Radiation Physics and Chemistry (1977)最新文献

A method of simultaneously removing sulfur dioxide and nitrogen oxides from high sulfur, coal-fired utility boiler combustion gases is discussed. Process development history is briefly presented and salient details of a commercial demonstration unit currently under construction at an electric utility power plant in Indiana are given. Detailed discussion on the design details and performance requirements of a cable connected set of 80 kW electron beam sources precedes a discussion of the projected economics of the process. Requirements for future electron beam machine configurations and capacities as well as impact on the radiation machine manufacturing industry, assuming acceptance of the process by the electric utilities, are presented.

The gamma irradiator GBZ 81 is a specific onion irradiator and easy to use for all types of bulk-cargo irradiation. It largely works automatically. The irradiator may be integrated into the storing line of onions from the field to the warehouse. Its output is about 7.5–8.0 ton/h, corresponding to 2000–3000 ton per harvest period. The efficiency of the gamma irradiator is about 13%. Considering the low building cost, the simple design and the automatic operation of the irradiation plant this comparatively low efficiency is acceptable, especially if the cobalt-60 sources are used during the remaining times of the year in another facility, e.g. a multipurpose irradiator of a higher efficiency. This programme is realized at present by the combination of a new multipurpose gamma-irradiation facility and some onion irradiators of the type GBZ 81.

The magnetic media industry is studying means to improve the recording density, durability, product uniformity and production efficiency and to reduce wetting agent migration in the magnetic film. The use of electron beam curable resin binders for magnetic coatings is one of the approaches being studied for this.

This paper compares the wetting efficiencies of several electron beam curable systems with a conventional resin and a conventional wetting agent. In this study it has been demonstrated that EB resins can be designed to effect proper magnetic pigment dispersion.

The relation between grafting conditions and antithrombogenicity has been examined from the purpose of clearing the necessity of controling grafting conditions to enhance blood compatibility. The grafting systems employed here were N, N-dimethylacrylamide (DMAA) — poly(tetrafluoroethylene) (PTFE) and DMAA- poly(ethylene-co-tetrafluoroethylene) (AFLON) and grafting parameters were dose rate, monomer concentration and total dose (irradiation time). Grafting DMAA onto the substrates was carried out by using simultaneous irradiation method of gamma rays from a ⁶⁰Co source. After evaluation of blood compatibility of the grafted films by using in vitro tests, it has been clear that control of grafting conditions is important. Especially, in both grafting systems, dose rate control has found to be very important for blood compatibility. When higher dose rate of 1.0 × 10⁵ to 3.0 × 10⁵ rad/hr was used for grafting DMAA onto PTFE or AFLON, blood compatibility of the substrates was not enhanced, whereas it was improved when the grafting was carried out at lower dose rate of 0.97 × 10⁴ rad/hr. The correlation between dose rate and antithrombogenicity has been interpretated in terms of surface-roughness of the grafted films. By scanning electron microscope (SEM) — observation, it has been observed that higher dose rate makes the surface rough, whereas lower dose rate does it smooth. In the grafting systems used here, therefore, dose rate is the most important factor to control the roughness of surface which gives a profound effect on antithrombogenicity.

The radiation effect of various pH values on polyvinyl alcohol aqueous solutions and on organic solutions, as well as those of scavengers in the aqueous solutions were examined. The gelation dose R_g changes with various pH values; a small amount of free radical scavengers in the system inhibits the crosslinking of polymer molecules and raises R_g. Degradation of polyvinyl in alcohol dimethyl sulfone solution occurs after irradiation, providing a mechanism of radiation-induced crosslinking of polyvinyl alcohol aqueous solutions is initiated by the transient species H and OH of water, but not the species e^-_aq.

Modern physical ideas and technical possibilities of long-distance electrivity transmission to large distances by the intensive beams of relativistic electrons are considered. The basic scheme of line of electrical energy transmission by electron beam (LEETEE) is presented and the methods of technical realization of such line are discussed. The description of stands simulating LEETEB is given.

Casting process of optical plastic and its characteristics has been studied by radiation polymerization. The technique was applied to the production of various plastic lenses.