[1] High‐silica materials have been observed on Mars, both from orbit by the CRISM spectrometer and in situ by the Spirit rover at Gusev Crater. These observations potentially imply a wet, geologically active Martian surface. To understand silica formation on Mars, it is useful to study analogous terrestrial silica deposits. We studied silica coatings that occur on the 1974 Kilauea flow in the ...

Nanoparticles of a novel organic zwitterionic Meisenheimer complex, N',N' ',N' ''-tri(isopropyl)-4-oxo-6-(isopropyliminio)-2-s-(2H)triazinespiro-1'-2',4',6'-trinitrocyclohexadienylide, were synthesized by reprecipitation in water under different conditions. While reprecipitation alone resulted in a suspension of amorphous particles that fell out of solution within hours, sonication for differen...

Focused ion-beam (FIB) milling is a commonly used technique for transmission electron microscopy (TEM) sample preparation of inorganic materials. In this study, we seek to evaluate the FIB as a TEM preparation tool for human dentin. Two particular problems involving dentin, a structural analog of bone that makes up the bulk of the human tooth, are examined. Firstly, the process of aging is stud...

Cross-sectional study of sound primary dental enamel revealed hardness zonation and, in parallel, significant change the Mg content below prismless layer. is known to play an important role apatite biomineralization, therefore, ion exchange experiments were carried out on outer surface molars and reference abiogenic Ca-phosphates using MgCl2 solution. Effects incorporation crystal/particle size...

Abstract Quartz segregations in paragneisses from the Paleozoic basement of North Patagonian Andes contain highly saline multiphase fluid inclusions with rare daughter mineral ferropyrosmalite detected by Raman analysis, besides halite, sylvite, hematite, and/or magnetite. During heating experiments, L-V homogenization occurs (256–515 °C), followed halite dissolution (287–556 °C) and at 550–581...

The alkaline playas near Atlin, British Columbia, Canada are likely one of the few surface environments on Earth where contemporaneous formation hydromagnesite and magnesite occurs at temperatures that do not exceed 15 °C. This environment offers a unique opportunity to examine impact different mechanisms Mg isotope compositions Mg-carbonate minerals low temperature. In this study, we report co...

Water-dispersed organic nanoparticles (NPs) constructed by the conjugated molecule 2,5,2',5'-tetra(4'-N,N-diphenylaminostyryl)biphenyl (DPA-TSB) with a high luminescence and large two-photon absorption (TPA) section were fabricated via the reprecipitation method. The average size of the NPs can be controlled from 40 nm to 80 nm by adjusting the reprecipitation conditions. The NPs in water dispe...

The welding of materials by applying Friction Stir Welding technique is a new solid-state joining technique. The main advantage of this method compared to the traditional joining process is that it minimizes problem-related to metal resolidification as the method incorporates no melting phase. In this experimental work, the effect of friction stir welding (FSW) technique on the microstructu...

A partially recrystallized sample of the Ni-based superalloy AD730 was taken from an intermediate stage ingot to billet conversion process and isothermally forged in a single stroke compression test at sub-solvus temperature (1080 °C). The as-received material had heterogeneous microstructure, containing mixture coarse much finer grains as well unrecrystallized ones, also γ′ precipitation. recr...

Cementitious materials are frequently applied in environments which they exposed to acid attack, e.g., sewer systems, biogas plants, and agricultural/food-related industries. Alkali-activated (AAMs) have repeatedly been shown exhibit a remarkably high resistance against attack by organic inorganic acids and, thus, promising candidates for the construction repair of acid-exposed structures. Howe...