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Photolysis of water: H 2 O → H + + OH (hydroxyl radical) + e − O 2 + e − → O 2 − (a superoxide ion) The overall reaction is therefore: H 2 O + O 2 → H + + O 2 − + OH. The hydroxyl radical is a powerful oxidizing agent and can oxidize nitrogen dioxide to nitrate ions: NO 2 + OH → H + + NO 3 −. The superoxide ion is also able to ...
When atmospheric carbon dioxide (CO 2), or carbonate ions (HCO − 3, CO 2− 3 dissolved in water) diffuse into concrete from its external surface, they react with calcium hydroxide (portlandite, Ca(OH) 2) and the pH of the concrete pore water progressively decreases from 13.5 – 12.5 to 8.5 (pH of water in equilibrium with calcite).
Gamow [3] first solved the one-dimensional case of quantum tunneling using the WKB approximation.Considering a wave function of a particle of mass m, we take area 1 to be where a wave is emitted, area 2 the potential barrier which has height V and width l (at < <), and area 3 its other side, where the wave is arriving, partly transmitted and partly reflected.
Pycnonuclear fusion (Ancient Greek: πυκνός, romanized: pyknós, lit. 'dense, compact, thick') is a type of nuclear fusion reaction which occurs due to zero-point oscillations of nuclei around their equilibrium point bound in their crystal lattice.
A series of mixed vertical oscillators A plot of the peak acceleration for the mixed vertical oscillators. A response spectrum is a plot of the peak or steady-state response (displacement, velocity or acceleration) of a series of oscillators of varying natural frequency, that are forced into motion by the same base vibration or shock.
In solid mechanics, the Johnson–Holmquist damage model is used to model the mechanical behavior of damaged brittle materials, such as ceramics, rocks, and concrete, over a range of strain rates. Such materials usually have high compressive strength but low tensile strength and tend to exhibit progressive damage under load due to the growth of ...
[18] [19] [20] This work, in turn, evolved from his fundamental discovery of quantum tunneling as the mechanism of nuclear alpha decay, and his application of this theory to the inverse process to calculate rates of thermonuclear reaction. At first, Gamow believed that all the elements might be produced in the very high temperature and density ...
On the other hand, for completely dry concrete, the chemical reaction of carbonation cannot occur. Another influencing factor for CO 2 diffusion rate is concrete porosity. Concrete obtained with higher w/c ratio or obtained with an incorrect curing process presents higher porosity at hardened state, and is therefore subjected to a higher ...