Theoretical surface velocity distributions on acoustic splitter geometries for an engine inlet

The potential-flow velocity distributions on several splitter geometries in an engine inlet and their variation with different splitter leading-edge shapes and distances from the inlet highlight were analyzed. The velocity distributions on the inner and outer surfaces of the splitters are presented for low-speed and cruise conditions. At zero incidence angle, the splitter with the 4-to-1 elliptical leading edge had lower peak velocities and velocity gradients than the splitter with the 2-to-1 elliptical leading edge. The velocity gradients decreased as the distance from the inlet highlight to the splitter leading edge was increased. For a given distance, the peak velocity on the splitter inner surface increased with increasing inlet incidence angle. At an incidence angle of 50 deg, the velocity level and gradients on the inner surface of the splitter in the forward position were sufficiently severe to suggest local separation

Spatial and Temporal Modeling of Community Non-Timber Forest Extraction

This paper examines the interaction of spatial and dynamic aspects of resource extraction from forests by local people. Highly cyclical and varied across both space and time, the patterns of resource extraction resulting from the spatial-temporal model bear little resemblance to the patterns drawn from focusing either on spatial or temporal aspects of extraction, as is typical in both the modeling and empirical literature to date. Combining the spatial-temporal model with a measure of success in community forest management.the ability to avoid open-access resource degradation.characterizes the impact of incomplete property rights on patterns of resource extraction and stocks. Key words: Spatial and temporal modeling; renewable resources; non-timber forest products; common property resources

Analyzing the Impact of Excluding Rural People from Protected Forests: Spatial Resource Degradation and Rural Welfare

This paper examines how forest-dependent villagers meet a resource requirement when they are excluded from some area of a forest. Forest managers who value both pristine and degraded forest should take into account a .displacement effect. resulting in more intensive villager extraction elsewhere, and a .replacement effect. in which villagers purchase more of the resource from the market. Similarly, forest managers who have poverty concerns should recognize that exclusion zones tend to be more costly to villagers without market access and those with low opportunity costs of labour- typically the poorest villagers.

Persistent Chaos in High Dimensions

An extensive statistical survey of universal approximators shows that as the dimension of a typical dissipative dynamical system is increased, the number of positive Lyapunov exponents increases monotonically and the number of parameter windows with periodic behavior decreases. A subset of parameter space remains in which topological change induced by small parameter variation is very common. It turns out, however, that if the system's dimension is sufficiently high, this inevitable, and expected, topological change is never catastrophic, in the sense chaotic behavior is preserved. One concludes that deterministic chaos is persistent in high dimensions.Comment: 4 pages, 3 figures; Changes in response to referee comment