Missouri University of Science and Technology

About: Missouri University of Science and Technology is a education organization based out in Rolla, Missouri, United States. It is known for research contribution in the topics: Artificial neural network & Control theory. The organization has 9380 authors who have published 21161 publications receiving 462544 citations. The organization is also known as: Missouri S&T & University of Missouri–Rolla.

Enhancement factors for gas‐absorption with second‐order irreversible chemical reaction

Abstract: A relatively simple and explicit mathematical expression has been developed for estimating the enhancement factors for mass transfer accompanied by a second-order irreversible chemical reaction. The development is based on asymptotic characteristics, i.e., limiting solutions, for second-order enhancement factors. The resulting mathematical relation and other approximate analytical formulations previously presented in the literature have been critically compared with a numerical solution for the diffusion-reaction process based on film theory. On a mis au point une expression mathematique relativement simple et explicite pour evaluer les facteurs de promotion d'un transfert de masse accompagne d'un reaction chimique irreversible et de second ordre. Ledit developpement est base sur des caracteristiques asymptotiques, c'est-a-dire des solutions limiteuses, pour les facteurs de promotion de second ordre. On a compare d'une maniere critique la relation mathematique qui en resulte, et d'autres formulations analytiques et approximatives anterieurement presentees dans la litterature, avec une solution numerique pour le procede de reaction et diffusion base sur la theorie des pellicules.

Hydrothermal precipitation and characterization of nanocrystalline BaTiO3 particles

Abstract: Crystalline BaTiO3 powders were precipitated by reacting fine TiO2 particles with a strongly alkaline solution of Ba(OH)2 under hydrothermal conditions at 80°C to 240°C. The characteristics of the powders were investigated by X-ray diffraction, transmission electron microscopy, thermal analysis and atomic emission spectroscopy. For a fixed reaction time of 24 hours, the average particle size of BaTiO3 increased from ∼50 nm at 90°C to ∼100 nm at 240°C. At synthesis temperatures below ∼150°C, the BaTiO3 particles had a narrow size distribution and were predominantly cubic in structure. Higher synthesis temperatures produced a mixture of the cubic and tetragonal phases in which the concentration of the tetragonal phase increased with increasing temperature. A bimodal distribution of sizes developed for long reaction times (96 h) at the highest synthesis temperature (240°C). Thermal analysis revealed little weight loss on heating the powders to temperatures up to 700°C. The influence of particle size and processing-related hydroxyl defects on the crystal structure of the BaTiO3 powder is discussed.