Conservatism

But there is a price to be paid. Good Workmanship acceptance criteria for conventional techniques must, to a certain extent, be conservative, in order to compensate for the inherent "limitations" of conventional NDT. And, what is worse, the degree of conservatism is more or less unknown. Therefore the question can be asked "if the historic background of present NDT practice would not exist, what would we like to know today about a weld to be able to accept or reject it "... 

In an ideal situation we would like to have a balanced combination between evaluation of the welder s performance on one hand, and a fracture mechanics basis on the other hand in tenns of "being certain that a defect with dimensions exceeding a certain critical value is not present". The second aspect could be regarded as a safety net with a balanced conservatism. 

In Eqs. (9-28) and (9-29), the computations are based on unchanging values of the cost of land and other nondepreciable costs Cl. This is unreahstic, since the value of land has a tendency to rise. In such circumstances, the accountancy principle of conservatism requires that the lowest valuation be adopted. 

Accounting is also based on the following conventions (1) materiality, (2) conservatism, or prudence, and (3) consistency. 

Pressure drop is particularly sensitive to geometrical parameters, and available correlations should be extrapolated to geometries different from those on which the correlation is based only with great caution and conservatism. The best correlation is that of Robinson and Briggs [Chem. Eng. Prog., 62, Symp. Set 64, 177-184 (1966)]. 

Another way to evaluate risks is to calculate the sensitivity of the total risk estimates to changes in assumptions, frequencies, or consequences. Risk analysts tend to be conservative in their assumptions and calculations, and the cumulative effect of this conservatism may be a substantial overestimation of risk. For example, always assuming that short-term exposure to chemical concentrations above some threshold limit value will cause serious injury may severely skew the calculated risks of health effects. If you do not understand the sensitivity of the risk results to this conservative assumption, you may misallocate your loss prevention resources or misinform your company or the public about the actual risk. 

To build in conservatism, different factors can be used when going up in size, and when going down in size. For instance, if an ammonia plant has been built for 20 million that produces 250 tons per day, and two studies for plants producing 200 TPD and 300 TPD are being prepared, the estimates could be done as follows ... 

Latent cancer is calculated to be the primary risk from a nuclear accident (this may be due to the conservatism in the low-dose models). At Chernobyl, most of the deaths were from fire and impact. Chemical process risk depends on the chemicals being processed. Experience shows that processing poisons poses the highest risk to public and workers. 

Representativeness can be examined from two aspects statistical and deterministic. Any statistical test of representativeness is lacking becau.se many histories are needed for statistical significance. In the absence of this, PSAs use statistical methods to synthesize data to represent the equipment, operation, and maintenance. How well this represents the plant being modeled is not known. Deterministic representativeness can be answered by full-scale tests on like equipment. Such is the responsibility of the NSSS vendor, but for economic reasons, recourse to simplillcd and scaled models is often necessary. System success criteria for a PSA may be taken from the FSAR which may have a conservative bias for licensing. Realism is more expensive than conservatism. 

Certainly errors should be conservative, but cumulative conservatism reduces accuracy and usefulness while raising costs. 

Develop final Perform structural design of analysis of component acceptable accuracy Determine structural response—stresses, support reactions, deflections, and stability—based on a structural analysis of acceptable accuracy. Determine acceptable accuracy based on economic value of component, consequences of failure, state-of-the-art capability in stress and stability analysis, margin of safety, knowledge about loads and materials properties, conservatism of loads, provisions for further evaluation by prototype testing... 

The quantity K A. (ss) can independently be obtained from conservat on°of styrene. 

As a result, a considerable amount of effort has been expended in designing various methods for providing difference approximations of differential equations. The simplest and, in a certain sense, natural method is connected with selecting a, suitable pattern and imposing on this pattern a difference equation with undetermined coefficients which may depend on nodal points and step. Requirements of solvability and approximation of a certain order cause some limitations on a proper choice of coefficients. However, those constraints are rather mild and we get an infinite set (for instance, a multi-parameter family) of schemes. There is some consensus of opinion that this is acceptable if we wish to get more and more properties of schemes such as homogeneity, conservatism, etc., leaving us with narrower classes of admissible schemes. 

All the schemes with these properties are called fully conservative schemes. As a matter of fact, the requirement of the full conservatism is equivalent to being approximated of both equations (14) and (15) in addition to the usual requirements of approximation ... 

The notion of the conservatism of a difference scheme played a crucial... 

The property of the difference scheme conservatism for linear equations is generally equivalent to the self-adjointness of the relevant difference operator (see Chapters 3-4). 

Sidechain conservatism may be split up into at least two kinds 1) substitutions which conserve sidechain bonding forces - providing similar electrostatic, hydrophilic, or hydrogen bonding interactions, and 2) substitutions conserving secondary structure propensity. For instance, substitution of glutamic acid with aspartic acid conserves charge, but this could have a considerable effect upon the secondary structure propensity of the peptide. 

Again, since the purpose of both initial and consequence screenings is to establish which buildings in process plants require further evaluation and which buildings do not require further consideration, the assumptions made in the studies should be conservatively chosen. This conservatism will help ensure that all buildings potentially exposed to significant blast are appropriately evaluated. 

Recently a decreased level of CE activity has been noticed with a shift of attention towards other separation techniques such as electrochromatography. CE is apparently not more frequently used partly because of early instrumental problems associated with lower sensitivity, sample injection, and lack of precision and reliability compared with HPLC. CE has slumped in many application areas with relatively few accepted routine methods and few manufacturers in the market place. While the slow acceptance of electrokinetic separations in polymer analysis has been attributed to conservatism [905], it is more likely that as yet no unique information has been generated in this area or eventually only the same information has been gathered in a more efficient manner than by conventional means. The applications of CE have recently been reviewed [949,950] metal ion determination by CE was specifically addressed by Pacakova et al. [951]. 

Epstein, Klaus. The genesis of German conservatism. Princeton (NJ) Princeton Univ P, 1966. xii, 733 p. 

VT Air Pollution Control Div. 1998. State of Vermont, Natural Resources Agency, Department of Environmental Conservatism, Air Pollution Control Division. Vt. Code R. Chapter 5, Subchapter III. 

The lack of structural "conservatism in the siderochromes, as contrasted to cytochrome c, can be illustrated by comparing representatives of these two iron-containing compounds from two adjacent classes under the phylum Eumycophyta, the Ascomycetes and the Basidiomycetes. 

Mukherjee AB, Zevenhoven R, Brodersen J, Hylander LD, Bhattacharya P (2004) Mercury in waste in the European Union sources, disposal methods and risks. Resour Conservat Recycl 42 155-182... 

For example, E. G. Mazurs (note 2, p. 105) expresses the discord as follows The periodicity of atomic structure must be accepted as a Natural Law. Therefore, scientists have to change their minds, get away from the conservatism that accepts only Mendeleev s chemical table as right, and adjust the other phenomena to this phenomenon that is, derive the chemical and physical properties of the elements from the electronic structure of the atoms. ... 

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