Universal router concept

Portable universal router can cut holes of large diameter and irregular shapes, machine recesses, and drill holes with certain edge-distance limitations. Rectangular and round holes may be cut without a template

Variable-speed, portable routing skate

Lightweight, portable, variable-speed routing skate is used on heavy metal subassemblies which are impractical to move to a stationary machine. The assembly, consisting of the housing with rollers, router, and driving mechanism with transmission, weighs about forty pounds. Both speed and depth of cut are adjustable

Weakly Nonlinear Theory of Pattern-Forming Systems with Spontaneously Broken Isotropy

Quasi two-dimensional pattern forming systems with spontaneously broken isotropy represent a novel symmetry class, that is experimentally accessible in electroconvection of homeotropically aligned liquid crystals. We present a weakly nonlinear analysis leading to amplitude equations which couple the short-wavelength patterning mode with the Goldstone mode resulting from the broken isotropy. The new coefficients in these equations are calculated from the hydrodynamics. Simulations exhibit a new type of spatio-temporal chaos at onset. The results are compared with experiments.Comment: 4 pages, RevTeX, 4 PS-figures, to appear in PR

Miniature grinder for solid specimens

Machine grinds fines to appropriate micron sizes with the least biological trauma and greatest degree of reproducibility. Device controls destruction of material so that recovery of microorganisms is as great as possible and protects operation and grinding products from exogenous contamination

Semi Volatile Compounds (SVC) in PM Values

AbstractAir is the primary vector of SVCs to humans. They are deposited on animal feed such as grass and the contaminated feed is consumed by livestock. The SVCs are absorbed in the digestive tract and deposited in fatty tissue or milk fat, which in turn are the primary sources of human exposure to these compounds. Soil ingestion by livestock or humans is generally of little importance for human exposure, but the inhalation of some of these SVCs could cause severe problems. In addition, this is a certain part of the dust mass in the air and need to be determined. A new mass determination method will give access to a new automatic, continuous and real time calculation of the PM10, PM2.5 and even the PM1 mass concentrations of the SVC in μg/m3. Results from some field tests will be shown

Evapotranspiration of Rewetted and Drained Fen Soils With Grass – Long Term Lysimeter Studies

In the context of reducing greenhouse gas (GHG) emissions to combat climate change, rewetting of peatlands is of particular importance. High groundwater levels covering organic matter in the soil prevent its oxidation to CO2. The amount of water needed to allow the rewetting of peatlands can be determined in lysimeter studies. The evapotranspiration in fens depends essentially on the groundwater table, the vegetation (transpirational active biomass) and the saturation deficit of the atmosphere. After rewetting, these factors can lead to an evapotranspiration of 1000 l m-2 a-1 and even 2000 l m-2 a-1 in dry years depending on the vegetation. In a long term experiment over 20 years, the lysimeters planted with Phragmites australis showed the highest evapotranspiration rates, followed by those covered with Carex species. Evaluation of these results for a large, flooded, rewetted fen area in the Havelländisches Luch in the federal state of Brandenburg, Germany, with Phragmites confirmed the high values of evapotranspiration measured at the groundwater lysimeter station of ZALF in Paulinenau

Nutrient Balances of Rewetted Fens – Groundwater Lysimeter Results

With the raising of groundwater levels to protect fens and the climate, there may be a risk of nutrients, such as nitrogen or potassium, leaching into the groundwater. Great amounts of nutrients, which are accumulated largely by peat forming plants like Phragmites australis and Carex spec., are conveyed into rewetted fens through high amounts of introduced water. Nitrogen leaching into the groundwater is very low even at the beginning of flooding and there is no sudden, pronounced leaching. Only a portion of potassium is taken up by plants whereas the rest might be found in the groundwater. Increasing nutrient inputs must be expected as soon as more contaminated water is added contributing to the regeneration of groundwater and increasing the pollution with nutrients at once

Numerical study of domain coarsening in anisotropic stripe patterns

We study the coarsening of two-dimensional smectic polycrystals characterized by grains of oblique stripes with only two possible orientations. For this purpose, an anisotropic Swift-Hohenberg equation is solved. For quenches close enough to the onset of stripe formation, the average domain size increases with time as $t^{1/2}$. Further from onset, anisotropic pinning forces similar to Peierls stresses in solid crystals slow down defects, and growth becomes anisotropic. In a wide range of quench depths, dislocation arrays remain mobile and dislocation density roughly decays as $t^{-1/3}$, while chevron boundaries are totally pinned. We discuss some agreements and disagreements found with recent experimental results on the coarsening of anisotropic electroconvection patterns.Comment: 8 pages, 11 figures. Phys. Rev E, to appea