Carbon nanotubes (CNTs) are widely synthesized at high temperatures using floating catalyst chemical vapor deposition (FC-CVD) method. It is important to reduce the synthesis temperature of CNTs to prevent the self-pyrolysis of hydrocarbon to enhance the growth of CNTs. This work was addressed to synthesize CNTs at low temperature using some improvements on the technique used. In-situ monitoring device was used to monitor the temperature profile in the reactor and thus, to initiate the reaction. The preheating temperature was investigated in the ranging of temperature between 150°C and 300°C at 50°C interval. Benzene and ferrocene were used as the Carbon source and catalyst precursor, respectively. Estimating the minimum pyrolysis temperature of benzene was carried out in the absence of catalyst. Based on the results of characterization methods, multi-walled CNTs with high purity have been synthesized at synthesis temperature of 600°C. This work offers relatively low synthesis temperature of CNTs which gives real opportunity to synthesize CNTs for microelectronic applications.
Keywords: Carbon nanotubes, Floating catalyst, Preheating temperature, In-situ monitoring, Thermo gravimetric analysis
Introduction:
Over the past decade, carbon nanotubes (CNTs) have received a huge interest from scientists due to nanoscale dimensions and promising physical properties (1), (2). Various methods have been used to synthesize CNTs, such arc discharge, laser ablation, and chemical vapor deposition (3), (4), (5). Chemical vapor deposition (CVD) is considered the best compared to other methods due to low cost as well as it offers lowest synthesis temperature (6), (7). This method can be conducted via supporting catalyst or floati...
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Nano-thermal analysis methods are also known as micro-thermal procedures and they use the principle of characterizing highly localized materials on a micrometer. The characterization is then changed from a micrometer scale to a sub-micrometer scale with the temperature being regulated to the specified units. The application of nano-thermal analysis methods started towards the end of the 20th century. Although it has been applied in several other fields including microelectronics, its application in pharmaceuticals has not been that popular.
“The Industrial Revolution was another of those extraordinary jumps forward in the story of civilization” (Stephen Gardiner). One of the major parts of the industrial process has to do with metal production. Welding has been incorporated into the framework of metalworking. Welding dates back to the middle ages where forge welding processes were used to make tools and weapons, commonly known as blacksmiths. It is known that the Egyptians used forms of welding to make gold tools, jewelry, and decoration. During the 1800’s a new process was formed by using carbon electrodes to form an arc. This was done by Sir Humphrey Davy, which carried on to become Carbon Arc Welding and the most used process during the late 1800’s. As time evolved so did the
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The molar specific heats of most solids at room temperature and above are nearly constant, in agreement with the Law of Dulong and Petit. At lower temperatures the specific heats drop as quantum processes become significant. The Einstein-Debye model of specific heat describes the low temperature behavior.
Obtaining Zinc Oxide from Calamine Introduction Calamine is a mineral containing zinc carbonate (ZnCO₃) On heating it decomposes as: [IMAGE]ZnCO₃ ZnO + CO₂ (C = 12, 0 = 16, Zn = 65) This equation allows you to calculate a theoretical conversion of calamine into zinc oxide. As when using the theoretical conversion; [IMAGE]ZnCO₃ ZnO + CO₂ [IMAGE]65+12+48 65+16 + 12+32 [IMAGE]125 81 + 44 This means that one mole of calamine weighs 125g and when heated it produces 81g of zinc oxide and 44g of carbon dioxide. Therefore to work out how much zinc oxide is produced from 1g of calamine we divide 81 by 125.
The Electrolysis of Copper Sulphate Aim Analyse and evaluate the quantity of Copper (Cu) metal deposited during the electrolysis of Copper Sulphate solution (CuSo4) using Copper electrodes, when certain variables were changed. Results Voltage across Concentration of solution electrode 0.5M 1.0M 2.0M 2 5.0 10.6 19.5 4 10.5 19.8 40.3 6 14.3 26.0 60.2 8 15.2 40.4 80.3 10 15.0 40.2 99.6 12 15.1 40.0 117.0 Analysing/Conclusion The input variables in this experiment are; concentration of the solution and the voltage across the electrodes. The outcome is the amount of copper gained (measured in grams) at the electrodes. By analyzing the graph, we can see the rapid increase of weight gained for the 2.0 molar concentration as the gradient is steeper.
early 1990’s, no such material was known. In 1991, carbon nanotubes were discovered. Although not
brief overview on the structure and some properties of graphene, along with a presentation of graphene synthesis method and various applications.
Although Solar Energy is a flexible source of where energy could be directly or indirectly converted into forms of energy, it’s still not perfect. With its inefficiency, scientists are trying to find alternative solution to store solar cells for as long as possible. The main process of capturing solar energy happens at the nanoscale. With solar cells, it gets more efficient the tinier it gets. The converting rate of solar energy is equally price competitive as fossil fuel, with a dollar per watt of solar energy. With the help of nanotechnology, it could help raise solar energy conversion efficiency and help lower costs making it the ultimate method of raw energy conversion. To make sure the process of generating energy is kept at a low cost and energy output...
To investigate the temperature change in a displacement reaction between Copper Sulphate Solution and Zinc Powder
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Electroplating Experiment Aim To find the amount copper gains or loses on the electrodes using different amounts of current each time during electrolysis. How the changing of current affects the electroplating of copper. Introduction Electroplating is generally carried out in order to improve the appearance or corrosion resistance of the surface of a metal by electrodepositing a thin layer of metal ion on it. The metal substrate to be coated is made by the cathode in an electrolytic cell. The cell used in electroplating contains an electrolyte which is usually an aqueous solution containing a reasonably high concentration of an ion of the metal which is to be electroplated on the surface.
Recent years have shown an increasingly large need for a practical renewable energy source for such reasons as diminishing fossil fuels and increases in greenhouse gasses. Hydrogen appears to be a way out of this gasoline-dug hole, or at least, a way out in the future. Hydrogen fuel cell cars are being engineered as we speak as the technologies to refuel them cleanly are being proposed. Unfortunately, most of the technologies associated with hydrogen are still in the prototype/pre-production stages and require better enhancements before becoming mainstream. This paper assesses the practicality of hydrogen power in cars both now and in the future while explicating the actual process of how a hydrogen fuel cell works.