A parametric study of effect of forebody shape on flow angularity at Mach 8

Flow angularity and static pressure measurements have been made on the lower surface of nine forebody models that simulate the bottom forward surface of a hypersonic aircraft. Measurements were made in an area of the forebody that represents the location of an inlet of a scramjet engine. A parametric variation of the forebody surface investigated the effect of: (1) spanwise curvature; (2) longitudinal curvature; and (3) planform shape on both flow angularity and static pressure distribution. Results of each of the three parametric variations of geometry were compared to those for the same flat delta forebody. Spanwise curvature results showed that a concave shape and the flat delta had the lowest flow angularity and lowest rate of increase in flow angularity with angle of attack. Longitudinal curvature results showed a convex surface to give the better flow at the higher angles of attack. The better of the two planform shapes tested was a convex elliptical shape. Limited flow field calculations were made at angles of attack using a three dimensional, method-of-characteristics program. In general, at all angles of attack there was agreement between data and theory

Phyla lanceolata (Michx.) Greene

https://thekeep.eiu.edu/herbarium_specimens_byname/18994/thumbnail.jp

Phyla lanceolata (Michx.) Greene

https://thekeep.eiu.edu/herbarium_specimens_byname/18994/thumbnail.jp

Acer saccharinum L.

https://thekeep.eiu.edu/herbarium_specimens_byname/21609/thumbnail.jp

Lysimachia ciliata L.

https://thekeep.eiu.edu/herbarium_specimens_byname/20923/thumbnail.jp

Acer saccharinum L.

https://thekeep.eiu.edu/herbarium_specimens_byname/21609/thumbnail.jp

Clarification of the hybrid origin of carex x deamii Herm. (Cyperaceae) based on macro and micro morphological characters

The origin of Carex x deamii Herm. has been in question ever since it was named to science in 1938. Collections of the hybrid have always been associated with C. shortiana Dewey and either C. typhina Michx. or C. squarrosa L.. C. typhina and C. squarrosa are closely related taxa (Section Squarrosae) and often are morphologically similar. Because of this similarity, determining the correct parental species to the hybrid has been extremely difficult. It is known that the hybrid is sterile and only reproduces asexually. Pollen was analyzed to ascertain the viability of all four taxa. This study utilizes both macro and micro morphological characters in a numerical taxonomic analysis to determine the parental species of C. x deamii. Macromorphological characters include vegetative and reproductive parts. Micromorphological characters focused on surface features of leaves, perigynia, and pistillate scales. In addition, achenes were analyzed for distinctive features and X-Ray analysis was done on all plant parts to determine the presence and distribution of silica for these taxa. Data was analyzed using SAS and HYWIN (Hypothesizing hybrids using Weighted Intermediacy). Principal Component Analysis (PCA) and Canonical Discriminant Analysis (CDA) were done using the SAS program. The three putative parental species were all had ~90 % viable pollen. The hybrid, while sterile, did have 2.3 % of its pollen viable. All statistical analyses showed C. shortiana to be the most likely parent to the hybrid. Likewise, all analyses showed C. typhina to be the other parent species. The most important characters in both macro and micro morphological analysis were perigynia features (perigynium beak length in macromorphological analysis and perigynium epidermal cell length/width ratio in the micromorphological analysis

Viola sororia Willd.

https://thekeep.eiu.edu/herbarium_specimens_byname/20723/thumbnail.jp

Morus alba L.

https://thekeep.eiu.edu/herbarium_specimens_byname/19851/thumbnail.jp

Maclura pomifera (Raf.) Schneid.

https://thekeep.eiu.edu/herbarium_specimens_byname/19950/thumbnail.jp