Bias extension test

In a manner similar to that shown for the shear-frame test, DIC can be used to capture the shear-angle contours developed in the fabric during a bias-extension test, which can be compared to the shear angles predicted by the finite element model (Fig. 6.30). It is noted that the boundaries for the three different theoretical zones as viewed in the experiment (DIC image) do not exhibit as sharp a transition as is shown for the boundaries in the simulations. The sharp transitions observed in the model are due to the pin-jointed connections between the elements whereas in reality, the yams are continuous and are allowed to bend along a smooth curve (Fig. 6.31). 

Lebrun G, Bureau MN, Denault J. Evaluation of bias-extension and picture-frame test methods for the measurement of intraply shear properties of PP/glass commingled fabrics. Compos Stmct 2003 61 341-52. 

Knowledge of precision and bias is important if acceptance criteria are to be established. Confidence in the values obtained is necessary when a test is used to separate acceptable and unacceptable material. Generally, the establishment of acceptance criteria requires extensive testing of the product forms of interest. 

Other polyamides having higher moduli and T than nylon-6 and nylon-6,6 have been evaluated in an effort to reduce wrinkle resistance and eliminate flat-spotting of bias and bias-belted tires (Table 3). Nylons have also been tested extensively over the years for apparel and carpets (Table 4). 

Standard methods of analysis published by bodies such as the American Society for Testing and Materials (ASTM), de Normalisation (CEN), or ISO are rigorously tested and validated in method performance, or validation, studies. These interlaboratory trials can establish reproducibility and method bias and also give some confidence that the method can be used in different environments. Laboratories are chosen with an expectation that they can competently follow the proposed method, which will have already been extensively validated before an interlaboratory trial is contemplated. To this end, a pilot trial is sometimes undertaken to ensure the method description can be followed and to give an initial estimate of the precision of the method. 

In collaboration with Mieczkowski and associates, we have performed extensive epidemiological studies of drug use in arrestee populations in Pinellas County, Florida. The studies, by comparing hair, urine, and self-reports, also provided independent validation of our hair analysis technology. In addition, these studies provided further evidence for the absence of racial bias in hair testing, a correlation between frequency of cocaine use and cocaine levels in hair, and information on the relative effectiveness of hair and urine analysis for identifying drug use. 

Continued emphasis may be expected on interlaboratory testing and establishment of precision and bias for standard test methods. Equally necessary for quahty control is extensive evaluation of the product forms of interest to establish acceptance criteria that discriminate between satisfactory and unsatisfactory material. While rapid and inexpensive tests will be used for most quality control tests, an increase in more sophisticated techniques such as electrochemical testing and slow strain rate techniques is expected. Additional work is necessary to improve reproducibility of rusting, pitting/crevice, and SCC tests. In some cases, control of the specimen potential may improve test reproducibility. 

The equation of Johnson et alf is one of most accurate available for LJ chains, since it is heavily based on computer simulation data. Equally the soft-SAFT equation is very accurate for modelling mixtures of associating LJ fluids. In their extension to mixtures Bias and Vega performed extensive simulations on model homo- and heteronuclear fluids and their mixtures to test the soft-SAFT approach, before application of the theory to real fluids in a subsequent paper was undertaken by the authors. Soft-SAFT has been applied to the study of alkanes and their binary and ternary mixtures, perfluoro-alkanes, alcohols, carbon dioxide,polymers, and more recently room temperature ionic liquids. ... 

Such 3D cell cultures could be incorporated into a CCA device. Of particular interest may be 3D hydrogels, which are relatively easy to produce and are adaptable to cocultures. While extensive work has been done with hydrogel cultures [Drury and Mooney, 2003], these studies have not focused on applications to toxicity testing. Hydrogels are easy to make and it can be used to study cocultures. The hydrogel must be biocompatible, bioresorbable, and nontoxic such that it does not bias the experiments. 

As said, in a perfect world this would be great. However, some factors make this difficult even though every effort has been made to follow the MOU (1) As mentioned in the ISO section, EU members of ISO must operate under EU standards (2) some non-EU nations that participate in ISO have regulations governing the order in which they use standards from the various standards bodies. Eor example, if there is a standard within their own national body, that has first priority if not, then it may state a second and third order in which the nation is to use standards and (3) there are format differences. For example, there is a requirement within ASTM International that any test method must have a precision and bias statement in it. This requires an extensive laboratory test program to determine within-laboratory repeatability and interlabora-tory reproducibility of the test results. This is not a requirement within ISO. 

The testing that must be performed in order to assure the rehabflity of solder joints in a microelectronic assembly is extensive because of the large number of possible failure mechanisms that must be addressed. Most tests are the same for both lead-containing and lead-free solders. Among the tests conducted most frequently and rehed upon most heavily are high-temperature storage, temperature and humidity, temperature and humidity with bias, mechanical shock and vibration, and hostile environment exposure. This section discusses those tests specific to high-tin solders. 

---