Testing usefulness

Bearing elements made of bearing steel were subject to studies. External ring-type elements with an internal race of 20 mm diameter and 12 mm height (Fig.4) were subject to tests using the contact probe and internal volumetric ones. Results of tests are given in Table 2. 

A number of real objects with artificially made disbonds were tested using the Fokker Bond Tester and spectra were stored in a PC for the classification. One of the objects, "Lower wing skin is shown in Figure 4. As can be seen, the positions and sizes of flaws are marked. The same marks were also drawn on the actual objects to facilitate measurements. 

Classifier structures resulting from the training were verified in a blind test. To evaluate the reliability and performance of the NSC it was subjected to a blind test using unknown data containing spectra measured for various sizes and locations of the disbonds (from 50% to over 100% of the probe size). 

The 16-bit and 32-bit software for eddy current testing using PC measurement cards manufactured by SOFRATEST, France, is presented in this article. Microsoft Visual C/C++ Development System and Tools have been used. 

The CamuS system is currently in the form of a laboratory prototype and is undergoing a series of validation tests using an extensive set of test-pieces covering a range of geometries and classes of defect which has been manufactured for the purpose. 

Finally, a model has to be tested using an independent data set with compounds yet completely unknown to the model the test set. The complete process of building a prediction model is depicted in Figure 10.1-1 as a flow chart. 

HyperChem s im plem eti tatiori of/INDO/1 has been tested using param eters suggested by referen ces to work dorieby Zerueron first row transition metals. 

Fig. 9.35 Some typical molecules tested using the PROMET approach to predicting crystal structures.

Procedure. The method can be tested using the matrix of concentrations, in micromoles per liter (pmol L ), of tryptophan and tyrosine at 280 nrrr suitably rrrodified to take into account constant absorption at 280 nrrr of some absorber that is neither tryptophan nor tyrosine... 

TABLE 15.3 Benzene Single Point Calenlation Tests Using the ee—/ VTZ Basis Set (rnn on a Cray SVl eonflgnred with J90 CPUs eoinpnted with Ganssian 98 revision A.7)... 

HyperChem s implementation of ZINDO/1 has been tested using parameters suggested by references to work done by Zerner on first row transition metals. 

This is an example of a paired data set since the acquisition of samples over an extended period introduces a substantial time-dependent change in the concentration of monensin. The comparison of the two methods must be done with the paired f-test, using the following null and two-tailed alternative hypotheses... 

In Examples 14.7 and 14.8 we have seen how a collaborative test using a pair of closely related samples can be used to evaluate a method. Ideally, a collaborative test should involve several pairs of samples, whose concentrations of analyte span the... 

Aromatic and Nonaromatic Hydrocarbon Separation. Aromatics are partially removed from kerosines and jet fuels to improve smoke point and burning characteristics. This removal is commonly accompHshed by hydroprocessing, but can also be achieved by Hquid-Hquid extraction with solvents, such as furfural, or by adsorptive separation. Table 7 shows the results of a simulated moving-bed pilot-plant test using siHca gel adsorbent and feedstock components mainly in the C q—range. The extent of extraction does not vary gready for each of the various species of aromatics present. SiHca gel tends to extract all aromatics from nonaromatics (89). 

Auckland Regional Authority converted two M.A.N. buses to use a cetane improver and methanol and South Africa investigated the use of methanol with a proprietary cetane improver. Eour Renault buses were converted in Tours, Erance to operate on ethanol and a cetane improver, Avocet, manufactured by Imperial Chemical Industries (ICI). The results of these demonstrations were also technically successfiil slightly better fuel economy was obtained on an energy basis and durabiUty issues were much less than the earlier tests using dedicated engines. 

The correct viscose age or ripeness for spinning varies according to the type of fiber being made. Ripeness can be assessed by estabHshing the salt concentration necessary to just coagulate the viscose dope. The preferred test uses sodium chloride (salt figure) although ammonium chloride is the basis of the alternative method (Hottenroth number). 

One problem associated with discussing flame retardants is the lack of a clear, uniform definition of flammabiHty. Hence, no clear, uniform definition of decreased flammabiHty exists. The latest American Society for Testing and Materials (ASTM) compilation of fire tests Hsts over one hundred methods for assessing the flammabiHty of materials (2). These range in severity from small-scale measures of the ignitabiHty of a material to actual testing in a full-scale fire. Several of the most common tests used on plastics are summarized in Table 1. 

Factory Mutual Corner Test. This is a large-scale comer test used to test building products (18—20). The test rig consists of three sides of a cube. The two walls are 15.24 and 11.58 m by 7.62 m tall. The ceiling is 9.14 x 15.24 m. The product to be tested is mounted on the walls and ceilings ia a manner consistent with the iatended use. The fire source is a 340 kg stack of wood pallets located ia the corner. In order to pass the test, no flame can propagate to any extremity of the walls or ceiling. The Factory Mutual flammabiHty apparatus is proposed to replace this test for certain appHcations (21). 

The mechanical properties of rigid foams vary considerably from those of flexible foams. The tests used to characterize these two classes of foams are, therefore, quite different, and the properties of interest from an application standpoint are also quite different. In this discussion the ASTM definition of rigid and flexible foams given earlier is used. 

Species origin tests, used to determine whether the specimen is human or from another source, are immunological in nature. Host animals, usually rabbits, are injected with protein from another species. The animal creates antibodies to the unknown material. Semm from the host animal, containing species (human, bovine, equine, canine, etc) specific antibodies, is tested against a dilute solution of blood (antigens) collected as evidence. A positive reaction is determined by a visible band where the antibodies and antigens come into contact. 

Vickers Hardness. The Vickers or diamond pyramid hardness (DPH) developed in 1924 was an improvement over the Brinell test. The Vickers test used a pyramidal diamond as the indenter. This permitted the hardness testing of much harder materials, and the constant 136° angle of the indenter eliminated the problem of variable indentation shape encountered using spherical indenters (1). 

Ultrasonic Microhardness. A new microhardness test using ultrasonic vibrations has been developed and offers some advantages over conventional microhardness tests that rely on physical measurement of the remaining indentation size (6). The ultrasonic method uses the DPH diamond indenter under a constant load of 7.8 N (800 gf) or less. The hardness number is derived from a comparison of the natural frequency of the diamond indenter when free or loaded. Knowledge of the modulus of elasticity of the material under test and a smooth surface finish is required. The technique is fast and direct-reading, making it useful for production testing of similarly shaped parts. 

To extend the study of the apparent decomposition recombination reaction, and specifically to determine if the carbon atoms exchange with other atoms in other acetylene molecules, tests using carbon isotopes were conducted. A mixture of 50% regular acetylene, C2H2, and 50% heavy acetylene. 

Process variables also play a significant part in determination of surface finish. For example, the higher the current density, generally the smoother the finish on the workpiece surface. Tests using nickel machined in HCl solution show that the surface finish improves from an etched to a poHshed appearance when the current density is increased from ca 8 to 19 A/cm and the flow velocity is held constant. A similar effect is achieved when the electrolyte velocity is increased. Bright smooth finishes are obtained over the main machining zone using both NaCl and NaNO electrolyte solutions and current densities of 45-75 A/cm. ... 

To determine in the laboratory if a component survives in use, a test bogey is frequentiy estabUshed based on past experience. The test bogey is with the particular test used to dupUcate (or simulate) field conditions. The bogey can be stated in cycles, hours, revolutions, stress reversals, etc. of components are placed on test and each component either survives or faUs. The reUabiUty for this situation is estimated. 

Fig. 5. Hot workabihty of cast Nknonic 115 as determined by tensile testing using a Gleeble machine (O), heating (D), cooling 1135°C (A), cooling...

Overall, the test methods pubhshed by INDA (Table 4) continue to be the general tests used to characterize fabrics however, specific market apphcations often generate special test procedures to fiilfill unique needs. 

---