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Synthesis And Characterization Of Barium Lanthanum Titanates, Jyoti P. Guha
Synthesis And Characterization Of Barium Lanthanum Titanates, Jyoti P. Guha
Materials Science and Engineering Faculty Research & Creative Works
Ternary compounds in the system BaO—TiO2—La2O3 were prepared by the solid‐state reaction technique at temperatures between 1300° and 1400°C using precursor oxides as the starting materials. In an alternative processing technique, BaTiO3 was reacted with appropriate proportions of prefabricated lanthanum titanates at 1350°C to obtain the compounds. Two compounds were identified in the TiO2‐rich region of the system. The X‐ray powder diffraction pattern of a compound with a chemical composition BaLa2Ti3O10 (BaO·La2O3·3TiO2) is indexed on the basis of an orthorhombic unit …
Subsidence Resulting From Multiple-Seam Longwall Mining In The Western United States - A Characterization Study, United States Department Of The Interior, Bureau Of Mines
Subsidence Resulting From Multiple-Seam Longwall Mining In The Western United States - A Characterization Study, United States Department Of The Interior, Bureau Of Mines
Mines and Mineral Resources
This report details the investigation of multiple-seam longwall subsidence conducted by the U.S. Bureau of Mines from 1978 to 1989. A field investigation monitored ground surface movements over four upper-seam longwall panels and six lower-seam panels. The characteristics of the subsidence occurring as a result of mining these panels are examined; in particular, the angle of draw, subsidence development, total magnitude and areal extent, and critical width are evaluated and discussed. Comparisons are also made between the characteristics of multiple-seam longwall subsidence and single-seam longwall subsidence that occurred at the same site.