Worst-case calculations

Rather than take the case temperature as the local ambient temperature of the capacitor, which is more of a worst-case calculation, we could try to actually measure the local ambient. Assume that the general ambient is Lamb ext- The local ambient near the capacitor is Lamb. The procedure to factor out the heat from nearby components (i.e., heat which is not due to ripple current) is as follows ... 

I should also point out that 25V rated capacitors from Murata have a much better voltage stability curve—only 5 to 10% fall at maximum rated voltage. That is actually close to the voltage stability figure I used in my worst-case calculations previously. 

For the worst case, calculation of temperature rise within the sample due to mechanical energy dissipation is about 1"C. With heat loss from the sample, this value should be lower. 

Restrictions for the residual amount of a component instead of a specific migration limit are set by the legislator in cases where specific migration of a component is difficult to obtain (for example, because the component is very volatile) or impossible to determine directly (for example, if the component is very reactive and would react with the food simulant). There are two ways to determine the residual content, by worst-case calculation or by analytical determination. The generic approach is shown in Eig. 5.3. 

If the amount of a component is already known to be so small that the residual content limit is not exceeded, this is sufficient. This can be calculated using already available information like ingredient specification, the amount of chemical added, etc. One consequence is that this worst-case calculation is not possible for monomers, but only for additives and processing aids. In real-life this approach could be used in rare cases only and an analytical determination is the method most commonly used. 

When applying the conventional food contact ratio the worst-case migration potential did not exceed the SML for any of the substances derived from plastics nor did the calculated worst-case exposure exceed the ADI/TDI or other exposure restriction value in any products. However, when the actual food contact ratio was applied the ADI/TDI or other exposure restriction value of several substances could theoretically be exceeded. The worst-case calculations assume that intimate contact is made with the entire surface of the packaging. This is not the case for the majority of snack foods that are solids or semi-solids and so the actual area of contact made will be less than the total area available for contact (e.g. crisps). The levels of those migrants (diisobutyl phthalate, dicyclohexyl phthalate, dibutyl sebacate, diphenyl 2-ethylhexyl phosphate and 2-ethyl-1-hexanol) that had the potential to exceed the assigned restrictions, assuming 100% migration, were determined in foods. Of the five substances tested for, only one, dicyclohexyl phthalate, was detected in one of the foodstuffs (tortilla corn chips), at a concentration of 0.60 ppm. 

The first method is to do a worst-case calculation, which means that only the process limits of each processing step are taken into account. Unfortunately, this method is not applicable to most sensors in high-volume production today, because it is not realistic to treat a process flow by setting all parameters simultaneously to their process limits. 

All of the above calculations resulted In very small failure probabilities of the combustor, even for the worst case calculation. 

The process is often iterative. If an assessment made using worst-case assumptions shows that the risk would be acceptable, then no refinement is necessary if the worst-case calculations show that the risk would be significant, however, then the assessor often gathers additional information to refine the assumptions. 

The accommodation coefficient is a measure of how well a molecule comes to thermal equilibrium with a surface before leaving it. For a worst case calculation, take a = 1, but values of 0.8-0.5 are common, and 0.05 is possible. 

Before commencing calculations the worst case is assumed. For example it is assumed that the component operates continuously at the maximum temperature and under the maximum load encountered in its service life. 

Calculates the vulnerability zone based on the maximum quantity present for screening Calculations are based on credible worst case a.ssumptions identified in the Technical Guidance for Hazards Analvsis. 

Flare radiation level calculations are to be based on the worst case wind velocity, a design wind velocity of 40 Kph and a maximum of 100 Kph. Vendor shall provide radiation plots for each case. 

Critical GLC s can usually be calculated based on a unstable atmosphere, thus enabling the designer to determine a worst case scenario. For any given day, typical atmospheric stabihty data can usually be obtained from a local weather bureau, or may be estimated from the so-called Pasquill chart for the appropriate Atmospheric Stability Class (refer to Table 1). 

Tables 9 and 10 give the maximum ground level concentrations expected for worst case conditions for the 3-min. and 5-min. venting rates, respectively worst case conditions were obtained from Tables 7 and 8 (i.e., values were calculated based on the largest concentration found in Tables 7 and 8 for each distance within a stability class).

Stress calculations, fault tree analysis, failure modes analysis, and worst case analysis... 

T/ e effect of altering major assumptions on the downwind distance (radius) of the estimated vulnerable zone. Calculations made using (1) credible worst case assumptions for initial screening zone. (2) reevaluation and adjustment of quantity released and/or rate rf release cf chemical, (3) reevaluation and adjustment of wind speed (increase) and air stability (decrease), (4) selection of a higher level of concern. Note that adjustment oftwo or more variables can have an additive effect on reducing the size cf the estimated vulnerable zone. 

Before performing any calculations, a thorough examination of the possible causes and flow conditions of temperature and pressure should be evaluated. From this list, select the most probable and perhaps the worst case possibility and establish it as a design basis, Figure 7-14. See [80]. 

Moreover, calculations on the evaporation rate of bromine from the complex phase were carried out assuming a worst-case scenario, namely a complete spill age of the total bromine inventory (as poly bromide complex) of a fully charge (100% SOC) 15 kWh module which means -32.5 kg of available Br2, forming a 10 m2... 

Organotins have been detected in a wide range of consumer products these measured values have been used to calculate worst-case exposure of human consumers (adults and children). 

Based upon the various sources of adult consumer exposure to organotin compounds (section 6) and the TDI values derived above, it is possible to estimate the relative exposure from the various organotin compounds expressed as a percentage of the TDI values. The exposure calculations in section 6 were based on a realistic worst-case exposure assessment. Table 26 presents the results of this risk characterization. 

Which components are the key components will normally be clear, but sometimes, particularly if close boiling isomers are present, judgement must be used in their selection. If any uncertainty exists, trial calculations should be made using different components as the keys to determine the pair that requires the largest number of stages for separation (the worst case). The Fenske equation can be used for these calculations see Section 11.7.3. 

Compliance with U.S. EPA s design performance standards can be demonstrated through one-dimensional, steady-state flow calculations, instead of field tests. For detection sensitivity, the calculation of flow rates should assume uniform top liner leakage. For detection time, factors such as drain spacing, drainage media, bottom slope, and top and bottom liners should all be considered, and the worst-case leakage scenario calculated. 

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