Research challenges and opportunities in blockchain and cryptocurrencies

The blockchain is the underlying technology of the Bitcoin cryptocurrency, and it has created much excitement in the technology and research communities. A blockchain is a distributed ledger collectively maintained by a peer‐to‐peer network of participants who in Bitcoin are known as miners. This key innovation enables cryptocurrencies such as Bitcoin to operate in a decentralized manner with no intermediaries such as financial institutions. But the blockchain can be used to record things other than cryptocurrency transactions. While many of the concepts of Bitcoin build on what have been around since the 1980s and 1990s, the designer(s) of it have made important assumptions that make it work along with the use of an incentive protocol, leading to a major breakthrough from traditional academic thinking. In this paper, we present the state‐of‐the‐art of blockchain and cryptocurrencies along with research challenges and opportunities that would be of interest to researchers getting into this exciting field

X-ray diffraction of crystallization of copper (II) chloride for improved energy utilization in hydrogen production

Crystallization is an effective method to recover solids from solution, due to its relatively low energy utilization, low material requirements and lower cost compared to other alternatives. Hence, crystallization is of particular interest in the thermochemical copper-chlorine cycle for hydrogen production as an energy-saving means to extract solid CuCl2 from its aqueous solution. It has been determined from experiments that there is a range of concentrations that will demonstrate crystallization. If the initial concentration exceeds the upper bound of this range, the solution will be saturated and instantly become paste-like without forming crystals. Conversely, if the initial concentrations fall below the lower bound of a specified range, the solution will remain liquid upon cooling. As a result, it has been observed that crystallization does not occur for HCl concentrations below 3 M and above 9 M. Also, it has been found that anhydrous CuCl2 does not crystallize under any of the conditions tested. To analyze the composition of the recovered solids, X-ray diffraction (XRD) was employed. The samples were also analyzed using thermogravimetric analysis (TGA) in order to determine their thermochemical properties such as melting and decomposition temperatures. The stationary point on the TGA curve was found to be around 462 °C which is below the normal melting temperature of CuCl2. Also, the vaporization of the samples was found to be approximately 600 °C