Ring test method

The same test method, although not standardized, can be used to characterize the laminate in-plane shear behavior. This is accomplished by winding a multiorientation (hoop/helical and/or helical only) tube. Other test methods that can be used to measure in-plane shear stiffhess/strength of filament wound composites are discussed by Tamopol skii and Kinds [45]. These methods include schemes for torsion of intact rings and split rings. Both of these ring test methods are used to evaluate the in-plane shear modulii G0r and G0z for a filament-wound laminate. 

The laminate compressive hoop strength/stiflness of a filament-wound vessel can be evaluated using the externally pressurized ring test method [44] or the standardized ASTM D2586 test method. In the ASTM D2586 test method a filament-wound FRP cylinder is tested under hydrostatic pressure to simulate the loading conditions of a pressure vessel under an external pressure load. The main drawback of this test method is the influence of the end constraints on the test results. 

Method satisfactory for reference method but not EC ring tested. Method already has been tested in more than one laboratory or/and may already be officially used in an EC member state. 

Analytical and Test Methods. Most of the analytical and test methods described for THF and PTHF are appHcable to OX and POX with only minor modifications (346). Infrared and nmr are useful aids in the characterization of oxetanes and their polymers. The oxetane ring shows absorption between 960 and 980 cm , regardless of substituents on the ring (282). Dinitro oxetane (DNOX) has its absorption at 1000 cm . In addition, H-nmr chemical shifts for CH2 groups in OX and POX are typically at 4.0—4.8 5 and 3.5—4.7 5, respectively (6,347,348) C-nmr is especially useful for characterizing the microstmcture of polyoxetanes. 

Knight and Allen. This is a copper reduction method for reducing sugars in white sugar up to 0.02%. It utilizes EDTA to determine excess unreacted copper. Tests undertaken in 1994 to extend the range of this method were unsuccesshil. In spite of poor performance in ring tests, it remains an official ICUMSA method. 

It is important to note that simulated distillation does not always separate hydrocarbons in the order of their boiling point. For example, high-boihng multiple-ring-type compounds may be eluted earher than normal paraffins (used as the calibration standard) of the same boiling point. Gas chromatography is also used in the ASTM D 2427 test method to determine quantitatively ethane through pentane hydrocarbons. 

A ring test proved that surfactant-selective electrodes are suitable for quantitative determination of anionic surfactants including alkanesulfonates [21]. The precision of this method, however, does not yet correspond to the state-of-the-art of the two-phase titration. Therefore, further development is needed to enhance the reproducibility and competitiveness of surfactant-sensitive titration. 

Nyholm N, P Kristensen (1992) Screening methods for assessment of biodegradability of chemicals in seawater—results from a ring test. Ecotoxicol Environ Saf 23 161-172. 

Many experts in Europe have tested the methods of both standards with various pesticide-matrix combinations in their own laboratories. Consequently, the responsible working groups of CEN TC 275 concluded that these are the best methods available. Nevertheless, there is no complete validation of all possible pesticide-matrix combinations. However, for most multi-residue methods within the standards all those pesticides which had been successfully tested in method validation trials and/or proficiency tests are listed. Also, matrices which had been examined in ring tests are listed. 

The determination of LOD and/or LOQ is not officially required. In a ring test of more than 10 laboratories initiated in 1992 by the Society of German Chemists [Gesellschaft Deutscher Chemiker (GDCh)] it was shown that these characteristics differ between laboratories by about one order of magnitude, even if the same pesticides are determined in similar matrices with the same method and calculation of the LOD or LOQ is performed in an identical way. 

ISO 13844 2000 Plastics piping systems - Elastomeric-sealing-ring-type socket joints of unplasticized poly(vinyl chloride) (PVC-U) for use with PVC-U pipes - Test method for leaktightness under negative pressure... 

As shown in Figure 11, before extensive validation, the performance of the method is evaluated appropriately. Column durability tests, robustness testing for the chromatographic and sample preparation conditions, analytical method evaluation ring tests (AMERTs), method capability assessments, and pre-validation studies are applied to... 

At present (2007), lOOC is carrying out some ring tests in order to verify the accordance of the two methods of elution. Separation on the basis of unsaturation can be improved by modifying the stationary phase by Ag-F ions, as the dimension of Ag+ ion is suitable to interfere with n bonds. Christie [10-12] adopted this technique to carry out structural analysis of TAGs. TAGs were hydrolyzed by Grignard reaction, then the stereoisomers 1,2 and 1,3-diacylglyreols were transformed into diasteroisomers by derivatization with a chiral compound, and were separated on normal-phase (NP)-HPLC. 

In 2007 lOOC organized a ring test involving about 20 laboratories in order to standardize the method. The results showed a mean RSD of abont 20%. In the following sections, analytical approaches will be discussed for different kinds of food. 

Bowmer, C.T. (1993). Method for the assessment of acute toxicity of contaminated sediment using the burrowing heart vachm Echinocardium cordatum. Test Guideline for OSPAR sediment reworker ring test. Report IMW R93/317. 

ASTM D2290 standard test method for apparent tensile strength of ring tubular plastics... 

ASTM D2291 standard test method for fabrication of ring test specimens for glass-resin... 

Method ring tested and EC approved as reference method. 

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