Pit origin and formation in stainless steels are discussed according to results of investigations from the following points of view: 1. Conditions for the Existence of Pitting Corrosion. Pitting potential range and pitting potentials. Functions dependent on the potential which are important for pitting corrosion, effect of inhibitors and results of different methods of investigation are described. 2. Kinetics of Pitting Corrosion. Analysis of the current-time relationship gives information on dependence of potential on the anodic metal dissolution process. Pit growth under potentiostatic, galvanostatic and chemical corrosion conditions can be explained theoretically. 3. Physical Forms of Pitting Corrosion. Shape of pits that can be observed in different potential ranges and under different corrosion conditions are discussed: regular etch pits, hemispherically-shaped pits, under-hollowing and elongated areal pits. 4. Theoretical Explanation of Pitting Corrosion. In connection with the “all-or-none” principle of passivity, which holds that the active and passive states should not coexist at the same potential, it is shown under which circumstances stable pitting corrosion is possible. A concentration effect and a resistance polarization effect are discussed in detail. The origin of pitting corrosion and the pitting potentials are discussed in terms of a chemisorption process and a transport and/or transference theory.

Increasingly, land managers seek ways to manage forests for multiple ecosystem services and functions, yet considerable challenges exist in comparing disparate services and balancing trade‐offs among them. We applied multi‐criteria decision analysis (MCDA) and forest simulation models to simultaneously consider three objectives: (1) storing carbon, (2) producing timber and wood products, and (3) sustaining biodiversity. We used the Forest Vegetation Simulator (FVS) applied to 42 northern hardwood sites to simulate forest development over 100 years and to estimate carbon storage and timber production. We estimated biodiversity implications with occupancy models for 51 terrestrial bird species that were linked to FVS outputs. We simulated four alternative management prescriptions that spanned a range of harvesting intensities and forest structure retention. We found that silvicultural approaches emphasizing less frequent harvesting and greater structural retention could be expected to achieve the greatest net carbon storage but also produce less timber. More intensive prescriptions would enhance biodiversity because positive responses of early successional species exceeded negative responses of late successional species within the heavily forested study area. The combinations of weights assigned to objectives had a large influence on which prescriptions were scored as optimal. Overall, we found that a diversity of silvicultural approaches is likely to be preferable to any single approach, emphasizing the need for landscape‐scale management to provide a full range of ecosystem goods and services. Our analytical framework that combined MCDA with forest simulation modeling was a powerful tool in understanding trade‐offs among management objectives and how they can be simultaneously accommodated.

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Rapidly changing landscapes have spurred the need for quantitative methods for conservation assessment and planning that encompass large spatial extents. We devised and tested a multispecies framework for conservation planning to complement single-species assessments and ecosystem-level approaches. Our framework consisted of 4 elements: sampling to effectively estimate population parameters, measuring how human activity affects landscapes at multiple scales, analyzing the relation between landscape characteristics and individual species occurrences, and evaluating and comparing the responses of multiple species to landscape modification. We applied the approach to a community of terrestrial birds across 25,000 km(2) with a range of intensities of human development. Human modification of land cover, road density, and other elements of the landscape, measured at multiple spatial extents, had large effects on occupancy of the 67 species studied. Forest composition within 1 km of points had a strong effect on occupancy of many species and a range of negative, intermediate, and positive associations. Road density within 1 km of points, percent evergreen forest within 300 m, and distance from patch edge were also strongly associated with occupancy for many species. We used the occupancy results to group species into 11 guilds that shared patterns of association with landscape characteristics. Our multispecies approach to conservation planning allowed us to quantify the trade-offs of different scenarios of land-cover change in terms of species occupancy.