Exposure reduction factor

The effect of a given process such as plateout, filtration or field deposition on the PAEC is, however, better expressed by the ratio of the PAEC at a process level, r, to the PAEC at a process level of r =0. This quantity, which like the equilibrium factor is independent of the radon concentration, can adequately be named the ERF (energy- (or exposure) reduction factor)... 

This model describes potential exposures, which may then be modified with exposure reduction factors. The model contains no data on reduction factors. In the Dutch risk assessment for registration purposes, a factor of 10 may be proposed to account for personal protective measures for each relevant body part, or for inhalation. This presumes adequate personal behaviour and hygiene on the part of the worker. 

Options. Traditional control options for overexposure are material substitution, process change, containment, enclosure, isolation, source reduction, ventilation, provide personal protection, change work practices, and improve housekeeping. A simple way of looking at selection of control options is to find the cheapest option that results in the desired amount of exposure reduction. It is not actually that simple, however, because the various options differ in ways other than cost and degree of control. Some of the other factors to consider in selection of control options are operabiUty, rehabiUty, and acceptabihty. 

IP-2.2.7(d). The strength reduction factor represents the reduction in yield strength with long-term exposure of the material to elevated temperatures and, in the absence of more applicable data, shall be taken as 1.0 for austenitic stainless steel and 0.8 for other materials. For castings, the basic allowable stress shall be multiplied by the casting quality factor, Ec. Where the allowable stress value exceeds two-thirds of yield strength at temperature, the allowable stress value must be reduced as specified in para. IP-2.2.7(c). Wind and earthquake forces need not be considered as acting concurrently. At temperatures warmer than 427°C (800°F), use 1.33... 

The substances we have described in this book turn out to be, for the most part, minor threats to our health. There are, however, perhaps thousands of these threats, and so a regulatory system has evolved to reduce the risks of individual substances to very low levels. There is considerable work yet to be done, to learn the toxic properties of many poorly tested chemicals, and to assess their health risks, but once this is done, regulatory officials have available strong weapons (which they do not always choose to deploy) to reduce exposures when necessary. The burden for exposure reduction falls not on exposed individuals (as in the case of lifestyle factors), but rather upon those who have caused the exposures to occur. 

Only use substances that have been adequately tested. Avoid harmful effects through a combination of substance selection and exposure reduction, using uncertainty factors to compensate for uncertainty and indetectability. Whenever possible, exposures to substances not known to be harmful should also be reduced. 

When migration limits for substances are set a conventional system is applied to calculate exposure. It is assumed that a 60 kg person will consume 1 kg of packaged food per day. However, a different convention is sometimes necessary for some circumstances. One such arises in the case of lipophilic substances. Lipophilic substances migrate readily into fatty foods. The consumption of fatty foods is usually only 200 g or less per day. For these substances a reduction factor is therefore planned for use in compliance testing, taking into account the lower consumption of fat. 

Table XIII presents the results of the AHP ranking using the hierarchy and criteria weights developed by the study team. There appear to be three distinct groupings of options most preferred, least preferred, and a middle ground where no strong preference exists for one choice over another. Two major factors influenced the overall ranking of options exposure reduction and cost. Technical characteristics determine the rankings within the mid- and low-performance groups.

It is essential to establish certain criteria to evaluate the synthesized compounds, in particular their radioprotective effectiveness and their toxicity. For each of the molecules we synthesize, first we evaluate its acute (48 hours) and medium-term (2-30 days) toxicity in male Swiss CD1 mouse. The molecule is injected intraperitonally at different concentrations to determine the LD5o,ox/48h/ defined as the concentration which kills 50% ofthe animals at 48 hours. Then, radioprotective effectiveness is determined in the same animal model. In a preliminary study, the product is administered at the maximum tolerated dose (defined as 1/2 LD5otox/48h) 15 or 90 minutes before radiation exposure at doses LD,ooirr/3od nd LD,ooirr/3od + 2 Gy (LD,ooirr/3od is defined as the irradiation dose which kills 100% of the animals 30 days after exposure). Survival is observed for 30 days. In a second experiment we determine the Dose Reduction Factor (DRF) for the most radioprotective compounds. DRF is the ratio between the LDsoirr/sod of treated mice and that of non treated mice. 

Temp. °C Weight gain2 ng/cm Exposure Conditions Weight gain2 ng/cm Temp. °C Time h Carbon uptak rpg/an Deposition Reduction Factor (a) Temp. °C Time h Weight gaii ng/cm (b) Deposition Reduction Factor (a) ... 

Temp °C Time h Sulphur content % (a) Temp C Time h Acetone pressure Still Carbon uptake % (a) Deposition reduction factor (c) Sulphur content after exposure % (a)... 

Weight gain during lOOOh oxidation In CO, at 600 0 Deposition exposure conditions Sulphur uptak ug/cm Carbon uptakg mg/cm Deposition reduction factor a... 

Sulphur bearing Partial pressure (atm) Exposure Sulphur. uptake Carbon) uptake % Deposition reduction factor ... 

As a consequence, the reticle dimension control is a major concern with shrinking critical dimension and tolerance. The difference between the effective mask feature size (the reticle dimension divided by the exposure system reduction factor) and the target developed resist dimension is called the mask bias. 

Exposure condition Fibre and resin type Environmental reduction factor, Ce... 

Exposure condition Fiber type Environmental reduction factor Cg... 

Risk situation Exposure reduction methods (Temporal and/or spatMfactors between hazards and assets) Hazard reduction methods (Quantity, nature or severity factors) People/Assa reduction methods (Factors to reduce number or value of assets exposed to hazards)... 

The reduction factor, /t, for the effects of temperature exposure on an elastic adhesive was determined with the aid of a lap-shear test (Fig. 29). The strength of the adhesive decreases with a rise in temperature. 

The results of creep rupture tests on single-lap joints yielded the reduction factor, /l, for an adhesive bond subjected to constant static loading (Fig. 30). The strength of the adhesive decreases with increasing exposure. In constant-load tests of this kind, particularly at higher temperatures, creep strain is observed in the adhesive layer where a certain initial load is exceeded. 

Figure 31 Reduction factor,/z the effect of prolonged exposure to dynamic stress.

Subjecting a test piece to cyclic dynamic load determines the fatigue behaviour of adhesive bonds. When the test values are plotted on a Woehler diagram, the appropriate reduction factor, fz, for prolonged exposure to dynamic stress can be read off (Fig. 31). 

To estimate the required area of the bond face in joints subject to a constant static shear stress, the minimum safety factor of 2 combined with a reduction factor of 0.06 for exposure to constant static stress gives a design figure of 3% of the tensile lap-shear strength of the adhesive ... 

The standard windshield adhesive used has a tensile lap-shear strength of 4 MPa. Exposure to sunlight will inevitably cause the adhesive layer to heat up, so in this example a reduction factor of 0.5, corresponding to a temperature of 60°C (see Fig. 43), has been applied. To estimate the safety factor for this adhesive joint, the tensile lap-shear strength multiplied by this reduction factor is divided by the equivalent stress (Eq. 1)... 

A second scientific factor that complicates effective Pb regulation and population exposure reduction efforts is the environmental medium-specific temporality and persistence of Pb in environmental media. Pb emitted from a stationary source to the atmosphere results in relatively transitory elevations... 

For the exterior wall of double-walled containers and for containments, reduction factors R2B for non-swelling exposure media may be reduced to R2. For exposure media that cause swelling in contact with PE or PP materials, the R2B reduction factors fisted in Table A. 11 are applicable for the exterior walls of double-walled containers and for containments [7]. 

The reduction factors Rjb (see also Sections 1.6.3.1 and 1.6.3) describing the chem-ical/thermal effects of immersion in a specific medium were determined by creep rupture tests under water exposure and are valid only for the listed maximum service temperature [7]. 

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