English fiddling 1650-1850 : reconstructing a lost idiom

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Newly developed foam ceramic body shows promise as thermal insulation material at 3000 deg F

Optimized zirconia foam ceramic body shows promise for use as a thermal insulation material. The insulating media displays low density and thermal conductivity, good thermal shock resistance, high melting point, and mechanical strength

Oregon's nutria problem

The nutria or coypu, Myocastor coypus, is a large semi-aquatic rodent that superficially resembles an overgrown muskrat or a stunted beaver. They were introduced into Oregon from about 1930 to the 1950's. At one time Oregon had more than 600 fur farmers raising these animals for fur; now there are none. Some animals escaped and many others were released into the wild when it became apparent that pelt values were nonexistent and production costs greatly exceeded profits. Being prolific and quite mobile, the nutria quickly spread through much of western Oregon. By the 1960's damage to agricultural crops was common to severe in western Oregon. Crops damaged included seed, grain, forage, hay and trees. Burrowing damage to stream banks, field borders, and farm ponds was reported in many areas. Growth and reproduction data for Oregon nutria are included. Methods for controlling feral nutria including the use of prolin, red squill, strychnine alkaloid, and zinc phosphide are reported. Fur trapping and adverse weather as factors in population reduction are discussed

Reynolds-number effects and anisotropy in transverse-jet mixing

Experiments are described which measured concentration fields in liquid-phase strong transverse jets over the Reynolds-number range 1.0×10^3 ≤ Rej ≤ 20×10^3. Laser-induced-fluorescence measurements were made of the jet-fluid-concentration fields at a jet-to-freestream velocity ratio of Vr =10. The concentration-field data for far-field (x/dj =50) slices of the jet show that turbulent mixing in the transverse jet is Reynolds number dependent over the range investigated, with a scalar-field PDF that evolves with Reynolds number. A growing peak in the PDF, indicating enhanced spatial homogenization of the jet-fluid concentration field, is found with increasing Reynolds number. Comparisons between transverse jets and jets discharging into quiescent reservoirs show that the transverse jet is an efficient mixer in that it entrains more fluid than the ordinary jet, yet is able to effectively mix and homogenize the additional entrained fluid. Analysis of the structure of the scalar field using distributions of scalar increments shows evidence for well-mixed plateaux separated by sharp cliffs in the jet-fluid concentration field, as previously shown in other flows. Furthermore, the scalar field is found to be anisotropic, even at small length scales. Evidence for local anisotropy is seen in the scalar power spectra, scalar microscales, and PDFs of scalar increments in different directions. The scalar-field anisotropy is shown to be correlated to the vortex-induced large-scale strain field of the transverse jet. These experiments add to the existing evidence that the large and small scales of high-Schmidt-number turbulent mixing flows can be linked, with attendant consequences for the universality of small scales of the scalar field for Reynolds numbers up to at least Re=20×10^4

Transition stages of Rayleigh–Taylor instability between miscible fluids

Direct numerical simulations (DNS) are presented of three-dimensional, Rayleigh–Taylor instability (RTI) between two incompressible, miscible fluids, with a 3:1 density ratio. Periodic boundary conditions are imposed in the horizontal directions of a rectangular domain, with no-slip top and bottom walls. Solutions are obtained for the Navier–Stokes equations, augmented by a species transport-diffusion equation, with various initial perturbations. The DNS achieved outer-scale Reynolds numbers, based on mixing-zone height and its rate of growth, in excess of 3000. Initial growth is diffusive and independent of the initial perturbations. The onset of nonlinear growth is not predicted by available linear-stability theory. Following the diffusive-growth stage, growth rates are found to depend on the initial perturbations, up to the end of the simulations. Mixing is found to be even more sensitive to initial conditions than growth rates. Taylor microscales and Reynolds numbers are anisotropic throughout the simulations. Improved collapse of many statistics is achieved if the height of the mixing zone, rather than time, is used as the scaling or progress variable. Mixing has dynamical consequences for this flow, since it is driven by the action of the imposed acceleration field on local density differences

Paths to prosperity: knowledge is key for Fourth District states

Even as per capita income has increased across the United States, differences among states’ incomes remain. What are the sources of these remaining differences? This Commentary identifies and analyzes the key factors—patents, educational attainment, and industry structure—that influence income-growth rates and thus per capita incomes. It also explores where the Fourth District falls in relation to other states and the country as a whole.Economic development ; Income ; Education - Economic aspects

Glass formation, properties, and structure of soda-yttria-silicate glasses

The glass formation region of the soda yttria silicate system was determined. The glasses within this region were measured to have a density of 2.4 to 3.1 g/cu cm, a refractive index of 1.50 to 1.60, a coefficient of thermal expansion of 7 x 10(exp -6)/C, softening temperatures between 500 and 780 C, and Vickers hardness values of 3.7 to 5.8 GPa. Aqueous chemical durability measurements were made on select glass compositions while infrared transmission spectra were used to study the glass structure and its effect on glass properties. A compositional region was identified which exhibited high thermal expansion, high softening temperatures, and good chemical durability

Development of alkali metal peroxide and superoxide blown ceramic foams Final report, 22 Jun. 1965 - 15 Mar. 1966

Alkali metal peroxide and superoxide blown ceramic foam bodies for thermal insulatio

Evaluation of a stall-flutter spring-damper pushrod in the rotating control system of a CH-54B helicopter

Results of a design and flight test program conducted to define the effect of rotating pushrod damping on stall-flutter induced control loads are presented. The CH-54B helicopter was chosen as the test aircraft because it exhibited stall induced control loads. Damping was introduced into the CH-54B control system by replacing the standard pushrod with spring-damper assemblies. Design features of the spring-damper are described and the results of a dynamic analysis are shown which define the pushrod stiffness and damping requirements. Flight test measurements taken at 47,000 lb gross weight with and without the damper are presented. The results indicate that the spring-damper pushrods reduced high frequency, stall-induced rotating control loads by almost 50%. Fixed system control loads were reduced by 40%. Handling qualities in stall were unchanged, as expected