Passive state, definition

The current-potential relationship ABCDE, as obtained potentiosta-tically, has allowed a study of the passive phenomena in greater detail and the operational definition of the passive state with greater preciseness. Bonhoeffer, Vetter and many others have made extensive potentiostatic studies of iron which indicate that the metal has a thin film, composed of one or more oxides of iron, on its surface when in the passive state . Similar studies have been made with stainless steel, nickel, chromium and other metals... 

The presence of a thin oxide/anodized layer on aluminium alloy surfaces may shift the electrochemical potential (ECP) to more noble values (passive state). In another CRP, ECPs on 1050 (99.5% aluminium) coupons exposed in the same spent fuel storage pool [9.1] were measured. These ECP values (with respect to a saturated calomel electrode) varied in the range 107-382 mV, depending on sample location with respect to the stored spent fuels. Although no definite trend could be observed, all the ECP values were positive, indicating immediate passivation of the coupons upon immersion in the pool water. Detailed ECP measurements on aluminium alloy coupons with surfaces polished by different techniques could help substantiate the observations made in this study. 

A simplified working definition of a membrane can be conveniently stated as a semipermeable active or passive barrier which, under a certain driving force, permits preferential passage of one or more selected species or components (molecules, particles or polymers) of a gaseous and/or Uquid mixture or solution (Figure 1.1). 

The protocol should discuss the outcome ascertainment. This includes whether the outcome collection was part of the design of the individual trials or retrospectively collected, whether the outcome was actively collected or passively collected, whether the outcome was adjudicated, and if so how. A clear outcome definition and the outcome window should be stated. The primary outcome definition should be identified. 

It was also stated that a theoretical definition of effective cathodic protection is to depress the potential of the mo.st cathodic areas below that of the mo.st anodic areas. However, as time passes and negatively charged chloride ions move away from the negatively charged steel, the most anodic areas will move. Variation. in the resistance of the concrete will mean that current flow from the anode is more likely to reach the anodic areas of steel and polarize them, rather then the passive, cathodic, areas (e.specially if they are new patch repairs with higher resistance concrete). 

To deal with these problems we discuss in this paper the definition and implementation of a compaitywide hazard process in our organization. This process is part of the conpany s internal mandatory processes, and defines the lifecycle of a hazard all the steps, responsibilities and time frames from its detection to its complete elimination. The state of each hazard is published in the organization s intranet and can be viewed by every enployee, which makes the processing of hazards a transparent activity where everyone has to participate actively or passively. 

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