Term Test

The color durability of Iron Blue, in addition to other pigments, 

376 Quantum efficiency is that part of the absorbed light quants which leads to photo reactions under scrutiny, here from 10 to 40%. 

378 Photolysis of water leads to the splitting of water into uncharged parts with unpaired electrons (formation of radicals through homolytic splitting (homolysis) see also dissociation, note 339)  

Woodman, Hazard. Ind. Waste 21 (1989), pp. 282-290 S.A. Zaidi, J. Carey, in Proceedings of the Conference on Cyanide and the Environment, Colorado State University, 1984, pp. 363-377. 

380 Deutsche Chemische Gesellschaft (ed.), Gmelins Handbuch, op. cit. (note 335) Ullmanns Encyklopadie, op. cit. (note 374) L. Muller-Focken, op. cit. (note 374). 

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Slow Strain-Rate Test In its present state of development, the results from slow strain-rate tests (SSRT) with electrochemical monitoring are not always completely definitive but, for a short-term test, they do provide considerable useful SCC information. Work in our laboratory shows that the SSRT with electrochemical monitoring and the U-bend tests are essentially equivalent in sensitivity in finding SCC. The SSRT is more versatile and faster, providing both mechanical and electrochemical feedback during testing. 

Often, analysts will want to run special short-term tests with the operating unit in order to identify the cause of the trouble being experienced By the unit. Operators are naturally leery of running tests outside their normal operating experience because their primaiy focus is the stable control of the unit, and tests outside their experience may result in loss of control. Multiple tests with few results may decrease their cooperation. 

Glossary of Terms. Test Methods for Pressure Sensitive Adhesive Tapes, Pressure Sensitive Tape Council, 1996. 

The American Society for Testing Materials (ASTM) recommends 250 ml of solution for every square inch of area of test metal. Exposure time is also critical. Often it is desirable to extrapolate results from short time tests to long service periods. Typically, corrosion is more intense in its early stages (before protective coatings of corrosion products build up). Results obtained from short-term tests tend to overestimate corrosion rates which often results in an overly conservative design. 

Strength and Stiffness. Thermoplastic materials are viscoelastic which means that their mechanical properties reflect the characteristics of both viscous liquids and elastic solids. Thus when a thermoplastic is stressed it responds by exhibiting viscous flow (which dissipates energy) and by elastic displacement (which stores energy). The properties of viscoelastic materials are time, temperature and strain rate dependent. Nevertheless the conventional stress-strain test is frequently used to describe the (short-term) mechanical properties of plastics. It must be remembered, however, that as described in detail in Chapter 2 the information obtained from such tests may only be used for an initial sorting of materials. It is not suitable, or intended, to provide design data which must usually be obtained from long term tests. 

The questionable validity if animal studies and short-term tests with respect to the prediction of long-term, adverse liealUi impacts in a human population... 

Since lead is protected by relatively thick films of corrosion products, short-term tests can be misleading, as once the film has formed there will be a significant decrease in the corrosion rate. 

Uranium Short-term tests indicate that the practical upper limit for niobium as a container material for uranium is about 1 400°C . Niobium is dissolved in a uranium-bismuth alloy in less than lOOh at a temperature of 800°C". Uranium eutectics with iron, manganese or nickel, corroded niobium at 800°C and 1 000°C It is significantly attacked by uranium-chromium at 1 000°C . 

Uranium Short-term tests indicate the practical upper limits for tantalum as a container material for uranium to be 1450°C . However, attack below these temperatures is significant, since a tantalum crucible with a wall 1 52 mm thick was completely corroded in 50 h in 1275°C. 

The fatigue strength of most TPs is about 20 to 30% of the ultimate tensile strength determined in the short-term test but higher for RPs. It decreases with increases in temperature and stress-cycle frequency and with the presence of stress concentration peaks, as in notched components. 

This is the one serious limitation in plastic design problems. Even if the designer did wait for data on one material, chances are the final design might be switched to another plastic or formulation. Thus, as a compromise, data from relatively short-term tests are extrapolated by means of theory to long-term problems. However, when this is done, the limitations inherent in the procedure should be kept in mind. 

The accelerated aging test should take into account the associated materials as well as the atmosphere that will be encountered in actual use, since they are also controlling factors. It is helpful to include materials of known performance against which to rate the new material, since this allows a check of controlling factors and further validates the extrapolation. Thus, existing data from long term tests may be of considerable value. 

The findings from two long term test runs in the SASOL plant relevant to catalyst life under design conditions in a commercial methane synthesis plant have already been published (3). This paper reports further test results from both demonstration units concerning the effect of certain reaction parameters which are the basis for flexibility and operability of the Lurgi methanation scheme. 

The SASOL plant was operated with a surplus of C02 during a long term test of 4000 hrs. Of the C02 in the synthesis gas, 33.4% was metha-nated while the remaining 66.6% left the reaction system unconverted. Product gas from final methanation yielded specification grade SNG containing residual hydrogen of 0.7 vol % and residual CO of less than 0.1 vol %. The heating value was 973 Btu/standard cubic foot (scf) after C02 removal to 0.5 vol % (calc.). 

The Schwechat plant was operated with a stoichiometric synthesis gas in a long term test of 5000 hrs. The residual hydrogen content could be decreased to 2.2 vol % which resulted in a heating value of 950 Btu/scf when about 1 vol % nitrogen was present in the synthesis gas. 

The long term tests in the SASOL plant as well as in the Schwechat plant were run with outlet temperatures of 450°C, but both plants were also operated with higher loads that caused reactor outlet temperatures of 470°C or even higher. In comparison with the test run at 450°C, only a slight increase in deactivation rate was detectable which demonstrates the thermostability of the catalyst. From the aspect of thermostability, outlet temperatures of 450°-470°C are acceptable. Further considerations including the possibility of overload operation, the SNG specification to be achieved in final methanation, end-of-run conditions, and cost of reactor material will affect the selection of optimum outlet temperature. 

Monomethyltirf. Acute toxicity studies were identified for monomethyltin for algae, invertebrates, and fish. Chronic NOECs were available for algae and invertebrates. A chronic NOEC of 0.007 mg/1 for monomethyltin chloride in Scenedesmus subspica-tus was the lowest reported result. Since there were no long-term test results available for fish, it was necessary to apply an uncertainty factor of 50 to the critical study. 

Monobutyltirr. Four acute toxicity studies were identified for monobutyltin chloride. The critical study was an acute EC50, based on immobilization, for Daphnia magna at a concentration of 25 mg/1. All four tests were acute, and, in the absence of long-term tests, it was decided to apply an uncertainty factor of 1000. 

Dibutyltin. A larger data set exists for dibutyltin, including both acute and long-term test results. The lowest concentration identified was a chronic NOEC of 0.015 mg/1 for Daphnia magna exposure to dibutyltin chloride. Long-term values were available across three trophic levels, and, therefore, an uncertainty factor of 10 was considered appropriate. 

Waters MD, Stack HF, Jackson MA, et al. 1994. The performance of short-term tests in identifying potential germ cell mutagens A qualitative and quantitative analysis. Mutat Res 341 109-131. 

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