No abstract

In rabbit carotid arteries arteriosclerotic lesions were induced by repeated local transmural electrical stimulations. The sequence of early morphological alterations in the vessel wall and especially the kinetics of leukocytes were examined by transmission electron microscopy. After a stimulation period of only 1 day monocytes and heterophilic granulocytes adhered to the endothelial surface. In the subendothelium mainly beneath the anode, focal amorphous insudates were present together with mononuclear and granulocytic cells. Thereby, the endothelium was maintained as a continuous lining as shown by surface staining with silver nitrate. However, both pattern and size of the endothelial cells were altered in comparison to the controls. Some of the endothelial cells displayed a heavy cytoplasmic silver salt deposition. After 2 days of the electrical stimulation schedule, the first myocytes occurred in the subendothelial space. The mediamyocytes sending pseudopods through the internal elastic lamina still appeared to be in a contractile phenotype. In the 7-day-old proliferative lesion modulated smooth muscle cells were the predominant cell type; only 10%-20% of the subendothelial cells were identified as macrophages and heterophils. This proportion decreased further, and after a stimulation period of 28 days the granulocytes disappeared completely. At this stage of plaque development, the intimal myocyte population mainly consisted of contractile smooth muscle cells and intermediary states between the contractile and modulated phenotype. The insudation, immigration of white blood cells, and subsequent migration and proliferation of myocytes reinforces the view that the initial phases of arteriosclerotic lesions may represent a special form of an inflammatory response.

The objective of this work is to develop and explore methods to reduce combustor rumble in an industrial gas turbine in co-generation service that is operated with water injection reducing NOX emissions. Attempts to use water injection as a means to reduce NOX emissions in gas turbines have been largely unsuccessful because of increased combustion instability levels experienced. The increase in pulsation causes chronic fretting, wear, and fatigue that damages combustor components resulting in higher operation costs due to repair or replacement of parts. This combustion instability can be tied to the insufficient atomization of injected water; relatively large water droplets evaporate non-uniformly that lead to energy absorption in non-uniform chaotic pulses. This added pulsation is amplified by the combustion process and acoustic resonance. Effervescent atomization, where a gas bubbles are injected with the liquid, is beneficial in producing finely atomized droplets, because the gas bubbles burst as they exit the nozzles creating additional energy to disperse the liquid. A new concept for effervescent atomization dubbed “Flash Atomization” is presented where water is heated to just below its boiling point in the supply line so that some of it will flash to steam as it leaves the nozzle. An advantage of Flash Atomization is that available heat energy can be used rather than mechanical energy to compress injection gas for conventional effervescent atomization.

No abstract

In 1996, Cogeneration-Kraftwerke Management Steiermark (CMST), OMV Cogeneration, together with local partners, built a 25Mwel gas turbine plant with a hot water boiler for thermal energy to be used by a car manufacturer and the municipality Graz, Austria. The plant is driven by a FT8-30 (JT8D-219) Pratt & Whitney (P&W) jet engine, accumulating 8200 operating hours per annum. This paper outlines the technical experience and related problems with the existing equipment in the light of variable operating conditions and the investments for efficiency augmentation of the gas turbine trains. A joint-venture between Cogeneration Kraftwerke Management Obero¨sterreich GmbH (CMOO¨) and OMV Cogeneration GmbH as well as Energie AG. CMOO¨ has operated the Combined Heat Power CHP Plant (50 MW el) in the paper mill SCA GRAPHIC LAAKIRCHEN based on contracting since 1994. Because of a extension of the paper mill the energy supply had to be increased. So the delivery of two steam boilers with each 30 t steam per hour and water treatment took place in August 2001. The plant-extension will operate as an independent unit and will guarantee the full availability of the energy supply. Commercial operation will start in January 2002.