Types of Tests

Three types of tests can be distinguished according to where they are carried out [1, 2] in the laboratory, in outdoor exposure stations, or on prototypes. 

Laboratory tests are generally done in synthetic media that are as aggressive as possible (while still being selective) in order to assess as quickly as possible (the time scale is in 

The details of procedures and the like for all types of tests— physical, mechanical, chemical, optical, insulation, electrical, and so on— are reviewed in the different specifications such as the ASTM standards. These procedures explain the reasons for a test, how to conduct it, how to determine the results, and sometimes provide information on long-term test results such as fatigue, creep, and so on. With all the available tests, confusion could exist in deciding which ones to conduct if experience in them does not exist. To eliminate confusion it is important to determine what could occur on a product that would be damaging. Here basic logic has to be used—examine the tests that incorporate and evaluate the potential damage. Examples of these tests are presented in Tables 9-1 to 9-7. 

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Type of tests Pneumaic test on spherical gasholder... 

The case of thin-skin regime appears in various industrial sectors such as aerospace (with aluminium parts) and also nuclear in tubes (with ferromagnetic parts or mild steel components). The detection of deeper defects depends of course on the choice of the frequency and the dimension of the probe. Modelling can evaluate different solutions for a type of testing in order to help to choose the best NDT system. 

Figure 2. Standard types of testing loads and their spectrums a - small cyclic pulse loads b - step loads c - growing pulse loads.

Since the geometry of the wheel is also displayed during this type of test, it is important to distinguish between defects and geometrical influences. The tester can easily and reliably make these distinctions, if the distortions of the wheel s geometry and the display of the defects caused by the display of the test system are not to great. 

The System of accreditation is a mechanism that ensures official recognition that calibration or testing laboratory has right to perform testing of measuring devices, specific testing or specific types of testing. 

Eorensic science laboratories may have different missions and therefore conduct different types of testing on samples (21,22). Eor example, the United States Department of Justice, Dmg Enforcement Administration (DEA) forensic laboratories assist authorities ia criminal intelligence-gathering efforts. As such, DEA chemists routinely analyze both the iUicit dmg and excipient, the material used ia the cutting or diluting of the pure dmg, ia a given specimen. The excipient may provide information as to where the sample was produced. 

How Many Samples. A first step in deciding how many samples to collect is to divide what constitutes an overexposure by how much or how often an exposure can go over the exposure criteria limit before it is considered important. Given this quantification of importance it is then possible to calculate, using an assumed variabihty, how many samples are required to demonstrate just the significance of an important difference if one exists (5). This is the minimum number of samples required for each hypothesis test, but more samples are usually collected. In the usual tolerance limit type of testing where the criteria is not more than some fraction of predicted exceedances at some confidence level, increasing the number of samples does not increase confidence as much as in tests of means. Thus it works out that the incremental benefit above about seven samples is small. 

Test Methods. Two basic types of test methods are commonly used to measure sound-absorption in test laboratories the reverberation room method and the impedance tube method. 

Example 4. A particular microprocessor (MPU) is assigned for a fuel-injection system. The failure rate must be estimated, and 100 MPUs are tested. The test is terrninated when the fifth failure occurs. Failed items are not replaced. This type of testing, where n is the number placed on test and ris the number of failures specified, is termed a Type II censored life test. 

Tests using a constant stress (constant load) normally by direct tension have been described in ISO 6252 (262). This test takes the specimen to failure, or a minimum time without failure, and frequently has a flaw (drilled hole or notch) to act as a stress concentrator to target the area of failure. This type of testing, as well as the constant strain techniques, requires careful control of specimen preparation and test conditions to achieve consistent results (263,264). 

A thorough sampling plan should describe when the sample is to be taken and how many samples are required. It also specifies from what location within the equipment, such as the manway or discharge valve, to take the sample. The plan should also indicate what sampling equipment and sample container should be used, as well as the type of tests to be performed and the acceptance criteria. 

The characteristic separation curve can be deterrnined for any size separation device by sampling the feed, and coarse and fine streams during steady-state operation. A protocol for determining such selectivity functions has been pubHshed (4). This type of testing, when properly conducted, provides the relationships among d K, and a at operating conditions. These three parameters completely describe a size separation device and can be used to predict the size distribution of the fine and coarse streams. 

Since oxygen uptake is tested in a closed system, loss of volatilization is minimal. This type of test is not reUable for estimating service life under conditions in which the polymer is exposed to air movement. 

In a top-feed filter test, the filter cake will contain all of the solids, provided they are all emptied from the sample container. The danger in this type of test is that the solids will stratify, particularly if the c e formation time is prolonged. Close examination of the filter cake will... 

There is no standard or preferred way to cany out a corrosion test the method must be chosen to suit the purpose of the test. The principal types of tests are, in decreasing order of rehability ... 

In either type of test run, an opportunity exists to ensure the utilities for the process are capable of performing their function. 

This will be carried out under similar parameters of room condition and the type of test voltage wave to those for a switchgear assembly (Section 14.3.5). The current in each phase should be within 2% of the specified test value (rated current). 

This type of testing is worth continuing and should be extended to more complex cases. 

For question 13, what types of testing would you recommend to ensure uniformity of waste batches that enter the treatment facility to minimize violent exothermic reactions from occurring between waste treatments ... 

Although the Izod and Charpy tests are widely used for plastics, other types of test are also popular. These include tensile impact tests and flexural plate (falling weight) tests. The latter is particularly useful in situations where the effects of flow anisotropy are being assessed. In addition, arbitrary end-product tests are widely used to provide reassurance that unforseen factors have not emerged to reduce the impact performance of the product. 

During these types of test it is the energy absorbed at fracture, Uc, which is recorded. In terms of the applied force, Fc, and sample deformation, 5, this will be given by... 

Field test kits have been used with success on many sites for a variety of contaminants. The types of test kits available and their continued use appear to be a wave of the future. Certainly, the skills of the sampling technician and field test kit user are two very important areas for consideration. 

Three general types of testing that may make systems unavailability are ... 

Since the potentials were constructed by fitting equilibrium properties of the Llo lattice it is very important to test that spurious unphysical structures may not be stabilized in a defective environment. While this can never be done fully, two types of tests can be carried out that provide a reasonable assurance. 

Secondly, the Llo structure must be stable with respect to both small and large strains. The former is assured by the positive definiteness of elastic moduli. Clearly, an exhaustive test of the stability with respect to large strains cannot be made and the following two types of tests were performed. First, the energy of the structure was calculated as a function of strains corresponding to 20% changes in the lattice parameters a and... 

ASSESSMENT OF LEVEL OF CONTROL ANO TYPE OF TEST CONDITION AT TIME OF TEST ... 

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