Double swivel toggle release

A pyrotechnic actuated structural release device is disclosed which is mechanically two fault tolerant for release. The device comprises a fastener plate and fastener body each attachable to one of a pair of structures to be joined. The fastener plate and the fastener body are fastened by a dual swivel toggle member. The toggle member is supported at one end on the fastener plate and mounted for universal pivotal movement thereon. Its other end is received in a central opening in the fastener body, and has a universally mounted retainer ring member. The toggle member is restrained by three retractable latching pins symmetrically disposed in equiangular spacing about the axis of the toggle member and positionable in latching engagement with the retainer ring member on the toggle member. Each pin is retractable by a pyrotechnic charge, the expanding gases of which are applied to a pressure receiving face on the latch pins to effect retraction from the ring member. While retraction of all three pins releases the ring member, the fastener is mechanically two fault tolerant since the failure of any single one or pair of the latch pins to retract results in an asymmetrical loading on the ring member and its dual pivotal movement ensures a release

Piezoelectric copolymer hydrophones for ultrasonic field characterization

Hydrophones to be used in the characterization of medical ultrasonic transducers have been fabricated using a new polyvinylidene fluoride/trifluoroethylene (VF2/VF3) copolymer. The copolymer has an advantage over VF2 in that it does not require prestretching before poling. Thin copolymer films can be cast from solution and then poled using the corona discharge method. As there is a need for small‐diameter hydrophones to provide good spatial resolution in measuring highly focused ultrasonic beams, hydrophones with diameter as small as 0.1 mm have been made. Both needle‐type and line hydrophones have been tested and their performance reported. In the case of line hydrophones, the output signal is proportional to the line integral of the acoustic pressure and a computer tomographic technique has been used to reconstruct the beam profiles

The pulsed air gust generator Final report

Wind tunnel simulation of jet pulsing apparatus for controlled gust

The construction and evaluation of four series of lessons to stimulate the flow of ideas in the creative writing of fourth, fifth, and sixth grade pupils.

Thesis (Ed.M.)--Boston Universit

Nonlocal First-Order Hamilton-Jacobi Equations Modelling Dislocations Dynamics

We study nonlocal first-order equations arising in the theory of dislocations. We prove the existence and uniqueness of the solutions of these equations in the case of positive and negative velocities, under suitable regularity assumptions on the initial data and the velocity. These results are based on new $L^1$-type estimates on the viscosity solutions of first-order Hamilton-Jacobi Equations appearing in the so-called ``level-sets approach''. Our work is inspired by and simplifies a recent work of Alvarez, Cardaliaguet and Monneau

Bringing research results to users: the case for a knowledge resource centre

Poster presented at Scientific and Technical Information and Rural Development: Highlights of Innovative Practices. 13. IAALD World Congress. Montpellier (France), 26-29 Apr 201

Subscale, hydrogen-burning, airframe-integrated-scramjet: Experimental and theoretical evaluation of a water cooled strut airframe-integrated-scramjet: Experimental leading edge

A water-cooled leading-edge design for an engine/airframe integrated scramjet model strut leading edge was evaluated. The cooling design employs a copper cooling tube brazed just downstream of the leading edge of a wedge-shaped strut which is constructed of oxygen-free copper. The survival of the strut leading edge during a series of tests at stagnation point heating rates confirms the practicality of the cooling design. A finite difference thermal model of the strut was also proven valid by the reasonable agreement of calculated and measured values of surface temperature and cooling-water heat transfer

Space Station Gas-Grain Simulation Facility: Microgravity Particle Research

A wide variety of experiments significant to Exobiology, Planetary Science, Astrophysics, Atmospheric Science, and basic Chemistry and Physics involves the physical interactions of small particles (micrometer to centimeter in size). In many astro-geophysical systems (atmospheric clouds, interstellar clouds, planetary rings, Titan\u27s organic aerosols, Martian dust storms, lightning, etc.), processes involving small particles determine the overall behavior of the system. Condensation of particles from a gas, aggregation of small particles into larger ones, low velocity collisions, and charge accumulation are a few of the processes that influence particles in these systems. Examples of particles undergoing these processes include interstellar grains, protoplanetary particles, atmospheric aerosols, combustion products, and abiotic organic polymers. Although processes of the type described above span a wide range of disciplines, the study of these processes places common fundamental constraints on particle handling. Two common constraints are the need for long time periods during which the particles must be suspended and low relative velocities between particles. Experiments involving small particles generally require material be suspended for periods substantially longer than are practical in Earth\u27s 1 g gravitational field. However, one can investigate these processes with a general-purpose particle research facility (in particular, with the proposed Gas-Grain Simulation Facility) on the Space Station 1 \u273 . Because of the very low gravitational acceleration (microgravity) in the Earth orbital environment, many experiments deemed impractical or impossible to perform on Earth will become feasible. Such experiments are those in which gravity either interferes directly with the phenomenon under study (e.g., gravitational convection masks diffusional processes) or in which gravity precludes the establishment of the proper experimental conditions (e.g., in 1 g, gravity accelerates test objects to unacceptable velocities)