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11.
Iuga A. Cuglesan I. Samuila A. Blajan M. Vadan D. Dascalescu L. 《Industry Applications, IEEE Transactions on》2004,40(2):422-429
This paper aims at evaluating several electrostatic separation techniques that could be effective for the recovery of mica flakes from pegmatite ores characterized by grain sizes <0.5 mm: 1) triboadhesive separation; 2) dc electric field separation; 3) ac electric field separation; 4) corona field separation using a grounded metallic roll electrode and thermal conditioning; and 5) corona field separation using a grounded metallic roll electrode covered with an insulating layer. The experiments have been carried out on samples containing about 50% mica, 25% feldspar, 15% quartz, 10% iron oxides and hydroxides, as well as iron silicates, with grain sizes ranging between 0.16-0.4 mm. The experimental data confirmed the theoretical predictions: all four separation techniques using high-intensity electric fields improved the grade of muscovite mica concentrate to levels that fulfill the requirements of several industry applications such as welding wire manufacturing. The best results [46.11% SiO/sub 2/, 33.64% Al/sub 2/O/sub 3/, and 11.1% (K/sub 2/O+Na/sub 2/O)] were obtained when performing a three-stage separation using method 5). 相似文献
12.
Alexandru T. Balaban William A. Seitz Douglas J. Klein 《Fullerenes, Nanotubes and Carbon Nanostructures》2013,21(3):467-476
Abstract Three “onion type” double carbon cages (consisting of an inner sp3-hybridized C60 buckminsterfullerene skeleton and an outer larger carbon cage with icosahedral symmetry, with covalent bonds between the carbon atoms of the 5-membered rings) are described and their strain energies are discussed: (i) when the outer cage is a C120 cage derived from buckminsterfullerene by replacing each bond between two six-membered rings by an acetylenic group, the strain is smallest.; (ii) when the same derivation concerns each bond between 5- and 6-membered rings leading to a C180 outer cage, the strain is largest.; (iii) when the outer cage is C180 with benzenoid rings, the strain is intermediate. 相似文献
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14.
Mihail Elisa Lucica Boroica Bogdan Alexandru Sava Stefan Marian Iordache Ana-Maria Iordache Ileana Cristina Vasiliu Raluca Constantina Stefan Aurelian Catalin Galca Victor Kuncser Mihai Eftimie 《Journal of the American Ceramic Society》2020,103(7):3978-3990
This work is focused on investigation of thermal, structural, optical, magnetic, and magneto-optical properties of novel titanium phosphate-tellurite glass applied as Faraday rotators. The glass belonging to the system 35Li2O–10Al2O3–5TiO2–45P2O5–5TeO2 was prepared by a nonconventional wet route of raw materials processing, followed by melting-quenching-annealing steps. Some important physical properties of the investigated glass have been measured and calculated, providing knowledge related to glass compactness, electronic structure, glass forming capability, etc. XRD analysis evidenced an amorphous network structure of the investigated glass. The optical absorption in the Vis domain is mainly due to Ti3+ ions and Te2 clusters formed during the glass melting process. A relatively low optical absorption is noticed over 600 nm that activates a significant Faraday magneto-optical effect. Photoluminescence bands in the blue, red, and infrared domains are observed, caused by Te2 clusters formed during the glass melting process. The magnetization in dependency on applied magnetic field reveals a complex behavior of the glass, depending on temperature. Thus, it is found a ferromagnetic behavior up to 2000 Oe, a paramagnetic component up to 40 000 Oe, followed by a diamagnetic one over 40 000 Oe. Faraday rotation angle and Verdet constant values in the visible domain are correlated with the reduced TeO2 content of the glass. 相似文献
15.
Steve Trigwell Enkeleda Dervishi Alexandru S. Biris 《Particulate Science and Technology》2017,35(6):674-681
The modern strain sensors currently used in monitoring the structural properties of such tank structures suffer from a number of limitations, including a low level of sensitivity and detection. In this work, we present a novel method of structural monitoring utilizing a thin film of carbon nanotubes carefully deposited on carbon fiber composites. The nanotube film and raw material were first characterized via microscopy and spectroscopy techniques. Bowing of the tank wall was simulated by applying a three-point bend load test, which was found to strongly affect the electrical resistance of the carbon nanotube film. These measurements were very reproducible, as the film resistance returned to its original value each time that the load was slowly released. We believe that these highly sensitive carbon nanotube films are potential candidates as replacements for the current health-monitoring sensors. 相似文献
16.
Maria Cazacu Carmen Racles Mihaela Alexandru Aurelia Ioanid Angelica Vlad 《Polymer International》2009,58(6):697-702
BACKGROUND: It is well known that, due to their extremely low polarity, polysiloxanes are incompatible with almost any organic system. This incompatibility leads to phase separation in mixed siloxane–organic systems. RESULTS: Three siloxane–organic copolymers, poly[(5,5′‐methylene‐bis‐salicylaldehyde)‐imine‐(1,3‐bis(propylene)tetramethyldisiloxane)] (Paz1), poly[(2,5‐dihydroxy‐1,4‐benzoquinone)‐imine‐(1,3‐bis(propylene)tetramethyldisiloxane)] (Paz2) and poly[1,3‐bis(propylene)tetramethyldisiloxane diamide] (Pam), were prepared by the reaction of 1,3‐bis(3‐aminopropyl)tetramethyldisiloxane with appropriate organic partners (5,5′‐methylene‐bis‐salicylaldehyde, 2,5‐dihydroxy‐1,4‐benzoquinone and oxalyl chloride, respectively). The morphologies dictated by the incompatibility between siloxane and polar organic moieties were investigated using differential scanning calorimetry and scanning electron microscopy. The surface activity of the copolymers and water vapour sorption capacity were also measured. CONCLUSION: Even though the polar sequences are very short ones, the highly flexible siloxane‐containing sequence permits the self‐assembly of these into more or less polar domains. Such an organization influences the properties of the resulting materials, an important place being occupied by the surface properties. Copyright © 2009 Society of Chemical Industry 相似文献
17.
Adina L. Ghirişan Simion Drǎgan Alexandru Pop Marinela Simihǎian Vasile Miclǎuş 《加拿大化工杂志》2007,85(6):900-905
The influence of the apatite on the efficiency of neutralization and on heavy metal removal of acid mine waste water has been studied. The analysis of the treated waste water samples with apatite has shown an advanced purification, the concentration of the heavy metals after the treatment of the waste water with apatite being 25 to 1000 times less than the Maximum Concentration Limits admitted by European Norms (NTPA 001/2005). In order to establish the macro‐kinetic mechanism in the neutralization process, the activation energy, Ea, and the kinetic parameters, rate coefficient of reaction, kr, and kt were determined from the experimental results obtained in “ceramic ball‐mill” reactor. The obtained values of the activation energy Ea >> 42 kJ mol?1 (e.g. Ea = 115.50 ± 7.50 kJ mol?1 for a conversion of sulphuric acid ηH2SO4 = 0.05, Ea = 60.90 ± 9.50 kJ mol?1 for η H2SO4 = 0.10 and Ea = 55.75 ± 10.45 kJ mol‐1 for η H2SO4 = 0.15) suggest that up to a conversion of H2SO4 equal 0.15 the global process is controlled by the transformation process, adsorption followed by reaction, which means surface‐controlled reactions. At a conversion of sulphuric acid η H2SO4 > 0.15, the obtained values of activation energy Ea < 42 kJ mol‐1 (e.g. Ea = 37.55 ± 4.05 kJ mol‐1 for η H2SO4 = 0.2, Ea = 37.54 ± 2.54 kJ mol‐1 for η H2SO4 = 0.3 and Ea = 37.44 ± 2.90 kJ mol‐1 for η H2SO4 = 0.4) indicate diffusion‐controlled processes. This means a combined process model, which involves the transfer in the liquid phase followed by the chemical reaction at the surface of the solid. Kinetic parameters as rate coefficient of reaction, kr with values ranging from (5.02 ± 1.62) 10‐4 to (8.00 ± 1.55) 10‐4 (s‐1) and transfer coefficient, kt, ranging from (8.40 ± 0.50) 10‐5 to (10.42 ± 0.65) 10‐5 (m s‐1) were determined. 相似文献
18.
Gabriela Huminic Alexandru Vrdaru Angel Huminic Claudiu Fleac Florian Dumitrache Ion Morjan 《International journal of molecular sciences》2022,23(6)
In the current paper, a new hybrid nanofluid based on graphene oxide sheets and silicon nanoparticles is proposed for thermal applications. GO sheets and Si nanoparticles with different mixture ratios are dispersed in distilled water. Dynamic viscosity is measured at temperatures within the range 20–50 °C and the values are compared to the results available in the literature. The results indicated that the viscosity increases with increasing the mixture ratio of graphene oxide. A new correlation for the dynamic viscosity based on the experimental findings is proposed. Finally, the criteria for the performance of new hybrid nanofluid for thermal applications are analyzed. 相似文献
19.
Nanofiltration membranes have been developed by interfacial polymerization using base PES ultrafiltration membranes. By varying the concentration of the reactive monomers present as well as the reaction conditions, the structure of the polymerized barrier layer has been modified. Here, the ability to concentrate low molecular weight sugars while allowing dissolved ionic liquids in aqueous solution to be recovered in the permeate has been investigated for application in biomass hydrolysis. The results obtained here indicate that the selectivity for 1-butyl-3-methylimidazoliumchloride (BmimCl) over glucose can be as high as 36.6. The membrane permeance was 2.31 L m?2 h?1 bar?1. 相似文献
20.