Debris distribution

Suitable debris areas were selected that showed a characteristic debris distribution. This was quite a difficult task because new debris had to be found in a desert of stones. In the end, however, it was easier than expected because the shape of the crater debris, the vegetation under it, and the clean debris surface, without any lichens on it, made a distinction possible. Figure 26.9 shows two of the chosen fields. 

Debris Distribution versus Range. As mentioned in Section 26.1, it was the aim to develop not a model that calculates only quantity distances, but a formula that predicts densities of hazardous debris over a wider range. Therefore, the debris to be considered as hazardous... 

The size distribution function for the propagation phase (RUNl) is shown in Fig. 9, along with the debris distribution from the FITSOD test, an experiment that did not explode but that did have a surface "eruption. " Since... 

After the parts have been released they can be inspected to determine whether or not the release went well. If parts have not been properly anchored the die can look like a battleground with debris distributed over it. A good design practice is to include test structures in addition to the parts to assess the success of the release step. Common test structures... 

The experimental results of the IET-1/ IET-3/ and IET-6 tests [Refs. 1, 2, and 3] are described in this section. These experiments were designed to understand the effect of hydrogen combustion on DCH. The primary variables measured were the Surtsey vessel pressure/ cavity pressure/ hydrogen production/ hydrogen combustion/ and posttest debris distribution. 

In order to define the extent of emissions from automotive brakes and clutches, a study was carried out in which specially designed wear debris collectors were built for the dmm brake, the disk brake, and the clutch of a popular U.S. vehicle (1). The vehicle was driven through various test cycles to determine the extent and type of brake emissions generated under all driving conditions. Typical original equipment and aftermarket friction materials were evaluated. Brake relines were made to simulate consumer practices. The wear debris was analyzed by a combination of optical and electron microscopy to ascertain the asbestos content and its particle size distribution. It was found that more than 99.7% of the asbestos was converted to a nonfibrous form and... 

In developing a separation strategy, the size distribution of the components found in the contaminated medium can be used as a starting point. As an initial step, debris (such as rocks, etc.) can be separated from the remainder of the waste. After the debris is removed, other separation techniques can be employed to concentrate the waste further or physically manipulate the waste into a form suitable for treatment. 

The problem of corrosion debris and deposit pickup may happen anywhere in the steam distribution or CR systems (such as from a superheater, steam trap, surface condenser, FW preheater, or condensate tine). 

The pickup, transport, and redeposition of corrosion debris and deposits can happen anywhere in steam distribution and condensate return systems and are not confined to any particular boiler plant size or pressure rating. For example, deposit pickup may occur in a superheater with redeposition taking place perhaps in a pressure reducing station, steam trap, or condensate line. The starting point for transport mechanisms is often a combination of BW carryover and condensate line corrosion. 

In the South Pacific, man-made debris was surveyed on 24 islands in the Thousand Island archipelago north of Java in 1985 (66). Polyethylene bags, footwear and polystyrene blocks comprised more than 90% of the 27,600 items. The main source of this debris is the dumping of rubbish and domestic and industrial waste directly into the sea at Jakarta. On New Zealand beaches, plastic litter was widely distributed and predominantly in the form of polyethylene and polypropylene beads. Near Auckland and Wellington concentrations exceeded 10,000 and 40,000 beads m of beach, and the unweathered appearance of the beads implied a nearby source (66). 

Denmark 1.5 days after the explosion. Air samples collected at Roskilde, Denmark on April 27-28, contained a mean air concentration of 241Am of 5.2 pBq/m3 (0.14 fCi/m3). In May 1986, the mean concentration was 11 pBq/m3 (0.30 fCi/m3) (Aarkrog 1988). Whereas debris from nuclear weapons testing is injected into the stratosphere, debris from Chernobyl was injected into the troposphere. As the mean residence time in the troposphere is 20-40 days, it would appear that the fallout would have decreased to very low levels by the end of 1986. However, from the levels of other radioactive elements, this was not the case. Sequential extraction studies were performed on aerosols collected in Lithuania after dust storms in September 1992 carried radioactive aerosols to the region from contaminated areas of the Ukraine and Belarus. The fraction distribution of241 Am in the aerosol samples was approximately (fraction, percent) organically-bound, 18% oxide-bound, 10% acid-soluble, 36% and residual, 32% (Lujaniene et al. 1999). Very little americium was found in the more readily extractable exchangeable and water soluble and specifically adsorbed fractions. 

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