جستجوی مقالات مرتبط با کلیدواژه « Microwaves » در نشریات گروه « علوم پایه »

Domestic companies in metal and alloy production have faced many problems in providing the required energy. These companies often use traditional industrial furnaces, which consume a lot of energy, have a very negative impact on the environment. For this reason, the use of modern low-consumption processes for metal oxide reduction will be of great interest. In this research, the carbon bed of a new metal oxide reduction system operated under microwave heating is modeled. In this system, the carbon bed is responsible for the heating process and converts electromagnetic waves into heat. In this system, because the metal oxide granules are imbedded inside the carbon bed that converts almost all electromagnetic waves, the heating effects of metal oxides were ignored. Comparison of the modeling results with experimental data related to carbon bed temperature rising trend showed that the used model has good accuracy and the average error is less than 5%. Based on the modeling, it was found that the carbon bed temperature (excluding metal oxide granules) increased around 9% by increasing the microwave power from 1000 w to 1200 w. In addition, SiC had better performance compared to the carbon bed in terms of the rate of generated heat. It was determined that the maximum temperature decreased by increasing the carbon emissivity parameter and the final bed temperature increased by 9% after 15 minutes by changing the emissivity parameter from 0.95 to 0.65.

Metallic nanostructures have received a lot of attention. Rapid synthesis using microwaves is a suitable technology that has great potential for use in industrial fields due to the significant reduction in reaction time, increase in product yield, and the use of safe heating sources. The heating method with the help of microwaves has attracted a lot of attention as a suitable method for the synthesis of metal nanostructures in the solution phase. This method has been used to synthesize many nanostructures such as Ag, Au, Pt, Pd and Au-Pd. Not only spherical nanoparticles, but plate, rod, wire, tube and dendritic nanostructures are prepared in a few minutes. Generally, nanostructures with smaller size, narrower size distribution and higher degree of crystallinity are prepared method compared to conventional oil bath heating methods. On the other hand, room temperature ionic liquids (RTILs) have attracted much attention in recent years. ILs can absorb microwaves and increase the reaction speed and decrease the reaction time. The large cations with high polarizability in ILs make these materials suitable solvents for absorbing microwaves. Therefore, the use of microwaves as a heat source along with ILs as a catalyst, solvent, additive, co-solvent and template leads to the creation of a fast and environmentally friendly method (MAIL) for the synthesis of various nanostructures.

Wireless technology is so widespread today that its absence from communication systems would put the future of such systems in uncertainty. The idea that mobile phones, tablets, or even electric vehicles would have the smart charging capability in the not-so-distant future, is very exciting. From a different perspective, however, the thought of the huge impact that a full power loss would have upon human safety, and rescue operations in human adversities and natural disasters, is harrowing. Indeed, all of us have to deal with a much smaller scale of this problem, that is, the need for recharge or replacement of our mobile phone or tablet batteries, on a regular basis; since the operation of these communication systems is essentially limited to the life of their energy source, i.e. batteries. Therefore, considering the infrastructure in place for information transmission and the recent advances in wireless energy transfer, it is perhaps time to conceive a future of more than just a dream for simultaneous wireless information and power transfer (SWIPT). As a key enabling technology for truly perpetual communications, SWIPT offers the potential to build networks with larger throughput, higher robustness, and increased flexibility compared to battery-powered counterparts; though undoubtedly, it also introduces significant research and implementation challenges.