Arrest points

The shelves of the cooling curve are called arrest points. The two shown in the picture are at the boiling point and the melting point of the material, at the given pressure. 

Haltepunkt, m. halting point, arrest point critical point (in a curve) break. 

Butler does not agree that these arrest points are due to platinum covered by a layer of oxide the reader should consult the original papers for details. Fortunately there is no dispute as to the presence of the monatomic layer of oxygen on an electrode evolving oxygen, which is the most important point for overpotential theory. 

Figure 37.2 A simplified schematic view of cell cycle progression in diatoms, with critical arrest points and dominant processes indicated. Most diatoms arrest at the Gl/S boundary, but a secondary arrest point can occur during the G2/M phase. M mitosis S DNA replication (synthesis) G1 and G2 gap phases.

Fig. 8 Plot of Gjc-values versus delamination length for specimens tested at two laboratories same as Fig. 7 but with obvious arrest points removed unidirectional lay-up [0°]24 (light grey symbols), regular saw-tooth with lower and higher wavelength for symmetric lay-up [0790°]6s (black symbols) and non-symmetric lay-up [0790°] 12 (dark grey symbols), respectively (the open symbols and those coimected by dashed lines to guide the eye indicate those from the second laboratory).

Although DNA damage induces a slowing of DNA replication, under many conditions this response is transient and cells end up in G2 phase with damaged DNA. G2 is a major arrest point in response to damaged... 

The pure substances (curves for Xb = 0 and Xb = 1) yield arrest points at the crystallization temperature T i because during the process of isothermal solidification, the cooling is arrested by the entropy emitted by crystallization. Only when the entire melt has solidified, does the temperature begin to drop again. 

The discontinuities may not always be clearly defined on a cooling curve (temperature 6 versus time t plot). In such cases, the arrest points can often be greatly exaggerated by plotting an inverse rate curve (0 versus dt/dO, i.e. the inverse of the cooling rate). A typical plot is shown in Figure 4.14. 

Figure 4.14. Detection of the arrest point for a single substance a) on a temperature-time curve, b) on an inverse rate curve...

TaUe2.10. Critical arrest points in iron-carbon phase diagram Point Description... 

A, The first critical point occurs at 210°C, the temperature at which cementite loses its ferromagnetism (Curie point). This arrest point exhibits the same temperature either on heating or on cooling, and it has little importance in both iron- and steelmaking. 

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