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The four compounds referred as C 3 S, C 2 S, C 3 A and C 4 AF are known as the main crystalline phases of Portland cement. The phase composition of a particular cement can be quantified through a complex set of calculation known as the Bogue formula .
CO 2 + H 2 O + RuBP → (2) 3-phosphoglycerate. This reaction was first discovered by Melvin Calvin, Andrew Benson and James Bassham in 1950. [1] C 3 carbon fixation occurs in all plants as the first step of the Calvin–Benson cycle. (In C 4 and CAM plants, carbon dioxide is drawn out of malate and into this reaction rather than directly from ...
Overview of the Calvin cycle and carbon fixation C3 Pathway. 2 H 2 O + 2 NADP + + 3 ADP + 3 P i + light → 2 NADPH + 2 H + + 3 ATP + O 2. The light-independent reactions undergo the Calvin-Benson cycle, in which the energy from NADPH and ATP is used to convert carbon dioxide and water into organic compounds via the enzyme RuBisCO.
The hydrate phase, [3 CaO · 2 SiO 2 · 3 H 2 O], is referred to as the "C-S-H" phase. It grows as a mass of interlocking needles that provide the strength of the hydrated cement system. Relatively high belite reactivity is desirable in Portland cement manufacture, and the formation of the unreactive γ-form must be rigorously avoided.
Southern Ocean sediments are a major sink for biogenic silica (50-75% of the oceanic total of 4.5 × 10 14 g SiO 2 yr −1; DeMaster, 1981), but only a minor sink for organic carbon (<1% of the oceanic 2 × 10 14 g of organic C yr −1). These relatively high rates of biogenic silica accumulation in the Southern Ocean sediments (predominantly ...
The silica cycle plays an important role in long term global climate regulation. The global silica cycle also has large effects on the global carbon cycle through the carbonate-silicate cycle. [43] The process of silicate mineral weathering transfers atmospheric CO 2 to the hydrologic cycle through the chemical reaction displayed above. [4]
Alite is an impure form of tricalcium silicate, Ca 3 SiO 5, sometimes formulated as 3CaO·SiO 2 (C 3 S in cement chemist notation), typically with 3-4% of substituent oxides. [1] It is the major, and characteristic, phase in Portland cement.
Precipitated silica is an amorphous form of silica (silicon dioxide, SiO 2); it is a white, powdery material. Precipitated silica is produced by precipitation from a solution containing silicate salts. The three main classes of amorphous silica are pyrogenic silica, precipitated silica and silica gel.