Test increment

Gur D, Wagner RE, Chan HP (2004c) On the repeated use of databases for testing incremental improvement of computer-aided detection schemes. Acad Radiol 11 103-105... 

If one analysis is made on each of the h test increments (example above, Section 4.3) then the confidence limits of the mean are given by equation (2.9) ... 

For bulk materials the sampling variance depends on the size of the test increment relative to the scale of the inhomogeneities and decreases with increasing sample increment size. In some experiments it may be necessary to set an upper limit on the sampling variance so that changes in the mean can be detected. Preliminary measurements can be made to decide the minimum test increment size required to give an acceptable level of sampling variance. 

The vessels will be pressurised up to 1,1 - 1,25 fold of the normal service pressure of the drums, within stress increments of 50 kPa (0,5 bar) and a constant and smooth slope of less than 10 kPa.min . During the complete test the data will be acquired, stored and analysed. 

The assessment of the contribution of a product to the fire severity and the resulting hazard to people and property combines appropriate product flammabihty data, descriptions of the building and occupants, and computer software that includes the dynamics and chemistry of fires. This type of assessment offers benefits not available from stand-alone test methods quantitative appraisal of the incremental impact on fire safety of changes in a product appraisal of the use of a given material in a number of products and appraisal of the differing impacts of a product in different buildings and occupancies. One method, HAZARD I (11), has been used to determine that several commonly used fire-retardant—polymer systems reduced the overall fire hazard compared to similar nonfire retarded formulations (12). 

How Many Samples. A first step in deciding how many samples to collect is to divide what constitutes an overexposure by how much or how often an exposure can go over the exposure criteria limit before it is considered important. Given this quantification of importance it is then possible to calculate, using an assumed variabihty, how many samples are required to demonstrate just the significance of an important difference if one exists (5). This is the minimum number of samples required for each hypothesis test, but more samples are usually collected. In the usual tolerance limit type of testing where the criteria is not more than some fraction of predicted exceedances at some confidence level, increasing the number of samples does not increase confidence as much as in tests of means. Thus it works out that the incremental benefit above about seven samples is small. 

The vibration characteristics, determined by use of the instrumentation, will serve as the basis for acceptance or rejection of the machine. API standards generally require that the equipment be operated at speed increments of approximately 10% from zero to the maximum continuous speed and run at the maximum continuous speed until bearings, lube-oil temperatures, and shaft vibrations have stabilized. Next, the speed should be increased to trip speed and the equipment run for a minimum of 15 minutes. Finally, the speed should be reduced to the maximum continuous speed and the equipment should be run for four hours. API does not require that the four hours be uninterrupted however, it is generally interpreted that way. The interpretation is one of the many test criteria to be discussed. It would seem that a break in the test at the midpoint is not the same as having it cut short five minutes from the end because the vendor s boiler took an upset that was not related to the compressor test. The ibration during the shop test is normally specified as the API limit of 1.0 mils peak to peak, or the value from Equation 10.1, unfiltcred. whichever is lower. 

Occasionally, materials are tested in tension by applying the loads in increments. If this method is used for plastics then special caution is needed because during the delay between applying the load and recording the strain, the material creeps. Therefore if the delay is not uniform there may appear to be excessive scatter or non-linearity in the material. In addition, the way in which the loads are applied constitutes a loading history which can affect the performance of the material. A test in which the increments are large would quite probably give results which are different from those obtained from a test in which the increments were small or variable. 

These latter curves are particularly important when they are obtained experimentally because they are less time consuming and require less specimen preparation than creep curves. Isochronous graphs at several time intervals can also be used to build up creep curves and indicate areas where the main experimental creep programme could be most profitably concentrated. They are also popular as evaluations of deformational behaviour because the data presentation is similar to the conventional tensile test data referred to in Section 2.3. It is interesting to note that the isochronous test method only differs from that of a conventional incremental loading tensile test in that (a) the presence of creep is recognised, and (b) the memory which the material has for its stress history is accounted for by the recovery periods. 

The experimental specific volume data were available in the temperature range of 273K to 353K, with 20K increments. The nine types of siloxanes were arbitrarily divided into two groups, one each for training and testing. The compounds 1, 2, 4, 6, and 8 were utilized in the training phase. The trained network was then... 

Starting from zero, take a set of readings, then increase the load in increments of about 20 per cent, repeating at 15-min intervals. Note that if the supply air passes over a structural slab its elevated temperature from test 29.9.7 will briefly add load. 

The multivariable modeling/control package is able to hold more tightly against constraints and recover more quickly from disturbances. This results in an incremental capacity used to justify multivariable control. An extensive test run is necessary to measure the response of unit variables. 

Stress relaxation. In a stress-relaxation test a plastic is deformed by a fixed amount and the stress required to maintain this deformation is measured over a period of time (Fig. 2-33) where (a) recovery after creep, (b) strain increment caused by a stress step function, and (c) strain with stress applied (1) continuously and (2) intermittently. The maximum stress occurs as soon as the deformation takes place and decreases gradually with time from this value. From a practical standpoint, creep measurements are generally considered more important than stress-relaxation tests and are also easier to conduct. 

Turbidity measurements were determined using the dipping probe colorimeter. The light frequency was 650 nm. Deionized water transmittance was set at 90. The surfactant test solutions were stirred ( — 3500 rpm) and maintained at 75°C. Active surfactant concentration was 0.1% wt. Solution volume was 100 cm1. A 26.5% CaCU (95,699 ppm CaJ+) solution was added via syringe in 0,10 ml increments to the lower portion of the surfactant solution. 

The caffeine contracture test involves exposing viable muscle fibers to incremental doses of caffeine from 0.5-32 mM, the concentration being increased every four min if no contraction develops. A positive caffeine contracture test is defined as the development of 0.2 g tension at 2 tiM caffeine, or > 7% tension change from baseline with 2 mM caffeine. 

---