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Bagova, Zarina, Kurmanbek Zhantassov, Gaukhar Turebekova, Bayan Sapargaliyeva i Shermakhan Shapalov. "DISPOSAL OF LEAD PRODUCTION WASTES BY EXTRACTION OF LEAD AND ZINC OXIDES". Series of Geology and Technical Sciences 2, nr 446 (15.04.2021): 37–44. http://dx.doi.org/10.32014/2021.2518-170x.32.
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Information is given about the need to dispose of waste from the Shymkent lead plant in the form of slags, which have accumulated about 2 million tons. It is proved that lead production slags contain a large number of toxic compounds, such as lead, zinc, osmium, and cadmium, which are dangerous sources of environmental pollution. According to the results of X-ray diffractometric analysis and DTA, it was found that the slag of lead produc- tion contains a fairly high number of non-ferrous metal compounds: the content of lead oxide up to 2 %, zinc oxide up to 17% and copper oxide up to 1.25% of the total weight of the sample. The qualitative composition and content of non-ferrous metals of lead slags makes it possible to make the process of recycling toxic waste from lead production technically and economically feasible. The results of preliminary tests allow us to select a technology for more complete and selective extraction of lead and zinc oxides from the slag waste of lead production. When using a selective method for extracting non- ferrous metals, it is expected to improve the ecological state of the environment and reduce the negative impact on human health due to the disposal of toxic slags from lead production. At the same time, a significant contribution is made to the development of the system of rational use of natural and secondary resources.
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Gladinez, Kristof, Kris Rosseel, Jun Lim, Alessandro Marino, Geraldine Heynderickx i Alexander Aerts. "Formation and transport of lead oxide in a non-isothermal lead-bismuth eutectic loop". Nuclear Engineering and Design 349 (sierpień 2019): 78–85. http://dx.doi.org/10.1016/j.nucengdes.2019.04.021.
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Thiele, Günther, Thomas Krüger i Stefanie Dehnen. "K4[PbSe4]⋅en⋅NH3: A Non-Oxide, Non-Halide Inorganic Lead(IV) Compound". Angewandte Chemie International Edition 53, nr 18 (20.03.2014): 4699–703. http://dx.doi.org/10.1002/anie.201310455.
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Li, Cheng Peng, Mary She i Ling Xue Kong. "Non-Isothermal Crystallization Kinetics of Polyvinyl Alcohol-Graphene Oxide Composites". Applied Mechanics and Materials 446-447 (listopad 2013): 206–9. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.206.
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Polyvinlyl alcohol (PVA)/graphene oxide (GO) composites are prepared by solution blending method. And the non-isothermal crystallization kinetics of as-prepared composites is evaluated by differential scanning calorimetry (DSC). The results indicate the graphene oxide can significantly modify the non-isothermal crystallization behavior of the PVA, for instance improved crystallization temperature and prolonged crystallization time. Enhanced crystallization temperature illustrates that GO can act as effective nucleating agent. However, prolonged crystallization time means that GO can retard the whole crystallization. Further kinetics analysis indicates that both the crystallization kinetics of neat PVA and PVA/GO match the Mo model very well. According to the Mo model, during the whole crystallization process, graphene oxide perform as a retardant. In conclusion, graphene oxide can act as effective nucleating agent due to strong interaction bewteen graphene oxide and PVA matrix. On the other hand, graphene oxide loaded may lead to other side effects. This side effects may lead to the retarded crystallization speed finally.
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Thiele, Guenther, Thomas Krueger i Stefanie Dehnen. "ChemInform Abstract: K4[PbSe4]·en·NH3: A Non-Oxide, Non-Halide Inorganic Lead(IV) Compound." ChemInform 45, nr 28 (26.06.2014): no. http://dx.doi.org/10.1002/chin.201428018.
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Skobeev, D., i A. Legkikh. "INVESTIGATION OF THE CHARACTERISTICS OF LEAD OXIDE GRANULES AFTER PROLONGED EXPOSURE IN LIQUID LEAD". PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. SERIES: NUCLEAR AND REACTOR CONSTANTS 2021, nr 3 (26.09.2021): 184–90. http://dx.doi.org/10.55176/2414-1038-2021-3-184-190.
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In order to ensure the safe operation of reactor installations under development with heavy liquid metal coolants (HLMC), such as lead and lead-bismuth, it is necessary to address issues related to the control and regulation of the oxygen potential of the coolant. This is necessary to maintain the normalized range of dissolved oxygen concentrations to ensure the conditions for the formation and maintenance of the integrity of protective oxide coatings on structural materials, as well as to prevent the formation of oxide slags from the coolant during the operation of the reactor plant. Specialists of IPPE have developed a method and a means of solid-phase regulation of the thermo-dynamic activity of oxygen in HLMC. In mass transfer devices developed for the implementation of the solid-phase method of controlled feeding of a heavy liquid metal coolant with dissolved oxygen, lead oxide granules are used as a filler. One of the important issues in substantiating the reliability of mass transfer devices is the question of the constancy of the mechanical properties and chemical composition of lead oxide granules after their prolonged stay under the level of a heavy liquid metal coolant at operating temperature. The lead oxide granules were aged in a sealed container filled with lead. The tank was equipped with the necessary means to control the temperature of the lead and the pressure of the protective gas (argon). The article presents the results of experimental studies of lead oxide granules after their exposure in a lead melt at a temperature of (420±10) °C in a non-carbon mode for 6000 hours. To investigate the characteristics of the lead oxide pellets, a batch of pellets was excavated after 500, 750, 1000, 1750, 2500, 3000, 4500 and 6000 hours from the start of the tests. For the pellets from each recess, the following studies were performed: - pellet density measurements; - measurement of breaking forces of lead oxide granules; - determination of pellet impact strength; - chemical analysis of granule composition.
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Blankenburg, Jan, Martin Stark i Holger Frey. "Oxidation-responsive polyether block copolymers lead to non-ionic polymer surfactants with multiple amine N-oxides". Polymer Chemistry 10, nr 13 (2019): 1569–74. http://dx.doi.org/10.1039/c9py00093c.
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Tallant, D. R., R. W. Schwartz, B. A. Tuttle, S. C. Everist i B. C. Tafoya. "Raman analysis of microcircuits with lead zirconate titanate (PZT) films". Proceedings, annual meeting, Electron Microscopy Society of America 50, nr 2 (sierpień 1992): 1688–89. http://dx.doi.org/10.1017/s0424820100133072.
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Certain compositions and structural forms of lead zirconate titanate (PZT) materials have potential applications in microelectronics because of their ferroelectric properties. One such application is in the development of new types of non-volatile memories. PZT films are integrated into microcircuit components using sol-gel deposition techniques. The solution chemistry effects attendant to different sol-gel preparation procedures have been investigated by several researchers.We have used Raman spectroscopy both to characterize the metallo-organic species initially laid down on macroscopic platinum substrates during sol-gel processing and to follow the evolution of Pb-Zr-Ti oxide species through high temperature processing. The high temperature processing removes residual organics and creates Pb-Zr-Ti oxide structures that have ferroelectric properties. Low temperature pyrochlore structures, which are not ferroelectric, can be distinguished by Raman spectroscopy from tetragonal and pseudo-cubic/rhombohedral perovskite structures, which are usefully ferroelectric (Top Figure). In addition Raman spectroscopy has identified lead and titanium oxides that form as intermediates in the high temperature crystallization of ferroelectric PZT structures.
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Vusikhis, Alexander S., Evgeny N. Selivanov, Stanislav N. Tyushnyakov i Victor P. Chentsov. "Thermodynamic modeling of reduction of metals from B2O3-CaO-Ni(Zn,Pb,Cu)O melts carbon monoxide". Butlerov Communications 59, nr 9 (30.09.2019): 125–31. http://dx.doi.org/10.37952/roi-jbc-01/19-59-9-125.
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Thermodynamic modeling technique is used to describe the metal reduction from oxide melt by carbon monoxide. The B2O3-CaO-MeO (Me – Ni, Zn, Pb, Cu) system, was used with periodic output of the metal phase and gases from the working body. The approach originality is that the equilibrium is determined for each single portion of the gas injected into the working body, and the metal oxides content being reduced in each calculation cycle is taken from the previous data. This approach gives qualitative possibility to make simulated processes closer to real ones. The proposed method calculations allow determining, such parameters as the oxide melt and metal phase compositions, degree of elements reduction, oxide and metal phases mass ratio, equilibrium composition of the gas, reducing ability of gas utilization degree, and others, depending on the introduced gas quantities. Reducing process modeling of Nickel, Copper, Lead and Zinc from B2O3-CaO-MeO melts gives opportunity to determine the process for each metal. Copper reducing from CuO, goes with intermediate oxide (CuO → Cu2O → Cu) formation. Reduction of Nickel (NiO → Ni), Lead (PbO → Pbs + Pbg) and Zinc (ZnO → Zng) proceeds in one stage. The temperature dependence of the non-ferrous metals content in the oxide melt, its reduction degree and reducing agent quantity introduced are described by the second-order polynomial equations. The information obtained may be useful for thermo-extraction processes prognosis during the Nickel, Copper, Lead, and Zinc extraction from non-ferrous metallurgy slag in bubbling process of oxide melt by reducing gases.
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Kirkbir, F., D. Katz, R. Lysse i J. D. Mackenzie. "Formation of dense and non-agglomerated lead oxide particles by spray pyrolysis". Journal of Materials Science 27, nr 7 (1992): 1748–56. http://dx.doi.org/10.1007/bf01107199.
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Plášil, Jakub. "Hydrogen bonding in lead uranyl oxide mineral sayrite". Zeitschrift für Kristallographie - Crystalline Materials 234, nr 11-12 (18.12.2019): 733–38. http://dx.doi.org/10.1515/zkri-2019-0035.
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AbstractThe hydrogen bonding in the structure of the lead uranyl-oxide mineral sayrite has been refined and described directly from XRD data for the first time. Sayrite is monoclinic, a = 10.6925(4), b = 6.9593(2), c = 13.6035(5) Å, β = 107.680(3), with V = 964.46(6) Å3, and Z = 2, space group P 21/n. The structure has been refined to an R = 2.34% based on 2252 unique [I > 3σI] reflections. Sayrite possesses a layered structure with the uranyl-hydroxo-oxide sheets of the topology characterized by the topology symbol P4(UD)8R5. Between adjacent sheets, there are Pb2+ cations and molecular H2O. All H2O groups in sayrite belong to non-transformer groups, which distribute bond-valence from equally from all the cationic parts of the structure to anions. The structural formula of sayrite is Pb2(H2[4]O)4[(UO2)5O6(OH)2].
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Tileuberdi, A. N., S. T. Tleuova, A. S. Tleuov i D. T. Pazylova. "RESEARCH OF PHYSICO-CHEMICAL REGULARITIES OF ENVIRONMENTALLY SAFE TECHNOLOGY FOR EXTRACTION OF METALS FROM DUMP SLAG". RASAYAN Journal of Chemistry 15, nr 04 (2022): 2605–11. http://dx.doi.org/10.31788/rjc.2022.1547082.
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Pollution of the environment with metals such as lead, nickel, copper, titanium, and zinc is a worldwide public problem, as evidenced by the elevated levels in the blood of people living in polluted areas. The physicochemical analysis of the initial waste slags determined the phase and mineralogical features, as well as the elemental composition of the waste slags of lead production and refractory clays of the Sairam district of the Turkestan region. Thermodynamic studies of the calculation of the Gibbs energy of possible reactions of joint chlorinating roasting of non-ferrous and refractory metals have established the probability of reactions involving lead oxides, and nickel oxides in the presence of aluminum oxides, iron, and calcium chloride. An analysis of the obtained calculated data of the Gibbs energy showed that only in the high-temperature region is possible the joint chlorination of copper and nickel oxides in the presence of aluminum oxide, and in the presence of iron oxide, thermodynamic reaction 6 is likely. Mathematical planning of the experiment determined the technological parameters of the process, ensuring the extraction of nickel up to 94% when firing a mixture of slag and clay at 87-8%.
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Sasimma, Watthanapong, i Amnart Suksri. "Performance Investigation of Non-Linear Insulator against Surface Tracking on Wind Turbine Blade Surface". Advanced Materials Research 911 (marzec 2014): 190–94. http://dx.doi.org/10.4028/www.scientific.net/amr.911.190.
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This research work investigates the surface degradation of wind turbine blade surface insulator which is made from modified epoxy resin mixed with Zinc oxide (ZnO) and Aluminium oxide (Al2O3) in different percentage as a filler elements. Accelerated test with AC voltage of 4.5 kV 50 Hz with NH4Cl saline solution using flow rate of contaminant equals to 0.6 ml/min according to IEC 60587 standard. It was found that, the solid insulators which has 30 % of Zinc oxide (ZnO) and 20% of Aluminium oxide (Al2O3) fillers prolong the process of surface tracking to the order of 5.41 for Zinc oxide (ZnO) filler and also to the order of 30.68 for Aluminium oxide (Al2O3) filler. On the other hand, if the amount of Aluminium oxide (Al2O3) filler is more than 20% by weight, it will lead to a rapid tracking phenomena.
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Raja, Shilpa N., Jessica G. Swallow, Sean R. Bishop, Yen-Ting Chi, Ting Chen, Nicola H. Perry, Harry L. Tuller i Krystyn J. Van Vliet. "Analysis of Electrochemomechanical Coupling in Non-Stoichiometric Oxide Thin Films". ECS Meeting Abstracts MA2018-01, nr 32 (13.04.2018): 1933. http://dx.doi.org/10.1149/ma2018-01/32/1933.
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Non-stoichiometric oxides are used in a wide variety of applications including solid oxide fuel cells (SOFCs), lithium ion batteries (LIBs), gas sensors, and catalysis. Through the capacity of such materials to support large point defect concentrations, these functional oxides can readily store, transport, and exchange ions. An important consequence of this non-stoichiometry is a tendency toward chemomechanical coupling, particularly in the form of chemical expansion, or the coupling between material volume and defect concentration. Thin films of non-stoichiometric oxides are of particular interest in such device designs, given the potential for strain engineering. For example, it has been shown for several materials that tensile strain can increase the ionic conductivity or gas exchange reactivity for oxygen by up to an order of magnitude, potentially enabling enhanced device efficiency or decreased operating temperatures1. In electrochemical devices, chemical expansion can generate stress or strain that can lead to mechanical failure, and/or changes in mechanical properties including elastic moduli. Given the extreme environments and range of non-stoichiometric oxides in which chemical expansion can be expected, robust device design requires accurate, flexible, and rapid characterization of environmental conditions and materials that maximize (or minimize) chemical expansion in situ. However, methods used at present for characterizing chemomechanical expansion, such as dilatometry, synchrotron techniques, reflectometry, and others, are not amenable to thin films or are difficult to implement in standard laboratory settings. Recently, Swallow et al. described an approach for characterizing thin film non-stoichiometric oxide chemical expansion at high temperatures by way of electrochemically induced actuation that addresses the above needs2. That work characterized volume change within a fluorite film of PrxCe1-xO2-δ (PCO) and structural deflection of the PCO/YSZ (yttria-stablized zirconia) bilayer during electrochemical pumping of oxygen ions into the PCO film. It also demonstrated a positive attribute of such chemical expansion in the form of high temperature oxide actuators, which harness electrochemically generated chemical strain to produce measurable, nanoscale device deflections. The actuation produced ranged between 5-15 nm of displacement amplitude depending on the experimental conditions2. Here, we provide an extended and graphically rich analysis of electrical and mechanical response data from such experiments. We model the current and mechanical response of PCO to an electrochemical driving force using previously established defect equilibria and kinetic relationships for that oxide, demonstrating the contributions that material properties and sample geometries make to device deflection and electrochemical pumping. We also extend the measurement approach to an additional material system, the perovskite-structured oxide SrTi0.65Fe0,35O3-δ (STF) used as part of magnetic memory devices, gas transport membranes, and fuel cells. This case study demonstrates the broad applicability of this measurement method, as well as means to leverage chemical expansion effects at elevated temperatures for diverse actuating and functional devices. Yildiz, B. ‘Stretching’ the energy landscape of oxides—Effects on electrocatalysis and diffusion. MRS Bull. 39, 147–156 (2014). Swallow, J. G. et al. Dynamic chemical expansion of thin-film non-stoichiometric oxides at extreme temperatures. Nat Mater (2017). doi:10.1038/nmat4898
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Turebekova, Gaukhar Zahievna, Saule Ospandiyarovna Akhmetova i Zarina Ilesovna Bagova. "Ways of the lead-bearing slag waste utilization". E3S Web of Conferences 262 (2021): 04003. http://dx.doi.org/10.1051/e3sconf/202126204003.
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The article presents the results of research on the influence of lead production slag on the environment and ecology of the city. Due to the open storage of slags, an excess of maximum permissible levels (MPL) of lead was established: near the plant, the concentration of lead in the soil exceeds 3000 mg/kg, while the MPL is 3.2 mg/kg. The data of analyzes obtained by methods of scanning electron microscopy and X-ray microanalysis, performed on a scanning electron microscope (SEM), as well as the results of X-ray fluorescence semi-quantitative analysis, performed on an X-ray fluorescence wave-dispersive spectrometer, have been presented. The results of thermal analysis of samples in air in the 20-1000 °C temperature range are presented.It was revealed that lead slag contains a fairly high amount of toxic metal compounds. It has been established that the average content of toxic metals in slags formed as a result of the activity of a lead plant is: lead - 2, 38%; zinc - 9.81%; copper - 0.97%; iron - 25.31%; silicon oxide - 24.62%; calcium oxide - 16.21%; potassium oxide - 1.42%; sulfur - 1.35% of the total sample weight.The offered technology of a selective method for the extraction of non-ferrous metals allows to enhance the ecological state of the environment and reduce their negative impact on human health by means of the disposal of the lead production slags.
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Krasovskyy, V. P., i N. A. Krasovskaya. "Study of wetting and impregnation kinetics of oxide fibers with lead melts and its alloys". Uspihi materialoznavstva 2021, nr 2 (1.06.2021): 107–13. http://dx.doi.org/10.15407/materials2021.02.107.
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The effect of metal coverings on wetting of oxide fibers by lead, bismuth, tin-lead-bismuth-cadmium alloy in vacuum 2·10-3 Pa in the temperature range 400–600 oC was studied by the sessile drop method using the capillary purification method of melt. Oxide fibers plaits that have been placed on a silicon oxide substrate as wetting substrates used. Titanium and nickel powders were used as metal coatings. There is no wetting. The contact angles are close to or greater than 90 degrees and only in the case of the lead-titanium melt system at 600 oC the value of the angle is 15, respectively. The use of a dropper allows separate heating of the melt and the substrate, capillary and thermo vacuum cleaning of the melt, as well as thermo vacuum cleaning of the coatings surface. This is a model scheme of the impregnation process of non-metallic frames with matrix melts in the manufacture of composite materials by spontaneous free impregnation. The metal titanium, nickel powder coatings for the method of spon¬taneous free impregnation was used. The study of the kinetics of impregnation of plaits of oxide fibers with melts of lead and tin-lead-bismuth-cadmium alloy was performed at 600–700 oC. The metal melt impregnates metal powders well. The rate of impregnation is quite high 1,1–1,8 mm/s. The obtained results allow the use of titanium pastes for the manufacture of composites from oxide materials with lead matrices. Composites were made. Oxide fiberglass made of CRT waste was selected as the reinforcing material. Lead was chosen as the matrix metal. Despite the fact that lead is a harmful material, but its use as a matrix phase for composites from the action of ionizing radiation is indispensable. Keywords: spontaneous free impregnation, composites, lead melts, oxide fibers, wetting, metal coverings.
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Sareein, Thanapong, Wandee Thamjaree, Wim Nhuapeng i Tawee Tunkasiri. "Fabrication of 0-3 Non-Lead Based Piezoceramic/Polymer Composites Using Suction Technique". Advanced Materials Research 55-57 (sierpień 2008): 141–44. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.141.
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In this research, 0-3 composites between non-lead based piezoceramic and polymer were fabricated using the suction technique. Bismuth sodium titanate (Bi0.5Na0.5TiO3:BNT) which prepared from conventional mixed oxide method was used as active phase whereas epoxy resin was used as matrix phase. The 50% volumetric fraction of BNT/epoxy resin can obtain from suction technique. The physical and piezoelectric properties of composites samples were examined. It can be found that density of composite samples were about 1.78 g/cm3. Moreover, the piezoelectric coefficient (d33) of sample was 13 pC/N. Furthermore, the microstructure of composites was determined using SEM technique.
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Schneider, Ricardo, Rodrigo Schneider, Elvio A. de Campos, Joaquim Bonfim Santos Mendes, Jorlandio Francisco Felix i Petrus A. Santa-Cruz. "Lead–germanate glasses: an easy growth process for silver nanoparticles and their promising applications in photonics and catalysis". RSC Advances 7, nr 66 (2017): 41479–85. http://dx.doi.org/10.1039/c7ra07434d.
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Kabir, Ahsanul, Victor Buratto Tinti, Maxim Varenik, Igor Lubomirsky i Vincenzo Esposito. "Electromechanical dopant–defect interaction in acceptor-doped ceria". Materials Advances 1, nr 8 (2020): 2717–20. http://dx.doi.org/10.1039/d0ma00563k.
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Vusikhis, Alexander S., Evgeny N. Selivanov, Stanislav N. Tyushnyakov i Viktor P. Chentsov. "Metal reduction by hydrogen from the B2O3-СaO-Ni(Zn, Pb, Cu)O melts thermodynamic modeling". Butlerov Communications 61, nr 2 (29.02.2020): 145–51. http://dx.doi.org/10.37952/roi-jbc-01/20-61-2-145.
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Thermodynamic modeling is used to describe the metal reduction processes by hydrogen from oxide melt in the B2O3-CaO- MeO (Me – Ni, Zn, Pb, Cu) system. Open systems approximation with periodic removal of metal particles and gases from the working melt composition is used in the method. By this work we present the thermodynamic modeling results of metal reduction processes (Ni, Cu, Pb, Zn) by Hydrogen. The reducible metals oxides content in the all melts was 3 mass %, and the mass ratio of B2O3/CaO was taken as 3 to be close to eutectic composition. The calculations made it possible to determine such parameters as oxide melt compositions and elements reduction degree depending on the induced gas quantity. of the Nickel, Copper, Lead and Zinc reduction process simulation from B2O3-CaO-MeO melts proved the reduction process by Hydrogen is similar to that which was earlier established when Carbon monoxide was used as the reducing agent. When Copper is reduced from CuO, the process occurs with intermediate Cu2O oxide formation (CuO → Cu2O → Cu). The Nickel (NiO → Ni), Lead (PbO → Pbs + Pbg) and Zinc (ZnO → Zng) recovery have been realized by one stage. The non-ferrous metals change content in the oxide melt and the degrees of its reduction depending on temperature and reducing agent quantity introduced are described by the second-order polynomial functional equations. Comparison of the Carbon monoxide and Hydrogen used for Nickel, Copper, Lead, and Zinc reducing to 90% metallization degree proved much less Hydrogen consumption.
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Chen, Xiang, Dengfei Duan, Yuhang Zhang, Fanyan Zhou, Xin Yuan i Yue Wu. "Genesis of the Giant Huoshaoyun Non-Sulfide Zinc–Lead Deposit in Karakoram, Xinjiang: Constraints from Mineralogy and Trace Element Geochemistry". Minerals 13, nr 7 (22.06.2023): 842. http://dx.doi.org/10.3390/min13070842.
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The Huoshaoyun zinc–lead deposit, a giant non-sulfide deposit in Xinjiang, is one of the most significant discoveries of zinc–lead deposit in China and globally in recent years. The deposit is dominated by zinc–lead non-sulfides, with minor occurrences of sulfides such as sphalerite, galena, and pyrite. The non-sulfide minerals include smithsonite, cerussite, anglesite, and Fe-oxide. This study focuses on the mineralogical characteristics of sulfide and non-sulfide ores, as well as the trace element characteristics of sphalerite, smithsonite, and Fe-oxide. Mineralogical analysis reveals that smithsonite is derived from the oxidation of primary sulfide minerals and can be classified into three types that are generated during different stages of supergene oxidation. The three types of smithsonite are formed through replacing the sphalerite and host limestone, as well as directly precipitating in the fissures and vugs. Trace element analysis of sphalerite indicates that it is rich in Cd, Tl, and Ge, but poor in Fe and Mn. The ore-forming temperature, calculated using the GGIMFis geothermometer, is mostly within the range of 100~150 °C. Moreover, the trace element characteristics, ore-forming temperature, and S and Pb isotope compositions of the sulfide ores of the Huoshaoyun deposit are similar to those of the Jinding and Duocaima MVT lead–zinc deposits, which are also located in the Eastern Tethyan zinc–lead belt. This suggests that the sulfide orebody in the Huoshaoyun Zn-Pb deposit could also be the MVT deposit. Study of the trace element of the non-sulfide minerals shows that the Mn and Cd are relatively enriched in smithsonite, while Ga, Ge, and Pb are enriched in Fe-oxide. This can be attributed to distinct geochemical properties of the trace elements in the non-sulfide minerals of the Huoshaoyun deposit and is consistent with those of the other oxidized MVT deposits, thus indicating the supergene oxidation process of this deposit.
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Koshelev, M., V. Ulyanov i S. Kharchuk. "INVESTIGATION OF THE SLAGS ACCUMULATION MECHANISM IN LEAD-CONTAINING COOLANTS LOOPS AND ITS PREVENTION BY HIGH-TEMPERATURE TREATMENT WITH HYDROGEN AND WATER STEAM MIXTURES". PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. SERIES: NUCLEAR AND REACTOR CONSTANTS 2021, nr 3 (26.09.2021): 191–205. http://dx.doi.org/10.55176/2414-1038-2021-3-191-205.
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The results of computational and experimental studies of the properties of lead and lead-bismuth coolants and the mechanism of physicochemical processes occurring in their circulation circuits explain the reasons for the formation of slag deposits based on lead oxide. First of all, this is the uncontrolled interaction of lead and lead-bismuth coolants with gaseous oxygen, which, along with nitrogen, is one of the main components of air. Slag deposits are based on lead oxides, but they also contain a significant amount of unoxidized lead (and bismuth in the case of using a lead-bismuth coolant) bound by a lead oxide framework into a single structure, as well as a small amount of components of construction materials (iron , chrome, nickel). The formation of slags in the circulation loop with a lead-containing coolant has a negative effect on its operation: the flow cross-sections are narrowed; heat transfer surfaces are blocked; the normal operation of pipeline fittings is disrupted. To minimize slag accumulation, it is necessary to limit the contact of the coolant with air oxygen, avoid draining the coolant from the circulation circuit, control whether the circulation circuit is in a depressurized state both during research and during non-working periods, when heating and filling the circuits with a coolant, create and maintain a vacuum. The best way to prevent slag accumulation is periodic hydrogen cleaning of the circuit with gas mixtures "hydrogen - water vapor - inert gas". The greatest cleaning efficiency is achieved when gas mixtures are introduced directly into the coolant flow using gas injection devices. Mechanical devices with moving parts, ejectors, nozzle nozzles can act as gas injection devices.
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El-Bahr, Sabry M., Amal M. Elbakery, Nashwa El-Gazzar, Aziza A. Amin, Saad Al-Sultan, Mohammed A. Alfattah, Saad Shousha i in. "Biosynthesized Iron Oxide Nanoparticles from Petroselinum crispum Leaf Extract Mitigate Lead-Acetate-Induced Anemia in Male Albino Rats: Hematological, Biochemical and Histopathological Features". Toxics 9, nr 6 (31.05.2021): 123. http://dx.doi.org/10.3390/toxics9060123.
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This study aimed to investigate the ameliorative effects of iron oxide nanoparticles (IONPs) prepared from leaf extract of Petroselinum crispum compared to those prepared using a chemical method in lead-acetate-induced anemic rats. Twenty rats were divided into four groups (five rats each). Throughout the experimental period (8 weeks), the rats in group 1 were not given any therapy. The rats in groups 2, 3 and 4 were given 400 ppm lead acetate orally for 2 weeks to make them anemic. Following that, these rats were either left untreated, given 27 ppm of chemical IONPs orally or given 27 ppm of natural IONPs orally for the remaining 6 weeks of the experiment. TEM analysis indicated that the chemically and naturally prepared IONPs had sizes of 6.22–9.7 and 64–68 nm, respectively. Serum ferritin and iron concentrations were reduced, whereas the total iron-binding capacity (TIBC), ALT, AST, urea and creatinine were significantly increased in the non-treated lead-acetate-induced anemic rats compared to those of the control. In addition, congestion, hemorrhage, necrosis, vacuolation and leukocytic infiltration in the kidneys, liver and spleen were observed in non-treated lead-acetate-induced anemic rats compared to the control. The effects of lead acetate were mitigated by IONPs, particularly the natural one. In conclusion, IONPs produced from Petroselinum crispum leaf extract can be used as an efficient and safe therapy in lead-acetate-induced anemic rats.
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Yakovlev, Igor, Daniil Astakhov, Sergey Zambalov, Nikita Pichugin i Anatoly Maznoy. "Oxidation-Affected Erosion of Porous Ni-Al Intermetallic Alloy in Combustion Applications: Pore-Scale Simulation". Metals 13, nr 2 (30.01.2023): 277. http://dx.doi.org/10.3390/met13020277.
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Advanced high-temperature oxidation resistance is a crucial characteristic of metallic materials in porous burners. Extreme combustion conditions could lead to oxidation-affected erosion of porous media at a long-time period of burner operation. In this paper, we numerically simulated oxide scale growth at a porous radiant burner fabricated by Ni-Al intermetallic alloy using the combustion synthesis method, focusing on the structure degradation caused by periodic oxide scale spallation. A three-dimensional geometrical model of a porous intermetallic scaffold was obtained by scanning the porous burner using the X-ray CT technique. The surface erosion was modeled by the surface reconstruction based on calculated values of spalled oxide layer thickness. The simulation revealed that the submerged flame results in non-uniform distribution of the temperature at the solid surface. Such non-isothermal conditions lead to a two-times thicker oxide scale at the external surface of the burner. Thin struts of the intermetallic scaffold are prone to oxidation-affected erosion first, which forms discontinues and further fragmentation. The porous scaffold could lose about 50% of initial weight before fragmentation under conditions with intense oxide spallation. In such large structural degradation, the average flow velocity could reduce by a factor of 3, leading to changing of flame stabilization region.
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B Gite, Anil, G. E. Patil i G. H. Jain. "Spray Pyrolysis Technique for the deposition of Lead Oxide (PbO) Thin Films; its Electrochemical behaviour and Structural and optical Properties". Material Science Research India 15, nr 2 (25.07.2018): 134–40. http://dx.doi.org/10.13005/msri/150204.
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Thin film of Lead oxide (PbO) was prepared by spray pyrolysis technique on glass substrate at 250°C. The cyclic voltammetry measurement was carried out to study the oxidation reduction reactions of non-aqueous lead ions at various molar concentrations which is from 0.01M to 0.09M. Elecrochemical studies were carried out with Ag/AgCl as a reference electrode , Pt as working electrode while platinum mesh as counter electrode.Lead oxide appears to be poisonous yellow or reddish yellow solid. Structural characterization of films was analyze with X- ray diffraction (XRD) and optical band gap was determined by UV-Vis Spectroscopy.
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Bagova, Z., K. Zhantassov, G. Turebekova i B. Sapargaliyeva. "ANALYSIS AND IMPACT OF LEAD-CONTAINING WASTE FROM LEAD PRODUCTION ON HUMAN LIFE AND THE ENVIRONMENT". REPORTS 2, nr 336 (13.04.2021): 99–104. http://dx.doi.org/10.32014/2021.2518-1483.36.
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As a result of the activities of the lead plant, about 2 million tons of waste in the form of lead- containing slags were accumulated. Lead production slags contain a large number of toxic heavy metal compounds, such as lead, zinc, osmium, and cadmium, which are dangerous sources of environmental pollution. Due to the open storage of slags, there is an excess of the maximum permissible concentrations (MPC) of lead: near the plant, the concentration of lead is more than 3000 mg/kg in the soil, with a MPC of 3.2 mg/kg. Lead and zinc compounds are dangerous to humans due to their significant toxicity and ability to accumulate in the body. Lead poisoning ranks first among professional intoxications. Waste water containing zinc compounds is not suitable for irrigation of fields, the negative effect of zinc compounds on microorganisms and microfauna of the soil reduces its fertility. The article presents the results of scientific studies of lead slag, conducted by scanning electron microscopy and X-ray microanalysis, performed on a scanning electron microscope (SEM) JEOL-6490 LV (Manufacturer: JEOL, Japan). The results of the thermal analysis of samples on the derivatograph of the F. Paulik, J. Paulik and L. Erdey system in the air environment, in the temperature range of 20-1000°C. are presented. According to the results of research, it was found that lead slags contain a sufficiently high amount of non- ferrous metal compounds: lead oxide up to 0.7 % and zinc oxide up to 8.5 % of the weight amount of slag, which makes the process of recycling toxic waste from lead production technically and economically feasible.
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Geburt, S., D. Stichtenoth, S. Müller, W. Dewald, C. Ronning, J. Wang, Y. Jiao, Y. Y. Rao, S. K. Hark i Quan Li. "Rare Earth Doped Zinc Oxide Nanowires". Journal of Nanoscience and Nanotechnology 8, nr 1 (1.01.2008): 244–51. http://dx.doi.org/10.1166/jnn.2008.n05.
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Zinc oxide (ZnO) nanowires were grown via thermal transport and subsequently doped with different concentrations of Tm, Yb, and Eu using ion implantation and post annealing. High ion fluences lead to morphology changes due to sputtering; however, freestanding nanowires become less damaged compared to those attached to substrates. No other phases like rare earth (RE) oxides were detected, no amorphization occurs in any sample, and homogeneous doping with the desired concentrations was achieved. Photoluminescence measurements demonstrate the optical activation of trivalent RE-elements and the emission of the characteristic intra-4f-luminescence of the respective RE atoms, which could be assigned according to the Dieke-diagram. An increasing RE concentration results into decreasing luminescence intensity caused by energy transfer mechanisms to non-radiative remaining implantation defect sites. Furthermore, low thermal quenching was observed due to the considerable wide band gap of ZnO.
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Rovin, S. L., i S. V. Grigoriev. "A STUDY OF WASTES GENERATED IN THE PRODUCTION OF LEAD". Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), nr 2 (7.07.2018): 43–49. http://dx.doi.org/10.21122/1683-6065-2018-2-43-49.
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Lead-containing wastes amount to more than half of the waste of non-ferrous metals formed in Belarus. At the same these wastes are the least studied and the most toxic of the metal wastes. The bulk of them consists of lead-acid batteries, 50–60% of the mass of which is oxide-sulphate lead paste. The article presents the results of a study of the composition and properties of characteristic lead-containing wastes generated both in the operation of lead-containing products and in the production of lead (slag, dust aspiration, etc.). Obtained data allow to optimize the technological regimes of processing of wastes: consumption of fluxes and temperature – time regime of the lead melting.
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Khozaee, Zahra, Isabelle Chambrier, L. Sosa Vargas, Andrew N. Cammidge i Asim K. Ray. "Impedance spectroscopic study on hybrid phthalocyanine/lead sulphide nanocomposite film". Journal of Porphyrins and Phthalocyanines 23, nr 11n12 (grudzień 2019): 1622–28. http://dx.doi.org/10.1142/s1088424619502055.
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A unique organic/inorganic nanocomposite of non-aggregated lead sulphide (PbS) quantum dots (QDs) dispersed within a spun film of non-peripherally octakis(hexyl)-substituted metal-free phthalocyanine (C[Formula: see text]H[Formula: see text]Pc) has been prepared at room temperature by a simple and low-cost method. The frequency response of alternating current (AC) conduction in a 130 nm thick C[Formula: see text]H[Formula: see text]Pc /PbS film sandwiched between the indium-tin-oxide (ITO) and aluminum (Al) electrodes is found to obey the universal power-law. The cryogenic study of AC conduction reveals that the correlated barrier hopping (CBH) model closely fits to the experimental data at temperatures below 240 K. The parameters obtained by fitting the CBH model point out that the hopping process cannot take place directly between neighboring PbS QDs but involves the localized states within the matrix.
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Herdiech, M. W., X. Zhu, M. D. Morales-Acosta, F. J. Walker i E. I. Altman. "The modification of ferroelectric LiNbO3(0001) surfaces using chromium oxide thin films". Physical Chemistry Chemical Physics 17, nr 14 (2015): 9488–98. http://dx.doi.org/10.1039/c4cp05875e.
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Illustration showing non-polar Cr2O3 deposition onto ferroelectric LiNbO3. Characterization of the interface suggests that the charge compensation layer migrates to the chromium oxide surface where it can lead to distinct chemistry on oppositely poled substrates.
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Möncke, Doris, Brian Topper i Alexis G. Clare. "Glass as a State of Matter—The “newer” Glass Families from Organic, Metallic, Ionic to Non-silicate Oxide and Non-oxide Glasses". Reviews in Mineralogy and Geochemistry 87, nr 1 (1.05.2022): 1039–88. http://dx.doi.org/10.2138/rmg.2022.87.23.
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OVERVIEW In theory, any molten material can form a glass when quenched fast enough. Most natural glasses are based on silicates and for thousands of years only alkali/alkaline earth silicate and lead-silicate glasses were prepared by humankind. After exploratory glass experiments by Lomonosov (18th ct) and Harcourt (19th ct), who introduced 20 more elements into glasses, it was Otto Schott who, in the years 1879–1881, melted his way through the periodic table of the elements so that Ernst Abbe could study all types of borate and phosphate glasses for their optical properties. This research also led to the development of the laboratory ware, low alkali borosilicate glasses. Today, not only can the glass former silicate be replaced, partially or fully, by other glass formers such as oxides of boron, phosphorous, tellurium or antimony, but also the oxygen anions can be substituted by fluorine or nitrogen. Chalcogens, the heavier ions in the group of oxygen in the periodic table (S, Se, Te), on their own or when paired with arsenic or germanium, can function as glass formers. Sulfate, nitrate, tungstate and acetate glasses lack the conventional anion and cation classification, as do metallic or organic glasses. The latter can occur naturally—amber predates anthropogenic glass manufacture by more than 200 million years. In this chapter, we are going to provide an overview of the different glass families, how the structure and properties of these different glass types differ from silicate glasses but also what similarities are dictated by the glassy state. Applications and technological aspects are discussed briefly for each glass family.
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Watson, Carla, Tara Peña, Marah Abdin, Tasneem Khan i Stephen M. Wu. "Dynamic adhesion of 2D materials to mixed-phase BiFeO3 structural phase transitions". Journal of Applied Physics 132, nr 4 (28.07.2022): 045301. http://dx.doi.org/10.1063/5.0096686.
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Two-dimensional materials, such as transition metal dichalcogenides, have generated much interest due to their strain-sensitive electronic, optical, magnetic, superconducting, or topological properties. Harnessing control over their strain state may enable new technologies that operate by controlling these materials’ properties in devices such as straintronic transistors. Piezoelectric oxides have been proposed as one method to control such strain states on the device scale. However, there are few studies of how conformal 2D materials remain on oxide materials with respect to dynamic applications of the strain. Non-conformality may lead to non-optimal strain transfer. In this work, we explore this aspect of oxide-2D adhesion in the nanoscale switching of the substrate structural phase in thin 1T′-MoTe2 attached to a mixed-phase thin-film BiFeO3 (BFO), a multiferroic oxide with an electric-field induced structural phase transition that can generate mechanical strains of up to 2%. We observe that flake thickness impacts the conformality of 1T′-MoTe2 to structural changes in BFO, but below four layers, 1T′-MoTe2 fully conforms to the nanoscale BFO structural changes. The conformality of few-layer 1T′-MoTe2 suggests that BFO is an excellent candidate for deterministic, nanoscale strain control for 2D materials.
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Konys, J., C. Schroer i O. Wedemeyer. "Electrochemical Oxygen Sensors for Corrosion Control in Lead-Cooled Nuclear Reactors". Corrosion 65, nr 12 (1.12.2009): 798–808. http://dx.doi.org/10.5006/1.3319106.
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Abstract Liquid metals have been used in various applications in nuclear systems. Lead-bismuth eutectic (LBE) is foreseen as a coolant and target for neutron generation in accelerator-driven systems (ADS), whereas pure lead will be used as coolant in Gen IV-type lead-cooled fast reactors (LFR). The advantage of heavy liquid metal alloys is their high thermal conductivity and their relative safety in case of an accident. A major problem in non-isothermal systems is the corrosion of their structural components, consisting mainly of ferritic/martensitic and austenitic stainless steels, since the solubility of dissolved elements depends strongly on temperature. The formation of oxide scales on structural components is considered a viable approach to limiting the corrosion rates. To maintain a specific oxygen content in lead or LBE, an oxygen control system (OCS) is crucial. This requires continuous measurement of the oxygen activity in the liquid metal by means of electrochemical sensors. It must be assured that no oxides of the liquid metal itself are formed; otherwise, the system can be blocked. Therefore, this paper addresses the development of oxygen sensors for corrosion control of martensitic and austenitic steels in a lead-bismuth eutectic system at Forschungszentrum Karlsruhe (FZK, Eggenstein-Leopoldshafen, Germany).
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Bratu, Ioan, Olivia Florena Mărunțoiu, Daniela Toader, Laura Troșan i Claudiu TĂNĂSELIA. "Investigarea științifică a icoanei pe lemn Bunavestire din patrimoniul Muzeului Etnografic al Transilvaniei". Anuarul Muzeului Etnograif al Transilvaniei 30 (20.12.2016): 278–92. http://dx.doi.org/10.47802/amet.2016.30.15.
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In order to preserve and restore the wooden icon “Bunavestire” belonging to the Transylvanian Museum of Ethnography, non-destrictive (XRF) and destructive (FTIR spectroscopy) investigation methods were employed. Spruce fir is the wood species for the icon and several painting materials were employed: Scheele green, diluted with lead white, red iron mixed with Vermillon, gold foil for gilded areas and copper oxide for black. For restoration malachite, titanium white, lead white, orpiment, lead yellow and red iron were employed. Before restoration a scientific investigation is necessary.
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Bagova, Z., K. Zhantasov, G. Turebekova, B. Sapargaliyeva i Javier Rodrigo-Ilarri. "ANALYSIS AND PROSPECTIVE UTILIZATION OF TECHNOGENIC SLAG WASTE FROM A LEAD PLANT". SERIES CHEMISTRY AND TECHNOLOGY 2, nr 446 (12.04.2021): 22–28. http://dx.doi.org/10.32014/2021.2518-1491.22.
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The article presents the analysis and results of the study of technogenic slag waste of lead-zinc production. Slags of lead-zinc production contain a large number of toxic compounds: lead, zinc, osmium, cadmium, which are dangerous sources of environmental pollution. Due to the open storage of slags, it was found that the maximum permissible concentrations of lead were exceeded. Utilization of man-made slag waste is of great importance for reducing the negative impact on the safety of life and improving the environmental situation in the region. At the same time, slags are valuable raw materials containing compounds of non-ferrous and rare-earth metals. The article shows the results of laboratory studies of slags to determine the qualitative and quantitative composition of valuable components in the waste of lead production and the possibility of their further processing and disposal. Studies of the material of the heavy slag fraction were carried out on an electron probe microanalyzer of the JEOL IXA-8230 Electron Probe microanalyzer brand. X-ray diffractometric analysis of the average slag sample was performed on a DRON-4 diffractometer with Cu radiation, graphite monochromator. Samples were selected heavy fraction and manufactured artificial polished sections (briquettes). The sections were studied under the microscope of the brand LEICA DM 2500P and immersion in liquids. According to the results of research, it was found that lead slags contain a sufficiently high amount of non-ferrous metal compounds: lead oxide up to 0.7 % and zinc oxide up to 8.5 % of the weight amount of slag, which makes the process of recycling toxic waste from lead production technically and economically feasible.
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Avdeenkov, Alexandr V., Oleg I. Achakovsky, Vladimir V. Ketlerov, Vladimir Ya Kumaev i Alexander I. Orlov. "Basic models and approximation for the engineering description of the kinetics of the oxide layer of steel in a flow of heavy liquid metal coolant under various oxygen conditions". Nuclear Energy and Technology 6, nr 3 (16.11.2020): 215–34. http://dx.doi.org/10.3897/nucet.6.59068.
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The article presents the results of corrosion processes, kinetics and changes in the oxide layer modeling using MASKA-LM software complex. The complex is intended for a numerical simulation of three-dimensional non-stationary processes of mass transfer and interaction of impurity components in a heavy liquid metal coolant (HLMC: lead, lead-bismuth). The software complex is based on the numerical solution of coupled three-dimensional equations of hydrodynamics, heat transfer, formation and convective-diffusive transport of chemically interacting components of impurities. Examples of calculations of mass transfer processes and interaction of impurity components in HLMC, formation of protective oxide films on the surfaces of steels are given to justify the coolant technology.
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Vusikhis, Alexander, Leopold Leontiev, Evgeniy Selivanov i Viktor Chentsov. "Simulation of combined reduction of iron and non-ferrous metals (nickel, copper, lead and zinc) from oxide melts by converted methane". Proceedings of Irkutsk State Technical University 24, nr 5 (październik 2020): 1113–25. http://dx.doi.org/10.21285/1814-3520-2020-5-1113-1125.
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The purpose of the article is to assess the application possibility of methane of various conversion methods (СО2, Н2О, О2) for combined reduction of iron and non-ferrous metals (nickel, copper, lead and zinc) from B2O3-CaO-Fe2O3-МеО oxide melts in the temperature range of 1273-1673 K. Thermodynamic modeling is carried out using a technique, which allows to estimate the variations in phase compositions depending on the amount of the reducing agent induced. The technique differs from the known ones by sequential calculation cycles with the removal of the formed gases and the metal phase from the working fluid composition. It is found that regardless of gas composition the process goes on in several stages. In the case of the combined reduction of iron and nickel (lead or zinc), the first stage is reduction of Fe2O3 to Fe3O4 and FeO. The content of Fe2O3 decreases, while the contents of FeO and Fe3O4 increase (at the end of the stage the content of Fe3O4 reaches its maximum value). At the second stage, there is the transition of Fe3O4 → FeO when the values of the contents of Fe2O3 and Fe3O4 decrease to negligible values. The third stage features the manifestation of the metallic phase. In the case of the combined reduction of iron and copper, the process can be divided into three stages according to the variations of the content of iron oxides, and into two stages according to the variations of the content of CuO and Cu2O. The first stage of iron reduction ends at the moment when the content of magnetite reaches its maximum value, the second stage finishes when the metallic phase appears. The first stage of copper reduction includes the transition of CuO to Cu2O and achievement of the maximum value of Cu2O content. The second stage includes the reduction of copper from Cu2O. A gas with the increased content of hydrogen, which corresponds to methane steam reforming is shown to be the most effective reducing agent. The results obtained make it possible to predict the parameters of the metal reduction process during oxide systems bubbling by methane conversion products. The results will be useful for the development of technologies for selective reduction of metals.
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Jacob, Reenu, i Jayakumari Isac. "Dielectric Response and Transport Properties of Pb2Sr2CaCu2O9 [Lead Strontium Calcium Copper Oxide]". Reports in Advances of Physical Sciences 01, nr 02 (czerwiec 2017): 1750003. http://dx.doi.org/10.1142/s2424942417500037.
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High dielectric permittivity, good mechanical properties and excellent thermal stability are highly desired qualities for the dielectric materials used in embedded capacitors and energy-storage devices. This study reports the temperature dependence and very low loss factor of Pb2Sr2CaCu2O9 ceramics. X-ray diffraction (XRD) and scanning electron microscope (SEM) are used to analyze the sample. The dielectric properties of the material prepared has been investigated in the frequency range 42–1[Formula: see text]MHz and in the temperature range 303–873[Formula: see text]K. The result reveals that Pb2Sr2CaCu2O9 have high dielectric constant with significant temperature and frequency dependence which makes them appropriate in the application of miniaturization of electronic devices. The dielectric constant and the loss factor decreases with increase in frequency of the applied field. Impedance studies confirm that dielectric relaxation in the material is of non-Debye type. Conductivity studies proves quality information related to the charge transport properties. The frequency analysis of modulus properties pictures a distribution of the relaxation time existing in the system. The new ceramic material Pb2Sr2CaCu2O9 will be a promising candidate for uses in embedded capacitors, especially in high-temperature circumstance.
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Noguera, C., i J. Goniakowski. "Mixing properties of Al2O3(0001)-supported M 2O3 and MM′O3 monolayers (M, M′ = Ti, V, Cr, Fe)". Journal of Physics: Condensed Matter 34, nr 3 (3.11.2021): 034002. http://dx.doi.org/10.1088/1361-648x/ac2c3d.
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Abstract Considering the importance of sub-monolayer transition metal oxides supported on another oxide in many industrial processes, with the help of a DFT + U approach, we provide information on the structural and electronic properties of pure M 2O3 and mixed MM′O3 oxide monolayers (M, M′ = Ti, V, Cr, Fe) supported on an α-Al2O3(0001) support. With their structure in the prolongation of the alumina corundum lattice, the monolayers have non-equivalent surface and interface cations, which leads to two different cation configurations in the mixed oxides. In all cases, the interfacial charge transfer is weak, but strong cation–cation electron redistributions may take place as in TiVO3, TiFeO3, VFeO3, and TiCrO3 in which actual redox processes lead to cation oxidation states different from the expected +3 value. We show that the tendency to mixing relies on the interplay between two very different driving forces. Cation–cation redox reactions, in most cases, strongly stabilise mixed configurations, but preference for a given cation position in the monolayer, because of surface energy reasons, may strengthen, weaken or even block the mixing tendency. By comparison with results obtained in bulk ilmenite, in free-standing monolayers and in MLs deposited on transition metal substrates, we evidence the flexibility of their electronic structure as a function of size, dimensionality and nature of support, as a lever to tune their properties for specific applications.
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Atkinson, N. R., E. H. Bailey, A. M. Tye, N. Breward i S. D. Young. "Fractionation of lead in soil by isotopic dilution and sequential extraction". Environmental Chemistry 8, nr 5 (2011): 493. http://dx.doi.org/10.1071/en11020.
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Environmental contextThe chemical reactivity of lead in soil is difficult to assess and depends on both soil conditions and the origins of the lead. This paper tests the combined application of lead isotopic techniques and chemical extraction against our understanding of lead fractionation in soils. Possibly against expectation, it appears that the ‘reactivity’ of lead can be high and yet there is tentative evidence that the original source of the metal affects its fractionation in soil, even after long contact times. Abstract‘Reactivity’ or ‘lability’ of lead is difficult to measure using traditional methods. We investigated the use of isotopic dilution with 204Pb to determine metal reactivity in four soils historically contaminated with contrasting sources of Pb, including (i) petrol-derived Pb, (ii) Pb/Zn minespoil, (iii) long-term sewage sludge application and (iv) 19th century urban waste disposal; total soil Pb concentrations ranged from 217 to 13 600 mg kg–1. A post-spike equilibration period of 3 days and suspension in 5.0 × 10–4 M ethylenediaminetetraacetic acid provided reasonably robust conditions for measuring isotopically exchangeable Pb. However, in acidic organic soils a dilute Ca(NO3)2 electrolyte may be preferable to avoid mobilisation of ‘non-labile’ Pb. Results showed that the reactive pool of soil Pb can be a large proportion of the total soil lead content but varies with the original Pb source. A comparison of isotopic exchangeability with the results of a sequential extraction procedure showed that (isotopically) ‘non-labile’ Pb may be broadly equated with ‘residual’ Pb in organic soils. However, in mineral soils the ‘carbonate’ and ‘oxide-bound’ Pb fractions included non-labile forms of Pb. The individual isotopic signatures of labile and non-labile Pb pools suggested that, despite prolonged contact with soil, differences between the lability of the original contaminant and the native soil Pb may remain.
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Michaliková, Kristýna, Jan Hrdlička, Matěj Vodička, Pavel Skopec, Jitka Jeníková i Lukáš Pilař. "Experimental verification of the efficiency of selective non-catalytic reduction in a bubbling fluidized bed combustor". Acta Polytechnica 62, nr 3 (30.06.2022): 361–69. http://dx.doi.org/10.14311/ap.2022.62.0361.
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Controlling nitrogen oxide (NOX) emissions is still a challenge as increasingly stringent emission limits are introduced. Strict regulations will lead to the need to introduce secondary measures even for boilers with bubbling fluidized bed (BFB), which are generally characterized by low NOX emissions. Selective non-catalytic reduction has lower investment costs compared to other secondary measures for NOX reduction, but the temperatures for its efficient utilization are difficult to achieve in BFBs. This paper studies the possibility of an effective application of selective non-catalytic reduction (SNCR) of nitrogen oxides in a pilot-scale facility with a bubbling fluidized bed. The effect of temperatures between 880 and 950 °C in the reagent injection zone on NOX reduction was investigated. For the selected temperature, the effect of the amount of injected reagent, urea solution with concentration 32.5%wt., was studied. The experiments were carried out using 500 kWth pilot scale BFB unit combusting lignite. In addition, an experiment was performed with the combustion of wooden pellets. With reagent injection, all experiments led to the reduction of nitrogen oxides and the highest NOX reduction of 58% was achieved.
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Shi, Lei, i De Sheng Zhu. "A Synthesized Process of Acidic Tin-Plating Waste Solution in Laboratory". Advanced Materials Research 503-504 (kwiecień 2012): 276–79. http://dx.doi.org/10.4028/www.scientific.net/amr.503-504.276.
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In the electroplating process of acidic tin-plating in laboratory, temperature is required to control at 5 °C or so, but conditions of the laboratory is limited, the average temperature is above 5 °C, which leads to Sn2+ in the bath hydrolyze, produce Sn(OH)2 impurities, and part of Sn2+ in the anode oxidize to produce metastannic acid. As time goes by, impurities increase gradually and eventually lead to the bath not be recycled. This paper mainly studied on impurities in the waste after electroplating were synthesized after a series of oxidation, filter and reduction, which makes recycled materials recycled to the greatest extent, non-recycling materials buried deep after high-temperature incineration. After the experiment, stannous oxide and distilled water in the waste get recycled, and the purity of stannous oxide gotten recycled is above 99.5%, which can be reused.
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Cabana, Jordi. "(Invited) Mg2+ Intercalation into Transition Metal Oxides: What Do We Know and What Would We like to Know?" ECS Meeting Abstracts MA2022-02, nr 4 (9.10.2022): 444. http://dx.doi.org/10.1149/ma2022-024444mtgabs.
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Li-ion batteries hold the commanding heights of energy storage today. In a quest to further boost energy density, interest exists in batteries that couple a Mg metal anode and an oxide cathode that can intercalate Mg2+ ions. Any technological hope hinges on developing robust experimental verification of intercalation in the oxide is indispensable because competing reactions that are not productive for storage often interfere. Such goal requires a combination of tools providing information at different scales, with synchrotron featuring prominently. In this talk, I will discuss the most up-to-date insight into the ability of oxides to reversibly intercalate Mg2+ in non-aqueous electrolytes, since the use of Mg metal requires rigorously anhydrous environments. We will not only discuss the evidence supporting intercalation of Mg2+, but also delineate emerging correlations with both the identity of the transition metal and the existence of defects in the oxide structure. Critical to the endeavor is the characterization of chemical and physical phenomena using a combination of tools providing information at different scales. The discussion will naturally lead us to reveal foundational bottlenecks and immediate questions that must be addressed to make Mg electrochemistry viable for energy storage.
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Mardare, Andrei Ionut, Ivana Zrinski, Alexey Minenkov i Achim Walter Hassel. "Defect-Engineered Composite Hf-Ta Anodic Memristors for Reram Applications". ECS Meeting Abstracts MA2022-01, nr 29 (7.07.2022): 1296. http://dx.doi.org/10.1149/ma2022-01291296mtgabs.
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Various oxides and especially their modifications are in actual scientific focus for memristors fabrication due to their applications in non-volatile memories. Such devices exceed most limits of conventional memory technology. Memristors are recognized as resistive random access memories (ReRAMs), in which the data storage profits from a non-volatile change in the material resistance. The switching between a high resistance state (HRS) and a low resistance state (LRS) depends on the selection of electrodes and active (oxide) layers. This generally impacts the conductive pathways (filaments) formation, which is mediated by oxygen vacancies and/or cations, and their field-activated movement inside the oxide. Anodic oxides of valve metals (Al, Hf, Ta, Ti, Nb, Zr) have shown remarkable performances as memristive elements. Studies on Hf- and Ta-based memristors reported excellent electrical and memory properties, such as multi-level switching, high endurance and data retention. Even though for research purposes the synthesis of such oxide layers is commonly done by atomic layer deposition or sputtering, the electrochemical anodization process should not be neglected. This is a faster, less complex and inexpensive method, with precise composition and oxide thickness control through electrochemical parameters. The value of this approach is clearly emphasized by its continuous industrial implementation in various sectors. Previous works have confirmed that the performance of Hf or Ta anodic memristors can be improved by carefully selecting the anodization electrolyte or other electrochemical parameters1,2. These play a crucial role in positioning and sizing of conductive filaments within the oxide. This approach directly leads to defect-engineered memristors fabrication, which is nowadays a major motivation for investigating devices based on mixed oxides formed in different electrolytes. Predicting the position and shape/thickness of a conducting filament may eventually lead to enhanced device stability and resistive states control. The focus of the current work is on the behavior of anodic memristors based on ultra-thin Hf superimposed on Ta films. The main idea linked to the control of resistive filaments is based on the particularities of the anodization process, when the interface between both oxides is dynamically changing. In situ oxide self-nanostructuring is already known for various superimposed valve metals, including Hf and Ta. Their anodization leads to nanoscale oxide columns (“fingers”) formation, when a metal producing a more resistive oxide is superimposed on a metal producing a less resistive one. This phenomenon is recognized as an electrical version of the Rayleigh-Taylor effect and results from the ionic current preferring the less resistive paths, enhancing the growth of the correspondent oxide. Oxide resistivities and structures, transport numbers, Pilling-Bedworth ratios are all considered as determining factors for the anodization process of such superimposed systems. In the current work, anodization of Hf/Ta system leads to Rayleigh-Taylor effects since HfO2 is the more resistive oxide. The boundary between Hf and Ta oxides may influence the conductive pathways required for the memristive effect, thus being most relevant for fabrication of highly stable and forming-free memristors. Additionally, the use of superimposed films with gradient but complementary thicknesses allows investigating the ideal Hf/Ta ratios for which the best memristive behavior is obtained.3 From this study, one pronounced zone prominent for memristive applications is found for Hf/Ta thickness ratios between 4 and 5. Here, unipolar and bipolar memristors are identified, with remarkable endurance and retention capabilities. The CFs positioning is predefined by the development of Ta2O5 columnar structures grown during the anodization process. It is also possible that few CFs may be found in parallel, according to TEM observations, showing more than one Ta2O5 “finger”. Previous studies on pure Hf anodic memristors have confirmed concurrent competing CFs formation.2 Thus, one could assume that the memristive switching mechanism can be conditioned by the formation of oxides with such structures. The identified Hf/Ta ratio could be an excellent choice for improved memristors fabrication. Controlled O vacancies generation is a critical factor in switching uniformity and reproducibility. Therefore, oxide “fingers” formation is a promising electrochemical approach towards defect-engineered memristors. Further investigation of the composite oxide formation, particularly in Hf/Ta superimposed system, is topical. Until now, such systems were not recognized in the literature for the ReRAM applications. This is highly promising since both memory and electrical characteristics are improved by the forming-free nature of the memristors with CFs mediated by oxide nanostructuring. I. Zrinski et al., Nanomaterials 11, 1 (2021) https://doi.org/10.3390/nano11030666 I. Zrinski et al. Appl. Surf. Sci. 565, 150608 (2021) https://doi.org/10.1016/j.apsusc.2021.150608 I. Zrinski et al., J. Phys. Chem. Lett. 12, 8917 (2021) https://doi.org/10.1021/acs.jpclett.1c02346 Figure 1
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Elamin, Nuha Y., Egbal Eltom i Rasha Ramadan. "Green Synthesis of Lead Oxide Nanoparticles, Characterization and Adsorption Study for Removal of Malachite Green Dye". Asian Journal of Applied Chemistry Research 13, nr 2 (10.03.2023): 16–22. http://dx.doi.org/10.9734/ajacr/2023/v13i2239.
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In this study lead oxide nanoparticles were synthesized by using ecofriendly and non-toxic Morus rubra extract. The obtained lead oxide nanoparticles were characterized by XRD, SEM, EDX, BET and FTIR techniques. Powder X-ray diffraction analysis revealed that synthesized PbO nanoparticles had crystallite structure of high purity. SEM survey shows that the obtained nanoparticles having in general uniform particle distribution and the particle sizes vary within the range of 22.4 to 29.2nm. As established by EDX to confirm the presence of lead and oxygen, the weight percentage of the latter was (71.5 % Pb and 28.5% O), respectively. FT-IR spectra exhibit a sharp peak at 439.38 and 595.46 cm−1 attributed to PbO vibration, confirming the formation of PbO nanoparticles. The effectiveness of PbO nanostructures for removing indigo carmine (MG) dye from an aqueous solution is demonstrated in this article. , the MG dye uptake and adsorption processes were investigated using a PbO sorbent. The maximum adsorption capacity and contact time were optimized which corresponding to 41.3 mg. g-1 and 60min respectively.
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Ravishankar, Harish, Jens Christy i Veeriah Jegatheesan. "Graphene Oxide (GO)-Blended Polysulfone (PSf) Ultrafiltration Membranes for Lead Ion Rejection". Membranes 8, nr 3 (6.09.2018): 77. http://dx.doi.org/10.3390/membranes8030077.
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Graphene oxide (GO) has been widely reported and used for treatment of heavy metals from different waste streams. Although their use as additives for membranes has greatly enhanced membrane properties, there is still a bottleneck in obtaining membranes with high heavy-metal rejection efficiencies while maintaining high flux, mechanical strength, and porosity. In the present study, different compositions of GO (0–1 wt %)-blended membranes were prepared using 1-methyl-2-pyrrolidone (NMP) as solvent and water with 5% ethanol as non-solvent, and studied for the rejection of the chosen model heavy-metal lead. The prepared membranes were characterized for hydrophilicity, membrane porosity, flux, permeability, pore-size, mechanical strength, and membrane morphology. From the results, it was inferred that membranes having maximum GO in their blend (1 wt %) showed better hydrophilicity (water contact angle 34.2°), porosity (82.2%), permeability (52.1 L/m2 h bar), and pure water flux (163.71 L/m2 h) at 3-bar pressure as opposed to other compositions. The pore sizes of the membranes ranged between 18 to 24 nm. Tensile strength tests showed the role of GO as a positive reinforcement on the mechanical properties of membranes through Young’s modulus (188.13 ± 15.36 MPa) for the membrane having 0.25 wt % GO composition. Environmental Scanning Electron Microscopy (ESEM) images displayed the dense top layer supported by a porous, finger-like structure, obtained from instantaneous de-mixing favored by NMP and GO. The observed reduction in flux of lead solution for GO-blended membranes was due to osmotic pressure build-up caused by the retained nitrate salt by GO on the retentate side of the membrane. A maximum rejection of 98% was achieved with 1 wt % GO membrane at 1-bar pressure with flux of 43.62 L/m2 h, which decreased to 94% at 3-bar pressure with flux of 142.95 L/m2 h. These results showed how the application of NMP as solvent and GO as an additive could facilitate in obtaining high-flux and high-rejection membranes.
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Martinelli, Laure, Fanny Balbaud-Célérier, Gerard Picard i Gerard Santarini. "High Temperature Oxidation of Fe-9Cr-1Mo Steel in Liquid Metal". Materials Science Forum 595-598 (wrzesień 2008): 519–28. http://dx.doi.org/10.4028/www.scientific.net/msf.595-598.519.
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The oxidation mechanism of the T91 martensitic steel in oxygen-saturated Pb-Bi eutectic at 470°C has been investigated to develop a long term predictive model of the steel oxidation kinetic. This work is performed in the frame of life duration studies carried out for the MEGAPIE spallation module demonstrator dedicated to the feasibility demonstration of an hybrid reactor. Our scientific approach has been based on an experimental characterization of the oxide scales and of the T91 steel oxidation kinetics. From these experimental results, an oxidation mechanism has been elaborated and then simulated. The oxide scale formed at the T91 surface has a duplex structure, constituted of an external magnetite scale and an internal Fe-Cr spinel scale. A scale growth mechanism has been proposed: the magnetite scale growth seems to be limited by the iron lattice diffusion inside the duplex oxide scale. At the same time, a self-regulation mechanism seems to govern the Fe-Cr spinel scale growth. This mechanism consists of a non-limiting oxygen diffusion step, which is carried out, across the oxide scale, inside liquid lead nano-channels and a limiting iron oxide lattice diffusion step. Considering the proposed oxidation mechanism, a simulation of the growth of the two oxides scales has been carried out and compared to the experimental oxidation kinetics. The excellent agreement between the experimental results and the simulations supports to accept the proposed mechanism, leading to prediction of kinetics for long oxidation durations.
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Zhang, Qi, Dong Chen, Dong Jing, Guijuan Fan, Liu He, Hongzhen Li, Wentao Wang i Fude Nie. "Access to green primary explosives via constructing coordination polymers based on bis-tetrazole oxide and non-lead metals". Green Chemistry 21, nr 8 (2019): 1947–55. http://dx.doi.org/10.1039/c8gc03973a.
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Pandas, Hossein Momenizadeh, i Mostafa Fazli. "Fabrication of Pb₃O₄ and Fe₂O₃ nanoparticles and their application as the catalysts in thermal decomposition of ammonium perchlorate". Chemical Reports 4, nr 1 (2022): 244–55. http://dx.doi.org/10.25082/cr.2022.01.003.
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Nanoparticles (NPs) of lead tetroxide (Pb3O4) with the spherical morphology were manufactured by the reaction of lead nitrate with sodium hydroxide, while the nanoparticles (NPs) of red iron oxide (Fe2O3) with similar morphology were fabricated by hydrothermal route in the presence of ferric chloride hexahydrate as the precursor. Evaluation of the chemical structure, the purity and the morphology of the manufactured Fe2O3 and Pb3O4 NPs was carried out by analysis via X-ray diffraction (XRD) as well as scanning electron microscope (SEM). The outcomes of XRD recognized establishment of the desired oxides, wherever the SEM images clearly exhibited the morphology of the manufactured Pb3O4 and Fe2O3 as the spherical NPs with an average particle sizes of near to 40 and 46 nm, respectively. The catalytic effect of the metallic oxide NPs on the perfection of ammonium perchlorate (AP) thermal decomposing was established by testing their AP nano-composites via differential scanning calorimetric (DSC) together with thermogravimetric analysis (TG). Thermal behavior studies displayed that adding of 5% Fe2O3/Pb3O4 NPs (as the mixture) delivers a concerned catalytic effect during AP thermal decomposition. Additionally, thermal decomposition of AP could be amended by adding of 2% Pb3O4 NPs. Further comparison of the NPs catalytic effects was obtained by computing the values of activation energies (E) and thermodynamic parameters (i.e., ΔS#, ΔH# and ΔG#) for their thermal decomposition by non-isothermal approaches.
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da Cruz, Ellen de Nazaré S., Luana de Sousa Peixoto, Jamile S. da Costa, Rosa Helena V. Mourão, Walnice Maria O. do Nascimento, José Guilherme S. Maia, William N. Setzer, Joyce Kelly da Silva i Pablo Luis B. Figueiredo. "Seasonal Variability of a Caryophyllane Chemotype Essential Oil of Eugenia patrisii Vahl Occurring in the Brazilian Amazon". Molecules 27, nr 8 (8.04.2022): 2417. http://dx.doi.org/10.3390/molecules27082417.
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Eugenia patrisii Vahl is a native and non-endemic myrtaceous species of the Brazilian Amazon. Due to few botanical and phytochemical reports of this species, the objective of the present work was to evaluate the seasonal variability of their leaf essential oils, performed by GC and GC-MS and chemometric analysis. The results indicated that the variation in oil yields (0.7 ± 0.1%) could be correlated with climatic conditions and rainy (R) and dry seasons (D). (E)-caryophyllene (R = 17.1% ± 16.0, D = 20.2% ± 17.7) and caryophyllene oxide (R = 30.1% ± 18.4, D = 14.1% ± 19.3) are the major constituents and did not display significant differences between the two seasons. However, statistically, a potential correlation between the main constituents of E. patrisii essential oil and the climatic parameters is possible. It was observed that the higher temperature and insolation rates and the lower humidity rate, which are characteristics of the dry season, lead to an increase in the (E)-caryophyllene contents, while lower temperature and insolation and higher humidity, which occur in the rainy season, lead to an increase in the caryophyllene oxide content. The knowledge of variations in the E. patrisii essential oil composition could help choose the best plant chemical profile for medicinal purposes.