(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.
Volcanic
Definition:
(a.) Of or pertaining to a volcano or volcanoes; as, volcanic heat.
(a.) Produced by a volcano, or, more generally, by igneous agencies; as, volcanic tufa.
(a.) Changed or affected by the heat of a volcano.
Example Sentences:
(1) But volcanic liberation has never really been his bag.
(2) Future ice loss and bending of the crust due to rising sea levels have the potential ultimately to raise levels of both earthquake and volcanic activity.
(3) He was a prowling, volcanic presence on the touchline.
(4) The Texas senator Ted Cruz says the rise of Donald Trump makes him “very optimistic” the next occupant of the White House will be a conservative – perhaps himself – propelled there by the “volcanic rage” of voters.
(5) In summary, volcanic ash alone or in combination with SO2 had only minimal effects on certain host defense mechanisms.
(6) Facebook Twitter Pinterest The landscape near San José I had started with a night in Rodalquilar, a white-washed village inside a large volcanic crater.
(7) If you only have an 20cm tin you can use that instead, but don't use all the batter – about 80% will suffice – otherwise you'll end up with a volcanic overspill, cake soldered to the floor of the oven and a frayed temper.
(8) Even by Congolese standards, Goma has endured much in its history , from mass looting by the army to the arrival of a million Rwandan Hutu refugees, years of cross-border wars and, in 2002, a volcanic eruption that poured a tide of lava through its heart.
(9) She writes about the nightmarish scenarios surrounding geoengineering, or hacking the planet, by spraying seawater into the sky to create cloud cover, or simulating a volcanic eruption to fill the lower atmosphere with ash.
(10) The telescope, which is perched on the summit of Mauna Kea, a volcanic island in Hawaii, picked up signs of methane in the planet's atmosphere that could not be seen by either Hubble or Spitzer .
(11) A thermoacidophilic micro-organism, isolated from volcanic hot springs near Naples, was cultivated in vitro, and examined by electron microscopy in sections and after negative staining.
(12) Festivalgoers in Edinburgh will witness the city’s birth from volcanic eruptions and the crushing force ice in a late-night spectacular that will open this year’s events.
(13) Triassic-Jurassic, c 200 million years ago Three-quarters of species were lost, again most likely due to another huge outburst of volcanism.
(14) But to do Hakone justice, find a reasonably priced ryokan and take a couple of days to explore the volcanic geysers of Owakudani, the botanical gardens, the cherry blossom in spring and Hakone shrine on the shore of the lake.
(15) Following the 1980 Mount St. Helens volcanic eruption, psychiatric reactions were studied in the disaster area and in a control community.
(16) A thousand years ago, it was responsible for one of the largest volcanic eruptions in human history.
(17) Edinburgh’s skyline is dominated by Castle Rock, Calton Hill nearby, the dramatic volcanic remnants of Arthur’s Seat and the cliffs of Salisbury Crags , but festival events rarely focus on the city’s geological history.
(18) Lake Nyos sits in a crater on the edge of an inactive volcano in the Oku volcanic field.
(19) Costs of the disruption to the global airline industry caused by the volcanic ash cloud have spiralled to $1.7bn (£1.1bn), according to new estimates today from the International Air Transport Association (Iata).
(20) On her newest album Haze recalls discovering rap as an outlet: " I was nothing Then all of a sudden I'm a volcanic eruption. "