Statistical energy methods Final report, 18 May 1969 - 18 May 1970

Statistical energy analysis for studying dynamic behavior of large, complex structures and acoustic space

Experimental study of sound and vibration transmission to a shroud-enclosed spacecraft Annual report, 20 Jan. 1967 - 20 Jan. 1968

Acoustic and mechanical vibration transmission paths to shroud enclosed spacecraf

Analytical procedure for determining random load acting on a spacecraft due to a primary random load acting on an exterior structure Quarterly report no. 2, 1 Sep. - 30 Nov. 1965

Sound and vibration transmission in OGO SPACECRAFT shroud syste

Women in the United States Congress: Historical Overview, Tables, and Discussion

A record 102 women currently serve in the 113th Congress: 82 in the House (63 Democrats and 19 Republicans) and 20 in the Senate (16 Democrats and 4 Republicans). One hundred one women were initially sworn in to the 113th Congress—1 female Republican House Member has since resigned, and 2 Democratic House Members have been elected. This is higher than the previous record number of 95 women who were initially elected to the 111th Congress. The first woman elected to Congress was Representative Jeannette Rankin (R- MT, 1917-1919, 1941-1943). The first woman to serve in the Senate was Rebecca Latimer Felton (D-GA). She was appointed in 1922 and served for only one day. Hattie Caraway (D-AR, 1931-1945) was the first Senator to succeed her husband and the first woman elected to a six-year Senate term. A total of 298 women have served in Congress, 194 Democrats and 104 Republicans. Of these women, 254 (165 Democrats, 89 Republicans) have served only in the House of Representatives; 34 (21 Democrats, 13 Republicans) have served only in the Senate; and 10 (8 Democrats, 2 Republicans) have served in both houses. These figures include 4 non-voting Delegates, 1 each from Guam, Hawaii, the District of Columbia, and the U.S. Virgin Islands. A total of 33 African American women have served in Congress (1 in the Senate, 32 in the House), including 17 serving in the 113th Congress. Ten Hispanic women have been elected to the House; nine serve in the 113th Congress. Nine Asian Pacific American women have served in Congress (8 in the House, 1 in both the House and Senate), including seven in the 113th Congress. Nineteen women in the House, and 10 women in the Senate, have chaired committees. In the 113th Congress, 1 woman chairs a House committee, and 5 women chair Senate committees, with 1 female Senator chairing two committees. This report includes a discussion of the impact of women in Congress as well as historical information, including the number and percentage of women in Congress over time, means of entry to Congress, comparisons to international and state legislatures, records for tenure, firsts for women in Congress, women in leadership, and African American and Asian Pacific American women in Congress. The report may reflect data at the beginning or end of each Congress, or changes during a Congress. See the notes throughout the report for information on the currency of the data

Development of rotorcraft interior. Noise control concepts. Phase 1: Definition study

A description of helicopter noise, diagnostic techniques for source and path identification, an interior noise prediction model, and a measurement program for model validation are provided

Shock transmission in coupled beams and rib stiffened structures

Shock transmission in a simple coupled beam structure and in a ring-stringer stiffened cylinder is investigated experimentally and analytically using wave transmission and statistical energy analysis concepts. The use of the response spectrum to characterize the excitation provided to a simple beam by a force pulse is studied. Analysis of the transmission of a dilatation wave in a periodically stiffened plate indicates that the stiffeners are fairly transparent to the wave, but some of the dilatational energy is scattered into bending at each support

Topological entropy and blocking cost for geodesics in riemannian manifolds

For a pair of points $x,y$ in a compact, riemannian manifold $M$ let $n_t(x,y)$ (resp. $s_t(x,y)$) be the number of geodesic segments with length $\leq t$ joining these points (resp. the minimal number of point obstacles needed to block them). We study relationships between the growth rates of $n_t(x,y)$ and $s_t(x,y)$ as $t\to\infty$. We derive lower bounds on $s_t(x,y)$ in terms of the topological entropy $h(M)$ and its fundamental group. This strengthens the results of Burns-Gutkin \cite{BG06} and Lafont-Schmidt \cite{LS}. For instance, by \cite{BG06,LS}, $h(M)>0$ implies that $s$ is unbounded; we show that $s$ grows exponentially, with the rate at least $h(M)/2$.Comment: 13 page

Transonic pressure measurements and comparison of theory to experiment for an arrow-wing configuration. Volume 1: Experimental data report, base configuration and effects of wing twist and leading-edge configuration

A wind tunnel test of an arrow-wing-body configuration consisting of flat and twisted wings, as well as a variety of leading- and trailing-edge control surface deflections, was conducted at Mach numbers from 0.4 to 1.1 to provide an experimental pressure data base for comparison with theoretical methods. Theory-to-experiment comparisons of detailed pressure distributions were made using current state-of-the-art attached and separated flow methods. The purpose of these comparisons was to delineate conditions under which these theories are valid for both flat and twisted wings and to explore the use of empirical methods to correct the theoretical methods where theory is deficient

Transonic pressure measurements and comparison of theory to experiment for an arrow-wing configuration. Volume 2: Experimental data report, effects of control surface deflection

For abstract, see N76-11034

Rate dependent shear bands in a shear transformation zone model of amorphous solids

We use Shear Transformation Zone (STZ) theory to develop a deformation map for amorphous solids as a function of the imposed shear rate and initial material preparation. The STZ formulation incorporates recent simulation results [Haxton and Liu, PRL 99 195701 (2007)] showing that the steady state effective temperature is rate dependent. The resulting model predicts a wide range of deformation behavior as a function of the initial conditions, including homogeneous deformation, broad shear bands, extremely thin shear bands, and the onset of material failure. In particular, the STZ model predicts homogeneous deformation for shorter quench times and lower strain rates, and inhomogeneous deformation for longer quench times and higher strain rates. The location of the transition between homogeneous and inhomogeneous flow on the deformation map is determined in part by the steady state effective temperature, which is likely material dependent. This model also suggests that material failure occurs due to a runaway feedback between shear heating and the local disorder, and provides an explanation for the thickness of shear bands near the onset of material failure. We find that this model, which resolves dynamics within a sheared material interface, predicts that the stress weakens with strain much more rapidly than a similar model which uses a single state variable to specify internal dynamics on the interface.Comment: 10 pages, 13 figures, corrected typos, added section on rate strengthening vs. rate weakening material