scholarly journals Variation of the rutile and anatase phase using a high energy planetary mill in a carbon dioxide atmosphere

2019 ◽  
Vol 1418 ◽  
pp. 012022
Author(s):  
C J Jaimes-Ochoa ◽  
J H Quintero-Orozco ◽  
R Ospina-Ospina
Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1558 ◽  
Author(s):  
George Mogildea ◽  
Marian Mogildea ◽  
Cristina Popa ◽  
Gabriel Chiritoi

This paper focuses on the dissociation of carbon dioxide (CO2) following the absorption processes of microwave radiation by noncontact metal wire (tungsten). Using a microwave plasma generator (MPG) with a single-mode cavity, we conducted an interaction of microwaves with a noncontact electrode in a CO2 atmosphere. High energy levels of electromagnetic radiation are generated in the focal point of the MPG’s cylindrical cavity. The metal wires are vaporized and ionized from this area, subsequently affecting the dissociation of CO2. The CO2 dissociation is highlighted through plasma characterization and carbon monoxide (CO) quantity determination. For plasma characterization, we used an optical emission spectroscopy method (OES), and for CO quantity determination, we used a gas analyzer instrument. Using an MPG in the CO2 atmosphere, we obtained a high electron temperature of the plasma and a strong dissociation of CO2. After 20 s of the interaction between microwaves and noncontact electrodes, the quantity of CO increased from 3 ppm to 1377 ppm (0.13% CO). This method can be used in space applications to dissociate CO2 and refresh the atmosphere of closed spaces.


2016 ◽  
Vol 830 ◽  
pp. 134-138 ◽  
Author(s):  
Camila Senna Figueiredo ◽  
Jailton Ferreira do Nascimento ◽  
Rony Oliveira de Sant'ana ◽  
Deborah Cordeiro de Andrade ◽  
Zaniel Souto Dantas Procópio ◽  
...  

Monoethylene glycol (MEG) is being widely applied as thermodynamic inhibitor to avoid formation of natural gas hydrates. High hydrophilicity, low toxicity, low viscosity, low solubility in liquid hydrocarbons and high capacity of dissolving salts are advantageous for the use of MEG in the natural gas production. In addition, MEG recovery can be easily achieved considering its low volatility in relation to water, which makes the process economical and environmentally feasible. The reuse of MEG is being theme of research and phase equilibrium data for the involved species are required. In this work, a experimental procedure to synthetize iron carbonate and, afterwards, determine its solubility in aqueous mixtures of MEG in the presence of carbon dioxide atmosphere have been developed. Furthermore, a series of solubility data has been measured. This work presents a worthy contribution to the description of iron carbonate aqueous solubilities in the presence of MEG and carbon dioxide, regarding the instability of the salt to respect of oxidation. Subsequently, the knowledge of the behavior of the iron carbonate solubilities is useful for the industrial unities of production of natural gas and recovery of MEG.


2004 ◽  
Vol 100 (5) ◽  
pp. 1167-1171 ◽  
Author(s):  
Gerald L. Wolf ◽  
George W. Sidebotham ◽  
Jackson L. P. Lazard ◽  
Jean G. Charchaflieh

Background Operating room fires fueled by surgical drapes and ignited by high-energy surgical tools in air and oxygen-enriched atmospheres continue to occur. Methods The authors examined the time to ignition of huck towels and three commonly used surgical drape materials in air, 50% oxygen, and 95% oxygen using a carbon dioxide surgical laser as an ignition source. In addition, a phenol-polymer fabric was tested. Results In air, polypropylene and phenol polymer do not ignite. For polypropylene, the laser instantly vaporized a hole, and therefore, interaction between the laser and material ceased. When tested in combination with another material, the polypropylene time to ignition assumed the behavior of the material with which it was combined. For phenol polymer, the laser did not penetrate the material. Huck towels, cotton-polyester, and non-woven cellulose-polyester ignited in air with decreasing times to ignition. All tested materials ignited in 50% and 95% oxygen. Conclusion The results of this study reveal that with increasing oxygen concentration, the time to ignition becomes shorter, and the consequences become more severe. The possibility exists for manufacturers to develop drape materials that are safer than existing materials.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1225
Author(s):  
Cristina García-Garrido ◽  
Ranier Sepúlveda Sepúlveda Ferrer ◽  
Christopher Salvo ◽  
Lucía García-Domínguez ◽  
Luis Pérez-Pozo ◽  
...  

In this work, a blend of Ti, Nb, and Mn powders, with a nominal composition of 15 wt.% of Mn, and balanced Ti and Nb wt.%, was selected to be mechanically alloyed by the following two alternative high-energy milling devices: a vibratory 8000D mixer/mill® and a PM400 Retsch® planetary ball mill. Two ball-to-powder ratio (BPR) conditions (10:1 and 20:1) were applied, to study the evolution of the synthesized phases under each of the two mechanical alloying conditions. The main findings observed include the following: (1) the sequence conversion evolved from raw elements to a transitory bcc-TiNbMn alloy, and subsequently to an fcc-TiNb15Mn alloy, independent of the milling conditions; (2) the total full conversion to the fcc-TiNb15Mn alloy was only reached by the planetary mill at a minimum of 12 h of milling time, for either of the BPR employed; (3) the planetary mill produced a non-negligible Fe contamination from the milling media, when the highest BPR and milling time were applied; and (4) the final fcc-TiNb15Mn alloy synthesized presents a nanocrystalline nature and a partial degree of amorphization.


2017 ◽  
Vol 28 (7) ◽  
pp. 687-705 ◽  
Author(s):  
Blanca Moreno ◽  
María T García-Álvarez

Spain and Portugal are highly dependent on energy from abroad, importing more than 70% of all the energy they consume. This high energy dependence could involve important effects on the level and stability of their electricity prices as a half the gross electricity generated in both countries came from power stations using imported combustible fuels (such as natural gas, coal and oil). In general, changes in the prices of these fossil fuels can directly affect household electricity prices, since generation costs are likely to be transmitted through to the wholesale electricity market. Moreover, in the framework of the European Union Emission Trading System, electricity production technologies tend to incorporate their costs of carbon dioxide emission allowances in sale offers with the consequent increase of the electricity prices. The objective of this paper is to analyze the influence of fossil fuel costs and prices of carbon dioxide emission allowances in the EU on the Spanish and Portuguese electricity prices. With this aim, a maximum entropy econometric approach is used. The obtained results indicate that not only the price of imported gas are very important in explaining Spanish and Portuguese electricity prices but also the price of carbon dioxide emission allowances in the EU.


2020 ◽  
Vol 299 ◽  
pp. 447-451 ◽  
Author(s):  
V.G. Gusev ◽  
A.V. Sobolkov ◽  
A.V. Aborkin

The paper presents the results of a computational study of the influence of the geometry of the working chamber on the energy-force interaction of grinding bodies in the process of the mixture processing in a planetary mill. The method of computer simulation, using the software system, based on the ideology of discrete elements, shows the high efficiency of processing in a planetary mill, using a working chamber with a square-shaped cavity. The values of the factors that have a dominant influence on the mechanical processing of the charge are determined. A comparison with the process of processing in the working chamber of the traditional cylindrical shape is made. The research results will be used in the appointment of large-size charge processing regimes that provide a high-energy grinding process.


2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940067
Author(s):  
P. Vitiaz ◽  
N. Lyakhov ◽  
T. Grigoreva ◽  
E. Pavlov

The interaction between a solid inert metal Ir and an active liquid metal Ga during mechanical activation in a high-energy planetary mill is studied by X-ray diffraction and scanning electron microscopy with high-resolution energy dispersive X-ray microanalysis. The effect of mechanical activation on the formation of GaxIry intermetallic compounds and GaxIry/Ir composites and their solubility in acids was investigated. The subsequent extraction of Ga from intermetallic compounds and composites in the mixture of concentrated acids [Formula: see text] makes it possible to produce nanoscale Ir.


Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1515 ◽  
Author(s):  
Jose Ángel Quintana-Cilleruelo ◽  
Vignaswaran K. Veerapandiyan ◽  
Marco Deluca ◽  
Miguel Algueró ◽  
Alicia Castro

Perovskite BiFeO3 and YMnO3 are both multiferroic materials with distinctive magnetoelectric coupling phenomena. Owing to this, the Y1−xBix Mn1−xFexO3 solid solution seems to be a promising system, though poorly studied. This is due to the metastable nature of the orthorhombic perovskite phase of YMnO3 at ambient pressure, and to the complexity of obtaining pure rhombohedral phases for BiFeO3-rich compositions. In this work, nanocrystalline powders across the whole perovskite system were prepared for the first time by mechanosynthesis in a high-energy planetary mill, avoiding high pressure and temperature routes. Thermal decomposition temperatures were determined, and structural characterization was carried out by X-ray powder diffraction and Raman spectroscopy on thermally treated samples of enhanced crystallinity. Two polymorphic phases with orthorhombic Pnma and rhombohedral R3c h symmetries, and their coexistence over a wide compositional range were found. A gradual evolution of the lattice parameters with the composition was revealed for both phases, which suggests the existence of two continuous solid solutions. Following bibliographic data for BiFeO3, first order ferroic phase transitions were located by differential thermal analysis in compositions with x ≥ 0.9. Furthermore, an orthorhombic-rhombohedral structural evolution across the ferroelectric transition was characterized with temperature-dependent X-ray diffraction.


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