Investigation of strength of isolated vertebrae, phase IV Final technical report, 29 Oct. 1965 - 28 Oct. 1966

Dynamic strength measurements of human vertebrae under axial compressio

Investigation of strength of isolated vertebrae Quarterly report, 30 Jan. - 29 May 1966

Strength of human vertebrae under various static and dynamic load

Advanced manufacturing development of a composite empennage component for L-1011 aircraft. Phase 2: Design and analysis

The composite fin design consists of two one-piece cocured covers, two one-piece cocured spars and eleven ribs. The lower ribs are truss ribs with graphite/epoxy caps and aluminum truss members. The upper three ribs are a sandwich design with graphite/epoxy face sheets and a syntactic epoxy core. The design achieves a 27% weight saving compared to the metal box. The fastener count has been reduced from over 40,000 to less than 7000. The structural integrity of the composite fin was verified by analysis and test. The static, fail-safe and flutter analyses were completed. An extensive test program has established the material behavior under a range of conditions and critical subcomponents were tested to verify the structural concepts

Teachers and Sanitation Promotion: An Assessment of Community-Led Total Sanitation in Ethiopia

Community-led total sanitation (CLTS) is a participatory approach to addressing open defecation that has demonstrated success in previous studies, yet there is no research on how implementation arrangements and context change effectiveness. We used a quasi-experimental study design to compare two interventions in Ethiopia: conventional CLTS in which health workers and local leaders provided facilitation and an alternative approach in which teachers provided facilitation. In 2012, Plan International Ethiopia trained teachers from 111 villages and health workers and leaders from 54 villages in CLTS facilitation. The trained facilitators then implemented CLTS in their respective villages for a year. Latrine ownership, use, and quality were measured with household surveys. Differences between interventions were explored using surveys and interviews. The decrease in open defecation associated with teacher-facilitated CLTS was 8.2 percentage points smaller than for conventional CLTS (p = 0.048). Teachers had competing responsibilities and initially lacked support from local leaders, which may have lessened their success. Teachers may be more appropriate for a supporting rather than leading role in sanitation promotion because they did demonstrate ability and engagement. Open defecation decreased by 15.3 percentage points overall but did not change where baseline open defecation was below 30%. Ownership of a latrine with stable flooring increased by 8.7 percentage points overall. Improved latrine ownership did not change during the intervention. CLTS is most appropriate where open defecation is high because there were no significant changes in sanitation practices or latrine upgrades where baseline open defecation was low

The symbiotic star CH Cygni. III. A precessing radio jet

VLA, MERLIN and Hubble Space Telescope imaging observations of the extended regions of the symbiotic system CH Cygni are analysed. These extensions are evidence of a strong collimation mechanism, probably an accretion disk surrounding the hot component of the system. Over 16 years (between 1985 and 2001) the general trend is that these jets are seen to precess. Fitting a simple ballistic model of matter ejection to the geometry of the extended regions suggests a period of 6520 +/- 150 days, with a precession cone opening angle of 35 +/- 1 degrees. This period is of the same order as that proposed for the orbital period of the outer giant in the system, suggesting a possible link between the two. Anomalous knots in the emission, not explained by the simple model, are believed to be the result of older, slower moving ejecta, or possibly jet material that has become disrupted through sideways interaction with the surrounding medium.Comment: 9 pages, 4 figure

Fluid Mechanical and Electrical Fluctuation Forces in Colloids

Fluctuations in fluid velocity and fluctuations in electric fields may both give rise to forces acting on small particles in colloidal suspensions. Such forces in part determine the thermodynamic stability of the colloid. At the classical statistical thermodynamic level, the fluid velocity and electric field contributions to the forces are comparable in magnitude. When quantum fluctuation effects are taken into account, the electric fluctuation induced van der Waals forces dominate those induced by purely fluid mechanical motions. The physical principles are applied in detail for the case of colloidal particle attraction to the walls of the suspension container and more briefly for the case of forces between colloidal particles.Comment: ReVTeX format, one *.eps figur

Two-point microrheology and the electrostatic analogy

The recent experiments of Crocker et al. suggest that microrheological measurements obtained from the correlated fluctuations of widely-separatedprobe particles determine the rheological properties of soft, complex materials more accurately than do the more traditional particle autocorrelations. This presents an interesting problem in viscoelastic dynamics. We develop an important, simplifing analogy between the present viscoelastic problem and classical electrostatics. Using this analogy and direct calculation we analyze both the one and two particle correlations in a viscoelastic medium in order to explain this observation