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This paper reviews the effects of the origin, occurrence, monitoring, control, fate and removal of siloxanes on the energetic valorization of sewage biogas, which can be severely compromised by its volatile organic silicon compound (VOSiC) content. Almost 25 years after identifying silicon dioxide in the exhaust gases from engines powered using sewage and landfill gas, a wide range of studies have been conducted addressing the different stages of the siloxane life cycle. The cycle starts with the production and use of polydimethylsiloxane polymers in a wide range of industrial and domestic applications and its further dispersal into environmental compartments. Siloxanes are subsequently introduced into wastewater treatment plants, where as a result of their low biodegradability and high affinity to dissolved and particulate matter, they are first transferred from wastewater into sludge and later volatilized in biogas in anaerobic digesters. Biogas treatment technologies can reduce siloxane concentrations to less than 0.1 mg/m3; adsorbent materials with micro- and mesoporous structures appear to be the most relevant technology in technical and economic terms. The state-of-the-art on siloxanes is vast and extensive, but there are still some knowledge gaps to be addressed in the future, such as the standardization of the methodology for off-line analysis, the development of on-line monitoring equipment, better understanding the fates of siloxanes in wastewater treatment processes to operate at specific conditions to avoid siloxanes-related problems, the development of more selective and regenerative removal technologies from biogas to reduce operating costs and even to recover silicon, and better understand the detrimental effects on energy recovery technologies to determine the inlet concentration limits. This work compiles the most relevant results available in the literature for each stage of the siloxane life cycle, Postprint (author's final draft)

For various soft tissues (e.g., breast, liver, etc.), we are developing the ultrasonic strain measurement-based shear modulus reconstruction/imaging technique. To clarify the limitation of this technique as the diagnostic tool, together with improving the technique we are collecting clinical shear modulus images. Furthermore, we are applying the technique as the monitoring technique for the effectiveness of chemical therapy (e.g., anticancer drug, ethanol) and thermal therapy (e.g., rf electromagnetic wave, HIFU, etc.). Here, we showed shear modulus images obtained in quasi-real time. Using the conventional Work Station, the quantitative images were obtained on ten seconds order. In particular, by exhibiting the superiorly of shear modulus imaging compared with simultaneous B-mode imaging, we delineated the effectiveness of the technique as the clinical visualization technique for diagnosis and therapy. For instance, shear modulus value of in vivo human breast carcinoma was significantly high (typical value: 6.33 x 10(exp 6) N/m(exp 2). Shear modulus images were also obtained on in vivo human liver tissues. On the in vitro calf liver, shear modulus value of electromagnetic wave-induced thermal lesion became about five times higher after cooling down. We believe that this technique is solo currently available as diagnosis or monitoring tool, and yet in the near future this technique will allow the combined diagnosis/therapy systems for opening up a novel clinical style., Papers from 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society, October 25-28, 2001, held in Istanbul, Turkey. See also ADM001351 for entire conference on cd-rom., The original document contains color images.

We proposed a technique for reconstructing bio-electric conductivity distribution from measured tangential magnet field data. That is, in the 2D ROI with an arbitrary depth two orthogonal tangential components of 3D current vector field were respectively estimated from the synthetically measured two tangential magnetic fields, from which the 2D conductivity distribution was estimated. To cope with inevitable measurement errors, a robust numerical solution was developed, in which the modification method and the regularization method were efficiently utilized. By performing this 2D reconstruction at each depth, 3D conductivity distribution could be estimated. As typical applications, pathological state and/or bio-electric conductive path can be evaluated by monitoring the temporal change of the reconstructed 3D conductivity distribution. The feasibility of this technique was briefly verified by reconstructing a conductivity distribution using simulated noise-filled magnetic field data, with resultant reconstruction indicating that the approach could provide a practical means for robustly reconstructing a conductivity distribution., Papers from the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 25-28 OCT 2001, Istanbul, Turkey. See also ADM001351 for entire conference on cd-rom.