Results 141 to 150 of about 8,767 (273)

Visible, near‐, and thermal infrared spectra of asteroid Bennu samples: Relationship to and implications for remote sensing of carbonaceous asteroids

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Remote spectroscopy is used to characterize the mineralogy and infer the history of planetary bodies. Carbonaceous asteroids, such as B‐type (101955) Bennu, represent the earliest stages of planet formation. B types have a blue (negative) spectral slope and comprise <5% of asteroids.
V. E. Hamilton   +32 more
wiley   +1 more source

The role of composition in the spectral evolution of carbonaceous asteroids as informed by Bennu sample return

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Near‐Earth rubble‐pile asteroids Bennu and Ryugu are part of the carbonaceous taxonomic complex (C‐complex), and samples returned from both bodies resemble the most aqueously altered carbonaceous chondrites. However, telescopic and spacecraft visible–near infrared (VIS–NIR) reflectance spectra of Ryugu exhibit a red (positive) spectral slope ...
Ralph E. Milliken   +10 more
wiley   +1 more source

Evaluating maturity of organic matter in hydrated C1 and CM‐like clasts and a dehydrated clast within a polymict eucrite and a howardite

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Volatile‐rich xenolithic clasts in different types of brecciated meteorites represent unique pristine solar system material. This study investigates the maturity and thermal history of organic matter using Raman spectroscopy and aqueous alteration effects using infrared spectroscopy in the matrix of 15 volatile‐rich clasts (C1 and CM‐like ...
Swarna Prava Das   +7 more
wiley   +1 more source

Characterization of calcium silicate hydrate and calcium hydroxide in nanosilica binder composites [PDF]

open access: yes, 2013
Pozzolanic reaction is the reaction of vitreous silica with calcium hydroxide (C–H), which is formed during the hydration of the ordinary Portland cement (OPC) binder producing additional calcium silicate hydrate (C–S–H) that resembles tobermorite or ...
Norsuzailina, Sutan   +2 more
core  

Influence of the Ca/Si ratio on the compressive strength of cementitious calcium–silicate–hydrate binders

open access: yes, 2017
Calcium–silicate–hydrate phases have been synthesized with Ca/Si ratios of 0.83–1.50 and it is demonstrated that the compressive strengths of the C–S–H pastes increase for decreasing Ca/Si ratio for all samples and testing ages.
Jørgen Skibsted   +2 more
core   +1 more source

Role of extracellular carbonic anhydrase in the polar diatom Fragilariopsis cylindrus

open access: yesNew Phytologist, EarlyView.
Summary Diatoms are major primary producers in productive polar oceans, where cold temperatures and high CO2 solubility raise questions as to whether they rely on the CO2‐concentrating mechanism (CCM) to saturate photosynthesis. Knowledge of CCM function will help better predict the sensitivity of diatom primary production to warming and acidifying ...
Meng Li, Jodi N. Young
wiley   +1 more source

Alkali uptake in calcium alumina silicate hydrate (C-A-S-H)

open access: yes
Uptake of the alkalis K and Na by calcium silicate hydrate (C-S-H) and calcium alumina silicate hydrate (C-A-S-H) of molar Ca/Si ratios = 0.6 to 1.6 and molar Al/Si ratio = 0 or 0.05 has been studied at 20 degrees C.
Scrivener, K.   +3 more
core   +1 more source

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