Load integration, including radar and advanced weapons

This paper summarizes work that addressed issues associated with the integration of various loads on an all-electric navy ship by the Electric Ship Research and Development Consortium (ESRDC) in the last ten years. The loads include ship service loads such as hotel loads, continuous high-power loads such as propulsion, vital high-power loads such as radar, multi-megawatt pulsed loads such as sensors and defensive systems, and very-high power, gigawatt-level, pulsed loads such as electromagnetic rail guns which require energy storage. The integration of energy storage received particular attention due to its vital role and is discussed accordingly. The analyses were conducted through modeling and simulation and complemented by design studies at component and system levels. Typical simulation results representing operational scenarios of various loads and their interaction with the power system are presented.Center for Electromechanic

Downstream fining, selective transport, and hillslope influence on channel bed sediment in mountain streams, Colorado Front Range, USA

Channel bed sediment is composed of a combination of upstream and local hillslope sources. Factors that influence downstream changes in size, sorting, and lithological characteristics of bed material are complex. In order to better understand this complexity, we measured grain sizes and channel geometry on five streams draining the Colorado Front Range. The studied streams flow from steeply incised canyons in the mountains onto the gently sloping Colorado High Plains. Downstream fining occurs at the scale of the entire study reach (~. 30. km), but not in each individual stream. Differences between streams are likely related to watershed size and discharge characteristics. At smaller spatial scales within each stream, the fining pattern is less clear and is disrupted by lateral inputs from locally steep hillslopes in the incised canyons of the Front Range. However, the exclusion of local hillslope influence by distinguishing among individual lithologies in the channel bed material that are not present in the local hillslopes shows that fining also occurs over these smaller spatial scales. In the absence of steep hillslopes adjacent to the channels, bed sediment becomes a better mix of lithologies from the whole watershed rather than dominated by local hillslope sediment influx. We propose four dominant factors that control the channel bed characteristics in the study area: inheritance, hydrodynamics, lithologically controlled sediment abrasion rates, and differences in denudation rates throughout the watershed with associated differences in hillslope steepness. Combining these factors leads to a conceptual model that explains our observations and illustrates the complexity of the behaviour of bed material in steep mountainous regions and their bounding basins. Distinguishing among the different lithologies in the bed material was instrumental in decomposing and understanding the complex trends in this system. © 2015 Elsevier B.V