FOD impact testing of composite fan blades

The results of impact tests on large, fiber composite fan blades for aircraft turbofan engine applications are discussed. Solid composite blades of two different sizes and designs were tested. Both graphite/epoxy and boron/epoxy were evaluated. In addition, a spar-shell blade design was tested that had a boron/epoxy shell bonded to a titanium spar. All blades were tested one at a time in a rotating arm rig to simulate engine operating conditions. Impacting media included small gravel, two inch diameter ice balls, gelatin and RTV foam-simulated birds, as well as starlings and pigeons. The results showed little difference in performance between the graphite and boron/epoxy blades. The results also indicate that composite blades may be able to tolerate ice ball and small bird impacts but need improvement to tolerate birds in the small duck and larger category

A study of energy release in rocket propellants by a projectile impact method Annual report, 10 May 1967 - 9 May 1968

Experimental measurement of rates of energy release in solid propellants subjected to strong shock waves from projectile impac

Computational engine structural analysis

A significant research activity at the NASA Lewis Research Center is the computational simulation of complex multidisciplinary engine structural problems. This simulation is performed using computational engine structural analysis (CESA) which consists of integrated multidisciplinary computer codes in conjunction with computer post-processing for problem-specific application. A variety of the computational simulations of specific cases are described in some detail in this paper. These case studies include: (1) aeroelastic behavior of bladed rotors, (2) high velocity impact of fan blades, (3) blade-loss transient response, (4) rotor/stator/squeeze-film/bearing interaction, (5) blade-fragment/rotor-burst containment, and (6) structural behavior of advanced swept turboprops. These representative case studies are selected to demonstrate the breath of the problems analyzed and the role of the computer including post-processing and graphical display of voluminous output data

Non-detection of the OH Meinel system in comet P/Swift-Tuttle

We report a search for emissions from the OH Meinel system in high-resolution near-infrared spectra of comet P/Swift-Tuttle. Because of the large cometary heliocentric velocity and high resolution of the spectrograph, the cometary lines should be well separated from the bright OH sky lines. Contrary to the findings of Tozzi et al. (1994) - who report seeing cometary OH at intensities comparable to the sky emissions in their low-resolution spectra - we find no OH in these spectra with an upper limit of 5% the value of the night sky lines. The non-detection of these cometary lines is consistent with theoretical calculations of expected emission strengths from prompt and fluorescent emission from cometary OH

A high-Resolution Catalog of Cometary Emission Lines

Using high-resolution spectra obtained with the Hamilton echelle spectrograph at Lick Observatory, we have constructed a catalog of emission lines observed in comets Swift-Tuttle and Brorsen-Metcalf. The spectra cover the range between 3800 Å and 9900 Å with a spectral resolution of λ/Δλ~42000. In the spectra, we catalog 2997 emission lines of which we identify 2438. We find cometary lines due to H, O, C_2, CN, NH_2, C_3, H_2O^+, CH, and CH^+. We list 559 unidentified lines compiled from the two spectra and comment on possibilities for their origins

Lightweight orthotic braces

Leg brace is constructed of fiber-reinforced polymer material. Composite material is stiffer, stronger, and lighter than most metals

Revelation and Creation in the Thought of Bernard L. Ramm and Carl F.H. Henry: the Creation Days as a Case Study

This study explores the relationship between the doctrines of creation and revelation within evangelical thought, especially focusing upon the writings of the two foremost leaders of Neo-evangelicalism, Bernard L. Ramm and Carl F. H. Henry. Neo-evangelicalism arose in America in the 1940s as a reaction against the Fundamentalism of the first decades of the twentieth century. One of its purposes was to free evangelicalism from the anti-intellectual tendencies of Fundamentalism while yet maintaining a belief in the full inspiration and historicity of Scripture. As a result, evangelicals have sought to harmonize the biblical record of creation with modern geological discoveries. The goals of this study are twofold: First, to explain how and why Bernard Ramm and Carl Henry differ in their understanding of the doctrines of revelation and creation, and second, to uncover the reasons why Ramm, Henry, and most evangelical theologians and scientists adopt a metaphorical understanding of the days of creation, when the large majority of scholars in the past one hundred years have understood the creation days to be literal, twenty-four-hour days. The approach of this study is descriptive, comparative, analytical, and evaluative. The first two chapters introduce the subject and provide a survey of the historical background for the evangelical understanding of revelation and creation, while the next two chapters, which are also descriptive, examine in detail the thought of Ramm and Henry on the doctrines of revelation and creation, and especially their views on the days of creation. Chapter 5, which is comparative and analytical for the large part, consists of comparisons and contrasts between the thought of Rammand Henry upon revelation and creation as well as upon the specific nature of the creation days. The evaluative phase involves a discussion of why this issue is important to evangelicalism, noted in the last part of chapter 5 and in the summary and conclusions found in chapter 6. The differences between Ramm and Henry on the doctrines of revelation and creation can be accounted for largely on the basis of the differing methodologies and philosophical positions of the two. The contrast between the evangelical approaches to understanding the days of creation and the approaches of non-evangelical scholarship is best explained on the basis of the evangelical understanding of revelation and inspiration

An experimental test of the Lashley hypothesis of selective attention and its relationship to the continuity-discontinuity issue in discrimination learning

Thesis (Ed.D.)--Boston Universit