Random and systematic measurement errors in acoustic impedance as determined by the transmission line method

The effect of random and systematic errors associated with the measurement of normal incidence acoustic impedance in a zero-mean-flow environment was investigated by the transmission line method. The influence of random measurement errors in the reflection coefficients and pressure minima positions was investigated by computing fractional standard deviations of the normalized impedance. Both the standard techniques of random process theory and a simplified technique were used. Over a wavelength range of 68 to 10 cm random measurement errors in the reflection coefficients and pressure minima positions could be described adequately by normal probability distributions with standard deviations of 0.001 and 0.0098 cm, respectively. An error propagation technique based on the observed concentration of the probability density functions was found to give essentially the same results but with a computation time of about 1 percent of that required for the standard technique. The results suggest that careful experimental design reduces the effect of random measurement errors to insignificant levels for moderate ranges of test specimen impedance component magnitudes. Most of the observed random scatter can be attributed to lack of control by the mounting arrangement over mechanical boundary conditions of the test sample

Power and Propulsion Element for Gateway: Configuration and Data Management of the NASA Power and Propulsion Element MBSE Model(s)

The following will be presented: CM/DM implementation environment for MBSE, traditional construct of CM/MBSE, goal for power and propulsion element team for CM/MBSE, steps to bridge the gap between CM and MBSE, how we implemented the standard tenets of CM, realized efficiencies, encountered challenges, lessons learned, and current state, and forward/future work

An experimental study of the effects of water repellant treatment on the acoustic properties of Kevlar

The treatment consisted of immersing samples of Kevlar in a solution of distilled water and Zepel. The samples were then drained, dried in a circulating over, and cured. Flow resistance tests showed approximately one percent decrease in flow resistance of the samples. Also there was a density increase of about three percent. It was found that the treatment caused a change in the texture of the samples. There were significant changes in the acoustic properties of the treated Kevlar over the frequency range 0.5 to 3.5 kHz. In general it was found that the propagation constant and characteristic impedance increased with increasing frequency. The real and imaginary components of the propagation constant for the treated Kevlar exhibited a decrease of 8 to 12 percent relative to that for the untreated Kevlar at the higher frequencies. The magnitude of the reactance component of the characteristic impedance decreased by about 40 percent at the higher frequencies

Economics of smoking cessation

Smoking imposes a huge economic burden on society— currently up to 15% of total healthcare costs in developed countries. Smoking cessation can save years of life, at a very low cost compared with alternative interventions. This chapter reviews some of the economic aspects of smoking cessation

A common graphical form

We present the Common Graphical Form, a low level, abstract machine independent structure which provides a basis for implementing graph reduction on distributed processors. A key feature of the structure is its ability to model disparate abstract machines in a uniform manner; this enables us to experiment with different abstract machines without having to recode major parts of the run-time system for each additional machine. Because we are dealing with a uniform data structure it is possible to build a suite of performance measurement tools to examine interprocessor data-flow and to apply these tools to different abstract machines in order to make relative comparisons between them at run-time. As a bonus to our design brief we exploit the unifying characteristics of the Common Graphical Form by using it as an intermediate language at compile-time

Mixing Calculations in a Rotating Partitioned Pipe

We consider laminar mixing in a steady incompressible Newtonian fluid. Through the use of particle tracking methods and analogous techniques applicable to material element vectors on a given velocity field, residence time distributions, Poincare maps and material element deformations are computed; all of which are useful tools in determining the efficacy of a mixing system. We analyse the accuracy of using solenoidal flux-interpolating splines to represent the underlying velocity field as a basis for determining mixing efficiencies. As a test case we use a rotating partitioned pipe mixer for which an approximate Stokes velocity field is available. The Stokes representation provides us with a benchmark with which to assess the accuracy of the spline interpolants

What a Wonderful World! Using Batchelder Books to Support Literacy

Are you searching for fresh opportunities to support literacy through reader response activities? Batchelder Awards and international stories are relatively untapped resources that offer a global approach for children to expand comprehension through tales from many nations. Pairing these stories with reader response exercises provides an outstanding opportunity for collaboration with social studies and language arts teachers. Handouts will be provided. (F4-E162

Mystery to History: An Uncommon Way to Teach the Common Core

With the transition to Common Core, school librarians are called to collaborate with teachers as well as to provide library media instruction for the preparation of our students in college and career readiness. How do we assist our teachers with Common Core instruction while preserving our love of fiction? How do we achieve Common Core Standards in our own instruction while sharing our treasured stories? Although Common Core focuses on informational text, there are numerous ways in which we can incorporate fiction as well as nonfiction into the curriculum

Implant Growth Stimulants for Growing and Finishing Cattle.

4 p