Exposure zone

CASRAM predicts discharge fractions, flash-entrainment quantities, and liquid pool evaporation rates used as input to the model s dispersion algorithm to estimate chemical hazard population exposure zones. The output of CASRAM is a deterministic estimate of the hazard zone (to estimate an associated population health risk value) or the probability distributions of hazard-zones (which is used to estimate an associated distribution population health risk). 

In the case of photoinitiated polymerization, an oxygen-free aqueous solution of acrylamide with a concentration of about 50% mixed with a photosensibilizer and other required additives is passed through a column-type apparatus with exterior water-cooling. A thin layer of the solution is exposed to a mercury lamp, acquires the consistency of a plastic film, which then can be passed through a second exposure zone, and is crushed and dried. Acrylamide polymers produced by this method are easily soluble and have a low residual monomer content. 

Distribution of steel pile corrosion as a function of marine exposure zone and marine fouling... 

Ocular surface dye staining assesses the ocular surface and will show blotchy or exposure-zone punctate areas in the dry eye. 

Perhaps the most catastrophic industrial accident involving dioxin occurred in S6veso, Italy in July, 1976. Here an entire community surrounding a trichlorophenol feedstock plant was contaminated 736 individuals were in the maximum exposure zone 4699 were in a less exposed zone, and 31.800 individuals were in the zone of least exposure. There were four spontaneous abortions and thirty voluntary interrupted pregnancies. The dose-related increase in chloracne occurred, but the spate of voluntary abortions obscured the teratogenicity data. 

Two sentinel species were caught in the reference and exposure zones in sufficient numbers (at least 12 fish) for statistical interpretation. The data for the white sucker, Catastomus comersoni and longnose sucker, Catastomus catastomus, are listed in Table 7. All endpoints (Beak International, 2000) and comparisons of exposure and reference area data involved appropriate statistical methods. Any significant difference or significant interaction in any endpoint was considered potentially mill-related. 

Increases in the risk of several types of cancer have been observed in residents of Seveso, Italy. In the residents with the highest exposure (zone A), no increases in the risk ratio of all malignancies were observed (Bertazzi et al. 1993). However, the small number of zone A residents (724) limits the statistical power of the analysis. Among residents living in zone B (4,824 people), significant increases were observed for the risk of hepatobiliary cancer (risk ratio of 3.3 95% CI=1.3-8.1) and multiple myeloma (risk ratio of 5.3 95% 0=1.2-22.6) in women and lymphoreticulosarcoma in men (RR of 5.7 95% 0=1.7-19). In zone R (31,647 residents), the risk ratio of soft-tissue sarcomas in men (2.8 95%... 

The corrosion rates of carbon steel pilings and test samples in different exposure zones with the placement of samples in vertical position show different degrees of severity of the zones. 

Corn, M. and N.A. Esmen (1979). Workplace exposure zones for classification of employee exposures to physical and chemical agents. Am. Ind. Hyg. Assoc. J., 40, 47-57. 

Approaches using exposure zones defined by a combination of job title and work location have also been employed (Com and Esmen 1979 Panko et al. 2009 Stewart et al. 1998). The use of exposure zones rather than the more traditional task-based exposure classification has been shown to be a statistically valid method of classification (Smith et al. 1997). Exposure zones, rather than job titles, have also been used to estimate noise exposures (Burgess et al. 2004). There can be a trade-off between using broader exposure classes—which reduces misclassification but results in poorer resolution between exposure distributions—and using narrower exposure classes, in which the opposite effect occurs (Esmen et al. 2007c). 

New York City area. They found 187 women who had been pregnant and present in any one of five exposure zones around Ground Zero, including iz women who were in the towers at the time of the attack. As a comparison group, they used 174 pregnant women who had been nowhere near the World Trade Center on the morning of the catastrophe. 

Glass, G.K., Hassanein, A.M. and Buenfeld, N.R. (2000). CP Criteria for Reinforced Concrete in Marine Exposure Zones. Journal of Materials in Civil Engineering, 12(2) 164-171. 

Protection of HCF personnel from potentially lethal radiation exposures Zone 2A canyon physical structures (concrete walls, shield steel, shielding windows) Worker safety Provide radiation protection such that worker exposures in continuously occupied areas under normal and abnormal conditions are in accordance with 10 CFR 835 Shield design (Design Feature) Radioactive material control (Administrative Control)... 

Exposure zones assessment of dangerous object transport... 

F) Review of the principles and practices of establishing exposure zones, proper decontamination and medical surveillance stations and procedures. 

The CASS test is conducted at an exposure zone temperature of 120°F. The electrolyte solution is a 5 % salt solution, with the addition of copper chloride and glacial acetic acid. The sodium chloride used must be reagent grade in order to produce the mass loss specified on the nickel panels. Similar to B 117, collection rates should be at 1-2 mL/h. 

Waterfront structures are exposed to a variety of marine environments. The resistance of materials to each of these environments may vary considerably, as weU as appHcabil-ity of various forms of corrosion control in mitigating the anticipated corrosion. The waterfront environment can be divided into five exposure zones sediment, immersion, intertidal, splash/spray, and atmospheric. In most cases, a single type of material will be used for the sediment, immersion, and intertidal zones. In some cases another material may be used for the splash and spray and atmospheric zones of the structure. An example of this would be the use of a reinforced concrete deck over steel pilings. Due to differences in corrosion activity between these zones, the corrosion performance of many materials is substantially different when exposed to two or more of these zones. Figure 1, taken from Ref 4, shows the result of a classical experiment where the corrosion of a continuous strip of... 

Cathodic protection is used widely for the protection of submerged steel in waterfront structures. It also can provide considerable benefit in the intertidal zone and can even reduce the usually high corrosion rate experienced at the boundary between the intertidal zone and the splash and spray zone. Cathodic protection also is used to prevent corrosion of the soil side of steel in marine structures such as sheet steel bulkheads. Cathodic protection also is effective in the control of the corrosion of reinforcing steel in concrete in all exposure zones in waterfiont structures. Particularly for impressed current systems, it is important to select materials for the cathodic protection system components such as rectifiers and junction boxes with consideration of the environment to which they will be exposed. When considering cathodic protection, periodic inspection and maintenance is required for proper system operation. The costs for inspection and maintenance must be considered in the overall cost of cathodic protection. While there are no specific standards for cathodic protection of piers and docks, information in NACE RP0176 (Corrosion Control of Fixed Offshore Platforms Associated with Petroleum Production) and NACE RP-0187 (Design Considerations for Corrosion Control of Reinforcing Steel in Concrete) contain information that is applicable to marine piers and docks. 

Environmental simulation is less desirable as many of the actual environmental conditions as well as the interaction between materials exposed to more than one exposure zone are difficult to simulate in the laboratory. 

Exposure zone Mass loss rate per unit area Corrosion rate... 

Hardness HV10 Chromium content Exposure zone Potential ... 

Zinc plating layers transformed by a heat treatment at 903 K (630 °C) completely into iron-zinc alloy phase (galvannealing) showed much better behaviour in the exposure zones. The corrosion protective effect of the hot-dip galvanised layers in seawater is thus not determined only by layer thickness, but also by the layer structure [216]. 

Hot, humid air is created by bubbling compressed air through a bubble (humidifying) tower containing hot, deionized water. Salt solution is typically moved from a reservoir through a filter to the nozzle by a gravity-feed system (Fig. 11.33). When the hot, humid air and the salt solution mix at the nozzle, it is atomized into a corrosive fog. This creates a 100 percent relative humidity condition in the exposure zone. For a low humidity state in the exposure zone of the chamber, air is forced into the exposure zone via a blower motor that directs air over the energized chamber heaters (Fig. 11.34). 

This test can be as brief as 16 h, although it normally ranges from 144 to 240 h or more. As in the neutral salt spray test, a 5% NaCl solution is used, but the solution is adjusted to a pH range of 3.1 to 3.3 by the addition of acetic acid, and again, the temperature of the salt spray cabinet is controlled to maintain 35 -l- 1.1 or —1.7 °C (95 -H 2 or — 3 °F) within the exposure zone of the closed cabinet. 

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