The Modern Face of Battle

New technology is entering the battlefield at a rapid pace, changing the way modern battle is conducted. This paper surveys the state of robotic systems, and identifies new technologies of war and the evolving military doctrine of the U.S. military. Our analysis is drawn from historical parallels and current publications. We conclude that the Department of Defense has adopted a high tempo, flexible doctrine that is capable of taking advantage of the evolving mission payloads of unmanned military systems

Flywheel-Accumulator for Compact Hydraulic Energy Storage

The energy density of hydraulic drive trains is inferior in comparison to electrical and mechanical systems. A solution to this problem is to improve the energy storage density by storing potential and rotating kinetic energy in a flywheel-accumulator. A flywheel-accumulator is a cylindrical pressure vessel with oil and gas volumes separated by a piston that is rotated about a central axis. A low-energy prototype was created and tested to verify an increase in energy density and to validate that a parabolic pressure distribution exists on the oil side due to centripetal acceleration. If an increase in energy density is proven, the flywheel-accumulator has the potential to revolutionize compact hydraulic energy storage

The concept of transport capacity in geomorphology

The notion of sediment-transport capacity has been engrained in geomorphological and related literature for over 50 years, although its earliest roots date back explicitly to Gilbert in fluvial geomorphology in the 1870s and implicitly to eighteenth to nineteenth century developments in engineering. Despite cross fertilization between different process domains, there seem to have been independent inventions of the idea in aeolian geomorphology by Bagnold in the 1930s and in hillslope studies by Ellison in the 1940s. Here we review the invention and development of the idea of transport capacity in the fluvial, aeolian, coastal, hillslope, débris flow, and glacial process domains. As these various developments have occurred, different definitions have been used, which makes it both a difficult concept to test, and one that may lead to poor communications between those working in different domains of geomorphology. We argue that the original relation between the power of a flow and its ability to transport sediment can be challenged for three reasons. First, as sediment becomes entrained in a flow, the nature of the flow changes and so it is unreasonable to link the capacity of the water or wind only to the ability of the fluid to move sediment. Secondly, environmental sediment transport is complicated, and the range of processes involved in most movements means that simple relationships are unlikely to hold, not least because the movement of sediment often changes the substrate, which in turn affects the flow conditions. Thirdly, the inherently stochastic nature of sediment transport means that any capacity relationships do not scale either in time or in space. Consequently, new theories of sediment transport are needed to improve understanding and prediction and to guide measurement and management of all geomorphic systems