Activated carbon derived from tree bark biomass with promising material properties for supercapacitors

Journal of Solid State Electrochemistry - Activated carbon from tree bark (ACB) has been synthesized by a facile and environmentally friendly activation and carbonization process at different...     

Bibliometric Mapping of Literature on High-Entropy/Multicomponent Alloys and Systematic Review of Emerging Applications

High-entropy/multicomponent alloy (HEA/MCA) has received significant research attention in the last decade. There is a dearth of data-driven works dedicated to assessing and visualizing the HEA/MCA literature from a global perspective. To this end, we present the first bibliometric literature analysis of more than 3500 HEA/MCA articles, published between 2004 and 2021, in the Scopus database. We identify the most prolific authors, their collaborators, institutions, and most prominent research outlet. Co-occurrence networks of keywords are mapped and analyzed. A steep rise in research outputs is observed from 2013, when the number of annual publications doubled the previous years. The top five preferred research outlets include Journal of Alloys and Compounds, Materials Science and Engineering A, Scripta Materialia, Intermetallics, and Acta Materialia. Most of these publications emanate from researchers and institutions within China, USA, and Germany, although international scientific collaboration among them is lacking. Research gaps and future research directions are proposed, based on co-occurrence frequencies of author keywords. Finally, a brief systematic review of emerging applications, covering hydrogen storage, additive manufacturing, catalysis, and superconductivity, is undertaken. This work provides an important comprehensive reference guide for researchers to deepen their knowledge of the field and pursue new research directions.     

Dissociation rates of urea in the presence of NiOOH catalyst: a DFT analysis

Single molecule reactions have been studied between nickel oxyhydroxide, urea, and the hydroxide ion to understand the process of urea dissociation into ammonia, isocyanic acid, cyanate ion, carbon dioxide, and nitrogen. In the absence of hydroxide ions, nickel oxyhydroxide will catalyze urea to form ammonia and isocyanic acid with the rate-limiting step being the formation of ammonia with a rate constant of 1.5 × 10?? s?1. In the presence of hydroxide, the evolution of ammonia was also the rate-limiting step with a rate constant of 1.4 × 10?2? s?1. In addition, desorption of the cyanate ion presented an energy barrier of 6190 kJ mol?1 suggesting that the cyanate ion cannot be separated from NiOOH unless further reactions occurred. Finally, elementary dissociation reactions with hydroxide ions deprotonating urea to produce nitrogen and carbon dioxide were analyzed. These elementary reactions were investigated along three paths differing in the order that protons were removed and the nitrogen atoms were rotated. The rate-limiting step was found to be the removal of carbon dioxide with a rate constant of 4.3 × 10??? s?1. Therefore, the catalyst could be deactivated by the surface blockage caused by carbon dioxide adsorption.     

Optimal Value and Post Optimal Solution in a Transportation Problem

In this work, we analyse the transportation problem of a real-life situation by obtaining the optimal feasible solutions, thus carrying out the sensitivity analysis of the problem. The work utilises the data obtained from the Asejire and Ikeja plants of Coca-Cola company, aiming to aid decision-making regarding the best possible options to satisfy customers at the barest minimum cost of transportation. Rerunning the optimization of a problem is an expensive scheme for gathering and obtaining enough data required for a problem. Thus, to minimize the transportation cost, the sensitivity analysis of parameters is a good tool to determine the behaviour of some input parameters where the values of these parameters are varied arbitrarily such that optimal results are verified. Maple 18 Software is used to solve the problem and the result obtained is compared with the values evaluated from northwest corner method, least cost method and Vogel''s approximation method. The study critically shows how a little change in a unit or more of any model parameter affects the expected results.