Configuration Controllability of Simple Mechanical Control Systems

In this paper we present a definition of "configuration controllability" for mechanical systems whose Lagrangian is kinetic energy with respect to a Riemannian metric minus potential energy. A computable test for this new version of controllability is derived. This condition involves an object which we call the symmetric product. Of particular interest is a definition of "equilibrium controllability" for which we are able to derive computable sufficient conditions. Examples illustrate the theory

Configuration Controllability of Simple Mechanical Control Systems

In this paper we present a definition of 'configuration controllability' for mechanical systems whose Lagrangian is kinetic energy with respect to a Riemannian metric minus potential energy. A computable test for this new version of controllability is derived. This condition involves an object that we call the symmetric product. Of particular interest is a definition of 'equilibrium controllability' for which we are able to derive computable sufficient conditions. Examples illustrate the theory

Lubricant life tests on ball bearings for space applications Final report

Ball bearing life tests in vacuum using molybdenum sulfide solid films with high vacuum oils as lubricant

Supersonic turbulent boundary-layer flows with mass injection through slots and/or porous walls

An implicit finite-difference method was used to solve the compressible boundary-layer equations, and to study the effects of mass transfer through porous plates, slots, and a combination of the two. The effects of the external pressure field were also included by using a global pressure interaction scheme. Two different eddy viscosity models were used for the slot and slot-porous combination cases: one was a two-layer model with inner and outer laws, and the other was a multi-layer model with as many as five separate layers. Results of the present method were compared with experimental data at a Mach number of 2.8. Comparisons of the skin friction reduction and Mach number profiles gave good to excellent agreement. Pressure interaction had little effect on the slot injection skin friction but increased the skin friction of the porous and slot-porous combination markedly

Glacial features in the D'Entrecasteaux valley

In 1928 (Lewis, 1928) one of the present authors reported Silurian quartzite conglomerates in the valley of the D'Entrecasteaux River-Recherche Bay area-South-Western Tasmania. In so doing he was influenced by Twelvetrees (1915). Considering the matter more recently, it appeared that this occurrence might be of glacial origin. If this proved to be correct, the original site of these rocks must be westward of the La Perouse Range. An opportunity to visit this difficult locality has now presented itself. The rocks in question are undoubtedly of glacial origin, but they are Triassic grits, and not of Silurian age. No one can now be sure whether the series is the same as that reported by Twelvetrees, but from his very brief description this may be so. In any case, some further observations were made which are worth recording. This paper must he cconsidered merely as an amplification of the previous account (Lewis, 1928)

Configuration Controllability of Simple Mechanical Control Systems

In this paper we present a definition of "configuration controllability" for mechanical systems whose Lagrangian is kinetic energy with respect to a Riemannian metric minus potential energy. A computable test for this new version of controllability is also derived. This condition involves a new object which we call the {\em symmetric product}. Of particular interest is a definition of "equilibrium controllability" for which we are able to derive computable sufficient conditions. Examples illustrate the theory

Configuration controllability for a class of mechanical systems

We define a notion of controllability for mechanical systems which determines the configurations which are accessible from a given configuration. We derive sufficient conditions for this notion of controllability in terms of the given inputs, their Lie brackets, and their covariant derivatives

Evaluation of Softneck and Hardneck Garlic Produced Within or Without High Tunnels

This is a compilation of 21 research trial reports from four land-grant universities in the Midwestern United States. Crops include cantaloupe, pickling cucumber, pepper, potato, pumpkin, summer squash and zucchini, sweet corn, tomato, and watermelon. Somecrops were evaluated in high tunnels or hoophouses. Most trials evaluated different cultivars or varieties. One report addressed plant spacing for sweet corn and one addressed soil block for production of tomato seedlings. A list of vegetable seed sources and a list of other online sources of vegetable trial reports are also included