Electron beam irradiation method components

To avoid this problem, Wills and Boyd have applied a semi-empirical method [18]. They used relative cross sections for 100 eV electrons and calculated the yields for the various processes based on the ff -values. This method is rather simple and contains many assumptions nevertheless, the results are a good indication for radiation chemists to provide a specific amount of initial species. The following equations [19] show the amounts of initial species from the main components of flue gas with electron beam irradiation based on the data listed in Ref. 18. 

The flue gas from municipal waste incinerator boilers contains SO2, and HCl. To remove these harmful components simultaneously by dry process, electron beam treatment method was investigated. The pilot-scale test was conducted in Matsudo, Japan, in 1992 with a flue gas of 1000 m /hr [34]. Recently, dioxins, namely, poly-chlorinated-di-benzo-paradioxins (PCDDs) and poly-chrorinated-di-benzo-furan (PCDFs), from incinerators have become a very serious problem because of their high toxicity. Pilot-scale tests to decompose dioxins by electron beam irradiation were conducted in Karlsruhe, Germany [35], and in Takahama, Japan [36], using almost the same capacity of flue gas, 1000 m /hr. Very promising results were obtained with decomposing more than 90% of dioxins. 

Figure 9.1 Characteristics of PIPAAm and conventional TRCS, which is PIPAAm-grafted TCPS prepared hy the electron beam irradiation (EB) irradiation method. TRCS shows cell adhesion and detachment (deadhesion) becanse of the reversible temperature-indnced hydrophilic and hydrophobic alternation. Detached cells contain an ECM component at the basal site of the cell. Cell adhesion and detachment process involves in metabohc adenosine triphosphate (ATP) consumption in the cell.

Plastic components (whether container or closure) can be sterilized using steam, ethylene oxide, hydrogen peroxide, or ionizing radiation. The y irradiation is accomplished off-site by a subcontractor with appropriate expertise as these methods are considered the province of specialists because of the extreme health hazards directly related to the sterilization method. Electron beam sterilization may also be done by a contractor, although compact lower energy electron beam systems have been introduced that allow sterilization in-house. Steam sterilization is ordinarily performed in house, though many common components are becoming available presterilized by the supplier. Preparation steps prior to sterilization vary with the component and the methods used to produce the component. Rubber components are washed to reduce particles, while this is less common with plastic materials. 

The method of differential radiation induced contrast depends on enhancement of contrast in multicomponent polymers where the components have different electron beam-polymer interactions [173]. Contrast has been observed in sections of styrene-acrylonitrile/poly(methyl methacrylate) (SAN/PMMA) polymers where the PMMA exhibits a high rate of mass loss compared to SAN, creating contrast between the phases. It is well known that electron irradiation results in chain scission and crosslinking, loss of mass and crystallinity [75]. Polystyrene, polyacrylonitrile and SAN crosslink and thus are stable in the electron beam whereas polymers exhibiting chain scission, PMMA and poly(vinyl methyl ether), degrade in the beam. It is suggested that experiments be conducted on the homopolymers to determine the expected irradiation damage mechanism in the multi-component system [173]. 

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