Investigations of Nematode-Destroying Fungi in Central Iowa

Three substrata, dung of Sylvilagus fioridanus, leaf mulch and rotting logs, from wooded areas in central Iowa are investigated for nematode-destroying fungi. Fifteen species are newly recorded for Iowa as follows: Acrostalagmus bactrosporus, Arthrobotrys cladodes var. macroides, A. dactyloides, A. robusta, Cystopage lateralis, Dactylaria candida, D. haptotyla, Dactylella bembicoides, D. ellipsospora., Harposporium helicoides, Meristacrum asterospermum, Nematoctonus haptocladus, N. leiosporus, N. robusta, and Stylopage hadra. Eight previously reported species are isolated. A species resembling Nematoctonus leiosporus but with shorter spores which were often hooked at the terminal end was found. All three substrata proved highly productive

A Study of Second-Order Supersonic Flow Theory

Second-order solutions of supersonic-flow problems are sought by iteration, using the linearized solution as the first step. For plane and axially symmetric flows, particular solutions of the iteration equation are discovered which reduce the second-order problem to an equivalent linearized problem. Comparison of second-order solutions with exact and numerical results shows great improvement over linearized theory. For full three-dimensional flow, only a partial particular solution is found. The inclined cone is solved, and the possibility of treating more general problems is considered

Second-order subsonic airfoil theory including edge effects

Several recent advances in plane subsonic flow theory are combined into a unified second-order theory for airfoil sections of arbitrary shape. The solution is reached in three steps: the incompressible result is found by integration, it is converted into the corresponding subsonic compressible result by means of the second-order compressibility rule, and it is rendered uniformly valid near stagnation points by further rules. Solutions for a number of airfoils are given and are compared with the results of other theories and of experiment. A straight-forward computing scheme is outlined for calculating the surface velocities and pressures on any airfoil at any angle of attac

Practical Calculation of Second-order Supersonic Flow past Nonlifting Bodies of Revolution

Calculation of second-order supersonic flow past bodies of revolution at zero angle of attack is described in detail, and reduced to routine computation. Use of an approximate tangency condition is shown to increase the accuracy for bodies with corners. Tables of basic functions and standard computing forms are presented. The procedure is summarized so that one can apply it without necessarily understanding the details of the theory. A sample calculation is given, and several examples are compared with solutions calculated by the method of characteristics

A study of hypersonic small-disturbance theory

A systematic study is made of the approximate inviscid theory of thin bodies moving at such high supersonic speeds that nonlinearity is an essential feature of the equations of flow. The first-order small-disturbance equations are derived for three-dimensional motions involving shock waves, and estimates are obtained for the order of error involved in the approximation. The hypersonic similarity rule of Tsien and Hayes, and Hayes' unsteady analogy appear in the course of the development. It is shown that the hypersonic theory can be interpreted so that it applies also in the range of linearized supersonic flow theory. Several examples are solved according to the small-disturbance theory, and compared with the full solutions when available