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.

A Raman Study of Iron–Phosphate Crystalline Compounds and Glasses

Abstract: Ferrous and ferric phosphate crystalline compounds and glasses were studied using Raman spectroscopy. A comparison of the spectra from crystalline and glassy ortho-, pyro-, and metaphosphates indicates that similar phosphate anions constitute the structures of the respective materials, and some information about the compositional dependence of the phosphate-site distributions in the glasses can be gleaned from relative peak intensities. A correlation exists between the average P–O bond distance and the Raman peak frequencies in the crystalline compounds, and this correlation is used to provide information about the structures of the iron phosphate glasses. For example, the average P–O bond distance is estimated to decrease from about 1.57 A for iron metaphosphate glasses (O/P∼3.0) to 1.54 A for iron orthophosphate glasses (O/P∼4.0). These bond distances are in good agreement with those reported from diffraction studies of similar glasses.

Properties improvement of fly ash cenosphere modified cement pastes using nano silica

Abstract: In this study, the effect of nano silica (NS) on the properties of cement pastes incorporated with of fly ash cenospheres (FACs) has been investigated. A fixed amount of 1 % NS was added to cement pastes containing various proportions of FAC. It was found that NS was beneficial in improving the mechanical strength of the FAC modified cement pastes. At the 7 – day age, the strength increase for NS modified pastes was about 17 % as compared to pastes without NS. However, the strength enhancement effect decreased with increasing age and FAC content. The dense microstructure of the NS modified pastes compensated for the higher porosity associated with FAC incorporation, leading to the reduced total porosity. With NS, there was better bonding of the FAC particles in the matrix, due to the enhanced interface. The reduced Ca(OH) 2 content and partially consumed FAC spherical shells at the early age showed that NS increased the pozzolanic activity of FAC in the cement pastes.