Application of Acoustic Agglomeration to Reduce Fine Particle Emissions from Coal Combustion Plants
Removal of fine particles (smaller than 2.5 μm) from industrial flue gases is, at present, one of the most important problems in air pollution abatement. These particles, which are hazardous because of their ability to penetrate deeply into the lungs, are difficult to remove by conventional separation technology. Sonic energy offers a means to solve this problem. The application of a high-intensity acoustic field to an aerosol induces agglomeration processes which changes the size distribution in favor of larger particles, which are then easier to precipitate with a conventional separator. In this work, we present a semiindustrial pilot plant in which this process is applied for reduction of particle emissions in coal combustion fumes. This installation basically consists of an acoustic agglomeration chamber with a rectangular cross-section, driven by four high-power and highly directional acoustic transducers of 10 and/or 20 kHz, and an electrostatic precipitator (ESP). In the experiments, a fluidized be...
Macrosonics: Phenomena, transducers and applications
15 pages, 17 figures.-- PACS nrs.: 43.35; 43.25.-- Communication presented at: Forum Acusticum Sevilla 2002 (Sevilla, Spain, 16-20 Sep 2002), comprising: 3rd European Congress on Acoustics; XXXIII Spanish Congress on Acoustics (TecniAcustica 2002); European and Japanese Symposium on Acoustics; 3rd Iberian Congress on Acoustics.-- Also published in the special issue of the journal Revista de Acustica, Vol. XXXIII, year 2002: http://digital.csic.es/handle/10261/4862.
Low dose radiation and intercellular induction of apoptosis: potential implications for the control of oncogenesis
Purpose: This review is focused on the potential impact of low dose radiation effects on intercellular induction of apoptosis and the underlying reactive-oxygen species (ROS)-mediated signaling pathways. Results: Transformed cells are subject to ROS-mediated apoptosis induction by non-transformed cells (‘intercellular induction of apoptosis’) and by ROS-mediated autocrine self-destruction. Sensitivity to intercellular induction of apoptosis and autocrine self-destruction are strictly correlated to the expression of the transformed state. Extracellular superoxide anions generated by transformed target cells drive the selectivity and sensitivity of this signaling system which is based on four different signaling pathways. Low dose irradiation of non-transformed cells enhances intercellular induction of apoptosis in transformed cells. This process is controlled by TGF-beta and seems to depend on the induction of peroxidase release. In addition, low dose radiation enhances superoxide anion generation of transformed target cells. Conclusions: Low dose radiation-triggered enhancement of intercellular induction of apoptosis and autocrine selfdestruction might represent a potential control system during carcinogenesis. It might be the underlying mechanism for the well-known inhibitory effect of low dose radiation on detectable transformation events. However, modifications of the complex intercellular ROS-based signaling system may also lead to configurations in which low dose radiation attenuates ROS-mediated apoptosis induction.