Defect Production in Single Crystals Resulting from Ion Bombardment Semiannual Status Report, 1 Jun. - 31 Dec. 1966

Damage produced on surface of metal single crystals during ion bombardmen

Defect Production in Single Crystal Resulting from Ion Bombardment Semiannual Status Report, 1 Jul. - 31 Dec. 1967

X ray spectrometer and vacuum system for single crystal defects studie

Thermal stresses in chemically hardening elastic media with application to the molding process

Thermal stresses in chemically hardened elastic media and applications to molding processe

The bond stress in a viscoelastic propellant disk during thermal shock

Analysis of bond stress in viscoelastic case bonded solid propellant rocket assembly during thermal shoc

Transient temperature distribution during an exothermic chemical reaction

Heat conduction equation for determining temperature distribution during exothermic chemical reactio

Residual stresses developed in molding a flat sheet of a chemically-hardening relatively incompressible material

Approximation of residual thermal stresses in flat sheet molded from chemical hardening material

Species Limits and Phylogeography of North American Cricket Frogs (Acris: Hylidae)

Cricket frogs are widely distributed across the eastern United States and two species, the northern cricket frog (Acris crepitans) and the southern cricket frog (A. gryllus) are currently recognized. We generated a phylogenetic hypothesis for Acris using fragments of nuclear and mitochondrial genes in separate and combined phylogenetic analyses. We also used distance methods and fixation indices to evaluate species limits within the genus and the validity of currently recognized subspecies of A. crepitans. The distributions of existing A. crepitans subspecies, defined by morphology and call types, do not match the distributions of evolutionary lineages recovered using our genetic data. We discuss a scenario of call evolution to explain this disparity. We also recovered distinct phylogeographic groups within A. crepitans and A. gryllus that are congruent with other codistributed taxa. Under a lineage-based species concept, we recognize Acris blanchardi as a distinct species. The importance of this revised taxonomy is discussed in light of the dramatic declines in A. blanchardi across the northern and western portions of its range

Effects of systematic errors on the mixing ratios of trace gases obtained from occulation spectra

The influence of systematic errors in the parameters of the models describing the geometry and the atmosphere on the profiles of trace gases retrieved from simulated solar occultation spectra, collected at satellite altitudes, is investigated. Because of smearing effects and other uncertainties, it may be preferable to calibrate the spectra internally by measuring absorption lines of an atmospheric gas such as CO2 whose vertical distribution is assumed rather than to relay on externally supplied information