Economical technique for fragmentation testing

Automatic rifle was modified for remote, single-shot use. To simulate statistically--determined fragment size from rocket-motor casing blunt-nosed bullet was made of same alloy. Cartridge was loaded with enough powder to make bullet reach target at same estimated velocity as shrapnel from rocket casing

SNAP-8 post shutdown gamma radiation approximations

Detector responses were calculated for normalized sources in the Perkins and King energy group structure for a SNAP 8 power system on a NASA space station. Gamma decay rates were then calculated by using an expanded, updated list of isotopic decay data, and from these, actual detector responses were found for the SNAP 8 system. The results indicate that energy-dependent calculations must be made to determine decay gamma dose rates for actual reactor configurations. A simplified method for making these calculations has been devised

Proposed Spontaneous Generation of Magnetic Fields by Curved Layers of a Chiral Superconductor

We demonstrate that two-dimensional chiral superconductors on curved surfaces spontaneously develop magnetic flux. This geometric Meissner effect provides an unequivocal signature of chiral super- conductivity, which could be observed in layered materials under stress. We also employ the effect to explain some puzzling questions related to the location of zero-energy Majorana modes

Effects of liquid slosh on rendezvous dynamics

Mathematical model using Euler-Lagrange equation to investigate liquid slosh effects on rendezvous dynamic

The modeling of piezoceramic patch interactions with shells, plates and beams

General models describing the interactions between a pair of piezoceramic patches and elastic substructures consisting of a cylindrical shell, plate and beam are presented. In each case, the manner in which the patch loads enter both the strong and weak forms of the time-dependent structural equations of motion is described. Through force and moment balancing, these loads are then determined in terms of material properties of the patch and substructure (thickness, elastic properties, Poisson ratios), the geometry of the patch placement, and the voltages into the patches. In the case of the shell, the coupling between banding and inplane deformations, which is due to the curvature, is retained. These models are sufficiently general to allow for potentially different patch voltages which implies that they can be suitably employed when using piezoceramic patches for controlling system dynamics when both extensional and bending vibrations are present

Well-posedness of a model for structural acoustic coupling in a cavity enclosed by a thin cylindrical shell

A fully coupled mathematical model describing the interactions between a vibrating thin cylindrical shell and enclosed acoustic field is presented. Because the model will ultimately be used in control applications involving piezoceramic actuators, the loads and material contributions resulting from piezoceramic patches bonded to the shell are included in the discussion. Theoretical and computational issues lead to the consideration of a weak form of the modeling set of partial differential equations (PDE's) and through the use of a semigroup formulation, well-posedness results for the system model are obtained

Development and evaluation of a fault-tolerant multiprocessor (FTMP) computer. Volume 1: FTMP principles of operation

The basic organization of the fault tolerant multiprocessor, (FTMP) is that of a general purpose homogeneous multiprocessor. Three processors operate on a shared system (memory and I/O) bus. Replication and tight synchronization of all elements and hardware voting is employed to detect and correct any single fault. Reconfiguration is then employed to repair a fault. Multiple faults may be tolerated as a sequence of single faults with repair between fault occurrences

Development and evaluation of a fault-tolerant multiprocessor (FTMP) computer. Volume 4: FTMP executive summary

The FTMP architecture is a high reliability computer concept modeled after a homogeneous multiprocessor architecture. Elements of the FTMP are operated in tight synchronism with one another and hardware fault-detection and fault-masking is provided which is transparent to the software. Operating system design and user software design is thus greatly simplified. Performance of the FTMP is also comparable to that of a simplex equivalent due to the efficiency of fault handling hardware. The FTMP project constructed an engineering module of the FTMP, programmed the machine and extensively tested the architecture through fault injection and other stress testing. This testing confirmed the soundness of the FTMP concepts

Copernicus observational searches for OH and H2O in diffuse clouds

An intensive search for OH and H2O in the directions of sigma Sco, alpha Cam, and micron Per was undertaken with the Copernicus satellite. Multiple scans were carried out over the wavelength region for the expected absorption features due to the OH D-X and H2O C-X transitions. The feature due to OH was detected marginally towards sigma Sco, and only an upper limit can be given towards alpha Cam. H2O was not detected in any of the stars at the signal level accumulated. The OH abundance towards sigma Sco and the respective lower limits for the OH/H2O ratios are discussed with regard to the extant models for the steady state abundances of OH and H2O, and shown not to be inconsistent with ion-molecule schemes

Development and evaluation of a Fault-Tolerant Multiprocessor (FTMP) computer. Volume 2: FTMP software

The software developed for the Fault-Tolerant Multiprocessor (FTMP) is described. The FTMP executive is a timer-interrupt driven dispatcher that schedules iterative tasks which run at 3.125, 12.5, and 25 Hz. Major tasks which run under the executive include system configuration control, flight control, and display. The flight control task includes autopilot and autoland functions for a jet transport aircraft. System Displays include status displays of all hardware elements (processors, memories, I/O ports, buses), failure log displays showing transient and hard faults, and an autopilot display. All software is in a higher order language (AED, an ALGOL derivative). The executive is a fully distributed general purpose executive which automatically balances the load among available processor triads. Provisions for graceful performance degradation under processing overload are an integral part of the scheduling algorithms