Articoli di riviste: "Productive agglomerates"

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Cordeiro, Valéria Vital, Mirele Costa da Silva, Hélio Lucena Lira, Normanda Lino de Freitas e Ana Cristina Figueiredo de Melo Costa. "Porous Anisotropic Alumina Ceramic Membrane: Preparation and Characterization". Materials Science Forum 727-728 (agosto 2012): 1485–89. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.1485.

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Through different field of application and productive growth that membrane technology has been presented in the last years, the aim of this work is to prepare and characterize anisotropic porous ceramic membrane. The membrane were done with alumina, prepared by combustion reaction in microwave oven from urea as combustible and after deposited on support based on a commercial alumina. The results showed that it was obtained α-alumina as unique phase with average agglomerate size of 10µ and surface area of 33 m2/g. The alumina morphology was constituted by pre-sintering particles with hard agglomerates and/or aggregates. In relation to the membranes, it was observed a longitudinal section without cracks and uncovers support surface, also it can be observed grain formation well distributed and a layer of alumina with approximately 35.25µm. In relation to the permeate flux, the membrane presented initially values relatively high that is decrease with the permeation time, due to adsorption of water in the internal surface of the pores of the membrane, experiencing a decrease in size.

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Sikora, Michal, Petr Janík, Pavlína Pustějovská e Simona Jursová. "The Anthracite as Sinter Fuels". New Trends in Production Engineering 2, n. 2 (1 dicembre 2019): 232–40. http://dx.doi.org/10.2478/ntpe-2019-0088.

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Abstract The chapter deals with the use of traditional carbonaceous fuels in the production of agglomerates. An important part is focused primarily on the use of these carbonaceous fuels in the production of various types of agglomerate. Anthracite together with coke breeze was tested as a fuel to assess the substitution of coke dust by anthracite for technological and qualitative parameters of sintering.

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Del Pino, Jose Claudio, Anildo Bristoti e Mario Pinheiro. "ELASTOMERIC COMPOSITIONS FOR THE PRODUCTION OF RUBBER ARTIFACTS USED IN SHOE MANUFACTURING AND CIVIL CONSTRUCTION". SOUTHERN BRAZILIAN JOURNAL OF CHEMISTRY 1, n. 1 (20 dicembre 1993): 23–28. http://dx.doi.org/10.48141/sbjchem.v1.n1.1993.28_1993.pdf.

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Sugar cane bagasse is a common byproduct of the aZaohoZ and sugar industries. In the present work, we describe the preparation of elastomeric agglomerates containing SBR [poly(styrene-butadiene)] and bagasse or kaolin as inert filler. The experimental results and a series of laboratory and field tests show that the sugar cane bagasse agglomerate can be very appropriate and useful for practical applications, especially in the manufacture of shoe soles.

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Kinoshita, Takahiro, e Atsushi Sugihashi. "Design and optimization of a slot antenna for microwave heating of agglomerates". COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 37, n. 6 (5 novembre 2018): 1886–92. http://dx.doi.org/10.1108/compel-03-2017-0127.

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Purpose The microwave heating technique can be used in the production of iron for productivity improvement when the consumption of low-quality iron ore increases. Iron-containing dust agglomerates are an important source of iron; however, the crushing strength of raw agglomerates is low, which decreases the yield owing to breaking. Therefore, they need to be dried using a “band dryer” to reduce the amount of excess water and improve their crushing strength. This paper aims to present the structure of an antenna that efficiently provides microwave energy to the agglomerate layer inside the band dryer. Design/methodology/approach Electromagnetic field analysis and experiments that simulate inside the band dryer were performed to evaluate the radiation efficiency of the slot antenna for microwave heating of the agglomerate layer in the presence of a metal conveyor. Findings The results show that slot height should be larger than the antenna position from the metal conveyor and smaller than the sum of the antenna position and quarter of the guide wavelength, to maximize the radiation efficiency of the antenna. By satisfying this condition, the radiation efficiency was higher than 75 per cent in the experiments. Originality/value This paper presents for the first time the optimum relation between slot height and antenna position to apply the microwave heating technique to iron-containing agglomerates in a band dryer.

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Zanghellini, Benjamin, Patrick Knaack, Sebastian Schörpf, Karl-Heinz Semlitsch, Helga C. Lichtenegger, Bernhard Praher, Maria Omastova e Harald Rennhofer. "Solvent-Free Ultrasonic Dispersion of Nanofillers in Epoxy Matrix". Polymers 13, n. 2 (19 gennaio 2021): 308. http://dx.doi.org/10.3390/polym13020308.

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Dispersion of carbon nanotubes and carbon nanofibers is a crucial processing step in the production of polymer-based nanocomposites and poses a great challenge due to the tendency of nanofillers to agglomerate. One of the most effective methods for dispersion is the use of a three-roll mill, which is a well-established method and results in agglomerates below 5 µm. Nevertheless, this process is time-consuming and thus a limiting factor for industrial applications. Our aim was to establish an easy and efficient ultrasonic dispersion process, characterize the dispersion parameters, and compare both methods, ultrasonication and the three-roll mill. We applied rheological tests and analyzed the agglomerate sizes by an image fit of the microscopy images. All these analyses combined deliver a valuable set of information about the dispersion’s quality and, therefore, allows the improvement and further adaptation of the dispersion process.

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Noël, Alexandra, e Ginette Truchon. "Inhaled Titanium Dioxide Nanoparticles: A Review of Their Pulmonary Responses with Particular Focus on the Agglomeration State". Nano LIFE 05, n. 01 (marzo 2015): 1450008. http://dx.doi.org/10.1142/s1793984414500081.

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Nanotechnology represents major scientific and economic issues for the future. TiO 2 is used as a reference nanoparticle (NP) for research and workplace exposure assessments due to its important industrial production. However, to date little consistent information exists about its human health effects. Approximately 50% of all TiO 2in vivo studies targeting the respiratory tract have been by inhalation and these exposures are often in the form of agglomerates rather than as individual NPs. Therefore, the size of the NP agglomerates represents the effective size interacting with the biological material and could thereby influence the NP mechanisms of action. Thus, interpretation of nanotoxicological data without considering the agglomeration state could partly explain the heterogeneous results found in the scientific literature for TiO 2 NPs. The objective of this review is to examine the literature concerning the importance of TiO 2 aerosol characterization in the assessment of pulmonary toxicity in rodents. In this way, this review reveals that the pulmonary responses following inhalation of TiO 2 NPs might not depend solely on the primary NP size, but also on the crystal phase, the NP agglomerate size, its structure and the mass concentration. It also shows that TiO 2 NPs may exert their toxicity mechanisms specifically because of the size of their agglomerates in aerosols, thus supporting the concept that aerosols composed essentially of small (< 100 nm) or large (> 100 nm) NP agglomerates do not seem to follow the same pulmonary toxicity mechanisms.

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Vasylkiv, Oleg, Yoshio Sakka e Valeriy Skorokhod. "Synthesis and Properties of Multimetal Oxide Nanopowders via Nano-Explosive Technique". Materials Science Forum 534-536 (gennaio 2007): 125–28. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.125.

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We demonstrate the methodology of engineering the multi-component ceramic nanopowder with precise morphology by ‘nano-blast’ calcinations decomposition of preliminary engineered nanoreactors. Multiple explosions of just melted C3H6N6O6 embedded into preliminary engineered nanoreactors break apart the agglomerates due to the highly energetic impacts of the blast waves. Also, the solid-solubility of one component into the other is enhanced by the extremely high local temperature generated during each nano-explosion in surrounding area. This methodology was applied for production of agglomerate-free nanoaggregates of Gd20Ce80O1.95 with an average size of 42 nm and LaSrGaMgO3-x nanopowder with an average aggregate size of 83 nm.

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V, Bochka, Tarakanov A, Sova A, Boyko M, Yaholnyk M e Dvoiehlazova A. "Improving the technology production of quality agglomerate". Theory and practice of metallurgy 1, n. 1 (21 gennaio 2019): 5–14. http://dx.doi.org/10.34185/tpm.1.2019.01.

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Purpose. The existing technological scheme of agglomeration does not allow obtaining a amount of agglomerate stabilized by size and strength with a small amount of trifle. The aim of the work is theoretical substantiation and development of measures to improve agglomerate production technology in modern conditions on the basis of the results of the study of effective methods of separate preparation of the charge before sintering, as well as methods of mechanical processing of sintered agglomerate in devices of special construction. Methodology. The analysis of the basic thermodynamic parameters and phase composition for the components of the sinter charge was carried out using the software complex HSC Chemistry 5.11. Investigation of the effect of separate preparation of the charge with the use of pre-prepared composites on the parameters of sintering and the quality of agglomerate was carried out in the laboratory of the department metallurgy of cast iron NMetAU at the aggregate for sintering. The determination of the effectiveness of the proposed measures was carried out by mechanical processing of agglomerates obtained after the classical and proposed scheme of preparation of the charge. The quality of the obtained agglomerate was estimated using indicators: uniformity of the granulometric composition, content of trifles, strength indicators after discharge to the steel plate [DSTU 3199-95], coefficient of shape of pieces of different sizes, chemical composition. Findings. It has been determined that the use of separate preparation of the charge has a positive effect: significantly decreases the amount of fraction 0-1 mm and increases the equivalent diameter of the granules; diminishes the mean square deviation and variation coefficient, indicating a more homogeneous granulometric composition of raw granules. The efficiency of separate preparation of a charge with the use of composite with the basicity of 0.9-1.0 is confirmed from a concentrate (size 0-0.1 mm), iron ore (0-3 mm), lime (0-3 mm) and limestone (0-3 mm) and residual blend with the basicity of 1.6-1.8 from iron ore (3-10 mm), sinter return (0-10 mm) and limestone (0-3 mm). Originality. The idea of interaction of different components of agglomeration charge during the separate processes of humidification and laceration is developed. The possibility of forming more homogeneous in size and composition of granules is substantiated, by their separate origin not only around large pieces of backs and ores, but also due to the separate interaction of small components with active surface properties, and subsequent joint granulation of the embryos of granules with the residual charge. It is shown that depending on the given conditions, at the stage of separate preparation of the charge, a binder part is formed predominantly of iron-calcium olivines and calcium ferrites. Practical value. Technological recommendations for increasing the efficiency of preparation of sinter charge to sintering and practical recomendations for the design and technological parameters of the drum-stabilizer work, which ensures the stabilization of agglomerate.

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Goncharov, I. A., L. I. Fajnberg, A. A. Rybakov e A. V. Netyaga. "Analysis of applicability of slag crust in production of agglomerated fluxes". Paton Welding Journal 2016, n. 2 (28 febbraio 2016): 40–44. http://dx.doi.org/10.15407/tpwj2016.02.07.

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Machiya, Koji, Keiichi Koga, Takashi Mukuta, Shigeru Moriki, Kooji Kagara e Hiroshi Ooshima. "Production of Spherical Agglomerates of Cephalosporin Antibiotic Crystals". JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 41, n. 11 (2008): 1017–23. http://dx.doi.org/10.1252/jcej.08we178.

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Savel’ev, S. G., e M. N. Kondratenko. "Technological parameters determining the sintering process intensity". Izvestiya. Ferrous Metallurgy 64, n. 3 (9 aprile 2021): 184–91. http://dx.doi.org/10.17073/0368-0797-2021-3-184-191.

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The sintering intensity is an important factor determining techno-economic efficiency of sinter production which provides the blast-furnace process with the main type of agglomerated iron ore raw materials. The charge sintering rate depends on technological parameters of the sintering process. Therefore, a systematic study of sintering technological parameters, which determine its intensity, is of practical and scientific interest. Indicators of the sintering process intensity are considered that assess it from both the mechanical and heat engineering positions. It is shown that in its purest form the sintering process intensity is characterized by the vertical agglomeration rate and combustion intensity of the sintering charge carbon. Two other indexes − the specific productivity for suitable sinter and intensity of heat output in the combustion zone – are less representative for the comparative estimation of sintering intensity, since their values depend on sintered mass strength and thermal effect of carbon combustion respectively. These factors go beyond the essence of the sintering intensity concept. Since content of fines of 5 – 0 mm at different sinter plants is not equal, representative performance comparison of sintering process is possible only taking into account the total amount of fines generated throughout the agglomerate transport path from sinter machine to blast furnace or the results of testing the agglomerate strength in a drum. A comprehensive systematic classification of techniques has been developed to intensify the sintering process based on the material-component principle using four levels of separation – objects, directions, paths and methods in which each subsequent level concretizes and develops the previous one. Its value is universality, which makes it possible to apply a systematization and separation system for almost all already known and future methods of sintering process intensification.

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Ledentsova, N. E., I. P. Li, V. S. Petrov e V. I. Kapustin. "Perspective nickel-oxide cathodes technologies for centimetric range microwave devices". Fine Chemical Technologies 11, n. 3 (28 giugno 2016): 74–81. http://dx.doi.org/10.32362/2410-6593-2016-11-3-74-81.

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Three technologies of nickel-oxide cathodes based on nickel powder and on barium-calciumstrontium triple carbonate powder for microwave ovens of the centimetric wave length range devices are suggested. The optimum fraction of nickel powder for the production of cathodes is 45-71 microns. The optimum content of the triple carbonate is 10%. The optimum pressure of pressing is 7 t/cm2. The optimum temperature of agglomeration is 1100°C for 10 min. The quality improvement and yield of suitable cathodes are provided by the use of agglomerates of nickel and triple carbonates. The agglomerates contain nickel particles of the 10-25 microns fraction coated with the triple carbonate containing 50% of the carbonate and baked in dried hydrogen at 1000°C for 10 min. The formation of the cathode is carried out by mixing and agglomerating the 45-63 microns fraction and the nickel 45-71 microns fraction with the carbonates concentration 10%. In order to improve the cathodes quality it is expedient to anneal the agglomerates after their production in carbon dioxide at 200-300°C with a final purge by nitrogen at 1000°C for 10 minutes. The use of agglomerates based on nickel and the triple carbonate for the production of oxide-nickel cathodes provides more uniform distribution of the emission-active agent in the volume and on the surface of the cathodes.

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Malamatari, Maria, Anastasia Charisi, Stavros Malamataris, Kyriakos Kachrimanis e Ioannis Nikolakakis. "Spray Drying for the Preparation of Nanoparticle-Based Drug Formulations as Dry Powders for Inhalation". Processes 8, n. 7 (6 luglio 2020): 788. http://dx.doi.org/10.3390/pr8070788.

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Nanoparticle-based therapeutics have been used in pulmonary formulations to enhance delivery of poorly water-soluble drugs, protect drugs against degradation and achieve modified release and drug targeting. This review focuses on the use of spray drying as a solidification technique to produce microparticles containing nanoparticles (i.e., nanoparticle (NP) agglomerates) with suitable properties as dry powders for inhalation. The review covers the general aspects of pulmonary drug delivery with emphasis on nanoparticle-based dry powders for inhalation and the principles of spray drying as a method for the conversion of nanosuspensions to microparticles. The production and therapeutic applications of the following types of NP agglomerates are presented: nanoporous microparticles, nanocrystalline agglomerates, lipid-based and polymeric formulations. The use of alternative spray-drying techniques, namely nano spray drying, and supercritical CO2-assisted spray drying is also discussed as a way to produce inhalable NP agglomerates.

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Seipenbusch, M., S. Froeschke, A. P. Weber e G. Kasper. "Investigations on the fracturing of nanoparticle agglomerates—first results". Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 216, n. 4 (1 novembre 2002): 219–25. http://dx.doi.org/10.1243/095440802321194495.

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The mechanical properties of nanoparticle agglomerates have been addressed in many studies. Agglomerates of nanoparticles grown by stochastic processes such as diffusion-limited cluster-cluster agglomeration represent fractal-like objects. These agglomerates are not in the most stable state, and delivering a certain minimum energy, i.e. the activation energy for restructuring, can induce rearrangement. However, in many applications of nanoparticles a high degree of dispersion in the carrier medium (gas or liquid) is desired. Thus, the fragmentation of the aggregates down to the primary particles would be optimal. Depending on the production process, the bond strength between the primary particles will exhibit a distribution that may range from weak van der Waals bonds to strong solid state necking. In the present study, the degree of fracturing as indicated by image analysis of electron micrographs from impacted agglomerates of nanoparticles of Ag and TiO2 was investigated. The influence of kinetic energy on fracturing was studied.

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Gao, Xiang, Alejandro Vidal, Alicia Bayon, Roman Bader, Jim Hinkley, Wojciech Lipiński e Antonio Tricoli. "Efficient ceria nanostructures for enhanced solar fuel production via high-temperature thermochemical redox cycles". Journal of Materials Chemistry A 4, n. 24 (2016): 9614–24. http://dx.doi.org/10.1039/c6ta02187e.

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Woods, Dawn, Mouna Saoudi, Clinton Mayhew e Rosaura Ham-Su. "CHARACTERIZATION OF PLUTONIUM DISTRIBUTION IN THO2–PUO2 MIXED OXIDES BY ELECTRON PROBE MICROANALYSIS". CNL Nuclear Review 7, n. 2 (1 dicembre 2018): 157–63. http://dx.doi.org/10.12943/cnr.2017.00014.

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Thoria–plutonia (ThO2–PuO2) pellets with a nominal composition of 9.0 wt% PuO2 were prepared using a fabrication route similar to an industrial process for production of urania–plutonia (UO2–PuO2) mixed oxide fuel. The green fuel pellets were separated into 2 batches and the sintering of each batch was carried out under a reducing atmosphere at 1820 °C or 1750 °C. The distribution of plutonium (Pu) in the sintered pellets was investigated by electron probe microanalysis using X-ray mapping and quantitative point analyses. The results show that the pellet samples consist of Pu-rich agglomerates with Pu content close to that of the mastermix blend and a thorium (Th)-rich matrix. The matrix and the Pu-rich agglomerates are separated by a transition zone with Pu content varying from practically nil to the Pu content of the Pu-rich agglomerates. X-ray maps taken from random regions of the centre of the pellets show different sizes of Pu-rich agglomerates irregularly dispersed in the Th-rich matrix. Image analysis of the Pu X-ray maps indicate that the average diameter of the Pu-rich agglomerates of the material sintered at 1820 °C and 1750 °C were 68 μm and 161 μm, respectively.

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Yin, Mingcai, Chaojun Wu, Fangfang Jia, Lijiao Wang, Pengfei Zheng e Yaoting Fan. "Efficient photocatalytic hydrogen production over eosin Y-sensitized MoS2". RSC Advances 6, n. 79 (2016): 75618–25. http://dx.doi.org/10.1039/c6ra14710k.

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Melz, Ederson Ilvar, Carlos Loss Junior, Joelson Sutil e Winston Xaubet Olivera. "Utilization of the soya husk in techno-agglomerates". Ciência e Natura 22, n. 22 (11 dicembre 2000): 37. http://dx.doi.org/10.5902/2179460x27111.

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The preservation of the environment bacame a fundamental practice nowadays all over the planet. Giving continuity to this ideology we researched an alternative material that uses quickly renewable natural resources for the production of agglomerate sheeting.In a strategic analysis of the possible materials that could be used for the production of agglomerate, we decided for the soy bean husks, for being a material of low cost, abundant and composed basically of fiber and cellulose. It confers a low density to the material and permits the agglomerate sheeting fabrication with varied densities. To obtain the agglomerate sheeting we took the following steps:- We used different soybean particle sizes besides the raw husk size;- We added tannin-formaldehyde glue to connect and waterproof the particles;- We carried out a compression and polymerization where we obtained quality sheeting, these being submitted to evaluation tests where we confirmed the applicability and efficiency of the soybean husk for agglomerate sheeting manufacturing.In the whole world, the research for new aggregate development has turned principally to synthetic materials or to the massive exploitation of non-renewable natural resources, while the use of the materials like soya husk, abundant and appropriate, can have a great tendency to minimize pollution, deforestation and final price products.This new technology turns the implantation of agglomerate producing industries viable, because the soya husk is derived from an amply implanted culture, which hold the concept of Zero Emission or whole usage of the prime material to the current application with low cost and high profitability.

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Gu, Jun, Xin Hong Li, Hao Ya Liu e Yu Tang Gao. "Laboratory Evaluation and Application of New Materials Based on Mud Cake to Agglomerated Cake (MTA) Method". Advanced Materials Research 148-149 (ottobre 2010): 449–52. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.449.

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In order to solve the interlayer channeling in the process of oil and gas production, the forming agent of agglomerated cake and mud cake modifier based on Mud Cake to Agglomerated Cake (MTA) method are developed. The evaluation results in laboratory show that the bond strength of cement-formation interface (BSCFI) with the new materials increases significantly with curing time by comparison with those without new materials. The analysis shows that the mechanism of new materials includes three steps. Firstly, the forming agent of agglomerated cake modifies and treats the surface of mud cake and it reacts primarily with the mud cake modifier. Secondly, the cement generates in agglomerated cake. Lastly, the compact agglomerated cake forms. Field applications show that the high quality rate and qualified rate of well cementing with the new materials increased by 13.01 percent points and 1.15 percent points respectively, and the proportion of isolation section length whose Bond Index is greater or equal to 0.8 with the new materials increased by 15.92 percent points compared with other wells in the same block.

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Fröhlichová, M., J. Legemza, R. Findorák e A. Mašlejová. "Biomass as a Source of Energy in Iron Ore Agglomerate Production Process". Archives of Metallurgy and Materials 59, n. 2 (1 giugno 2014): 815–20. http://dx.doi.org/10.2478/amm-2014-0139.

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Abstract This article contains characteristics of selected types of biomass, which can be considered as an alternative fuel in the production of iron ore agglomerate. Selected types of biomass were evaluated by chemical analysis, X-ray phase analysis and microscopic analysis using the camera on microscope Olympus BX 51. Biomass was characterized according to its structure, chemical composition and chemical composition of ash. The obtained data were confronted with the data for coke breeze and based on the results, conclusions were made about the possible use of selected types of biomass as an alternative fuel in the process of iron ore agglomerate production.

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Willms, Thomas, Thomas Echterhof, Stefan Steinlechner, Matti Aula, Ahmed Abdelrahim, Timo Fabritius, Davide Mombelli, Carlo Mapelli e Stefan Preiss. "Investigation on the Chemical and Thermal Behavior of Recycling Agglomerates from EAF by-Products". Applied Sciences 10, n. 22 (23 novembre 2020): 8309. http://dx.doi.org/10.3390/app10228309.

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In addition to the blast furnace converter route, electric steel production in the electric arc furnace (EAF) is one of the two main production routes for crude steel. In 2019, the global share of crude steel produced via the electric steel route was 28%, which in numbers is 517 million metric tons of crude steel. The production and processing of steel leads to the output of a variety of by-products, such as dusts, fines, sludges and scales. At the moment, 10–67% of these by-products are landfilled and not recycled. These by-products contain metal oxides and minerals including iron oxide, zinc oxide, magnesia or alumina. Apart from the wasted valuable materials, the restriction of landfill space and stricter environmental laws are additional motivations to avoid landfill. The aim of the Fines2EAF project, funded by the European Research Fund for Coal and Steel, is to develop a low-cost and flexible solution for the recycling of fines, dusts, slags and scales from electric steel production. During this project, an easy, on-site solution for the agglomeration of fine by-products from steel production has to be developed from lab scale to pilot production for industrial tests in steel plants. The solution is based on the stamp press as the central element of the agglomeration process. The stamp press provides the benefit of being easily adapted to different raw materials and different pressing parameters, such as pressing-force and -speed, or mold geometry. Further benefits are that the stamp press process requires less binding material than the pelletizing process, and that no drying process is required as is the case with the pelletizing process. Before advancing the agglomeration of by-products via stamp press to an industrial scale, different material recipes are produced in lab-scale experiments and the finished agglomerates are tested for their use as secondary raw materials in the EAF. Therefore, the tests focus on the chemical and thermal behavior of the agglomerates. Chemical behavior, volatilization and reduction behavior of the agglomerates were investigated by differential thermogravimetric analysis combined with mass spectroscopy (TGA-MS). In addition, two melts with different agglomerates are carried out in a technical-scale electric arc furnace to increase the sample size.

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Fahami, Abbas, Reza Ebrahimi-Kahrizsangi e Bahman Nasiri-Tabrizi. "Production of Magnesium Titanate-Based Nanocomposites via Mechanochemical Method". Key Engineering Materials 478 (aprile 2011): 1–6. http://dx.doi.org/10.4028/www.scientific.net/kem.478.1.

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The mechanical activation was employed to study the phase evolution of the Mg–TiO2–CaHPO4–CaO nanocrystalline system. The powders mixture with certain weight percent was grinded. Thermal annealing process at 650°C, 900°C and 1100°C temperatures resulted in generation of different compounds like MgTiO3/MgO/Hydroxyapatite (HAp) and MgTiO3/MgO/β-TCP and MgTiO3/Mg2TiO4/MgO/β-TCP, respectively. The compounds were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). The consequences of XRD analysis revealed that by increasing temperature, some composites with different morphological and structural features were detected. Beside, due to decomposing of HAp around 800°C, HAp converted to whitlockite (β-TCP) with growth of temperature. According to SEM and TEM observations, it was found that the synthesized powder contained large agglomerates which significant content of finer particles and agglomerates with spherical morphology. Because magnesium titanates based dielectric materials are useful for electrical applications, the electrical property of HAp has been proved, and the incorporation of these materials could result in new nanocrystalline dielectric materials.

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Sadowskaʼ, Urszula, Andrzej Żabiński e Krzysztof Mudryk. "Influence of fineness level and applied agglomeration pressure of peppermint herb (Mentha piperita L.) on the mechanical properties of the obtained product". BIO Web of Conferences 10 (2018): 02028. http://dx.doi.org/10.1051/bioconf/20181002028.

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The objective of the conducted study was to evaluate the impact of the pressure agglomeration process of peppermint herb on the mechanical properties of the obtained product. The separated fractions of peppermint with 0.5-2.5 and 2.5-5 mm particles were compacted using a hydraulic press Fritz Heckert EU 20, with pressure 50, 100, 150 and 200 MPa. A closed matrix with the compression chamber diameter of 15.6 mm was used. Every time, a 2-g herb sample (corresponding to the weight of tea used for the production of tea bags) was poured into the matrix. Thus, compacted herb in the form of a straight cylinder was obtained. When producing the agglomerate compaction work was determined. Strength tests of the obtained agglomerate were conducted using the MTS Insight 2 testing machine. The density of the produced agglomerate, its compaction level and strength in the Brazilian test was calculated. The obtained results indicate that the values of the tested parameters increase with the increase of pressure in the tested range, yet differences occur between the tested herb fractions. Typically, the agglomerate produced from 0.5-2.5 mm fraction is characterized by a greater density, and the higher level of agglomerate compaction is obtained using 2.5-5 mm herb fraction. The highest strength determined using Brazilian test was determined for agglomerate produced from 0.5-5 mm peppermint herb fraction at 200 MPa pressure and 0.5-2.5 mm fraction using 150 and 200 MPa pressure.

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Lebedev, Valery A., Yury M. Vernigorov, Andrey A. Shirin, Lidianna V. Chunakhova e Elena P. Melnikova. "Improving the Efficiency of Metal Production Waste Processing in Electromagnetic Field". Materials Science Forum 1037 (6 luglio 2021): 759–66. http://dx.doi.org/10.4028/www.scientific.net/msf.1037.759.

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A set of theoretical and experimental studies showing the promising application of devices with the rotating electromagnetic field in the technology of processing sludge wastes of metal production is presented in the paper. Regularities of magneto-vibrational layer formation in those devices and parameters of its energy state control are disclosed. There has also a model of agglomerate destruction in the magneto-vibrational layer been proposed, which establishes a connection of agglomerate particle sizes with the strength of magnetic field induction required for its destruction. The results of studies of the process of ferromagnetic particle grinding are presented, factors affecting the degree of grinding are determined. The possibility of forming an ultradisperse fraction during grinding in the rotating electromagnetic field has been experimentally proved. The effect of porousness on the degree of ferromagnetic particle grinding is shown.

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25

Andreeva, N., M. Tomkovich, A. Naberezhnov, B. Nacke, A. Filimonov, O. Alekseeva, P. Vanina e V. Nizhankovskii. "SEM and AFM Studies of Two-Phase Magnetic Alkali Borosilicate Glasses". Scientific World Journal 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/9078152.

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The morphology and composition of four types of two-phase alkali borosilicate glasses with magnetic atoms prepared by inductive melting have been studied. The results of scanning electron microscopy point to uniform distribution of Na, Si, and O atoms in these samples while magnetic iron atoms form ball-shaped agglomerates. The magnetic properties of these agglomerates have been confirmed by magnetic force microscopy. Atomic force microscopy had shown that in these samples two different morphological structures, drop-like and dendrite net, are formed. The formation of dendrite-like structure is a necessary condition for production of porous magnetic glasses. The obtained results allow us to optimize the melting and heat treatment processes leading to production of porous alkali borosilicate glasses with magnetic properties. The first results for nanocomposite materials on the basis of magnetic glasses containing the embedded ferroelectrics KH2PO4 demonstrate the effect of applied magnetic field on the ferroelectric phase transition.

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26

Khalifa, A. A., V. Yu Bazhin, M. E. М. К. Shalabi, A. Abdelmoneim e M. Omran. "Improving the efficiency of the carbothermal reduction of red mud by microwave treatment". Proceedings of Irkutsk State Technical University 25, n. 2 (2 maggio 2021): 264–79. http://dx.doi.org/10.21285/1814-3520-2021-2-264-279.

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In this work, we studied the effect of microwave treatment of red mud briquettes containting more than 48% of Fe on the process of iron reduction under various conditions of heat treatment. Research samples were collected from red mud formed during the production of alumina from bauxite at the Ural Aluminum Smelter. The chemical composition of mud samples was examined by X-ray fluorescence analysis. The composition of initial mud and that of agglomerates obtained after treatment in microwave and muffle furnaces was studied using the X-ray diffraction method. Phase transitions and structural changes occurring under the effect of heating were studied by scanning electron microscopy. The experimental briquettes comprising red mud and charcoal were treated at 850°C and 1000°C in a microwave furnace (under the frequency of 2.45 GHz and the power of 900 W). For reference, briquettes of analogous composition were heat-treated in a muffle furnace under the same conditions. It was found that, under the conditions of microwave heating to 1000°C for 10 min, hematite is completely reduced to metallic iron after the addition of wustite. An analysis of the m i-crostructure of the samples after microwave treatment showed that the particles of metallic iron in the as-obtained pellet-agglomerates have a larger size than in those after conventional thermal heating in a muffle furnace. The metallized phases of reduced iron at the end of heat treatment in a microwave furnace create a stable durable body of agglomerates. The evidence-based parameters of the process can become a basis for designing a technology for recycling such an industrial material as red mud. The obtained high-strength pellets from red mud with a high content of reduced iron (up to 85%) may be used as an alternative charge material for ferrous metallurgy. The proposed technology for recycling red mud into pellet-agglomerates can be applied in various industries to reduce environmental impact on the production areas of alumina plants.

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Vasseur-Coronado, Maria, Anthi Vlassi, Hervé Dupré du Boulois, Rainer Schuhmacher, Alexandra Parich, Ilaria Pertot e Gerardo Puopolo. "Ecological Role of Volatile Organic Compounds Emitted by Pantoea agglomerans as Interspecies and Interkingdom Signals". Microorganisms 9, n. 6 (31 maggio 2021): 1186. http://dx.doi.org/10.3390/microorganisms9061186.

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Volatile organic compounds (VOCs) play an essential role in microbe–microbe and plant–microbe interactions. We investigated the interaction between two plant growth-promoting rhizobacteria, and their interaction with tomato plants. VOCs produced by Pantoea agglomerans MVC 21 modulates the release of siderophores, the solubilisation of phosphate and potassium by Pseudomonas (Ps.) putida MVC 17. Moreover, VOCs produced by P. agglomerans MVC 21 increased lateral root density (LRD), root and shoot dry weight of tomato seedlings. Among the VOCs released by P. agglomerans MVC 21, only dimethyl disulfide (DMDS) showed effects similar to P. agglomerans MVC 21 VOCs. Because of the effects on plants and bacterial cells, we investigated how P. agglomerans MVC 21 VOCs might influence bacteria–plant interaction. Noteworthy, VOCs produced by P. agglomerans MVC 21 boosted the ability of Ps. putida MVC 17 to increase LRD and root dry weight of tomato seedlings. These results could be explained by the positive effect of DMDS and P. agglomerans MVC 21 VOCs on acid 3-indoleacetic production in Ps. putida MVC 17. Overall, our results clearly indicated that P. agglomerans MVC 21 is able to establish a beneficial interaction with Ps. putida MVC 17 and tomato plants through the emission of DMDS.

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Goncharov, I. A., L. I. Fajnberg, A. A. Rybakov e A. V. Netyaga. "Analysis of applicability of slag crust in production of agglomerated fluxes". Автоматическая сварка 2016, n. 2 (28 febbraio 2016): 48–53. http://dx.doi.org/10.15407/as2016.02.07.

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29

STEITZ, BENEDIKT, HEINRICH HOFMANN e ALKE PETRI-FINK. "PRODUCTION AND BIOFUNCTIONALIZATION OF MAGNETIC NANOBEADS FOR MAGNETIC SEPARATION OF MESSENGER RNA". Biophysical Reviews and Letters 02, n. 01 (gennaio 2007): 109–22. http://dx.doi.org/10.1142/s1793048007000465.

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The synthesis of nanosized beads of superparamagnetic iron oxide nanoparticles coated with 3-(aminopropyl)triethoxysilane is reported in this paper. The resulting beads are agglomerates of SPIONs with an open fractal like structure. These beads have been examined by means of transmission electron microscopy (TEM), photon correlation spectroscopy (PCS), and attenuated total reflection Fourier transformation infrared spectroscopy (ATR-FTIR). The resulting beads with a size of 88 nm have been further biofunctionalized with avidin and biotinylated oligo(dT).

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Yur'ev, Boris, Vyacheslav Dudko e Elena Korelina. "Optimization of Siderite Ore Sintering Operation Conditions". Materials Science Forum 989 (maggio 2020): 417–22. http://dx.doi.org/10.4028/www.scientific.net/msf.989.417.

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Research was сarried out on a pilot plant on sintering of various size siderite ore and limonite taken in various ratios. To study impact of a number of process factors on the sintering process performance and the obtained agglomerate quality at the minimum number of the carried out experiments, one of the experiment planning methods was used, and regression equations were derived. With these equations the effect of the ore size, siderite ore and limonite ratio, solid fuel consumption, sintered layer height on the agglomeration unit performance and the agglomerate metallurgical properties was reviewed. The obtained work results have great practical importance, as they allow optimization of siderite ore sintering operation conditions and production of high quality agglomerate. They may be used at a variety of the country agglomeration factories, where siderite ores will be used as iron ore component of the sinter burden.

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André, Catarina, Inês Delgado, Isabel Castanheira, João Bordado e Ana Sofia Matos. "Statistical experimental design screening strategies for free monomeric isocyanates determination by UPLC in materials used in cork stoppers manufacturing". ACTA IMEKO 6, n. 1 (25 aprile 2017): 50. http://dx.doi.org/10.21014/acta_imeko.v6i1.395.

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A statistical experimental design was used to screen variables of the analytical procedure to quantify free monomeric isocyanates presented in polyurethane based pre-polymers in trace amounts.For this purpose, diphenylmethane-4,4’-diisocyanate (4,4’-MDI), 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI) were analysed by Ultra Performance Liquid Chromatography with a Photo Diode Array detector (UPLC-PDA). A preliminary study was performed with three derivatization agents, being 1-(2-piridyl) piperazine (1,2-PP) the most suitable one. Column temperature, flow and percentage of ammonium acetate (% NH4Ac.) were the factors studied at two levels each. A sequence of experiments was planned according to a 23 full factorial design with three replicates and two repetitions. Analysis of variance (ANOVA) was applied for the identification of significant factors and interactions.Higher responses were achieved when the column temperature was 30 °C, a flow of 0.3 mL/min and a solvent with a percentage of ammonium acetate of 0.1 %. Figures of merit were assessed within-laboratory as a preliminary step for method validation. Similar values were obtained for TDI and MDI. Recoveries are approximately 100 %. In addition, the values of detection limits (LODs) for MDI and TDI were 0.08 and 0.11 microgram/mL, respectively, and quantification limits (LOQs) were 0.25 and 0.33 microgram/mL for MDI and TDI, respectively. The working range was between 0.01 and 10.00 microgram/mL for MDI and 0.01 – 4.95 microgram/mL for TDI. These figures of merit seemed adequate to detect low amounts of free monomeric isocyanates presented in agglomerates and foams for agglomerated cork stoppers production. This data is suitable to address the optimization of an analytical method by a response surface methodology.

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Lee, Han, Wen-Hao Wu, Bing-Hung Chen e Jiunn-Der Liao. "Heterogeneous Catalysts Using Strontium Oxide Agglomerates Depositing upon Titanium Plate for Enhancing Biodiesel Production". Catalysts 11, n. 1 (30 dicembre 2020): 30. http://dx.doi.org/10.3390/catal11010030.

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Strontium oxide (SrO) is an effective catalyst for transesterification. SrO powder that is firmly deposited onto a light titanium plate (TiO2_P), denoted as SrO/TiO2_P, can be reinforced by forming strontium titanate (SrTiO3) at the interface. Exposed SrO agglomerates can promote subsequent continuous transesterification process. In this work, conversion efficiency and production of biodiesel from olive oil on SrO/TiO2_P is investigated. The as-designed SrO/TiO2_P was followed by dip-coating and heat treatment. The physical properties of SrO/TiO2_P were verified through ASTM D3359; the chemical structures before and after transesterification, were respectively identified by X-ray photoelectron spectroscopy and Raman spectroscopy. A focused microwave heating system was utilized for transesterification. In the optimized sample SrO/TiO2_P (x) (x = 0.5 M), SrO firmly bonds with TiO2_P and forms the SrTiO3 structure. With the support of TiO2_P, the tested oil with SrO agglomerates subsequently reacts with SrO under microwave heating. The biodiesel conversion rate reaches 87.7% after a reaction time of 4 min, while the biodiesel product has an average of 39.37 MJ/kg of combustion heat and less than 1 vol% of water content. The as-designed SrO/TiO2_P (0.5) thus has great potential for biodiesel production and is promising with high stability in particular for a continuous fluid flow system.

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Hogekamp, Stefan. "Steam Jet Agglomeration - Part 1: Production of Redispersible Agglomerates by Steam Jet Agglomeration". Chemical Engineering & Technology 22, n. 5 (maggio 1999): 421–24. http://dx.doi.org/10.1002/(sici)1521-4125(199905)22:5<421::aid-ceat421>3.0.co;2-0.

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34

SATO, Hideaki, Satoshi MACHIDA, Koichi NUSHIRO, Koichi ICHIKAWA, Michitaka SATO, Tatsuro ARIYAMA e Kanji TAKEDA. "Development of Production Process for Pre-reduced Agglomerates and Evaluation of Its Quality". Tetsu-to-Hagane 92, n. 12 (2006): 815–24. http://dx.doi.org/10.2355/tetsutohagane1955.92.12_815.

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35

Cordeiro, V. V., Normanda Lino de Freitas, Kaline Melo de Souto Viana, G. Dias, Ana Cristina Figueiredo de Melo Costa e Hélio Lucena Lira. "Influence of the External Heating Type in the Morphological and Structural Characteristics of Alumina Powder Prepared by Combustion Reaction". Materials Science Forum 660-661 (ottobre 2010): 58–62. http://dx.doi.org/10.4028/www.scientific.net/msf.660-661.58.

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The aim of this work is to evaluate the influence of the external heating in the morphological and structural characteristics of the alumina powder prepared by combustion reaction. It was evaluated different types of external heating: muffle oven, microwave oven and ceramic plate with electrical spiral resistance. The powders were prepared according to the propellants and explosives theory, using urea in the stoichiometric proportion (Φe = 1). During the synthesis parameters such as flame combustion time and temperature were measured. The structural and morphological characteristics of the powders were evaluate by XRD, particle size distribution, SEM and nitrogen adsorption (BET). The results showed the production of -alumina as unique phase and formed by agglomerates with irregular plate shape of thin particles for all studied conditions. The powders prepared by electrical oven presented small particle size, with narrow agglomerates size distribution.

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36

Tóth, Mihály, Gréta Gergely, István Endre Lukács, Ferenc Wéber, Attila Lajos Tóth, Levente Illés e Csaba Balázsi. "Production of Polymer Nanofibers Containing Hydroxyapatite by Electrospinning". Materials Science Forum 659 (settembre 2010): 257–62. http://dx.doi.org/10.4028/www.scientific.net/msf.659.257.

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Hydroxyapatite (HAP) is the main inorganic component of mammal bone and teeth. It is one of the few bioactive materials, which helps cell growing. The objective of this study was to fabricate hydroxyapatite-biopolimer nanofiber mats. To achieve this goal, two different suspensions were used. Approximately 1 μm diameter size fibers with large HAP agglomerates were fabricated using acetone and acetic acid. Fibers with a larger diameter size and homogenous distributed HAP particles were produced applying acetone and isopropanol. During the experiment the effect of the processing parameters: applied voltage, diameter of needle, the distance of the needle tip and the collector, flow rate was analyzed.

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Pramanik, Susanta, e Swapan Kumar Mitra. "Development of Hollow Iron Ore Agglomerate and its Characterization". Materials Science Forum 783-786 (maggio 2014): 956–60. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.956.

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Abstract (sommario):

Blast Furnace remains to be one of main producers of molten iron. The secondary or alternate sources of producing molten iron have come in place and contribute around 30% of molten iron production in the world. Good iron ore reserves are fast depleting coupled with a huge amount of fines being produced during mining.

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de Oliveira da Mota, Izabel, e José Adilson de Castro. "A Theoretical Study on BTX Adsorption into the Surface of Compacted Activated Carbon Powders". Materials Science Forum 727-728 (agosto 2012): 1660–65. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.1660.

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Abstract (sommario):

The production of metallurgical coke and carbo chemicals generates residues that evaporate several persistent organic pollutants. Among them, the so-called BTX (benzene, toluene and xylene) are of special concern due to their accumulation into sources of vegetal and animal foods. Owing to the surface properties, large number of porosities and activated sites, activated carbon has been successfully used as a selective adsorbent material. In this study a theoretical model is proposed to analyze the rate of adsorption on the surface of activated carbon compacted produced from powders of micrometer size. The model considers the inner diffusion of BTX into the agglomerate particles. The model results confirm that the agglomerate produced by micro particles of activated carbon increases the amount of adsorption not only by the mechanism of surface action of the agglomerate but is enhanced by the gas diffusion into the pores and subsequent adsorption into the surfaces of the inner particles.

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Gutiérrez-Barranquero, José A., Francisco M. Cazorla, Juan Antonio Torés e Antonio de Vicente. "Pantoea agglomerans as a New Etiological Agent of a Bacterial Necrotic Disease of Mango Trees". Phytopathology® 109, n. 1 (gennaio 2019): 17–26. http://dx.doi.org/10.1094/phyto-06-18-0186-r.

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Bacterial apical necrosis of mango trees, a disease elicited by Pseudomonas syringae pv. syringae, is a primary limiting factor of mango crop production in the Mediterranean region. In this study, a collection of bacterial isolates associated with necrotic symptoms in mango trees similar to those produced by bacterial apical necrosis disease were isolated over five consecutive years in orchards from the Canary Islands. The bacterial isolates were characterized and identified as Pantoea agglomerans. Pathogenicity tests conducted on onion bulbs and mango plants confirmed that P. agglomerans strains isolated from mango trees are a new etiological agent of a bacterial necrotic disease in the Canary Islands. Pathogenicity plasmids of the pPATH family have been previously reported in P. agglomerans. The majority of putatively pathogenic (n = 23) and pathogenic (n = 4) P. agglomerans strains isolated from mango trees harbored four plasmids, one of which was close in size to the 135-kb pPATH pathogenicity plasmid. The analysis of the presence of two major genes in pPATH plasmids (repA and hrpJ) was undertaken in P. agglomerans strains isolated from mango trees. The hrpJ gene was detected in the 140-kb plasmid of pathogenic P. agglomerans strains isolated from mango trees but it showed differences in nucleotide sequences compared with other pathogenic strains. In contrast, the repA gene was not detected in any of the putatively pathogenic and pathogenic P. agglomerans strains isolated from mango trees. Finally, genetic characterization and phylogenetic analysis using the hrpJ gene and the housekeeping genes gyrB and rpoB showed that almost all P. agglomerans strains that were putatively pathogenic and pathogenic on mango trees clustered together, forming a differentiated phylogroup with respect to the other pathogenic P. agglomerans strains described from other hosts.

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Wang, Yao, Fei Wei, Guangsheng Gu e Hao Yu. "Agglomerated carbon nanotubes and its mass production in a fluidized-bed reactor". Physica B: Condensed Matter 323, n. 1-4 (ottobre 2002): 327–29. http://dx.doi.org/10.1016/s0921-4526(02)01041-4.

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41

Glumac, N. G., Y. J. Chen, G. Skandan e B. Kear. "Scalable high-rate production of non-agglomerated nanopowders in low pressure flames". Materials Letters 34, n. 3-6 (marzo 1998): 148–53. http://dx.doi.org/10.1016/s0167-577x(97)00162-6.

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42

Unal, Fatma, e Kursat Kazmanli. "Production and Characterization of RE³⁺:Yb₂O₃ Nanoparticles". Materials Science Forum 1034 (15 giugno 2021): 117–22. http://dx.doi.org/10.4028/www.scientific.net/msf.1034.117.

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Abstract (sommario):

In this study, doped ytterbium oxide (Yb2O3) nanoparticles (NPs) with different dopant type (Eu and / or Tb) and undoped were synthesized by wet chemical method using nitrate salt as a starting source. Afterwards, they were calcined at 900 °C for 4 h. The crystal structure phase, size, and morphology of undoped and doped Yb2O3 nanoparticles (NPs) were characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Undoped and doped NPs were exhibited cubic bixbyite-type crystal structure (Ia-3 space group). Lattice parameter changes caused by dopant element in NPs were examined using X-ray peak profile analysis. In order to investigate the occuring changes in the crystal structure, average crystallite size (CS) and lattice parameter (LP) values were computed with Williamson–Hall (W–H) and Cohen-Wagner (C–W) methods, respectively. It was observed that the crystal structure of the doped NPs expanded compared to the undoped Yb2O3 NPs, which explains the increase in the LP and CS values. The LP values of all the NPs were ranged from 10.444 Å (R2 = 94.9) to 10.453 Å (R2 = 81.8) while the CS of them were between 19 nm (R2 = 95.9) and 24 nm (R2 = 88.8). All the NPs exhibited nearly spherical and agglomerate structure and there were also few pores between the agglomerate particles in the structure. Besides, continuous agglomerate morphology formation was observed in particles containing Tb. The average nanoparticle size values were varied between 46 and 115 nm depending on the dopant element.

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ZHANG, QIANG, HAO YU, YI LIU, WEIZHONG QIAN, YAO WANG, GUOHUA LUO e FEI WEI. "FEW WALLED CARBON NANOTUBE PRODUCTION IN LARGE-SCALE BY NANO-AGGLOMERATE FLUIDIZED-BED PROCESS". Nano 03, n. 01 (febbraio 2008): 45–50. http://dx.doi.org/10.1142/s1793292008000782.

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Abstract (sommario):

Few walled carbon nanotubes (FWCNTs) have been successfully synthesized using a nano-agglomerate fluidized-bed process. FWCNTs can be obtained by fluidization of Fe ( Co / Ni )/ Mo / MgO catalysts at a high temperature with methane cracking in a nano-agglomerate fluidized-bed reactor. The products were mainly 2 to 5 walled CNTs with an outer diameter of 1–7 nm in high purity, as revealed by Raman spectrometry, SEM, and HRTEM analysis. Two keys were crucial for this process. The first key was to get the small size of activity catalyst particles which was realized by Mo addition in catalyst. The graphitization of FWCNTs strongly depended on the composition of catalyst. Fe / Mo / MgO catalyst showed the highest activity and the FWCNT product with the best graphitization. Another key for this process was that the particles must be kept in fluidized state during FWCNT formation. Detailed process information was reported in this article, which showed a potential way for the large scale production of FWCNTs, thereby the urgent need for FWCNTs in high performance will be overcome.

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Subero, J., D. Pascual e M. Ghadiri. "Production of Agglomerates of Well-Defined Structures and Bond Properties Using a Novel Technique". Chemical Engineering Research and Design 78, n. 1 (gennaio 2000): 55–60. http://dx.doi.org/10.1205/026387600527077.

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45

Dastgheyb, Sana S., Amer E. Villaruz, Katherine Y. Le, Vee Y. Tan, Anthony C. Duong, Som S. Chatterjee, Gordon Y. C. Cheung, Hwang-Soo Joo, Noreen J. Hickok e Michael Otto. "Role of Phenol-Soluble Modulins in Formation of Staphylococcus aureus Biofilms in Synovial Fluid". Infection and Immunity 83, n. 7 (11 maggio 2015): 2966–75. http://dx.doi.org/10.1128/iai.00394-15.

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Abstract (sommario):

Staphylococcus aureusis a leading cause of prosthetic joint infections, which, as we recently showed, proceed with the involvement of biofilm-like clusters that cause recalcitrance to antibiotic treatment. Here we analyzed why these clusters grow extraordinarily large, reaching macroscopically visible extensions (>1 mm). We found that while specificS. aureussurface proteins are a prerequisite for agglomeration in synovial fluid, low activity of the Agr regulatory system and subsequent low production of the phenol-soluble modulin (PSM) surfactant peptides cause agglomerates to grow to exceptional dimensions. Our results indicate that PSMs function by disrupting interactions of biofilm matrix molecules, such as the polysaccharide intercellular adhesin (PIA), with the bacterial cell surface. Together, our findings support a two-step model of staphylococcal prosthetic joint infection: As we previously reported, interaction ofS. aureussurface proteins with host matrix proteins such as fibrin initiates agglomeration; our present results show that, thereafter, the bacterial agglomerates grow to extremely large sizes owing to the lack of PSM expression under the specific conditions present in joints. Our findings provide a mechanistic explanation for the reported extreme resistance of joint infection to antibiotic treatment, lend support to the notions that Agr functionality and PSM production play a major role in defining different forms ofS. aureusinfection, and have important implications for antistaphylococcal therapeutic strategies.

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Findorák, Róbert, Jaroslav Legemza, Mária Fröhlichová, Gabriela Fabriciová e Martina Džupková. "New Utilization of Specific Biomass: Lignin in the Iron Ore Sintering Process". Metals 10, n. 9 (31 agosto 2020): 1170. http://dx.doi.org/10.3390/met10091170.

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Abstract (sommario):

The use of lignin can be one of the methods of coke powder substitution in the agglomeration process. This article specifies the material research of lignin and the technological and ecological parameters of the agglomeration process in laboratory conditions using biomass lignin. The methodology of the Raman and infrared spectroscopy, representing a new approach in the analysis and assessment for the purposes of material characteristics for the agglomeration process, was applied to study the structure of carbonaceous matter. The material research of lignin has determined that its calorific value corresponds to ca. 80% of the calorific value of coke powder, while its reactivity is higher than that of the coke. Although the substitution of coke powder using different types of waste biomass (e.g., wood sawdust) in the production of the agglomerate is limited to the maximum of 8–15%, in case of lignin, more than 20% can be substituted, while the standard properties of the produced agglomerate are maintained. The lower emissions of sulfur and nitrogen oxides as well as the reduction of carbon footprint in the agglomeration process as a result of the so-called zero CO2 balance in the formation and processing of the biomass represent its positive aspects. Based on the laboratory research of lignin, up to a 50% substitution of coke powder with this type of biomass can be predicted for the technology of agglomerate production in real operation.

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Ortiz de Zárate, David, Carlos García-Meca, Elena Pinilla-Cienfuegos, José A. Ayúcar, Amadeu Griol, Laurent Bellières, Esther Hontañón, Frank E. Kruis e Javier Martí. "Green and Sustainable Manufacture of Ultrapure Engineered Nanomaterials". Nanomaterials 10, n. 3 (5 marzo 2020): 466. http://dx.doi.org/10.3390/nano10030466.

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Abstract (sommario):

Nanomaterials with very specific features (purity, colloidal stability, composition, size, shape, location…) are commonly requested by cutting-edge technologic applications, and hence a sustainable process for the mass-production of tunable/engineered nanomaterials would be desirable. Despite this, tuning nano-scale features when scaling-up the production of nanoparticles/nanomaterials has been considered the main technological barrier for the development of nanotechnology. Aimed at overcoming these challenging frontier, a new gas-phase reactor design providing a shorter residence time, and thus a faster quenching of nanoclusters growth, is proposed for the green, sustainable, versatile, cost-effective, and scalable manufacture of ultrapure engineered nanomaterials (ranging from nanoclusters and nanoalloys to engineered nanostructures) with a tunable degree of agglomeration, composition, size, shape, and location. This method enables: (1) more homogeneous, non-agglomerated ultrapure Au-Ag nanoalloys under 10 nm; (2) 3-nm non-agglomerated ultrapure Au nanoclusters with lower gas flow rates; (3) shape-controlled Ag NPs; and (4) stable Au and Ag engineered nanostructures: nanodisks, nanocrosses, and 3D nanopillars. In conclusion, this new approach paves the way for the green and sustainable mass-production of ultrapure engineered nanomaterials.

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Ardila-Barragán, Marco Antonio, Carlos Francisco Valdés-Rentería, Brennan Pecha, Alfonso López-Díaz, Eduardo Gil-Lancheros, Marley Cecilia Vanegas-Chamorro, Jesús Emilio Camporredondo-Saucedo e Luis Fernando Lozano-Gómez. "Gasification of coal, Chenopodium Album biomass, and co-gasification of a coal-biomass mixture by thermogravimetric-gas analysis". Revista Facultad de Ingeniería 28, n. 53 (2 ottobre 2019): 53–77. http://dx.doi.org/10.19053/01211129.v28.n53.2019.10147.

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Gasification studies were performed on sub-bituminous coal of the province Centro in Boyacá state of Colombia, vegetable biomass Chenopodium album (cenizo) and co-gasification of coal-biomass mixtures agglomerated with paraffin in a thermogravimetric analyzer. Biomass synergistically promoted thermochemical transformation of the coal was observed. Experimental results were compared to equilibrium composition simulations. Ash fusibility tests of the coal-biomass mixture were carried out, which allowed to clarify its behavior, such as dry or fluid ash according to own chemical composition, during the gasification process. The experimental tests allowed determining the differences in thermal decomposition, between coal, cenizo and coal-biomass blend, which are attributable to the physicochemical properties of each one solid fuel. During the tests, gas chromatography analyses were performed to establish the compositions of the syngas. The syngas obtained from biomass had the highest concentration of CO and the lowest H2; the coal and the coal-biomass mixture were slightly minor respectively. Concentrations of CH4, CO2 and C2H4 were similar between coal and biomass. This result is consistent with the higher calorific value of the coal syngas. The production of syngas from the coal-biomass mixture had the lowest contents of H2 and CO due to synergistic phenomena that occur with the fuel mixture. The co-gasification of the mixture gave the highest syngas production, carbon conversion, and thermal efficiency. These results indicate the viability of co-gasification of coal-Chenopodium album agglomerated mixtures. In gasification of non-agglomerated mixtures of coal-cenizo, the biomass can be burned directly without producing syngas.

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49

Pereira, H., e C. Baptista. "Influence of raw-material quality and process parameters in the production of insulation cork agglomerates". Holz als Roh- und Werkstoff 51, n. 5 (settembre 1993): 301–8. http://dx.doi.org/10.1007/bf02663799.

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50

Chayka, T. "THE EFFECT OF TUNGSTEN CARBIDE NANOPOWDER AGGLOMERATES ON THE PROPERTIES OF CEMENT MATERIALS". Bulletin of Belgorod State Technological University named after. V. G. Shukhov 6, n. 7 (10 luglio 2021): 8–16. http://dx.doi.org/10.34031/2071-7318-2021-6-7-8-16.

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The object of the research is cement samples modified by agglomerates of tungsten carbide nanopowders obtained from carbide waste. The paper considers the influence of tungsten carbide nanopowder on the change in the main cement characteristics (density, water demand, setting time, kinetics of strength gain, compressive strength, bending strength). The optimum additive content in cement materials is 3%. This parameter is estimated by the maximum growth of compressive and flexural strength at all stages of hardening. The effect of WC powder additive on the structure of the cement matrix has been shown. Due to the high dispersibility of WC nanopowder, its particles act as additional crystallization centers, fill in the micropores of the cement stone and create a denser and stronger structure. The results of studying the microstructure of the cement stone with additions of WC powder indirectly confirm the results of strength characteristics. The cement-sand samples with the modifier are found to have a denser crystallized cement-sand stone compared to the control sample (without WC powder addition). The conducted researches have shown perspectivity of application of WC nanoparticles agglomerates as modifying additives for cement materials, which can be used in production of special purpose concrete (hydraulic, radioprotective, etc.). The economic effect of the use of WC nanoadditives obtained from hard-alloy production wastes can be obtained due to a reduction in costs at the stages of construction and operation of structures, buildings, structures based on it.

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