Signal processing in prolonged EEG recordings during intensive care

Methods for analyzing and displaying EEG signals are discussed. The increasing availability and affordability of powerful computer equipment makes possible the use of ever more sophisticated signal processing techniques, which extract relevant (but not readily discernible) information from long-term EEG recordings and can easily identify important features in the EEG. Whether these techniques are actually taken up in clinical practice is heavily dependent on how well they match clinical requirements. This article concentrates on requirements set in the context of long-term recordings in the ICU that demand the ability to process short-term discrete events as well as long-term trend information. A huge range of potentially useful signal processing techniques exists. This article illustrates the value of some of these techniques for ICU signals using the EEG recordings collected during the IMPROVE project     

铅始极片生产自动线设计与应用

论述了铅始极片生产自动线各机构的工作原理，主要运行参数的分析与选取，该生产线技术先进，经构紧凑合理，指标稳定，运行可靠。     

Performance of an Adaptive Threshold Receiver in a Dynamic Optical Burst-Switched Network

We compare the performance of a digital receiver operating with both a fixed and adaptive decision threshold in response to gain transients arising from network operation of an optically gain-clamped erbium-doped fiber amplifier. An optical burst switching link, based on a recirculating transmission loop, is used to study the effect of transients accumulated across a number wavelength-routing nodes linked by amplified fiber spans where bursts are added and dropped at each node. The use of an adaptive threshold reduces the amount of optical feedback required by a factor of 6 and, in some cases, allows for unclamped operation.     

Long-term human exposure to lead from different media and intake pathways

Lead (Pb) is well known as an environmental pollutant: it can accumulate in various media, so actual lead exposure reflects both historical and present contaminations. Two main challenges then emerge: obtaining updated information to gain an overall picture of the sources of exposure, and predicting the resulting internal body exposure levels and effects that occur under long-term exposure conditions. In this paper, a modeling approach is used to meet these challenges with reference to Danish exposure conditions. Levels of lead content in various media have been coupled with data for lead intake and absorption in the human body, for both children and adults. An age-dependent biokinetic model allows then for determination of the blood lead levels resulting from chronic exposure. The study shows that the actual intake of lead is up to 27% of the Provisional Tolerable Daily Intake (PTDI) for children and around 8% for adults. It is confirmed that the critical route of exposure is via ingestion, accounting for 99% of total lead intake, while inhalation contributes only to 1% of total lead intake. The resulting lead levels in the blood after 2 years of exposure to actual contamination conditions have been estimated as up to 2.2 μg/dl in children and almost 1 μg/dl in adults. Impacts from lead can occur even at such levels. The role of historical and present sources to lead in the environment is discussed, and, for specific child and adult exposure scenarios, external-internal concentration relationships for the direct linkage between lead in environmental media and resulting concentrations of lead in blood are then presented.     

Design of a Eutectic Freeze Crystallization process for multicomponent waste water stream

Complex, hypersaline brines originating from the mining and extractive metallurgical industries have the potential to be treated using Eutectic Freeze Crystallization (EFC). Although EFC has been shown to be effective in separating a single salt and water, it has yet to be applied to the complex hypersaline brines that are typical of reverse osmosis retentates in South Africa. This paper focuses on the application of EFC for the purification of a typical brine containing high levels of sodium, chlorine, sulphate and ammonia that cannot be achieved with other separation techniques. The presence of ammonia prevents the application of membrane technology to treat the brine, leaving only cooling or evaporation as other possible options. Evaporation produces a mixed salt that requires further treatment. Modelling tools were applied to describe the phase behaviour of the complex saline systems under different process conditions and were experimentally validated. The results showed that Eutectic Freeze Crystallization could be used to selectively recover the sodium as a sodium sulphate salt. The simulation tools were especially useful in the design and optimisation of the process.     

Kohn anomaly in graphene

Symmetry based analysis of the Kohn anomaly is performed. Kohn phonon frequencies and displacements are calculated by force constant method. It is shown that Kohn phonon vibrations cause electronic band gap opening.     

Cuff electrodes for long-term recording of natural sensoryinformation

Cuff electrodes for recording of the electro-neurogram from peripheral nerves were introduced by Hoffer [1974] and Stein, et al. [1975]. The cuffs were used to obtain higher signal amplitudes than previously possible, at least in chronic recordings, and to decrease the pick-up of noise, especially from muscles. Cuff electrodes are relatively stable in long-term recordings, but the stability has never been quantified in terms of input-output relationships; i.e., in terms of responses to repeatable stimuli over time. Moreover. The relationship between nerve damage and electrophysiological parameters has never been assessed. In this article, after reviewing the development of cuff electrodes and their applications, we present a long-term study of tactile peripheral nerve signals, electrically activated nerve signals, and impedance measurements. We show how the recordings vary over a 16-month period after implantation of nerve cuff electrodes in rabbits, and how nerve damage is reflected in the recorded signals     

Forming of bulk metallic glass microcomponents

The present article considers forward extrusion, closed-die forging and backward extrusion processes for fabrication of individual microcomponents from two bulk metallic glass (BMG) compositions: Mg₆₀Cu₃₀Y₁₀ and Zr₄₄Cu₄₀Ag₈Al₈. Two types of tooling were used in the present work: relatively massive die sets characteristic of cold forming operations for crystalline metals and lightweight die sets adapted to the special characteristics of BMGs. In addition to demonstrating that microcomponents of several geometries can be readily fabricated from BMGs, rheological properties are combined with crystallization kinetics to formulate a generally applicable method that can guide selection of optimal forming parameters. Finally, the use of particulate-based lubricants for BMG forming is shown to result in individual lubricant particles becoming mechanically locked into the BMG surface.