Peak-to-Peak Amplitude in Neonatal Brain Monitoring of Premature Infants

Objective: To assess the strength of association between alternative measures of electroencephalographic (EEG) signal peak-to-peak amplitude (ppA) and postmenstrual age (PMA) among a cohort of extremely premature infants. Methods: 177 Two-channel EEG recordings 3–6 h long were collected from 26 infants born before 29 weeks of gestation. The raw EEG was converted into four different continuous measures of ppA: amplitude-integrated EEG (aEEG), range-EEG (rEEG), Gotman and Gloor’s half-wave decomposition (HWD), and root of mean squares (RMS). For each ppA-measure EEG indices including mean, median, and 5% margins; indices of spread (width, standard deviation, coefficient of variation), and asymmetry were calculated for each 1 min epoch. The medians of each index for the entire recording were tested for association with PMA using linear mixed models. Results: The log-transformed values of aEEG and rEEG indices of spread were highly associated with PMA. Conclusions: Indices of spread by aEEG or rEEG can be used as indicators of neonatal brain maturation. However, rEEG produces the absolute values that most closely approximate the raw EEG amplitudes. Significance: The indices of spread and rEEG as a measure of ppA provide a basis for improvements in neonatal EEG monitoring

Firing complex for explosive pulsed power

A modern firing complex has been constructed for the dedicated development and application of explosive pulsed power (i.e., flux compression generators). The complex consists of three underground and interconnected buildings. The buildings, which employ several types of structural design, are engineered for above ground, open air detonations involving up to 1000 kg (TNT-equivalent) of high explosive. The explosive rating is necessary for the production of electrical pulses with energy content of hundreds of megajoules. 4 refs., 7 figs., 2 tabs

Design of foil implosion system for Pioneer I experiments

A foil implosion system is described that integrates an explosive flux-compression generator, a flat plate feed section with power conditioning switches, and a vacuum electrode region containing a cylindrical foil/plasma load. Power conditioning, obtained with an explosive-driven plasma compression opening switch and explosive-actuated closing switches, provides a submicrosecond multimegampere pulse for the implosion of an aluminum plasma. The flat plate section is configured for bidirectional feed to the coaxial vacuum electrodes. Important considerations in the design of the vacuum power flow region include gap failure, feed symmetry, and radial diagnostic access. The system presently accommodates a foil radius of 3 cm. Innovative foil insertion and clamping techniques are also described