(a.) Pertaining to, having the nature of, fire; containing fire; resembling fire; as, an igneous appearance.
(a.) Resulting from, or produced by, the action of fire; as, lavas and basalt are igneous rocks.
Example Sentences:
(1) The gamma-ray absorbed dose rates in air above igneous rocks generally vary with their silica contents, and with the exception of shale, sedimentary rocks have lower K:U and K:Th ratios than most igneous rocks.
(2) Igneous activity is especially characterised by oscillating conditions.
(3) It was concluded that Hungarian rock-soil systems, especially the acid igneous rocks and the widely distributed young sediments (loess and sand formations) with most of the agricultural activity, are low in Se, and the mean serum Se level of the blood samples were also low.
(4) The aluminosilicate minerals of igneous and metamorphic rocks are mostly unstable in earth-surface weathering conditions.
(5) Seen from above, the concentric rings of hills and valleys make a near perfect circle, with different rings composed of different types of igneous rock.
(6) These fungi were incubated with the following iron-containing minerals: augite, hornblende, biotite, magnetite, hematite, and the igneous rock granodiorite.
(7) Uranium-rich igneous rock is dissolved by groundwater that emerges to the surface in nine hot springs (which are used for bathing).
(8) The phosphorus was locked in an igneous lithosphere as orthophosphate.
(9) The primitive Earth was highly deficient in the total available phosphorus until a sufficient quantity of phosphorus weathered from the igneous rocks in which it was entrapped.
(10) A natural, igneous fluorapatite was found to be even more effective in nucleotide synthesis than the more soluble hydroxylapatite.
(11) With the advent of the first primitive rainstorms the slow endless process of liberating the phosphorus from the igneous rock strata had begun.
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.