Dual Fronts Propagating into an Unstable State

The interface between an unstable state and a stable state usually develops a single confined front travelling with constant velocity into the unstable state. Recently, the splitting of such an interface into {\em two} fronts propagating with {\em different} velocities was observed numerically in a magnetic system. The intermediate state is unstable and grows linearly in time. We first establish rigorously the existence of this phenomenon, called ``dual front,'' for a class of structurally unstable one-component models. Then we use this insight to explain dual fronts for a generic two-component reaction-diffusion system, and for the magnetic system.Comment: 19 pages, Postscript, A

The geology of the Grassy Butte area, McKenzie County, North Dakota

The Grassy Butte area lies in southern McKenzie County, just southwest of the deepest part of the Williston Basin, and is bordered on the north by the North Unit of the Theodore Roosevelt National Memorial Park. the purpose of this investigation was: (1) to prepare a geological map of the area; (2) to map the geologic structure of the area; (3) to measure and describe detailed stratigraphic sections which would aid in correlating rock units in this area with previously described rock units in adjacent areas; (4) to indicate lignite beds of possible economic value. The western three-fifths of the Grassy Butte area is thoroughly dissected into badland topography, but the eastern two-fifths is an upland plain, the Missouri Plateau. The Tongue River formation, including the Sentinel Butte member, and the Golden Valley formation are exposed at the surface. The Tongue River formation is Paleocene in age. The Golden Valley formation, of Eocene age, was determined to be more extensive in this area than was previously supposed, and the writer used as the base of the formation an horizon approximately 25 feet lower than the “orange marker bed” which had usually been used for mapping purposes before. A series of north plunging noses and troughs were found to be present in the western part of the Grassy Butte area. To the south, in the adjacent Elkhorn Ranch area, the plunge of the easternmost nose is reversed and anticlinal closure results. The village of Grassy Butte is located on the crest of another anticline, trending northwest-southeast. The Little Missouri River flows over the easternmost nose, which seems to exert directional control on the course of that river. The outcrop pattern also seems to be controlled to some extent by the structure of the Paleocene beds in this area

Greenhouse Gas Emission of Rice Production System in the Philippines Based on Life Cycle Inventory Analysis

Poster Presentatio

Borate Rods as an On-Site Remedial Treatment for Control of Decay in Wood Decks

A conventional wood recreational deck constructed with spruce-pine-fir lumber was sampled for active growth of wood decay fungi before and 10 months after remedial preservation treatment with fused disodium octaborate rods (IMPEL®) at boric acid levels from 1.5-10 kg/m3. Extent of boron distribution was observed with a color indicator dye (curcumin) after 10 months exposure. Remedial treatment with the boron rods. was nearly 100% effective. Active decay cultures from treated material were found only in samples obtained from boards treated at the inhibition dosage level (1.5kg/m3) of boric acid. Suggested lethal dosages (\u3e3kg/m3) were effective in all cases as indicated by the failure to recover any decay fungi. In contrast, the numbers of active decay cultures from nontreated boards increased over the exposure period. Curcumin tests for diffusion indicated excellent distribution of boric acid in wood material where moisture contents exceeded 25% (ovendry weight basis)