Thermomagnetic Convective Cooling of Hall Effect Thruster

This work proposes and shows that thermomagnetic convection could be used in zero gravity to cool components of a Hall-effect thruster. A ferrofluid cavity was develop in the thermal and geometric model of a Hall-effect thruster. Simulations show that with an Ionic Liquid Ferrofluid after two minutes of thruster operations thermomagnetic convection occurs and in zero gravity will produce a larger velocity then natural convection that occurs in earth gravity. However, experiments did not result in heat transfer enhancement due to the limitation of the ferrofluid. Replacement of the Ferrotec EFH1 dispersant with dodecylbenzene did not result in Ionic Liquid Ferrofluid equivalent ferrofluid and did not lower of vapor pressure as intended and limited test to 60 °C. This limitation did not allow for the fluid to experience the largest difference in magnetic susceptibility that occurs near the Curie temperature

Hearing aids do not alter cortical entrainment to speech at audible levels in mild-to-moderately hearing-impaired subjects

Background: Cortical entrainment to speech correlates with speech intelligibility and attention to a speech stream in noisy environments. However, there is a lack of data on whether cortical entrainment can help in evaluating hearing aid fittings for subjects with mild to moderate hearing loss. One particular problem that may arise is that hearing aids may alter the speech stimulus during (pre-)processing steps, which might alter cortical entrainment to the speech. Here, the effect of hearing aid processing on cortical entrainment to running speech in hearing impaired subjects was investigated. Methodology: Seventeen native English-speaking subjects with mild-to-moderate hearing loss participated in the study. Hearing function and hearing aid fitting were evaluated using standard clinical procedures. Participants then listened to a 25-minute audiobook under aided and unaided conditions at 70 dB A sound pressure level (SPL) in quiet conditions. EEG data were collected using a 32-channel system. Cortical entrainment to speech was evaluated using decoders reconstructing the speech envelope from the EEG data. Null decoders, obtained from EEG and the time-reversed speech envelope, were used to assess the chance level reconstructions. Entrainment in the delta- (1-4 Hz) and theta- (4-8 Hz) band, as well as wideband (1-20 Hz) EEG data was investigated. Results: Significant cortical responses could be detected for all but one subject in all three frequency bands under both aided and unaided conditions. However, no significant differences could be found between the two conditions in the number of responses detected, nor in the strength of cortical entrainment. The results show that the relatively small change in speech input provided by the hearing aid was not sufficient to elicit a detectable change in cortical entrainment. Conclusion: For subjects with mild to moderate hearing loss, cortical entrainment to speech in quiet at an audible level is not affected by hearing aids. These results clear the pathway for exploring the potential to use cortical entrainment to running speech for evaluating hearing aid fitting at lower speech intensities (which could be inaudible when unaided), or using speech in noise conditions

QT analysis of intrauterine growth retarded and normal children at 10 years old

The main objective of the work described in this paper is to develop an algorithm to detect QT, other ECG intervals and to find any correlation between QT, ST, QRS, Heart rate (HR) of normal and IUGR children at 10 yrs. The cohort under study is described in chapter 2 as 41 IUGR and 34 as normal. The ECGs of 24 hour for each child were used to find any differences between the two groups. Normal children have QRS intervals during awake (73.96 ±13.65 ms) and asleep (78.75±14.76 ms), and IUGR has (73.94 ±12.85 ms day, 75.98±14.80 ms night), and IUGR children have a slightly higher corrected QTc (418.25±28.92ms Day, 437.22±20.17 ms night), compared to normal (411.37 ±36.13 ms day, 431.79±20.12 ms night). At 10 years of age the measured ECG intervals of all normal and IUGR children was unable to show any deviation from the normal paediatric limits. IUGR children are relatively more prone to longer QTc intervals

Enhancement of Exciton Emission from Zno Nanocrystalline Films by Pulsed Laser Annealing

Pulsed ArF laser annealing in air and in hydrogen atmosphere improves the optical properties of ZnO nanostructured films. Independently on the ambient atmosphere, laser annealing produces two major effects on the photoluminescence (PL) spectra: first, the efficiency of the exciton PL increases due to decrease of the number of non-radiative recombination centers; second, the intensity of the defect-related orange band decreases because of the removing of excessive oxygen trapped into the films during deposition. However, annealing in the ambient air also increases the intensity of the green band related to oxygen vacancies. We show that the combination of laser annealing and passivation of oxygen vacancies by hydrogen results in films free of defect-related emission and keeps intact their nanostructural character

THE EFFECT OF NEAR-INTERFACE NETWORK STRAIN ON THE MOBILITY OF PROTONS IN Si02

35-word abstract Our data suggest a correlation between near-interface strain in SiOz and the ratio of fixed vs. mobile positive charge generated at the interface during forming gas annealing. A model based on firstprinciples quantum mechanical calculations supports this correlation

Persistent atrial fibrillation hierarchical activation: from highest DF sites to wave fractionation at the boundaries

Preclinical studies showed a relationship between high dominant frequency areas (HDFA) and wave fractionation, but evidence in patient who atrial fibrillation (AF) persists for long-term periods (persAF) it is not well defined. This study aims to assess the spatiotemporal organization characteristics at HDFAs is persAF and its impact after per standard pulmonary vein isolation (PVI). Eight persAF patients had a non-contact array catheter deployed into the left atrium to collect up to 2048 AF electrograms (AEG) for 15 s. AEGs were band-pass filtered (3-30 Hz) followed by ventricular farfield cancellation. DF between 4-10 Hz and its respective organization index (OI) were calculated (4 s with 50% overlap) to produce 3D DF and OI maps. HDFA defined as the regions within a 0.25 Hz drop from the highest DF were determined and their centre of gravity (CG) calculated. Highest DF sites showed a higher OI at their core when compared to the periphery (0.422±0.101 vs. 0.386±0.126, p=0.02) and increased again organization at sites distant from the HDFAs. Similarly, after PVI, OI remained higher as compared to their periphery (0.372±0.026 vs. 0.332±0.036, p=0.22), but with significant lower values when compared with baseline (p<0.0001). PersAF patients showed higher organization in the HDFAs core when compared with its periphery

A Nonvolatile MOSFET Memory Device Based on Mobile Protons in SiO(2) Thin Films

It is shown how mobile H{sup +} ions can be generated thermally inside the oxide layer of Si/SiO{sub 2}/Si structures. The technique involves only standard silicon processing steps: the nonvolatile field effect transistor (NVFET) is based on a standard MOSFET with thermally grown SiO{sub 2} capped with a poly-silicon layer. The capped thermal oxide receives an anneal at {approximately}1100 C that enables the incorporation of the mobile protons into the gate oxide. The introduction of the protons is achieved by a subsequent 500-800 C anneal in a hydrogen-containing ambient, such as forming gas (N{sub 2}:H{sub 2} 95:5). The mobile protons are stable and entrapped inside the oxide layer, and unlike alkali ions, their space-charge distribution can be controlled and rapidly rearranged at room temperature by an applied electric field. Using this principle, a standard MOS transistor can be converted into a nonvolatile memory transistor that can be switched between normally on and normally off. Switching speed, retention, endurance, and radiation tolerance data are presented showing that this non-volatile memory technology can be competitive with existing Si-based non-volatile memory technologies such as the floating gate technologies (e.g. Flash memory)

Nonvolatile Field Effect Transistors Based on Protons and Si/SiO{Sub 2}Si Structures

Recently, the authors have demonstrated that annealing Si/SiO{sub 2}/Si structures in a hydrogen containing ambient introduces mobile H{sup +} ions into the buried SiO{sub 2} layer. Changes in the H{sup +} spatial distribution within the SiO{sub 2} layer were electrically monitored by current-voltage (I-V) measurements. The ability to directly probe reversible protonic motion in Si/SiO{sub 2}/Si structures makes this an exemplar system to explore the physics and chemistry of hydrogen in the technologically relevant Si/SiO{sub 2} structure. In this work, they illustrate that this effect can be used as the basis for a programmable nonvolatile field effect transistor (NVFET) memory that may compete with other Si-based memory devices. The power of this novel device is its simplicity; it is based upon standard Si/SiO{sub 2}/Si technology and forming gas annealing, a common treatment used in integrated circuit processing. They also briefly discuss the effects of radiation on its retention properties

Nature of the green luminescent center in zinc oxide

EPR, optical absorption, and photoluminescence spectroscopies are used to characterize a wide range of different ZnO phosphor powders. A good correlation is generally observed between the 510-nm green emission intensity and the density of paramagnetic isolated oxygen vacancies. Both quantities are found to peak at a free-carrier density of about 1.4x10{sup 18}cm{sup -3}. The green emission intensity can be strongly influenced by free-carrier depletion at the particle surface, especially for small particles and/or low doping. The data suggest that the green PL in ZnO phosphors is due to recombination of electrons in singly occupied oxygen vacancies with photoexcited holes in the valence band