 22 (18 novembre 2021) : 16793–95. http://dx.doi.org/10.5194/acp-21-16793-2021.

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Abstract. Chai et al. (2021) recently published measurements of wildfire-derived (WF) oxides of nitrogen (NOx) and nitrous acid (HONO) and their isotopic composition. The method used to sample NOx, collection in alkaline solution, has a known 1:1 interference from another reactive nitrogen compound, acetyl peroxynitrate (PAN). Although PAN is thermally unstable, subsequent reactions with nitrogen dioxide (NO2) in effect extend the lifetime of PAN many times longer than the initial decomposition reaction would indicate. This, coupled with the rapid and efficient formation of PAN in WF plumes, means the NOx measurements reported by Chai et al. were severely impacted by PAN. In addition, the model reactions in the original paper included neither the reactions of NO2 with hydroxyl radical (OH) to form nitric acid nor the efficient reaction of larger organic radicals with nitric oxide to form organic nitrates (RONO2).

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MISITI, Francesco, Massimo CASTAGNOLA, Cecilia ZUPPI, Bruno GIARDINA et Irene MESSANA. « Role of ergothioneine on S-nitrosoglutathione catabolism ». Biochemical Journal 356, n^o 3 (8 juin 2001) : 799–804. http://dx.doi.org/10.1042/bj3560799.

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Ergothioneine (ESH) is a low-molecular-mass thiol present in millimolar concentrations in a limited number of tissues, including erythrocytes, kidney, seminal fluid and liver; however, its biological function is still unclear. In the present study we investigated the role of ESH in the catabolism of S-nitrosoglutathione (GSNO). The results show that: (1) GSNO decomposition is strongly influenced by ESH (k′′ = 0.178±0.032M−1·s−1); (2) ammonia is the main nitrogen-containing compound generated by the reaction; and (3) nitrite is practically absent under both aerobic and anaerobic conditions. These findings are markedly different from those reported for the GSH-induced decomposition of GSNO, in which the nitrogen-containing end products are nitrite, ammonia and nitrous oxide (N2O) under aerobic conditions but nitrite, ammonia, nitric oxide (NO) and small quantities of hydroxylamine under anaerobic conditions. Considering the high concentration of ESH in specific cells, the reaction with GSNO should be considered as an important molecular event occurring in the cell.

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Takakai, Fumiaki, Mimori Goto, Haruki Watanabe, Keiko Hatakeyama, Kentaro Yasuda, Takashi Sato et Yoshihiro Kaneta. « Effects of the Autumn Incorporation of Rice Straw and Application of Lime Nitrogen on Methane and Nitrous Oxide Emissions and Rice Growth of a High-Yielding Paddy Field in a Cool-Temperate Region in Japan ». Agriculture 11, n^o 12 (20 décembre 2021) : 1298. http://dx.doi.org/10.3390/agriculture11121298.

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The effects of autumn plowing and lime nitrogen application on rice straw decomposition, CH4 and N2O emission and rice growth in the following year in a high-yielding rice cultivated paddy field were evaluated for two years. The experimental plots were set up, combining different times of rice straw (750 g m−2) incorporation into the soil by plowing (autumn or the following spring), with and without lime nitrogen application in autumn (5 g-N m−2). Autumn plowing promoted the decomposition of rice straw, but the application of lime nitrogen did not show a consistent trend. The soil pH was high (7.3) at the studied site, and the alkaline effect of lime nitrogen may not have been significant. As with straw decomposition, CH4 emissions were suppressed by autumn plowing, and no effect from the lime nitrogen application was observed. It was also suggested that the straw decomposition period may be shorter and the CH4 emissions may be higher in high-yielding cultivars that require a longer ripening period than in normal cultivars. The effect of both treatments on N2O emission was not clear. Both the autumn plowing of rice straw and lime nitrogen application were effective in promoting rice growth and increasing rice yield.

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Raj, Benjamin, Kishor Kumar Sahu, Mamata Mohapatra et Arun Kumar Padhy. « N-doped ZnO : Efficient Photocatalyst for Decomposition of Methylene Blue ». Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) 13, n^o 4 (2 juin 2020) : 332–42. http://dx.doi.org/10.2174/2405520413666200224113901.

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Background: Herein, we have synthesized nitrogen doped zinc oxide (N-ZnO) by using imidazole derivative as an organic precursor. Methods: The metal oxide nanoparticles were characterized by scanning electron microscope (SEM), and UV-visible spectroscopic techniques. The surface area and pore size distribution were also measured by the BET surface area analyzer. The enhanced surface area reveals that the synthesized materials have better active sites for the amputation of organic dyes. Results and Conclusion: The photocatalytic degradation of methylene blue was chosen to evaluate the photocatalytic activity of N-ZnO nanoparticles, with results indicating that the material exhibited higher activity towards the degradation of methylene blue.

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Shimizu, Tadaaki, et Makoto Inagaki. « Decomposition of nitrogen oxide (N2O) over limestone under fluidized bed combustion conditions ». Energy & ; Fuels 7, n^o 5 (septembre 1993) : 648–54. http://dx.doi.org/10.1021/ef00041a014.

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Tsoncheva, Tanya, Gloria Issa, Radostina Ivanova, Momtchil Dimitrov, Daniela Kovacheva, Genoveva Atanasova et Jiří Henych. « Design Control of Copper-Doped Titania–Zirconia Catalysts for Methanol Decomposition and Total Oxidation of Ethyl Acetate ». Symmetry 14, n^o 4 (6 avril 2022) : 751. http://dx.doi.org/10.3390/sym14040751.

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This study is focused on the design control of Cu–Zr–Ti oxide composites by the variation of the Zr/Ti ratio and the copper deposition procedure used. For the first time, these ternary composites were obtained by a combination of template-assisted hydrothermal techniques for the preparation of mesoporous ZrO2–TiO2 mixed oxides with diverse compositions, followed by the consecutive chemisorption and hydrolysis of copper ammonia complexes on them. The nitrogen physisorption, XRD, SEM, HRTEM, TPR, XPS, UV-Vis, and Raman spectroscopies were applied for the catalysts’ characterization. Methanol decomposition and the total oxidation of ethyl acetate, both of which with potential for sustainable environmental protection, were used as catalytic tests. The complex relationship between the phase composition, structure, and morphology of titania–zirconia mixed oxides and the state and catalytic behavior of the copper oxide species supported on them was investigated. In comparison with the conventional impregnation technique, the novel preparation procedure revealed the generation of more uniform and homogeneously dispersed needle-like copper oxide crystallites in the mesoporous TiO2–ZrO2 host matrix, which typically ensure improved catalytic performance. The synergistic activity between the loaded copper species and TiO2–ZrO2 support was discussed. All ternary composites exhibited superior catalytic activity in total oxidation of ethyl acetate. The specific behavior of the catalysts in methanol decomposition was related to the irreversible phase transformations by the influence of the reaction medium.

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Zhang, Chongmin, Xiaolong Fu, Xuexue Zhang, Jizhen Li, Xuezhong Fan et Guofang Zhang. « The Effects of Metal Complexes of Nano-Graphene Oxide to Thermal Decomposition of FOX-7 ». Nanomaterials 10, n^o 1 (13 janvier 2020) : 144. http://dx.doi.org/10.3390/nano10010144.

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1,1-diamino-2,2-dinitroethene (FOX-7) an insensitive high-energetic compound, has rarely been reported previously with respect to combustion performance. In order to quickly apply it to propellants, the thermal decomposition behaviors of FOX-7 should be optimized. Metal complexes of nano-graphene oxide have an obvious effect on the thermal decomposition of energy materials. In this paper, the metal (Cu2+ and Fe3+) complexes of nano-graphene oxide (nGO) have been synthesized using nGO as a ligand and metal ions as a coordination center. They were mixed with FOX-7 as additives to form energetic composites, and the chemical bond distributions and thermal decomposition processes of these composites have been investigated. The results show that Cu2+ and Fe3+ are uniformly distributed on the surface of the nGO. The thermal decomposition processes of nGO-metal-FOX-7 composites have been fully characterized by Differential scanning calorimeter (DSC) and Thermal gravimetric analyzer-Differential scanning calorimeter-Infrared spectroscopy-Mass spectrum (TG-DSC-IR-MS) coupling technology. The results show that the Fe3+ based complex affect the decomposition of FOX-7 than the Cu2+ based one with the initial decomposition temperature of 230 °C and the apparent heat release of 3535.6 J·g−1. Moreover, the addition of nGO-metal complexes could promote the formation of nitrogen during the decomposition of FOX-7, indicating a more complete decomposition.

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Hu, Cheng-Ching, Tzu-Chien Hsu et Li-Heng Kao. « One-Step Cohydrothermal Synthesis of Nitrogen-Doped Titanium Oxide Nanotubes with Enhanced Visible Light Photocatalytic Activity ». International Journal of Photoenergy 2012 (2012) : 1–9. http://dx.doi.org/10.1155/2012/391958.

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Nitrogen-doped TiO2nanotubes with enhanced visible light photocatalytic activity have been synthesized using commercial titania P25 as raw material by a facile P25/urea cohydrothermal method. Morphological and microstructural characteristics were conducted by transmission electron microscopy, powder X-ray diffraction, and nitrogen adsorption/desorption isotherms; chemical identifications were performed using X-ray photoelectron spectroscopy, and the interstitial nitrogen linkage to the TiO2nanotubes is identified. The photocatalytic activity of nitrogen-doped TiO2nanotubes, evaluated by the decomposition of rhodamine B dye solution under visible light using UV-vis absorption spectroscopy, is found to exhibit ~ four times higher than that of P25 and undoped titanate nanotubes. Factors affecting the photocatalytic activity are analyzed; it is found that the nitrogen content and surface area, rather than the crystallinity, are more crucial in affecting the photocatalytic efficiency of the nitrogen-doped TiO2nanotubes.

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Denisova, Kristina, Alexander A. Ilyin, Ruslan Rumyantsev, Julia Sakharova, Alexander P. Ilyin et Natalya Gordina. « Low-Temperature Synthesis and Catalytic Activity of Cobalt Ferrite in Nitrous Oxide (N2O) Decomposition Reaction ». Catalysts 11, n^o 8 (22 juillet 2021) : 889. http://dx.doi.org/10.3390/catal11080889.

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Cobalt ferrite (CoFe2O4) nanoparticles were synthesized and investigated as a catalyst in the reaction of nitrous oxide (N2O) decomposition. Cobalt ferrite was synthesized by solid–phase interaction at 1100 °C and by preliminary mechanochemical activation in a roller-ring vibrating mill at 400 °C. The nanoparticles were characterized by X-ray diffraction (XRD), synchronous thermal analysis (TG and DSC) and scanning electron microscopy (SEM). A low-temperature nitrogen adsorption/desorption test was used to evaluate the catalytic activity of the cobalt ferrite nanoparticles. Correlations between the structure and catalytic properties of the catalysts are reported. The highest catalytic activity of CoFe2O4 in the reaction of nitrous oxide decomposition was 98.1% at 475 °C for cobalt ferrite obtained by mechanochemical activation.

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34

Glatzel, S., I. Forbrich, C. Krüger, S. Lemke et G. Gerold. « Small scale controls of greenhouse gas release under elevated N deposition rates in a restoring peat bog in NW Germany ». Biogeosciences 5, n^o 3 (11 juin 2008) : 925–35. http://dx.doi.org/10.5194/bg-5-925-2008.

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Abstract. In Central Europe, most bogs have a history of drainage and many of them are currently being restored. Success of restoration as well as greenhouse gas exchange of these bogs is influenced by environmental stress factors as drought and atmospheric nitrogen deposition. We determined the methane and nitrous oxide exchange of sites in the strongly decomposed center and less decomposed edge of the Pietzmoor bog in NW Germany in 2004. Also, we examined the methane and nitrous oxide exchange of mesocosms from the center and edge before, during, and following a drainage experiment as well as carbon dioxide release from disturbed unfertilized and nitrogen fertilized surface peat. In the field, methane fluxes ranged from 0 to 3.8 mg m−2 h−1 and were highest from hollows. Field nitrous oxide fluxes ranged from 0 to 574 μg m−2 h−1 and were elevated at the edge. A large Eriophorum vaginatum tussock showed decreasing nitrous oxide release as the season progressed. Drainage of mesocosms decreased methane release to 0, even during rewetting. There was a tendency for a decrease of nitrous oxide release during drainage and for an increase in nitrous oxide release during rewetting. Nitrogen fertilization did not increase decomposition of surface peat. Our examinations suggest a competition between vascular vegetation and denitrifiers for excess nitrogen. We also provide evidence that the von Post humification index can be used to explain nitrous oxide release from bogs, if the role of vascular vegetation is also considered. An assessment of the greenhouse gas release from nitrogen saturated restoring bogs needs to take into account elevated release from fresh Sphagnum peat as well as from sedges growing on decomposed peat. Given the high atmospheric nitrogen deposition, restoration will not be able to achieve an oligotrophic ecosystem in the short term.

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Hadnadjev-Kostic, Milica, Tatjana Vulic, Dmitar Zoric et Radmila Marinkovic-Neducin. « The influence of the UV irradiation intensity on photocatalytic activity of ZnAl layered double hydroxides and derived mixed oxides ». Chemical Industry and Chemical Engineering Quarterly 18, n^o 2 (2012) : 295–303. http://dx.doi.org/10.2298/ciceq110923006h.

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Layered double hydroxides (LDHs) have been studied to a great extent as environmental-friendly complex materials that can be used as photocatalysts or photocatalyst supports. ZnAl layered double hydroxides and their derived mixed oxides were chosen for the investigation of photocatalytic performances in correlation with the UV intensities measured in the South Pannonia region. Low supersaturation coprecipitation method was used for the ZnAl LDH synthesis. For the characterization of LDH and thermal treated samples powder X-ray diffraction (XRD), scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), nitrogen adsorption-desorption were used. The decomposition of azodye, methylene blue was chosen as photocatalytic test reaction. The study showed that the ZnAl mixed oxide obtained by thermal decomposition of ZnAl LDH has stable activity in the broader UV light irradiation range characterizing the selected region. Photocatalytic activity could be mainly attributed to the ZnO phase, detected both in LDH and thermally treated samples. The study showed that the ZnAl mixed oxide obtained by the calcination of ZnAl LDH has a stable activity within the measured UV light irradiation range; whereas the parent ZnAl LDH catalyst did not perform satisfactory when low UV irradiation intensity is implied.

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U Din Dar, Mehraj, J. P. Singh et Kuldip Singh. « SIMULATION OF NITROGEN BALANCE UNDER SUB-SURFACE DRAINAGE CONDITIONS AT THEHRI MUKTSAR PUNJAB, USING THE DNDC MODEL V. 9.5 ». Acta Scientiarum Polonorum Formatio Circumiectus 22, n^o 2 (7 juillet 2023) : 3–16. http://dx.doi.org/10.15576/asp.fc/2023.22.2.01.

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Aim of the study: The aim of the study is DNDC model simulation for nitrogen balance in rice-wheat cropping system. Material and methods: The DeNitrification-DeComposition (DNDC) model is a computer simulation model for the biogeochemistry of carbon and nitrogen in agro ecosystems that takes a process-oriented approach. The DNDC model version 9.5 (http:// www.dndc.sr.unh.edu) was selected for estimating nitrogen balance. The model consists of two modules. The first component simulates moisture, soil temperature, pH, and substrate concentration, which are determined by ecological parameters such as soil, climate, anthropogenic activities, and vegetation. It consists of sub-models for plant growth, decomposition, and soil climate. The second module predicts the emission of gasses from plant-soil systems such as methane (CH4), nitrous oxide (N2O), nitrogen oxide (NO), dinitrogen (N2), ammonia (NH3), and carbon dioxide (CO2). The model includes empirical equations developed from laboratory studies and is based on the classical laws of chemistry, physics, and biology. The empirical equations included parameterizing specific biochemical or geochemical reactions. The entire model bridges the primary ecological drivers with the biogeochemical cycles of C and N (see: Figures 1 and 2). Results and conclusions: This study used the DNDC model to estimate nitrogen balance in the study area. A calibrated and validated DNDC model was used to simulate NO3-N loss in runoff and leachate from a rice–wheat cropping system from 2018 to 2020. The total nitrogen balance estimated by the DNDC model was negative (–99.44 kg N ha–1 yr–1) and positive (69.1 kg N ha–1 yr–1) for rice and wheat cropping systems, respectively, in the study area.

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Glatzel, S., I. Forbrich, C. Krüger, S. Lemke et G. Gerold. « Environmental controls of greenhouse gas release in a restoring peat bog in NW Germany ». Biogeosciences Discussions 5, n^o 1 (16 janvier 2008) : 213–42. http://dx.doi.org/10.5194/bgd-5-213-2008.

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Abstract. In Central Europe, most bogs have a history of drainage and many of them are currently being restored. Success of restoration as well as greenhouse gas exchange of these bogs is influenced by environmental stress factors as drought and atmospheric nitrogen deposition. We determined the methane and nitrous oxide exchange of sites in the strongly decomposed center and less decomposed edge of the Pietzmoor bog in NW Germany in 2004. Also, we examined the methane and nitrous oxide exchange of mesocosms from the center and edge before, during, and following a drainage experiment as well as carbon dioxide release from disturbed unfertilized and nitrogen fertilized surface peat. In the field, methane fluxes ranged from 0 to 3.8 mg m−2 h−1 and were highest from hollows. Field nitrous oxide fluxes ranged from 0 to 574 μg m−2 h−1 and were elevated at the edge. A large Eriophorum vaginatum tussock showed decreasing nitrous oxide release as the season progressed. Drainage of mesocosms decreased methane release to 0, even during rewetting. There was a tendency for a decrease of nitrous oxide release during drainage and for an increase in nitrous oxide release during rewetting. Nitrogen fertilization did not increase decomposition of surface peat. Our examinations suggest a competition between vascular vegetation and denitrifiers for excess nitrogen. We also provide evidence that the von Post humification index can be used to explain greenhouse gas release from bogs, if the role of vascular vegetation is also considered. An assessment of the greenhouse gas release from nitrogen saturated restoring bogs needs to take into account elevated release from fresh Sphagnum peat as well as from sedges growing on decomposed peat. Given the high atmospheric nitrogen deposition, restoration will not be able to achieve an oligotrophic ecosystem in the short term.

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Shi, Libin, Suitao Qi, Tianyou Jiao, Jifeng Qu, Xiao Tan, Chunhai Yi et Bolun Yang. « Catalytic Decomposition of Nitrogen Oxides by Bimetallic Catalysts Synthesized by Dielectric Barrier Discharge Plasma Technology ». E3S Web of Conferences 53 (2018) : 01032. http://dx.doi.org/10.1051/e3sconf/20185301032.

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Nitrous oxide (N2O) is a common greenhouse gas and urgent need to be contained. Direct catalytic decomposition of N2O by high activity catalyst into N2 and O2 is a low-cost and harmless method. Bimetallic catalysts show good catalytic activity in many classes of reactions, and plasma technologies, applied to prepare of catalyst, are considered to be a promising method. In our contribution, DBD cold plasma is applied to synthesize Rhodium and Cobalt bimetallic catalysts for catalytic N2O decomposition. The influence of cobalt and rhodium content on N2O decomposition activity shows that the optimal amount of metal is determined as 5wt. % cobalt and 0.5wt. % rhodium loaded on Al2O3. The best working voltage is determined as 18kV. The results indicated that the Rh/Al2O3 catalysts prepared by atmospheric-pressure DBD cold plasma showed smaller size and high dispersion of Rh particles, so that the metal-support interaction and the catalytic activity are enhanced. Atmospheric-pressure DBD cold plasma is proved to be an environmentally friendly and efficient method for preparing high performance Rhodium and Cobalt bimetallic catalysts for catalytic N2O decomposition.

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Caires, CF J., L. S. Lima, C. T. Carvalho et M. Ionashiro. « Thermal behaviour of succinic acid, sodium succinate and its compounds with some bivalent transitions metal ions in dynamic N2 and CO2 atmospheres ». Eclética Química 35, n^o 4 (2010) : 73–80. http://dx.doi.org/10.1590/s0100-46702010000400009.

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Thermal stability and thermal decomposition of succinic acid, sodium succinate and its compounds with Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) were investigated employing simultaneous thermogravimetry and differential thermal analysis (TG-DTA) in nitrogen and carbon dioxide atmospheres and TG-FTIR in nitrogen atmosphere. On heating, in both atmospheres the succinic acid melt and evaporate, while for the sodium succinate the thermal decomposition occurs with the formation of sodium carbonate. For the transition metal succinates the final residue up to 1180 ºC in N2 atmosphere was a mixture of metal and metal oxide in no simple stoichiometric relation, except for Zn compound, where the residue was a small quantity of carbonaceous residue. For the CO2 atmosphere the final residue up to 980 ºC was: MnO, Fe3O4, CoO, ZnO and mixtures of Ni, NiO and Cu, Cu2O.

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Cheng, Lin, et Rui Wang. « Preparation and Application of Nano Ce-Zr Mixed Oxides Supported H3PW12O40 in Nitrogen Oxide Capture and Decomposition ». Materials Science Forum 745-746 (février 2013) : 485–90. http://dx.doi.org/10.4028/www.scientific.net/msf.745-746.485.

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In this study, nanoCe-Zr mixed oxides (CeZrO) were prepared, and XRD, BET surface areas, TEM and TPD-MS were employed for characterization and mechanism analysis. CeZrO was initially used as support for solid tungstophosphoric acid (H3PW12O40 or HPW) and was found to have promotion effect on the adsorption and decomposition of NOx. After loading with HPW, the NOx adsorption efficiency increased, and the highest efficiency of HPW/CeZrO was 98%, much higher than that of pure HPW (ca. 60%). With the increase of HPW loading, the NOx adsorption efficiency tended to reach a peak value before dropping down. The mechanical grinding method was much more suitable than the incipient impregnation method for CeZrO to load HPW. Furthermore, the adsorbed NOx was found to decompose into N2, O2 and N2O, and yields of N2 of 29.7% for HPW/CeZrO was obtained upon heating at a ramp rate of 50 °C/min.

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Likhanov, V. A., et O. P. Lopatin. « Modeling of nitrogen oxides emission in the cylinder of tractor gas-diesel engine ». Traktory i sel hozmashiny 83, n^o 7 (15 juillet 2016) : 3–8. http://dx.doi.org/10.17816/0321-4443-66171.

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The article is devoted to the modeling of process of nitrogen oxides formation in the cylinder of diesel engine operating on compressed natural gas. The combustion of methane-air mixture, ignited by atomized pilot oil that is injected through multijet nozzle, in the cylinder of gas-diesel engine increases the rate of turbulent fluctuations, which leads to intensification of heat and mass exchange in the plume, and significantly increases the rate of formation and decomposition of nitrogen oxides. The calculation of expected emissions of nitrogen oxides in the cylinder of diesel engine and their content in the exhaust gases is carried out. It is done on the basis of the results of kinetic systems modeling for calculation of the kinetics of nitrogen oxides formation during combustion of natural gas and diesel fuel, taking into account the influence of turbocharging, intermediate cooling of charged air and exhaust gas recirculation. In the mathematical modeling of nitrogen oxide formation in the cylinder of diesel engine, the combustion process is divided into two zones, namely the zone of fresh mixture and the zone of combustion products. First zone is a mixture of fresh air with recycled gases (if there is a process of recycling) and residual gases. Before combustion starts, this zone occupies the whole cylinder. During combustion, the volume of zone of combustion products increases. Theoretical researches are carried out on the basis of developed mathematical model for calculation of nitrogen oxides in the cylinders of 4Ch 11.0/12.5 and 4ChN 11.0/12.5 diesel engines. The high precision of theoretical calculations of volumetric content and mass concentration of nitrogen oxides is confirmed, compared to the results of experimental researches (the difference does not exceed 5%).

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Dědeček, Jiří, Alena Vondrová et Jiří Čejka. « Effect of Framework Charge Density on Catalytic Activity of Copper Loaded Molecular Sieves of Chabazite Structure in Nitrogen(II) Oxide Decomposition ». Collection of Czechoslovak Chemical Communications 65, n^o 3 (2000) : 343–51. http://dx.doi.org/10.1135/cccc20000343.

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NO decomposition over Cu-loaded molecular sieves of chabazite structure with different framework negative charge density was investigated. Cu-ZnAlPO-34 with framework charge density (Al + P)/Zn = 15 exhibited high and stable catalytic activity in NO decomposition while Cu-chabazite with Si/Al = 2.7 was inactive. This evidences that the number of aluminum atoms balancing Cu ions in cationic sites controls the catalytic activity of Cu ion. Ions balanced by single framework aluminum atoms exhibit high activity in NO decomposition while ions balanced by two framework aluminum atoms are inactive. Topology of cationic sites is not the limiting parameter for NO decomposition over Cu ions located in molecular sieves.

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Meloni, Eugenio, Marco Martino, Simona Renda, Olga Muccioli, Pluton Pullumbi, Federico Brandani et Vincenzo Palma. « Development of Innovative Structured Catalysts for the Catalytic Decomposition of N2O at Low Temperatures ». Catalysts 12, n^o 11 (10 novembre 2022) : 1405. http://dx.doi.org/10.3390/catal12111405.

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Nitrous oxide (N2O), produced from several human activities, is considered a greenhouse gas with significant environmental impacts. The most promising abatement technology consists of the catalytic decomposition of N2O into nitrogen and oxygen. Many recently published papers dealing with N2O catalytic decomposition over Ni-substituted Co3O4 are related to the treatment of N2O concentrations less than 2 vol% in the feed stream. The present work is focused on developing catalysts active in the presence of a gaseous stream richer in N2O, up to 20 vol%, both as powder and in structured configurations suitable for industrial application. With this aim, different nickel-cobalt mixed oxides (NixCo1−xCo2O4) were prepared, characterized, and tested. Subsequently, since alumina-based slurries assure successful deposition of the catalytic species on the structured carrier, a screening was performed on three nickel-cobalt-alumina mixed oxides. As the latter samples turned out to be excellent catalysts for the N2O decomposition reaction, the final catalytic formulation was transferred to a silicon carbide monolith. The structured catalyst led to the following very promising results: total N2O conversion and selectivity towards N2 and O2 were reached at 510 °C by feeding 20 vol% of N2O. It represents an important achievement in the view of developing a more concretely applicable catalytic system for industrial processes.

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Lofaj, František, Hiroyoshi Tanaka, Radovan Bureš, Margita Kabátová et Yoshinori Sawae. « Tribochemistry of Transfer Layer Evolution during Friction in HiPIMS W-C and W-C:H Coatings in Humid Oxidizing and Dry Inert Atmospheres ». Coatings 12, n^o 4 (6 avril 2022) : 493. http://dx.doi.org/10.3390/coatings12040493.

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The experimental and theoretical investigations of transfer layers in the dry sliding contacts between steel ball and HiPIMS W-C and W-C:H coatings were performed in humid air, dry nitrogen, hydrogen and vacuum on a series of coatings with different contents of carbon and hydrogen in the matrix. Transfer layers formed on the ball in all friction tests, but their composition varied depending on the environment. In humid air, the mechano(tribo)chemical reactions necessary for the obtained phases involved oxidation of WC and Fe, water vapor decomposition and hydrogenation of carbon. Modeling indicated that humidity enhanced oxidation and carbon hydrogenation. In nitrogen, WC decomposition generating carbon was dominant, whereas, in hydrogen, it was carbon hydrogenation. In vacuum, WC decomposition producing W was found to be responsible for high coefficients of friction (COFs). COFs approaching superlubricity were obtained in the H2 atmosphere in the coatings with sufficiently high matrix C:H content. COFs seem to be controlled by the ratio of hydrogenated carbon and oxide phases in transfer layer, which depends on the reactions possible in the surrounding atmosphere.

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Верещагин, А. Л., Е. Д. Минин, Н. В. Бычин et Е. А. Морозова. « THERMAL DECOMPOSITION OF CALCIUM HYPOPHOSPHITE ». Южно-Сибирский научный вестник, n^o 1(53) (29 février 2024) : 39–42. http://dx.doi.org/10.25699/sssb.2024.53.1.006.

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Термическое разложение гипофосфита кальция изучали методом синхронного термического анализа ДТА/ТГА в диапазоне температур от 25°C до 600 °C со скоростью нагревания 10 град/мин в атмосфере азота и в атмосфере воздуха. В атмосфере азота разложение состоит из обширного экзоэффекта, состоящего из четырех последовательных стадий с максимумами при 368, 386, 400 и 434 °C с суммарным тепловыделением 1,51 кДж/г. При разложении в атмосфере воздуха наблюдается экзоэффект с тепловыделением 9,01 кДж/г.При этом было Экспериментально установлено увеличение массы образца в области 370-400 °С 6 масс.%, что может быть объяснено окислением фосфора. Образующиеся конденсированные продукты термического разложения представляют собой пористую массу красно-коричневого цвета, что может быть объяснено образованием промежуточного продукта разложения - фосфида кальция. Образование фосфида кальция термодинамически предпочтительно при взаимодействии продуктов разложения гипофосфита кальция – оксида кальция и фосфина. Удельная теплота образования оксида кальция в 4,18 раза больше значений удельной теплоты образования фосфида. В связи с этим можно предположить, что образование фосфида, - промежуточного продукта, обусловлено неравновесностью процесса, кинетическим факторами и диффузионными ограничениями, поскольку фосфид кальция термодинамически устойчив до 1000 °С. Ранее эти факторы рассматривались применительно к процессам самораспространяющегося высокотемпературного синтеза фосфидов. К тому же образование оксида кальция и фосфина in suti в процессе термораспада в соответствие с эффектом Хедвала может объяснить высокую скорость образования фосфида кальция и его сохранность. The thermal decomposition of calcium hypophosphite was studied by synchronous DTA/TGA thermal analysis in the temperature range from 25 °C to 600 °C at a heating rate of 10 deg/min in a nitrogen atmosphere and in an air atmosphere. In nitrogen atmosphere, the decomposition consists of an extensive exo-effect consisting of four consecutive stages with maxima at 368, 386, 400 and 434 °C with a total heat release of 1.51 kJ/g. Upon decomposition in an air atmosphere, an exoeffect with a heat release of 9.01 kJ/g was observed. An increase of the sample mass in the region 370-400 °C of 6 wt.% was experimentally found, which can be explained by the oxidation of phosphorus. The formed condensed products of thermal decomposition are a porous mass of red-brown color, which can be explained by the formation of an intermediate product of decomposition - calcium phosphide. Formation of calcium phosphide is thermodynamically preferable in the interaction of calcium oxide and phosphine, the products of decomposition of calcium hypophosphite. The specific heat of formation of calcium oxide is 4.18 times higher than the values of specific heat of formation of phosphide. In this connection it is possible to assume that the formation of phosphide, - an intermediate product, is conditioned by non-equilibrium of the process, kinetic factors and diffusion limitations, since calcium phosphide is thermodynamically stable up to 1000 °С. Previously, these factors were considered in relation to the processes of self-propagating high-temperature synthesis of phosphides. In addition, the formation of calcium oxide and phosphine in suti during thermal decay in accordance with the Headwall effect can explain the high rate of calcium phosphide formation and its preservation.

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Volchyn, I., S. Kryvosheiev, A. Yasynetskyi, A. Zaitsev et O. Samchenko. « Selective non-catalytic reduction of nitrogen oxides in the production of iron ore pellets ». Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, n^o 1 (28 février 2022) : 88–94. http://dx.doi.org/10.33271/nvngu/2022-1/088.

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Purpose. Using mathematical modeling, to assess the feasibility of introducing a Selective Non-Catalytic Reduction (SNCR) system as a measure to reduce nitrogen oxide emissions from the production of iron ore pellets. To determine the peculiarities of using ammonia solution and urea solution as reagents for the SNCR process, the influence of the injection of these reagents on the temperature regime during iron pellet production, as well as assess the expected efficiency of the SNCR method for purification of exhaust gases from nitrogen oxides. Methodology. The research results have been obtained using CFD-modeling in the ANSYS Fluent software package. To model this process, a computational domain is constructed, which corresponds in size to the preheating zone (PRE zone) of the actual iron pellet production plant. Two series of calculations are performed for this domain: the first, without adding a reagent, and the second, with a urea solution as a reagent for the SNCR system. Findings. For the first series of calculations, the temperature field and the pressure field in the computational domain is obtained. Experimental research makes it possible to assert that the physical conditions of the mathematical model are close to those at a real plant for the production of pellets. In the second series of calculations, the temperature field in the computational domain is obtained and the influence of the reagent injection of the SNCR system is determined, namely, the temperature decrease in the PRE zone of the pellet production plant by 1025 . The expected efficiency of reduction of nitrogen oxides using a 50% urea solution is about 60%. Originality. It has been revealed that the process of urea solution evaporation is intense, which accelerates the beginning of urea decomposition and, accordingly, the reduction reaction of nitrogen oxides. The temperature drop in the zone of moisture evaporation does not exceed 1025 C. The reagent injection (50% urea solution) with a consumption of 219 kg/h does not significantly affect the temperature regime in the PRE zone. Modeling the chemical reactions of the SNCR process with the injection of 50% urea solution droplets through lances into the PRE zone chamber indicates a 60% reduction in nitrogen oxide emissions. Practical value. The introduction of the SNCR system at pellet production plant can reduce nitrogen oxide emissions, which will have a positive impact on the environmental situation in metallurgical regions.

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Caires, Flávio Junior, Liliane Spazzapam Lima, Cláudio Teodoro De Carvalho et Massao Ionashiro. « THERMAL BEHAVIOUR OF SUCCINIC ACID, SODIUM SUCCINATE AND ITS COMPOUNDS WITH SOME BIVALENT TRANSITIONS METAL IONS IN DYNAMIC N 2 AND CO ATMOSPHERES ». Eclética Química Journal 35, n^o 4 (22 janvier 2018) : 73. http://dx.doi.org/10.26850/1678-4618eqj.v35.4.2010.p73-79.

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Thermal stability and thermal decomposition of succinic acid, sodium succinate and its compounds with Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) were investigated employing simultaneous thermogravimetry and differential thermal analysis (TG-DTA) in nitrogen and carbon dioxide atmospheres and TG-FTIR in nitrogen atmosphere. On heating, in both atmospheres the succinic acid melt and evaporate, while for the sodium succinate the thermal decomposition occurs with the formation of sodium carbonate. For the transition metal succinates the final residue up to 1180 ºC in N atmosphere was a mixture of metal and metal oxide in no 2 simple stoichiometric relation, except for Zn compound, where the residue was a small quantity of carbonaceous residue. For the CO atmosphere the final residue up to 980 ºC was: MnO, FeO, CoO, ZnO and 2 3 4 mixtures of Ni, NiO and Cu, Cu O.

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Zieliński, M., A. Zielińska, H. Papiernik-Zielińska et P. E. Yankwich. « Nitrogen-15 Fractionation in the Thermal Decomposition of Nitrous Oxide of Natural Isotopic Composition ». Isotopes in Environmental and Health Studies 38, n^o 3 (septembre 2002) : 159–72. http://dx.doi.org/10.1080/10256010208033323.

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M., ZIELIN´SKI, ZIELIN´SKA A., PAPIERNIK-ZIELIN´SKA H. et P. E. YANKWICH. « NITROGEN-15 FRACTIONATION IN THE THERMAL DECOMPOSITION OF NITROUS OXIDE OF NATURAL ISOTOPIC COMPOSITION ». Isotopes in Environmental and Health Studies 38, n^o 3 (1 janvier 2002) : 159–72. http://dx.doi.org/10.1080/10256010215135.

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Krištof, Koloman, Tomáš Šima, Ladislav Nozdrovický, Ján Jobbágy, Jan Mareček et Vlastimil Slaný. « Application of Nitrogen Fertilizers and Its Effect on Timeliness of Fertilizers Decomposition Resulting in Lost of Nitrogen Through Nitrous Oxide Emissions from Soil ». Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 66, n^o 3 (2018) : 691–700. http://dx.doi.org/10.11118/actaun201866030691.

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Fertilizers are an important tool to maintain soil fertility and as an enhancement for the efficient crop production. The system of fertilizers application affects the final dose and commonly causes local overdosing or insuficient spatial distribution of fertilizers which are a very important source of nitrous oxide emissions (N2O) from the soil into the atmospher observation of such phenomenon are among the key factors defining environmental impacts of agriculture. A study was conducted to observe the effect of application dose of fertilizer on N2O emission from the soil. CAN (Calcium ammonium nitrate – consist of 27 % nitrogen) was spread by a fertiliser spreader Kuhn Axera 1102 H-EMC aggregated with a tractor John Deere 6150 M. Incorporation of fertilizer into the soil was done by power harrow Pöttinger Lion 302. The application dose was set at 0, 100, 200 and 300 kg.ha–1 while monitoring points were selected at the base of this application doses in respective places. Measurements were conducted at time intervals 7, 14, 21 and 28 days after fertiliser application and following incorporation. Nitrous oxide emissions were measured by field gas monitor set INNOVA consisting of a photoacoustic gas monitor INNOVA 1412 and a multipoint sampler INNOVA 1309. Statistically significant differences was found among time intervals and among the application dose (p > 0.05). It was observed that the application dose of selected fertilizers has the direct effect on nitrous oxide (N2O) emissions released from soil into the atmosphere. An increase of greenhouse gas emissions was observed in range from 0.83 to 152.33 %. It can be concluded that the local overdose of fertilizers negatively affects environmental impact of agricultural practices at greenhouse gas emissions (GHGs).

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