A method for the routine determination of compression modulus of rubber vulcanizates

A novel method for determining the compression modulus of rubber vulcanizates is described. The test is rapid and the results are repeatable and, moreover, relatively free of operator dependence. The test machine is simple and inexpensive. The test meets most of the criteria for an ideal test method for routine application in a quality control laboratory, and it should prove useful to manufacturers of engineered rubber components where the control of component stiffness is important.     

Modified V-notched rail shear test fixture for shear characterisation of textile-reinforced composite materials

The V-notched rail shear test (VNRS) is recognised as a standard test method for the determination of shear modulus and shear strength of fibre-reinforced composite materials. This method is based on a double V-notched specimen with a large gauge section and an approximately uniform shear stress distribution between the two notches. The construction of the test device prescribed in standards was revised with the main focus of lines of force as well as precise and economic specimen clamping. Therefore, the modified test fixture has been equipped with guide units and the number of clamping bolts could be reduced. The standardised and modified VNRS fixtures were evaluated using a finite element method. It can be shown that the modified VNRS test fixture is well suited for robust and reliable material characterisation of shear property data.     

Modifications to the AOAC use-dilution test for quaternary ammonium compound-based disinfectants that significantly improve method reliability

The AOAC use-dilution test (UDT) for bactericidal disinfectant efficacy (Method 964.02) has often been criticized for its extreme variability in test results, particularly for quaternary ammonium compound (QAC)-based disinfectants against Pseudomonas aeruginosa. While efforts are under way to develop a new and better test method for hospital disinfectant products that is globally acceptable, U.S. manufacturers and formulators of QAC products must continue in the interim to measure their product performance against the current UDT method. Therefore, continued variability in the UDT places an unnecessary and unfair burden on U.S. QAC product manufacturers to ensure that their products perform against an, at best, unreliable test method. This article reports on evaluations that were conducted to attempt to identify key sources of UDT method variability and to find ways to mitigate their impact on test outcomes for the method. The results of testing across 4 laboratories, involving over 6015 carriers, determined that operator error was a key factor in test variability. This variability was found to be significantly minimized by the inclusion of a simple culture dilution step. The findings from this study suggest possible refinements to the current AOAC UDT method that would serve to improve the overall ruggedness and reliability of the method and to optimize recovery of cells from the carrier surface, thereby further improving the accuracy and reproducibility of counts and test outcomes until such time as a replacement method is implemented.     

A new approach for proficiency test exercise data evaluation

In this paper, a new data evaluation method for proficiency test exercises consisting of a combination of a z-test, a zeta test and an uncertainty outlier test is presented. This new method is compared with eight other evaluation methods (both measurement uncertainty using and measurement uncertainty ignoring) in common use and/or recommended by ISO 13528. The data set used to test the evaluation methods is real data and consists of the ⁹⁵Nb results of the National Physical Laboratory Environmental Radioactivity Proficiency Test Exercise 2007. The evaluation of 14 out of 32 results were affected by the choice of method.     

面接触三探针测试硅外延片的电阻率

本法(以下简称面三探针)是我国首创,它比点接触方法优越得多,可扩大目前外延片电阻率三探针测试的范围。本文阐述使用该法对校正样块硅单晶和外延片测试的情况。     

The Use of Miniature Disc Bend Tests with Plastic Materials

The use of miniaturised disc bend tests, a method that is commonly used with metallic materials, is assessed for use with polymeric materials. The test method uses the indention force/displacement characteristics for a hemispherical-ended punch forced onto a small disc of the test material. Characterisation tests were performed using acetal, PMMA and polypropylene, under a range of different test rates and temperatures. These were compared with conventional tensile tests under the same conditions. Although no quantitative comparison between the two methods has been formulated, good qualitative agreement was found for all materials, including a wider comparison with nine materials. The advantages of the disc bend test are that smaller amounts of material are needed, the sample preparation is easier, the test is often easier to perform, it shows ductile–brittle transitions more sharply and is a very convenient method of performing environmental stress cracking tests.     

香菇(干品)中微量二氧化硫的测定

讨论了用氮气吹脱蒸馏法测定香菇（干品）中ＳＯ２含量的方法,选择了测定的最佳条件。     

Scratch test measurement of tribological hard coatings in practice

The adhesion is a fundamental property of hard coatings in view of tribological-mechanical demands. The quantification of adhesion between coating and substrate is with respect to practice not easy to handle, even so the scratch test is the best established and well discussed test method. The present study analyzes the test procedure and proposes a possible evaluation method and interpretation of the results to reach sufficient reproducibility due to a better standardization. Received: 24 June 1996 / Accepted: 5 December 1996     

Proficiency testing: binary data analysis

A method for evaluating qualitative proficiency testing (PT) of laboratories conducting binary tests is proposed. The method is based on the scale-invariant item response model proposed by the authors in earlier publications. We consider the case where the laboratories under the PT conduct test consisting of a set of test items/species presenting different, but unknown beforehand levels of difficulty when trying to detect a particular property of theirs, and we need to evaluate/compare both the intrinsic abilities of the participating laboratories and the level of difficulty of the test items. We assume that the responses to different test items do not affect one another and discuss how to get and interpret the most likely estimates/scores. The method is illustrated by the example presented in a recent publication by our colleagues from QuoData GmbH and can be considered as an alternative to that proposed in their publication method of scoring.