The Experts below are selected from a list of 3528474 Experts worldwide ranked by ideXlab platform
Hiroki Nada - One of the best experts on this subject based on the ideXlab platform.
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growth mechanism of a gas clathrate hydrate from a dilute aqueous gas solution a molecular dynamics simulation of a three phase System
Journal of Physical Chemistry B, 2006Co-Authors: Hiroki NadaAbstract:A molecular dynamics simulation of a Three-Phase System including a gas clathrate, liquid water, and a gas was carried out at 298 K and high pressure in order to investigate the growth mechanism of the clathrate from a dilute aqueous gas solution. The simulation indicated that the clathrate grew on interfaces between the clathrate and the liquid water, after transfer of the gas molecules from the gas phase to the interfaces. The results suggest a two-step process for growth: first, gas molecules are arranged at cage sites, and second, H2O molecules are ordered near the gas molecules. The results also suggest that only the H2O molecules, which are surrounded or sandwiched by the gas molecules, form the stable polygons that constitute the cages of the clathrate. In addition, the growth of the clathrate from a concentrated aqueous gas solution was also simulated, and the results suggested a growth mechanism in which many H2O and gas molecules correctively form the structure of the clathrate. The clathrate g...
A. Yu. Krylova - One of the best experts on this subject based on the ideXlab platform.
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Fischer-Tropsch process in a Three-Phase System over iron-cobalt catalyst nanoparticles in situ synthesized in a hydrocarbon medium
Petroleum Chemistry, 2014Co-Authors: S. N. Khadzhiev, A. S. Lyadov, S. A. Sagitov, M. V. Kulikova, A. Yu. KrylovaAbstract:It has been shown that Fe-Co nanocatalysts in situ synthesized in a hydrocarbon medium with a Fe/Co weight ratio of 2–6 can mediate the Fischer-Tropsch synthesis in a Three-Phase System at a pressure of 20 atm, a temperature of 250–300°C, and a CO/H_2 ratio of 1: 1. The introduction of CO leads to a significant increase in the total activity of the catalyst System ( K _CO reaches 85% at 300°C). However, gas evolution is enhanced and the highest yield of liquid products is as low as 74 g/m^3 in this case. The introduction of K and Al into the Fe-Co catalysts and the optimization of the Fe/Co ratio make it possible to increase the yield of liquid products to 143 g/m^3 (Fe/Co = 2.4) and achieve an efficiency of 337 g/(kg Me h). The Fe-Co nanocatalysts exhibit a high polymerizing activity (Schulz-Flory alpha is higher than 0.8). Hydrocarbons obtained over Fe-Co-K-Al catalysts contain more than 20% olefins. Their amount increases with the increasing Fe concentration in the sample. Oxygenates formed over these catalysts are composed of alcohols by over 90%, of which ethanol prevails (65–70%).
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Fischer-Tropsch synthesis in presence of composite materials containing iron and cobalt nanoparticles
Chemistry and Technology of Fuels and Oils, 2012Co-Authors: Yu. M. Mikhailov, A. Yu. Krylova, S. A. Sagitov, M. V. Kulikova, A. V. Aleshin, L. V. Zhemchugova, A. A. Panin, V. I. Kurkin, S. N. KhadzhievAbstract:Fischer-Tropsch synthesis in a static catalyst bed and in a Three-Phase System in the presence of composite materials containing iron and cobalt particles in the nano-size range 30-60 nm is investigated. It is shown that in both process implementation methods the yield and selectivity of liquid hydrocarbon formation increase with iron content in the composite material. In this case, the catalysts exhibit higher activity in the static bed and greater selectivity in the Three-Phase System. In the static bed of the most active catalyst containing 44.4 % iron and 33.3 % cobalt, the yield of C_5+ hydrocarbons was 103 g/m^3.
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Fischer-tropsch synthesis in a Three-Phase System over nanocatalysts (review)
Petroleum Chemistry, 2011Co-Authors: S. N. Khadzhiev, A. Yu. KrylovaAbstract:The modern methods of preparation of nanoparticles of metals (cobalt and iron) and their oxides are described. The results of Fischer-Tropsch synthesis in a Three-Phase (gas-liquid-solid) System over iron and cobalt nanocatalysts are discussed. It is noted that in most cases, nanocatalysts exhibit a higher activity in comparison with conventional catalysts that are used for the liquid-phase synthesis. Under certain conditions, the efficiency of a nanocatalyst can achieve 5 kg/(kg cat h), which is an order of magnitude higher than that of conventional catalyst Systems.
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Fischer-Tropsch synthesis in a Three-Phase System with iron catalyst nanoparticles
Petroleum Chemistry, 2011Co-Authors: S. N. Khadzhiev, A. S. Lyadov, M. V. Krylova, A. Yu. KrylovaAbstract:The features of the Fischer-Tropsch synthesis in the presence of 100Fe: 8Al2O3: 3K2O (parts by weight) catalyst nanoparticles under the slurry reactor conditions have been studied. The catalyst is prepared in situ and activated in the reactor. It has been found that during the preparation process, the catalyst reacts with the dispersion medium to form a structured System that is not liable to sedimentation. It is shown that the use of CO as a reducing agent makes it possible to increase the yield of liquid hydrocarbons by a factor of 1.5. An increase in the syngas pressure has almost no effect on the yield of liquid hydrocarbons; however, it gives the possibility of enhancing the catalyst efficiency up to 700 g/(kg Fe · h) at 40 atm. In conditions of a Three-Phase System, gasoline-fraction hydrocarbons, half of which consist of olefins, are mostly formed on the nanosized catalyst.
S. N. Khadzhiev - One of the best experts on this subject based on the ideXlab platform.
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Fischer-Tropsch process in a Three-Phase System over iron-cobalt catalyst nanoparticles in situ synthesized in a hydrocarbon medium
Petroleum Chemistry, 2014Co-Authors: S. N. Khadzhiev, A. S. Lyadov, S. A. Sagitov, M. V. Kulikova, A. Yu. KrylovaAbstract:It has been shown that Fe-Co nanocatalysts in situ synthesized in a hydrocarbon medium with a Fe/Co weight ratio of 2–6 can mediate the Fischer-Tropsch synthesis in a Three-Phase System at a pressure of 20 atm, a temperature of 250–300°C, and a CO/H_2 ratio of 1: 1. The introduction of CO leads to a significant increase in the total activity of the catalyst System ( K _CO reaches 85% at 300°C). However, gas evolution is enhanced and the highest yield of liquid products is as low as 74 g/m^3 in this case. The introduction of K and Al into the Fe-Co catalysts and the optimization of the Fe/Co ratio make it possible to increase the yield of liquid products to 143 g/m^3 (Fe/Co = 2.4) and achieve an efficiency of 337 g/(kg Me h). The Fe-Co nanocatalysts exhibit a high polymerizing activity (Schulz-Flory alpha is higher than 0.8). Hydrocarbons obtained over Fe-Co-K-Al catalysts contain more than 20% olefins. Their amount increases with the increasing Fe concentration in the sample. Oxygenates formed over these catalysts are composed of alcohols by over 90%, of which ethanol prevails (65–70%).
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Fischer-Tropsch synthesis in presence of composite materials containing iron and cobalt nanoparticles
Chemistry and Technology of Fuels and Oils, 2012Co-Authors: Yu. M. Mikhailov, A. Yu. Krylova, S. A. Sagitov, M. V. Kulikova, A. V. Aleshin, L. V. Zhemchugova, A. A. Panin, V. I. Kurkin, S. N. KhadzhievAbstract:Fischer-Tropsch synthesis in a static catalyst bed and in a Three-Phase System in the presence of composite materials containing iron and cobalt particles in the nano-size range 30-60 nm is investigated. It is shown that in both process implementation methods the yield and selectivity of liquid hydrocarbon formation increase with iron content in the composite material. In this case, the catalysts exhibit higher activity in the static bed and greater selectivity in the Three-Phase System. In the static bed of the most active catalyst containing 44.4 % iron and 33.3 % cobalt, the yield of C_5+ hydrocarbons was 103 g/m^3.
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Fischer-tropsch synthesis in a Three-Phase System over nanocatalysts (review)
Petroleum Chemistry, 2011Co-Authors: S. N. Khadzhiev, A. Yu. KrylovaAbstract:The modern methods of preparation of nanoparticles of metals (cobalt and iron) and their oxides are described. The results of Fischer-Tropsch synthesis in a Three-Phase (gas-liquid-solid) System over iron and cobalt nanocatalysts are discussed. It is noted that in most cases, nanocatalysts exhibit a higher activity in comparison with conventional catalysts that are used for the liquid-phase synthesis. Under certain conditions, the efficiency of a nanocatalyst can achieve 5 kg/(kg cat h), which is an order of magnitude higher than that of conventional catalyst Systems.
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Fischer-Tropsch synthesis in a Three-Phase System with iron catalyst nanoparticles
Petroleum Chemistry, 2011Co-Authors: S. N. Khadzhiev, A. S. Lyadov, M. V. Krylova, A. Yu. KrylovaAbstract:The features of the Fischer-Tropsch synthesis in the presence of 100Fe: 8Al2O3: 3K2O (parts by weight) catalyst nanoparticles under the slurry reactor conditions have been studied. The catalyst is prepared in situ and activated in the reactor. It has been found that during the preparation process, the catalyst reacts with the dispersion medium to form a structured System that is not liable to sedimentation. It is shown that the use of CO as a reducing agent makes it possible to increase the yield of liquid hydrocarbons by a factor of 1.5. An increase in the syngas pressure has almost no effect on the yield of liquid hydrocarbons; however, it gives the possibility of enhancing the catalyst efficiency up to 700 g/(kg Fe · h) at 40 atm. In conditions of a Three-Phase System, gasoline-fraction hydrocarbons, half of which consist of olefins, are mostly formed on the nanosized catalyst.
Nicolo Savalli - One of the best experts on this subject based on the ideXlab platform.
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Approaching e-learning on Three-Phase System measurements
2005Co-Authors: Salvatore Baglio, Nicola Pitrone, P. Barreca, Nicolo SavalliAbstract:Training on measurements to determine the characteristics of the Three-Phase electrical System is very useful for a deep knowledge of the various theoretical aspects, in the different load conditions. The use of advanced technologies are suitable to obtain many advantages: the values of the various parameters can be detected and/or computed, presented on the user friendly interface and stored in a file. By using advanced technologies a laboratory session for measurements on Three-Phase Systems has been realised. A user-friendly virtual instrument enables the student attending an electric measurement course (or any other operator) to perform the experiment. The software that has been realised for this work consists of a virtual instrument, implemented in the LabVIEW™ environment: it can be easily improved. A digital acquisition board installed in the PC and software managed acquires the values of the voltages and the currents used by the software, which computes the active power and the reactive power. The web cam gives an overview on the details of the System adopted and enhances the "presence feeling" to the far user.
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Training on Three-Phase System measurements by advanced technologies
2004Co-Authors: Salvatore Baglio, Nicolo Savalli, Nicola PitroneAbstract:Training on measurements to determine the characteristics of the three-wires Three-Phase electrical System is very useful for a deep knowledge of the various theoretical aspects, in the different load conditions, in particular, for balanced as well as unbalanced loads. The use of advanced technologies are suitable to obtain many advantages: the values of the various parameters can be detected and/or computed, presented on the user friendly interface and stored in a file. By using advanced technologies a laboratory session for measurements on Three-Phase Systems has been realised. A user-friendly virtual instrument enables the student attending an electric measurement course (or any other operator) choosing the experiment to perform. The software that has been realised for this work consists of a virtual instrument, implemented in the LabVIEW/spl trade/ environment: it enables the student performing the management of the experiment. A digital acquisition board installed in the PC and software managed acquires the values of the voltages and the currents used by the software, which computes the active power and the reactive power.
Avanish Kumar Dubey - One of the best experts on this subject based on the ideXlab platform.
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Study of Surface Properties in Laser Surface Alloying of Al_xCu_0.5FeNiTi High-Entropy Alloy
Journal of Materials Engineering and Performance, 2020Co-Authors: Anas Ahmad Siddiqui, Avanish Kumar DubeyAbstract:Due to better alloying characteristics, high-entropy alloys may result in superior surface properties. The present paper investigates the microhardness and erosion behavior of laser surface alloyed Al_ x Cu_0.5FeNiTi high-entropy alloy on aluminum alloy (AA1050) substrate. The effects of laser power, scan speed, and powder feed rate on microhardness and erosion rates are studied comprehensively. X-ray diffraction confirms the presence of a Three-Phase System and a shift in the peak at high power density, which indicates more significant lattice distortion. Scanning electron microscopy images show good dispersion of the Three-Phase System at optimum parameters. Energy dispersive spectroscopy confirms the presence of elements with negligible precipitation. Further, experimental data are used to develop empirical models. The optimizations of these models show an appropriate selection of parameter levels that may result in an erosion-resistant alloy. At optimum parameters, microhardness and erosion rate improve by 11.56 and 22.44%, respectively.
