Taylor's (1935) dissipation surrogate reinterpreted

New results from direct numerical simulation of decaying isotropic turbulence show that Taylor’s expression for the viscous dissipation rate ε = CεU3/L is more appropriately interpreted as a surrogate for the inertial energy flux. As a consequence, the well known dependence of the Taylor prefactor Cε on Reynolds number Cε(RL)→Cε,∞ can be understood as corresponding to the onset of an inertial range

Research in nonlinear structural and solid mechanics

Recent and projected advances in applied mechanics, numerical analysis, computer hardware and engineering software, and their impact on modeling and solution techniques in nonlinear structural and solid mechanics are discussed. The fields covered are rapidly changing and are strongly impacted by current and projected advances in computer hardware. To foster effective development of the technology perceptions on computing systems and nonlinear analysis software systems are presented

Forest and Erosion Concepts

Much has been said within the past few years about soil and water conservation and especially about the relations between forestry and the conservation of these resources. For this reason it may now not be out of place to review some of the fundamental conceptions regarding soil erosion and the relation of forestry to this process

Some fertilizer experiments with deciduous forest tree seedlings on several Iowa soils

The growth of seedling green ash, American elm, red oak and black locust was studied in relation to nitrogen, phosphorus and potassium fertilization of four Iowa soils. Fertilizers were added to Band C horizon soil materials and growth compared with that obtained on unfertilized surface and sub-soils. The soils employed were the gray-brown podzolic forest Lindley and prairie Clarion, Tama and O\u27Neill. Factors causing chlorosis on calcareous Clarion C horizon soil were also investigated. Nitrogen was found deficient for growth of ash, elm and oak. Black locust, a legume, did not respond to nitrogen fertilization. As the residual soil nitrogen supply increased, growth response decreased in magnitude. On Tama C horizon soil with residual total nitrogen at 600 pounds per acre the response of American elm to added nitrogen was 600 percent, while on O\u27Neill soil containing 1900 pounds residual nitrogen responses were small or nil. The evidence suggests that about 2000 pounds total nitrogen per acre is a level above which seedling nitrogen responses could not be expected under average conditions