Digital filter synthesis computer program

Digital filter synthesis computer program expresses any continuous function of a complex variable in approximate form as a computational algorithm or difference equation. Once the difference equation has been developed, digital filtering can be performed by the program on any input data list

Ablative response of a silica phenolic to simulated liquid propellant rocket engine operating conditions

Ablative response of silica phenolic to simulated liquid propellant rocket engine operating condition

Ultrafast magnetophotoconductivity of semi-insulating gallium arsenide

The speed of opto-electronic switches is increased or decreased by the application of a magnetic field. This is achieved by inducing a carrier drift toward or away from the semiconductor surface, resulting in the enhancement or suppression of surface recombination. We establish that surface recombination plays a major role in determining the speed of the opto-electronic switch

Interpretation of runaway electron synchrotron and bremsstrahlung images

The crescent spot shape observed in DIII-D runaway electron synchrotron radiation images is shown to result from the high degree of anisotropy in the emitted radiation, the finite spectral range of the camera and the distribution of runaways. The finite spectral camera range is found to be particularly important, as the radiation from the high-field side can be stronger by a factor $10^6$ than the radiation from the low-field side in DIII-D. By combining a kinetic model of the runaway dynamics with a synthetic synchrotron diagnostic we see that physical processes not described by the kinetic model (such as radial transport) are likely to be limiting the energy of the runaways. We show that a population of runaways with lower dominant energies and larger pitch-angles than those predicted by the kinetic model provide a better match to the synchrotron measurements. Using a new synthetic bremsstrahlung diagnostic we also simulate the view of the Gamma Ray Imager (GRI) diagnostic used at DIII-D to resolve the spatial distribution of runaway-generated bremsstrahlung.Comment: 21 pages, 11 figure

The radial electric field as a measure for field penetration of resonant magnetic perturbations

In this paper we introduce a new indirect method for identifying the radial extent of the stochastic layer due to applying resonant magnetic perturbations (RMPs) in H-mode plasmas by measuring the spin-up of the plasma near the separatrix. This spin-up is a predicted consequence of enhanced electron loss, due to magnetic stochastization (Kaveeva et al 2008 Nucl. Fusion 48 075003). We find that in DIII-D H-mode plasmas with n = 3 RMPs applied for edge localized mode suppression, the stochastic layer is limited to the outer 5% region in normalized magnetic flux, Psi(N). This is in contrast to vacuum modelling predictions where this layer can penetrate up to 20% in Psi(N). Theoretical predictions of a stochastic radial electric field, Er component exceed the experimental measurements by about a factor 3 close to the separatrix, suggesting that the outer region of the plasma is weakly stochastic. Linear response calculations with M3D-C1, a resistive two-fluid model, show that in this outer 5% region, plasma response often reduces the resonant magnetic field components by 67% or more in comparison with vacuum calculations. These results for DIII-D are in reasonable agreement with results from the MAST tokamak, where the magnetic field perturbation from vacuum field calculations needed to be reduced by 75% for agreement with experimental measurements of the x-point lobe structure

Preeclampsia knowledge among postpartum women treated for preeclampsia and eclampsia at Korle Bu Teaching Hospital in Accra, Ghana

BACKGROUND: Preeclampsia/eclampsia is a major cause of maternal morbidity and mortality worldwide, yet patients\u27 perspectives about their diagnosis are not well understood. Our study examines patient knowledge among women with preeclampsia/eclampsia in a large urban hospital in Ghana. METHODS: Postpartum women diagnosed with preeclampsia or eclampsia were asked to complete a survey 2-5 days after delivery that assessed demographic information, key obstetric factors, and questions regarding provider counseling. Provider counseling on diagnosis, causes, complications, and future health effects of preeclampsia/eclampsia was quantified on a 4-point scale (\u27Counseling Composite Score\u27). Participants also completed an objective knowledge assessment regarding preeclampsia/eclampsia, scored from 0 to 22 points (\u27Preeclampsia/Eclampsia Knowledge Score\u27 (PEKS)). Linear regression was used to identify predictors of knowledge score. RESULTS: A total of 150 participants were recruited, 88.7% (133) with preeclampsia and 11.3% (17) with eclampsia. Participants had a median age of 32 years, median parity of 2, and mean number of 5.4 antenatal visits. Approximately half of participants reported primary education as their highest level of education. While 74% of women reported having a complication during pregnancy, only 32% of participants with preeclampsia were able to correctly identify their diagnosis, and no participants diagnosed with eclampsia could correctly identify their diagnosis. Thirty-one percent of participants reported receiving no counseling from providers, and only 11% received counseling in all four categories. Even when counseled, 40-50% of participants reported incomplete understanding. Out of 22 possible points on a cumulative knowledge assessment scale, participants had a mean score of 12.9 +/- 0.38. Adjusting for age, parity, and the number of antenatal visits, higher scores on the knowledge assessment are associated with more provider counseling (beta 1.4, SE 0.3, p \u3c 0.001) and higher level of education (beta 1.3, SE 0.48, p = 0.008). CONCLUSIONS: Counseling by healthcare providers is associated with higher performance on a knowledge assessment about preeclampsia/eclampsia. Patient knowledge about preeclampsia/eclampsia is important for efforts to encourage informed healthcare decisions, promote early antenatal care, and improve self-recognition of warning signs-ultimately improving morbidity and reducing mortality

Stability and electronic structure of the complex K2_2PtCl6_6 structure-type hydrides

The stability and bonding of the ternary complex K$_2$PtCl$_6$ structure hydrides is discussed using first principles density functional calculations. The cohesion is dominated by ionic contributions, but ligand field effects are important, and are responsible for the 18-electron rule. Similarities to oxides are discussed in terms of the electronic structure. However, phonon calculations for Sr$_2$RuH$_6$ also show differences, particularly in the polarizability of the RuH$_6$ octahedra. Nevertheless, the yet to be made compounds Pb$_2$RuH$_6$ and Be$_2$FeH$_6$ are possible ferroelectrics. The electronic structure and magnetic properties of the decomposition product, FeBe$_2$ are reported. Implications of the results for H storage are discussed