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The abiotic processes include the rusting of iron-bearing metals, where Fe 2+ is abiotically oxidized to Fe 3+ in the presence of oxygen, and the reduction of Fe 3+ to Fe 2+ by iron-sulfide minerals. The biological cycling of Fe 2+ is done by iron oxidizing and reducing microbes. [14] [15] Iron is an essential micronutrient for almost every ...
Iron is both necessary to the body and potentially toxic. Controlling iron levels in the body is a critically important part of many aspects of human health and disease. Hematologists have been especially interested in systemic iron metabolism, because iron is essential for red blood cells, where most of the human body's iron is contained.
In physics and engineering, a free body diagram (FBD; also called a force diagram) [1] is a graphical illustration used to visualize the applied forces, moments, and resulting reactions on a free body in a given condition. It depicts a body or connected bodies with all the applied forces and moments, and reactions, which act on the body(ies).
Hexaferrum and epsilon iron (ε-Fe) are synonyms for the hexagonal close-packed (HCP) phase of iron that is stable only at extremely high pressure.. A 1964 study at the University of Rochester mixed 99.8% pure α-iron powder with sodium chloride, and pressed a 0.5-mm diameter pellet between the flat faces of two diamond anvils.
Hephaestin, a ferroxidase that can oxidize Fe 2+ to Fe 3+ and is found mainly in the small intestine, helps ferroportin transfer iron across the basolateral end of the intestine cells. In contrast, ferroportin is post-translationally repressed by hepcidin, a 25-amino acid peptide hormone. The body regulates iron levels by regulating each of ...
The nuclide 54 Fe theoretically can undergo double electron capture to 54 Cr, but the process has never been observed and only a lower limit on the half-life of 4.4×10 20 years has been established. [22] 60 Fe is an extinct radionuclide of long half-life (2.6 million years). [23]
Diagram of a ball placed in an unstable equilibrium. Second derivative < 0 The potential energy is at a local maximum, which means that the system is in an unstable equilibrium state. If the system is displaced an arbitrarily small distance from the equilibrium state, the forces of the system cause it to move even farther away.
Pourbaix diagram of iron. [1] The Y axis corresponds to voltage potential. In electrochemistry, and more generally in solution chemistry, a Pourbaix diagram, also known as a potential/pH diagram, E H –pH diagram or a pE/pH diagram, is a plot of possible thermodynamically stable phases (i.e., at chemical equilibrium) of an aqueous electrochemical system.