(1) The quantitative mineralogical analysis of small samples (less than 20 mg) of china clay has been investigated using x ray diffractometry to determine kaolinite, mica, quartz, and feldspar.
(2) The resulting feldspar-alumina composites were compared for shrinkage then cut and prepared into disc specimens.
(3) The lung dust composition in this case was approximately 43% silicon carbide, 24% aluminium oxide, 2.3% cristobalite, 2.0% quartz, and trace of talc and feldspar.
(4) Quartz, calcite, feldspar, smectite, inter-stratified phases, kaolinite, amphibole, muscovite and dolomite are other contaminating minerals.
(5) The conventional feldspar ceramic is then placed onto this very resistant (more than 580 MPa flexural strength) and exceptionally well adapted framework.
(6) The adhesion of Salmonella typhimurium to the mineral particles quartz, albite, feldspar, and magnetite was shown to correlate with the hydrophobicity of the cell surface as measured by hydrophobic interaction chromatography.
(7) Significant numbers of primary lung tumors, principally adenocarcinomas and adenomas, were seen in the copper slag (p = 0.005 and p = 0.022 for the primary and secondary slags, respectively), in the feldspar (p = 0.007), in the novaculite (p less than 0.001), and in the Min-U-Sil (p less than 0.001) groups when compared to the vehicle control group.
(8) Besides low leucite and glass, we have found a second crystalline phase in the sintered and slow-cooled porcelains that we propose to be potash feldspar (K2O.Al2O3.6SiO2).
(9) An application of high-resolution transmission electron microscopy (HRTEM) to the study of two types of dislocations in potassium feldspars (K-feldspars) is shown here.
(10) Eighty-eight were of mineral origin, mainly quartz and feldspar, and it is believed that the great majority were submitted for secondary gain or for psychiatric reasons.
(11) Feldspar-alumina composites shrank approximately 30%; shrinkage of 15-20% occurred only in composites involving spherical alumina (average particle size 5.4 microns).
(12) Kaolinite, talc, mica, feldspars, and crystalline silica comprised the majority of particles of both groups.
(13) If the soil where potatoes are grown contains feldspars, sprout inhibition treatment with 100-200-Gy doses can also be detected for up to one year, using the 90-250 degrees C low-temperature part of the TL spectrum for evaluation.
(14) Composites of feldspar and spherical alumina were observed to be stronger than those of feldspar and nonspherical alumina.
(15) The major reaction seen in both the feldspar- and the novaculite-treated rats was a granulomatous inflammation with varying degrees of fibrosis associated with the granulomas.
(16) A 140% increase in the breaking strength of Keradens facings may be achieved by ion exchange, i.e., by substitution of the small sodium ions in soda feldspar by the larger potassium ions, which is done by melting the soda feldspar with potassium nitrate.
(17) The rare earths were added to a potassium feldspar glass host and emission spectra were measured.
(18) Exposure to mica is usually associated with exposure to other minerals such as quartz and feldspar.
(19) Quartz and feldspar were determined direct from prepared calibration graphs.
(20) The degradability of DNA adsorbed to minor mineral fractions (feldspar and heavy minerals) of the sand differed from that of quartz-adsorbed DNA.
Leucite
Definition:
(n.) A mineral having a glassy fracture, occurring in translucent trapezohedral crystals. It is a silicate of alumina and potash. It is found in the volcanic rocks of Italy, especially at Vesuvius.
(n.) A leucoplast.
Example Sentences:
(1) Quantitative x-ray diffraction was performed on the fast- and slow-cooled porcelain specimens with standards containing leucite volume fractions of 0.111, 0.223, 0.334, and 0.445.
(2) Recently introduced with pleasing aesthetic qualities, IPS-Empress (Ivoclar, Schaan, Liechtenstein), a new European leucite-reinforced glass-ceramic, has finally drawn attention in some journals and has been reviewed with promising in vitro test results.
(3) Unpaired, one-tailed t tests were performed on the fast- and slow-cool data, and a significant increase (p less than 0.05) in the amount of leucite (as a function of the slow cooling) was found for each of the porcelains.
(4) A better understanding of compatibility of alloy and ceramic during refiring schedules based upon leucite phase transformations and the ramifications for porcelain failure is emerging.
(5) Besides low leucite and glass, we have found a second crystalline phase in the sintered and slow-cooled porcelains that we propose to be potash feldspar (K2O.Al2O3.6SiO2).
(6) The present study was undertaken to determine whether the increase in porcelain thermal expansion might be attributable to crystallization of additional leucite during slow cooling of the porcelain.
(7) Ceramography confirms the martensitic (displacive) nature of the transformation from high (cubic) to low (tetragonal) leucite upon cooling.
(8) X-ray diffraction analyses verified the leucite content in metal ceramic systems and ceramics of the nonbonded systems.
(9) The chief ingredient of each porcelain was leucite (K2O .
(10) Comparing the metal ceramic systems with the nonbonded systems, an increase in leucite content was observed in the nonbonded systems.
(11) Most commercial dental porcelains designed for ceramo-metallic restorations are partially crystallized feldspathic glasses (glass-ceramics) that consist of low (tetragonal) leucite (K2O.Al2O3.4SiO2) crystals embedded in a glassy matrix.
(12) The purpose of this study was to test the hypothesis that high-leucite content feldspathic porcelain can be strengthened best by thermal tempering followed by ion exchange, compared with either thermal tempering or ion exchange alone.
(13) The increases in the leucite volume fractions resulting from the slow cooling ranged from a low of 8.5% to a high of 55.8%, with an average increase of 26.9%.
(14) The structure analysed in the scanning electron microscope showed leucite in the dendritic and idiomorphic form.
(15) Some other components were metal oxides used as pigment and opaque, for regulating the recrystallization of leucite in the fused porcelain, for controlling the thermal expansion, and for diffusing in the both sides of alloy and porcelain.
(16) The dentine materials of the metal ceramic systems VMK 68 and Biodent as well as the ceramics of all ceramic systems Duceram, Cosmotech, Optec, IPS-Empress and Corum were tested for their leucite content.