A class of evolutionary operators and its applications to electroseismic waves in anisotropic, inhomogeneous media

In the framework of a comprehensive theory for a new class of evolutionary problems wellposedness of associated initial boundary value problems is considered. The dynamic linear model for electroseismic waves in anisotropic, inhomogeneous, time-shift invariant media is used as an illustration of the theory

The effect of acceleration versus displacement methods on steady-state boundary forces

This study describes the acceleration and displacement methods for use in the recovery of coupled system boundary forces. A simple two degree of freedom system has been used for illustration. The effect of the choice of method for use with indeterminate or over-constrained boundaries has been investigated. It has specifically looked at results from a simple two dimensional beam problem using both methods. Much work has been done on the effect of Craig-Bampton modal truncation system displacements and forces, however, little work has been done on system level modal truncation. The findings of this study indicate that the effect of this system level truncation is significant. This may be particularly true for the 35 Hz system cutoff frequency that is required by the space shuttle. From this study's findings, recommendations for areas of study with space shuttle payload systems are made

A numerical method for interface problems in elastodynamics

The numerical implementation of a formulation for a class of interface problems in elastodynamics is discussed. This formulation combines the use of the finite element and boundary integral methods to represent the interior and the exteriro regions, respectively. In particular, the response of a semicylindrical alluvial valley in a homogeneous halfspace to incident antiplane SH waves is considered to determine the accuracy and convergence of the numerical procedure. Numerical results are obtained from several combinations of the incidence angle, frequency of excitation, and relative stiffness between the inclusion and the surrounding halfspace. The results tend to confirm the theoretical estimates that the convergence is of the order H(2) for the piecewise linear elements used. It was also observed that the accuracy descreases as the frequency of excitation increases or as the relative stiffness of the inclusion decreases

COMPARING TWO TRANSECT METHODS FOR THE DETECTION OF RED-BACKED SALAMANDERS

Typical monitoring methods for terrestrial salamanders are subject to extensive variation, driven by the environmental conditions in effect during sampling. As rigorous salamander sampling methods are needed to monitor populations, there is a need to assess commonly used methods under a variety of environmental conditions. We hypothesized that of two methods used for capturing red-backed salamanders (Plethodon cinereus), leaf litter searches and natural cover searches, the latter would perform best for adults and in situations where moisture was limiting. We compared captures for paired transect surveys: one a leaf litter search and the other a natural cover search, relative to age, proximity to streams, rainfall events, vapor pressure deficit and season. We found that natural cover searches outperformed leaf litter searches when conducted away from streams and in the absence of rainfall. Natural cover searches performed better regardless of vapor pressure deficit and season (spring or fall). Natural cover searches detected more adults than juveniles. We recommend natural cover searches as more efficient than leaf litter searches

An Exploratory Investigation of the Effects of a Thin Plastic Film Cover on the Profile Drag of an Aircraft Wing Panel

Exploratory wind tunnel tests were conducted on a large chord aircraft wing panel to evaluate the potential for drag reduction resulting from the application of a thin plastic film cover. The tests were conducted at a Mach number of 0.15 over a Reynolds number range from about 7 x 10 to the 6th power to 63 x 10 to the 6th power

Wind-tunnel results for an improved 21-percent-thick low-speed airfoil section

Low speed wind tunnel tests were conducted to evaluate the effects on performance of modifying a 23 percent thick low speed airfoil. The airfoil contour was altered to reduce the upper-surface adverse pressure gradient and hence reduce boundary layer separation. The chord Reynolds number varied from about 2,000,000 to 9,000,000

Low-speed aerodynamic characteristics of a 13-percent-thick airfoil section designed for general aviation applications

Wind-tunnel tests were conducted to determine the low-speed section characteristics of a 13 percent-thick airfoil designed for general aviation applications. The results were compared with NACA 12 percent-thick sections and with the 17 percent-thick NASA airfoil. The tests were conducted ovar a Mach number range from 0.10 to 0.35. Chord Reynolds numbers varied from about 2,000,000 to 9,000,000

Children's Enjoyment of a Physical Activity Incorporated into the School Day

Abstract Walking, jogging and running (WJR) are popular fitness activities and some of the best cardiovascular activities for individual health that persons of all ages can perform. Most persons recall how much fun they had as young children in free play, running and jumping and just playing with their friends, however research suggests that many children do not engage in the recommended amount of daily physical activity. The purpose of this study was to assess the experience of 5th grade students in a Mid-Western Elementary school (N = 67) participating in a two-week WJR intervention during their school day. Students were given the opportunity to participate in WJR for a daily 10- minute continuous period each day, and they completed surveys prior to the intervention, at the end of the intervention, and a final time 1- week post- intervention. Students completed pre and post measures of participation in, and enjoyment and benefit of WJR outside the school setting, and pre and post measures of participation in, enjoyment, and benefit of the WJR intervention. It was hypothesized that students' WJR activity outside the school day would be higher immediately post intervention and 1- week post intervention than prior to the intervention. In addition, it was hypothesized that students would enjoy the WJR activity and report higher enjoyment of WJR outside the school day immediately post- intervention and 1- week post intervention than prior to the intervention. Finally, it was hypothesized that students would report academic and health benefits as a result of participating in the WJR intervention immediate post intervention and 1- week post intervention. No gender differences were expected. Keywords: exercise, enjoyment, elementary schoo

Occupancy Rates and Detection Probabilities of Red-Backed Salamanders on the Virginia Fall Line

To meet the conservation needs of declining amphibian populations, there is a need to assess monitoring techniques in various habitat types and seasons. I assessed detection rates and proportion of area occupied via transect monitoring for red-backed salamanders at a site along the Virginia Fall Line in Doswell, Virginia. I established 24 transects in a 3.2-ha area in both riparian and upland habitats. Objects providing natural cover along these transects were sampled 3 times a week in fall and spring over a two-year period. Models of occupancy and detection were developed and compared using Akaike’s Information Criterion. Based on 113 captures, model selection indicated a low fixed initial occupancy of transects with seasonal changes in colonization and extinction. Detection probability was uniformly low, possibly contributing to model uncertainty in determining the best explanatory variables. I infer that the increased colonization of transect cover objects during fall and increased emigration from cover objects during spring is a result of changing moisture conditions and feeding opportunities. It is likely that occupancy and detection will vary substantially for survey sites based on habitat, season, or even by transect placement, and thus managers will need to estimate these parameters for any population monitoring program of red-backed salamanders