Pessimists

In recent years general purpose polystyrene and high-impact polystyrenes have had to face intensive competition from other materials, particularly polypropylene, which has been available in recent years at what may best be described as an abnormally low price. Whilst polystyrene has lost some of it markets it has generally enjoyed increasing consumption and the more pessimistic predictions of a decline have as yet failed to materialise. Today about 75% of these materials are injection moulded whilst the rest is extruded and/or thermoformed. 

The integrated terms are simply the specific heat of the unit mass of adsorbent and its associated adsorbate. The specific heat at constant volume has been used for the adsorbate since, theoretically, there is no expansion of the adsorbate volume and the heat required to raise the temperature is the change in internal energy. In practice there will be some expansion and a pessimistically high estimate could use the specific heat at constant pressure The specific heat of the adsorbed phase is in any case difficult to estimate and it is common to approximate it to that of saturated liquid adsorbate at the same temperature. 

The bicyclo[2.2.0]hexa-2,5-diene ring system is a valence isomer of the benzene ring and is often referred to as Dewar benzene. After many attempts to prepare Dewar benzene derivatives failed, a pessimistic opinion existed that all such efforts would be finitless because Dewar benzene would be so unstable as to immediately revert to benzene. Then, in 1962, van Tamelen and Pappas isolated a stable Dewar benzene derivative by photolysis of 1,2,4-tri(/-butyl)benzene. ... 

Thus, based on the above, it is not surprising that even under the best conditions an uncertainty factor of approximately 2 is likely in estimates of the plume rise. Despite this somewhat pessimistic introduction, estimations of plume rise are worthwhile and an integral part of the dispersion analysis. Table 2 presents some of the well-known plume rise formulas used in different model approaches. The two major controlling variables which appear in many, if not all, of the plume rise formulas surveyed are ... 

Cross-comparing the risks of various activities is difficult because of the lack of a common basis of comparison, however Cohen and Lee, 1979 provide such a comparison on the basis of loss of life expectancy. Solomon and Abraham, 1979 used an index of harm in a study of 6 occupational harms - three radiological and three nonradiological to bracket high and low estimates of radiological effects. The index of harm consists of a weighting factor for parametric study the lost time in an industry and the worker population at risk. The conclusions were that the data are too imprecise for firm conclusions but it is possible for a radiation worker under pessimistic health effects assumptions to have as high index of harm as the other industries compared. 

Operator error probabilities were estimated using NUREG/CR-4910 normalized to errors determined in the internal events analysis. This allowed for varying number of personnel, amount of time available, and stress level. When more pessimistic values were substituted for best estimate values, the calculated core melt frequency increased by a factor of at least three. 

Both the.se methods have weaknesses. The historical data, implicit in both, may not be appropriate for the component in the assumed environment for the particular circumslances considered and may be irrelevant because of design rectification based on knowledge of previous failure. The broad approach may then be unduly pessimistic. On the other hand, the fault tree may fail to identify a primary cause which may have been missed by the plant designer to underestimate the probability of failure. The fault tree approach also takes credit for the preventative measures which may not be present in practice. The broad approach is likely to overestimate the risks because of insufficient account of preventative measures. The PSA team used the broad approach, recognizing that more accuracy may be attained by detailed industry studies. 

Confidence limits for the conclusions cannot be expressed simply because of the complexity of hazard assessments. The estimation of uncertainties is itself a process subject to professional judgment. However, the team s estimates of probability are believed to be realistic, but may be pessimistic by a factor of perhaps two or three, but less than a factor of ten. Uncertainties also exist... 

Decisions affecting the future direction of the organization and its products and services are made from information gleaned through market research. Should this information be grossly inaccurate, over optimistic or pessimistic the result may well be the loss of many customers to the competition. It is therefore vital that objective data is used to make these decisions. The data can be primary data (data collected for the first time during a market research study) or secondary data (previously collected data). However, you need to be cautious with secondary data, as it could be obsolete or have been collected on a different basis than needed for the present study. 

Schwarz-schmelz, m. black enamel, -scher, m. pessimist, -senfol, n, black ustard oil, -silbererz, n.. -sllberglanz, m. black silver (stephanite), -spiessglanzerz, n. boumonite, -strahlen, m.pl. black radiation,... 

Resource pessimists counter that this process cannot proceed forever because the eternal persistence of demand for any given commodity that is destroyed by use must inevitably lead to its depletion. I lowever, the eternal persistence assumption is not necessarily correct. The life of a solar system apparently is long but finite. Energy sources such as nuclear fusion and solar energy in time could replace more limited resources such as oil and natural gas. Already, oil, gas, nuclear power, and coal from better sources have displaced traditional sources of coal in, for example, Britain, Germany, Japan, and France. 

Principle of Population, as pessimistic in its conclusions as the Marquis de Condorcet s work was optimistic... 

In ventilation systems the temperature rise calculated on the basis of specific heat alone will be pessimistic by one or two degrees because of the effect of building mass. Unless an extract is specifically designed to remove heat from hot spots or lights, the extract and room temperature can be taken to be the same. 

To = The optimistic (shortest) time within which only 1% of similar projects are completed Tp = The pessimistic (longest) time within which 99% of similar projects are completed T. = The calculated time estimate... 

This is actually the pessimistic meta-induction associated with Larry Laudan among other philosophers. L. Laudan, A Confutation of Convergent Realism, Philosophy of Science, 48 1-49, 1981. 

A reaction interface is the zone immediately adjoining the surface of contact between reactant and product and within which bond redistributions occur. Prevailing conditions are different from those characteristic of the reactant bulk as demonstrated by the enhanced reactivity, usually attributed to local strain, catalysis by products, etc. Considerable difficulties attend investigation of the mechanisms of interface reactions because this thin zone is interposed between two relatively much larger particles. Accordingly, many proposed reaction models are necessarily based on indirect evidence. Without wishing to appear unnecessarily pessimistic, we consider it appropriate to mention here some of the problems inherent in the provision of detailed mechanisms for solid phase rate processes. These difficulties are not always apparent in interpretations and proposals appearing in the literature. 

Consequently the proven functional identity of classical promotion, electrochemical promotion and metal-support interactions should not lead the reader to pessimistic conclusions regarding the practical usefulness of electrochemical promotion. Operational differences exist between the three phenomena and it is very difficult to imagine how one can use metal-support interactions with conventional supports to promote an electrophilic reaction or how one can use classical promotion to generate the strongest electronegative promoter, O2, on a catalyst surface. Furthermore there is no reason to expect that a metal-support-interaction-promoted catalyst is at its best electrochemically promoted state. Thus the experimental problem of inducing electrochemical promotion on fully-dispersed catalysts remains an important one, as discussed in the next Chapter. 

Fignir 5. Variation of du fm) versus wave-lengih 0. m). Solid lines opiimisltc Hiifiiagel-Valley model for C f, hy, dotted lilies pessimistic model thick lines DO high LGS thin lines 20 hn high LOS ( Sasiela, 1994),... 

Based on prevalence estimates and mortality rates for the French AIDS epidemic, Lambert (1995) calculated indirect cost by using the human capital approach in 1992 as US 3.054 billion. Future indirect costs up to 2020 were simulated under different scenarios of the HIV prevalence. According to a pessimistic scenario, indirect cost would rise until 2010 (US 9.381 billion) and then keep almost stable until 2020 (US 9.069 billion). If the infection rate could be reduced, indirect costs would decrease to US 1.507 billion in 2020. 

Figure 4.7. Consequences for the case that the proposed regulation is enforced The target level for an impurity is shown for several assumptions in percent of the level found in the official reference sample that was accepted by the authorities. The curves marked A (pessimistic), B, and C (optimistic) indicate how much the detected signal needs to be below the approved limits for assumptions concerning the signal-to-noise relationship, while the curves marked 1-3 give the LOQ in percent of this limit for LOQs of 0.02, 0.01, resp. 0.005. The circle where curves B and 1 intersect points to the lowest concentration of impurity that could just be handled, namely 0.031 %. The square is for an impurity limit of 0.1%, for which the maximal signal (<= 0.087%) would be just a factor of = 4.4 above the highest of these LOQs.

All these factors should be carefully considered in the design and implementation of any bioremediation program. The rather pessimistic views presented above are supported by quoting the succinct conclnsions of a study on PAH loss in laboratory microcosms using soil from a site contaminated with PAHs from a previous gas manufacturing facility (Erickson et al. 1993). 

Then appeared the time of computers. Quantum chemists developed semi-empirical codes that rapidly evolved into ab-initio complex systems of programs. According to their optimistic or pessimistic views, colleagues have seen this period either as that of semi -quantitative or of semi-qualitative theoretical chemistry. Very recently came the age of super computers, and a generation of quantum chemists have seen their dream come true at last, the quality of the calculation is in harmony with the quality of the concepts. 

Gen Pessimistic attitude, apathetic, looks older than stated... 

The critical flux in forced-convection boiling is difficult to predict. Kern (1950) recommends that for commercial reboiler designs the heat flux should not exceed 63,000 W/m2 (20,000 Btu/ft2h) for organics and 95,000 W/m2 (30,000 Btu/ft2h) for water and dilute aqueous solutions. These values are now generally considered to be too pessimistic. 

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