scholarly journals Synthesis of Carbon Nanostructures on Iron Nanopowders Obtained by Electrical Explosion of Wires

2015 ◽  
Vol 17 (3) ◽  
pp. 201 ◽  
Author(s):  
G. Partizan ◽  
B. Мansurov ◽  
B. Мedyanova ◽  
B. Аliyev ◽  
Xin Jiang
Keyword(s):  
Carbon Nanostructures ◽  
Chemical Vapor ◽  
Electrical Explosion ◽  
Temperature Limit ◽  
Nucleation And Growth ◽  
Lower Temperature Limit ◽  
Different Temperatures ◽  
Electrical Explosion Of Wires ◽  
Stable Growth ◽  
Lower Temperature

This work presents the results of experiments on synthesis of carbon nanostructures by the method of thermal chemical vapor deposition using iron nanopowders obtained by the method of electrical explosion of wires as catalysts. To study the process of nucleation and growth of individual carbon nanostructures, experiments were conducted not only on nanopowders, but also on the separated clusters. To determine the optimum conditions of the carbon nanostructures synthesis and lower temperature limit, experiments were performed at different temperatures (300–700 °C) and pressures (100–400 mbar). The experiments have shown that the lower temperature limit for carbon nanostructures synthesis on the iron nanopowders is 350 °C and in this process the growth of carbon nanostructures is not so massive. Stable growth of carbon nanostructures for nanopowders as well as for the separated clusters began from 400 °C during the entire range of pressures. In contrast to the carbon nanostructures on nanopowders, in the case of the separated clusters a strong<br />dependence of their nucleation and growth on temperature and pressure was traced.

Effect of Irradiation of the Extraction Mixture with 30% TBP in ISOPAR-M on the Lower Temperature Limit of Flame Propagation

2020 ◽  
Vol 62 (6) ◽  
pp. 723-729
Author(s):  
A. V. Rodin ◽  
I. V. Skvortsov ◽  
E. V. Belova ◽  
K. N. Dvoeglazov ◽  
B. F. Myasoedov
Keyword(s):  
Flame Propagation ◽  
Temperature Limit ◽  
Lower Temperature Limit ◽  
Lower Temperature ◽  
Extraction Mixture

scholarly journals Researches on the mixture limits of animal fats with liquid hydrocarbons for combustion at industrial level

2019 ◽  
Vol 112 ◽  
pp. 02001
Author(s):  
Dana Andreya Bondrea ◽  
Lucian Mihaescu ◽  
Gheorghe Lazaroiu ◽  
Ionel Pisa ◽  
Gabriel Negreanu
Keyword(s):  
Temperature Limit ◽  
Electric Heater ◽  
Liquid Hydrocarbons ◽  
Animal Fats ◽  
Lower Temperature Limit ◽  
Perfect Mixing ◽  
Efficient Combustion ◽  
Lower Temperature ◽  
Industrial Level ◽  
Experimental Researches

The experimental research has highlighted the variety of possibilities of combustion of animal fat from bovine and swine mixed with liquid hydrocarbons. Previous research has established that the upper limit for an efficient combustion was 30 %. For a perfect mixing, the lower temperature limit was set to 40 °C. In the fuel laboratory, at the department TMETF was determined the viscosity of the mixtures for different proportions. The values obtained for various concentrations and preheating temperatures were close to the values for liquid hydrocarbons. The experimental researches have studied the combustion of the mixture using a mechanically spraying burner with constant pressure between 14 and 18 bar. The aspiration of the mixture is done from a specially designed tank; this tank is equipped with an electric heater, in order to maintain the mixture at a constant temperature between 40 °C to 50 °C. After that, the burner heats again the mixture with an integrated heating device up to 75 °C. The burner is also equipped with an air blower, pump and a calibrated nozzle. The combustion resulted from the experimental boiler with a power rated to 55 kW were monitored with a thermal vision camera and an exhaust gas analyser. This research has demonstrated the viability of using this type of mixtures in energetic burning equipment designed for liquid hydrocarbons.

A lower temperature limit for the RIED effect

1994 ◽  
Vol 212-215 ◽  
pp. 1119-1122 ◽  
Author(s):  
A. Moroño ◽  
E.R. Hodgson
Keyword(s):  
Temperature Limit ◽  
Lower Temperature Limit ◽  
Lower Temperature

Different Adaptation Strategies of Atlantic Salmon (Salmo salar) Populations to Extreme Climates with Special Reference to some Cold Norwegian Rivers

1986 ◽  
Vol 43 (5) ◽  
pp. 980-984 ◽  
Author(s):  
Arne Johan Jensen ◽  
Bjørn Ove Johnsen
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Temperature Regime ◽  
Growth Rates ◽  
Temperature Limit ◽  
Fixed Temperature ◽  
Sea Temperature ◽  
Atlantic Salmon Salmo Salar ◽  
Lower Temperature Limit ◽  
Lower Temperature

Some of the salmon rivers on the western and northern coasts of Norway are very cold, and the sea temperature outside these rivers is almost always higher than that in the river. Growth rates of Atlantic salmon (Salmo salar) parr and smolt ages and sizes have been examined in three such cold rivers. We found indications that the lower temperature limit for growth of Atlantic salmon is not a fixed temperature, but varies from population to population according to the temperature regime of their environment. Smolts are small, with average sizes of 12–13 cm total length. Females dominated in number among the smolts, but the dominance was less pronounced than in most other rivers. Strategies used by Norwegian salmon in cold rivers are therefore different from those employed by salmon in the northern extremes of the salmon's range in Canada.

The Effects of Chloromethane on Diamond Nucleation and Growth in a Hot-filament Chemical Vapor Deposition Reactor

1998 ◽  
Vol 13 (9) ◽  
pp. 2498-2504 ◽  
Author(s):  
Jih-Jen Wu ◽  
Franklin Chau-Nan Hong
Keyword(s):  
Film Growth ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Diamond Growth ◽  
Nucleation Density ◽  
Diamond Grit ◽  
Diamond Nucleation ◽  
Nucleation Sites ◽  
Lower Temperature ◽  
Hot Filament

The effects of chloromethane on diamond nucleation and growth were studied by employing laser reflective interferometry. Chloromethane enhances the film-growth rate only slightly compared to methane. However, chloromethane greatly enhances the nucleation density and shortens the film-forming stage, more significantly at a lower temperature. Thus, chloromethane facilitates the low temperature growth mainly through the enhancement of nucleation. Nucleation density is strongly dependent on the compositions of H atoms and carbon species prior to diamond growth. The residual diamond seeds by diamond-grit scratching are suggested to be the major nucleation sites. Chloromethane can enhance diamond nucleation by protecting the residual seeds from being etched by H atoms.

scholarly journals Nucleation and growth dynamics of graphene grown by radio frequency plasma-enhanced chemical vapor deposition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Na Li ◽  
Zhen Zhen ◽  
Rujing Zhang ◽  
Zhenhua Xu ◽  
Zhen Zheng ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Radio Frequency ◽  
Grain Growth ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Rf Plasma ◽  
Radio Frequency Plasma ◽  
Frequency Plasma ◽  
Different Temperatures

AbstractWe investigated the nucleation and grain growth of graphene grown on Cu through radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) at different temperatures. A reasonable shielding method for the placement of copper was employed to achieve graphene by RF-PECVD. The nucleation and growth of graphene grains during PECVD were strongly temperature dependent. A high growth temperature facilitated the growth of polycrystalline graphene grains with a large size (~ 2 μm), whereas low temperature induced the formation of nanocrystalline grains. At a moderate temperature (790 to 850 °C), both nanocrystalline and micron-scale polycrystalline graphene grew simultaneously on Cu within 60 s with 50 W RF plasma power. As the growth time increased, the large graphene grains preferentially nucleated and grew rapidly, followed by the nucleation and growth of nanograins. There was competition between the growth of the two grain sizes. In addition, a model of graphene nucleation and grain growth during PECVD at different temperatures was established.

Growth of Monolayer WS2 Single Crystals with Atmospheric Pressure CVD: Role of Temperature

MRS Advances ◽  
2019 ◽  
Vol 4 (3-4) ◽  
pp. 255-262
Author(s):  
Yong Xie ◽  
Guanfei Wang ◽  
Zhan Wang ◽  
Tang Nan ◽  
Haolin Wang ◽  
...  
Keyword(s):  
Vapor Deposition ◽  
Atmospheric Pressure ◽  
Chemical Vapor ◽  
Optical Microscope ◽  
Nucleation And Growth ◽  
Pressure Chemical ◽  
Different Temperatures ◽  
Individual Domain

ABTRACTIt has been demonstrated that the introduction of NaCl can significantly improve the quality of monolayer WS2 at the growth temperatures ranging from 700°C to 850°C by atmospheric pressure chemical vapor deposition (APCVD) without the assistant of hydrogen. Here, the influence of NaCl on the nucleation and growth of WS2 has been thoroughly investigated. The morphology and quality of WS2 grown with different temperatures are discussed by optical microscope, Raman and Photoluminescence (PL) spectra. It was found that amount of NaCl can efficiently influence the morphology and quality of WS2 crystals. PL intensity of WS2 crystal increases around three times from the center region to the edge of an individual domain, which may be attributed to the appearance of small triangle hollows formed during the growth at the edge of single crystal WS2.

scholarly journals Low-temperature limitation of bioreactor sludge in anaerobic treatment of domestic wastewater

2013 ◽  
Vol 69 (5) ◽  
pp. 1004-1013 ◽  
Author(s):  
Emma J. Bowen ◽  
Jan Dolfing ◽  
Russell J. Davenport ◽  
Fiona L. Read ◽  
Thomas P. Curtis
Keyword(s):  
Low Temperature ◽  
Domestic Wastewater ◽  
Temperature Limit ◽  
Anaerobic Treatment ◽  
Anaerobic Sludge ◽  
Anaerobic Reactors ◽  
Theoretical Yield ◽  
Lower Temperature Limit ◽  
Temperature Limitation ◽  
Lower Temperature

Two strategies exist for seeding low-temperature anaerobic reactors: the use of specialist psychrophilic biomass or mesophilic bioreactor sludge acclimated to low temperature. We sought to determine the low-temperature limitation of anaerobic sludge from a bioreactor acclimated to UK temperatures (&lt;15 °C). Anaerobic incubation tests using low-strength real domestic wastewater (DWW) and various alternative soluble COD sources were conducted at 4, 8 and 15 °C; methanogenesis and acidogenesis were monitored separately. Production of methane and acetate was observed; decreasing temperature resulted in decreased yields and increased ‘start-up’ times. At 4 °C methanogenesis not hydrolysis/acidogenesis was rate-limiting. The final methane yields at 4 °C were less than 35% of the theoretical potential whilst at 8 and 15 °C more than 75 and 100% of the theoretical yield was achieved respectively. We propose that the lower temperature limit for DWW treatment with anaerobic bioreactor sludge lies between 8 and 4 °C and that 8 °C is the threshold for reliable operation.

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