Results 41 to 50 of about 13,108 (235)
Geologia USP. Série Científica, 2021 Micaschists that host the Acari batholith (Ediacaran age, 572 to 577 My) are characterized by a large number of quartz veins. The veins are more abundant in higher-temperature metamorphic zones and, together with lower metamorphic zones, form an aureole ...
Laécio Cunha de Souza +2 more
doaj
Emergence of Continents Stabilized the Bioavailability of Boron
Terra Nova, EarlyView.ABSTRACT Boron is an essential element for the development of life on Earth; borates stabilize ribose in prebiotic reactions and facilitate metabolism in higher plants. There is, however, a relatively narrow surface boron concentration range over which borates stabilize and serve as a micronutrient rather than a toxin.
Brendan V. Dyck, Jon Wade
wiley +1 more source
Gemological Characteristics of Blue-Violet Cordierite
CrystalsCordierite is a violet-blue gem mineral primarily composed of magnesium aluminum silicate. This study employed three samples of Mg-cordierite and conducted tests on their gemological characteristics, spectroscopic features, and chemical composition using
Wenjie Yan +3 more
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Modeling of porous material fracture [PDF]
Инженерно-строительный журнал, 2017 Wide use of various porous materials in construction engineering applications requires development of up to date methods of non-destructive characterization and optimization of such materials.
A.N. Levandovskiy +2 more
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New Zealand Journal of Geology and Geophysics, Volume 69, Issue 2, June 2026.Clasts of albite‐porphyroblastic quartzofeldspathic schist, derived from the Otago Schist basement, occur within the Port Chalmers Breccia, a diatreme at the centre of the Dunedin stratovolcano, New Zealand. Schists have undergone varying degrees of replacement reactions (at temperatures of 300° to >500°C) producing hornfelses, with Ca‐ and K‐enriched ...
Alan F. Cooper
wiley +1 more source
Study of optical constants and dielectric properties of nanocrystalline α-cordierite ceramic
Journal of Asian Ceramic Societies, 2020 The nanocrystalline 2 Mg.2Al2O3.5SiO2 as amorphous-type α-cordierite was prepared by the modified sol-gel (or Pechini) technique. After calcination at 800ºC, the pressed powder as disk pellets was sintered at 1150ºC, 1250ºC, and 1350ºC.
Marzieh Nadafan, Roya Majidi
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The influence of activation and relaxation time on the synthesis of cordierite ceramics [PDF]
Journal of the Serbian Chemical Society, 2006 Due to its properties, cordierite, 2MgO.2Al2O3 .5SiO2, is nowadays an attractive ceramic material for various applications. Mechanochemical activation of the initial components was used in order to decrease the sintering temperature.
Đorđević Nataša, Pavlović Ljubica
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Journal of Metamorphic Geology, Volume 44, Issue 4, Page 265-286, May 2026.ABSTRACT The Quetico subprovince of the Superior Province is among the largest metasedimentary belts globally and provides evidence of tectonic processes at play during the final stages of Archean cratonization. Although previous studies have shown that deformation and metamorphism of the 2.7‐Ga turbiditic protolith resulted in regional subvertical ...
Adrian G. Rehm +4 more
wiley +1 more source
Densification and crystallization behaviour of colloidal cordierite-type gels [PDF]
Journal of the Serbian Chemical Society, 2001 Three cordierite-type gels were prepared from an aqueous solution of Mg(NO3)2, a boehmite sol and silica sols of very small particle sizes. The effect of varying the silica particle size on the crystallization and densification behaviour was ...
Petrović Rada +4 more
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Coupled Al/Si and O/N order/disorder in BaYb[Si4–xAlxOxN7–x]sialon [PDF]
, 2007 The fractions of aluminium, [Al]/[Al + Si], and oxygen, [O]/[O + N], in crystallographically distinct sites of BaYb[Si4–xAlxOxN7–x] oxonitridoaluminosilicate (space group P63mc, No. 186) were refined based on the results of neutron powder diffraction for
Gale, Julian D. +6 more
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