Testing duration

Velocity, m /min Wear factor Dynamic K X 10-", 1/Pa " coefficient of friction Test duration, h... 

Example 5. There are six dynamometers available for engine testing. The test duration is set at 200 h which is assumed to be equivalent to 20,000 km of customer use. Failed engines are removed from testing for analysis and replaced. The objective of the test is to analy2e the emission-control system. Failure is defined as the time at which certain emission levels are exceeded. 

Favorable polymer physical properties include water solubiUty and sample purity. Environmental conditions to consider in evaluating biodegradabihty are temperature, pH, moisture, oxygen, nutrients, suitable microbial population (fungal, algae, bacterial), concentration, and test duration. 

Density,g/mL T emperature, K StressJVIPa a Creep rate,s Deformation,p.m Test duration,10 s... 

If anticipated corrosion rates are moderate or low, the following equation gives a suggested test duration ... 

Type of apparatus used for test Duration of each test (start, finish)... 

Test duration at 1 min/m of the surface area under test, subject to a minimum of 3 minutes. After the le.st, there will be no penetration of water inside the enclosure. 

The test must be conducted at the rated current, at a frequency with a tolerance of -t-2% and -5% of the rated frequency and the voltage in a sinusoidal waveform, as much as practicable. See also Section 11.3.2. The test is earned out until the temperature reaches almost a stable state, i.e. when the variation does not exceed 1°C per hour. To shorten the test duration, the current may be enhanced during the initial period to reach a fast, stable state. 

However, due to the minor variations in the phase impedances, all the phases may not be subjected to identical severity of faults. For instance, in the above test each phase has recorded a different fault cunent. To evaluate the fault level from these test data, the general practice has been to consider the phase that has recorded the highest fault current as the base, which may occur in any of the phases. In the above test, it has occurred in phase Y. For this fault current, the test duration is adjusted to achieve the required severity of fault in terms of thermal effect (50 x 1 in the above case). 

Some users/consultants, however, are of the opinion that by this method the other phases are not subjected to the same severity. Accordingly, they prefer to consider the phase that is subjected to the least fault current as the base. Accordingly, the test duration should be adjusted for this phase. In the above case, the minimum severity has occurred in phase R, with only 39.6 kA. According to this philosophy the test duration should be enhanced to... 

Test Duration Test Duration Test Duration Test Dur... 

This is another name for a heat run test. A voltage sufficient to cause an output of the capacitor unit equal to 1.5 times the rated output is applied at the rated frequency and test conducted for at least 48 hours. During the last six hours of the test the temperature rise and tan 5 are measured at least four times. The temperature rise during the last six hours should not exceed 1 C, otherwise the test duration must be extended until the temperature stabilizes to a rise of only l°C. The final test results... 

If il is not possible lo carry out the lest al 75%, 80% or 85% of the lest values, as prescribed above or for some reasons the lest duration may have to be increased by more than one minute, then it is permissible for the test voltage to be further reduced to suit the site and instead, the test duration increased The reduced test voltages for longer test durations are provided in Table 14.8. 

Another modification to the slow strain-rate test involves the superimposition of a low amplitude sine wave ripple on the slow uniform extension (Fig. 8.47). In effect this produces higher strain rates (which appear to be more damaging for hydrogen embrittlement), while still giving a long test duration, with adequate time for the accumulation of hydrogen in the steeps. 

The methanation section was operated for a total of 561 hrs. The runs, test duration, and total coal feed during methanation testing are summarized in Table II. 

The length and amount of cracks is assessed according to the Bayer method [72,73]. The ISO standard ozone test conditions involve a test temperature of 40°C zE 1°C and an ozone level of 50 5 pphm, with a test duration of 72 h. Testing is done under static [72] and/or dynamic strain [73]. These are accelerated tests and should be used for the relative comparison of compounds, rather than for the prediction of long-term service life. The method is rather complicated and demands a long duration of ozone exposure. Therefore, in some cases the rate constants of the antiozonants reaction with ozone in solution are used instead to evaluate the efficiency of different antiozonants [74]. 

Many factors can contribute to reducing testing durations compared with anticipated component service life. However, in the simplest case where conditions of strain, pressure, and temperature are the same for both service and testing, test acceleration can arise simply because there are situations where test simulations can be continual in the laboratory, whereas in practice actual events occur only every few days or weeks, as illustrated below. 

In a Japanese plasma wind tunnel, SPA specimens were tested up to 3.8 MW/m2 at 0.7 bar aerodynamic pressure (Fig. 12). After a test duration of 60 s, no obvious damage was visible. The surface temperature of about 2600°C was reduced to 100°C within 20 min. Further analysis showed a maximum charred depth of the ablator of 15 mm. The carbonization process did not change the geometric dimensions, the new heat protection system can be considered absolutely stable to deformation. The carbonized layer still has a noticeable pressure resistance and transfers the load applied by the dynamic pressure to the structure. 

Classical heat transfer provides expressions for quantities such as view factors, radiation and temperature fields in semi—infinite bodies. The lining materials studied here were treated as semi-infinite bodies since the test duration is relatively short. 

LC50 Lethal concentration 50% (dose required to kill half the members of a tested population after a specified test duration)... 

Creep testing of weld joints to determine weld joint strength reduction factors should be full thickness crossweld specimens with test durations of at least 1 000 h. Full thickness tests shall be used unless the designer otherwise considers effects such as stress redistribution across the weld. 

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