Sample applying initial load

After an initial loading of the sample in the injection channel, inject sample injected by applying voltage of 1500 V between the sample... 

The influence of temperature on the compressibility of unsaturated clay has been studied by compression tests in oedometric conditions. The initial dry density of the samples has been 1.70 g/cm, and the clay was compacted uniaxially with its hygroscopic water content inside the oedometer ring (diameter of 5.0 cm, length of the specimen of 1.2 cm). A vertical pressure between 22 and 26 MPa was applied to manufacture the specimens. Three different samples were heated up to 25, 60 and 80 °C under a low vertical load (0.4 MPa). Afterwards, the samples were progressively loaded by steps up to 20 MPa. The tests were performed in an... 

Wang and Campbell studied the stress relaxation curves for their samples by applying a 25 % constant strain and measuring the normalized stress relaxation for 30 s. They also performed creep measurement. The initial load was applied by compressing the samples at 4 mm/s ( 33 %/s) up to 25 % strain or when it reached 223 N and holding the force for 30 s [54]. 

It is also recommended that the initial load be applied after the polymer equilibrates at a temperature below its Tg for a certain period of time (usually 10-15 minutes). Sircar and Chartoff (1994) demonstrated poor reproducibihty of coefficient of thermal expansion with a number of elastomeric samples when the load was apphed at room temperature. 

Fig. 14 History dependence of creep in a single (one sample) polypyirole film. An initial load of 2 MPa is applied. Stress is then increased to 20 MPa for 100 min and returned to 2 MPa for the final 150 min. The dashed-curve data was taken 2 days after immersion of the sample in propylene carbonate, and the solid-curve data was obtained a finiher 6 days later. Measurements were performed at 24 °C (Reprinted from Madden et al. (2007))...

An alternative to the measurement of the dimensions of the indentation by means of a microscope is the direct reading method, of which the Rockwell method is an example. The Rockwell hardness is based on indentation into the sample under the action of two consecutively applied loads - a minor load (initial) and a standardised major load (final). In order to eliminate zero error and possible surface effects due to roughness or scale, the initial or minor load is first applied and produce an initial indentation. The Rockwell hardness is based on the increment in the indentation depth produced by the major load over that produced by the minor load. Rockwell hardness scales are divided into a number of groups, each one of these corresponding to a specified penetrator and a specified value of the major load. The different combinations are designated by different subscripts used to express the Rockwell hardness number. Thus, when the test is performed with 150 kg load and a diamond cone indentor, the resulting hardness number is called the Rockwell C (Rc) hardness. If the applied load is 100 kg and the indentor used is a 1.58 mm diameter hardened steel ball, a Rockwell B (RB) hardness number is obtained. The facts that the dial has several scales and that different indentation tools can be filled, enable Rockwell machine to be used equally well for hard and soft materials and for small and thin specimens. Rockwell hardness number is dimensionless. The test is easy to carry out and rapidly accomplished. As a result it is used widely in industrial applications, particularly in quality situations. 

Determination of column stability test the column stability by applying a known amount of analyte perform sample loading, column wash, analyte elution, column regeneration, and storage cycle steps for multiple analyses. Initially we test the columns reusability daily for a week, then weekly for a month, then monthly for up to 3 mo. 

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