Testing acceleration test

Real time stability tests based upon the identity tests for the active ingredient(s) and/or physio-chemical and biological tests accelerated tests may be acceptable in USA (USDA) on a provisional base, e.g. 7 days/37 C for 1 year/4 C. 

Prediction of corrosion performance can be done from published data and testing. Accelerated testing should involve the same mode of failure and reflect a known order of resistance of some alloys in service media (128). The common test objectives of SCC are high stresses, slow continuous straining, precracked specimens, higher concentration of corrosive agent than in service medium, higher temperature, and electrochemical stimulation (129). For electrochemical corrosion, the properties of the medium at the interface should be noted in accelerated tests. 

Again because of the restricted time available for testing, accelerated testing will be required to determine long term properties. However, the results should be treated with caution unless they are consistent and have a predicable trend, say are linear against the logarithm of time. In addition some correlation must be made with real-time tests to validate the accelerated testing. 

Accelerated tests are often performed to shorten the time needed for durability tests. Accelerated tests are carried out in a condition that is not good for MEA, such as high temperature and low RH. An MEA decays much faster during an accelerated test, and could shorten the durability test from thousands of hours to hundreds of hours. If a regular durability test and an... 

Accelerated testing has little application to the generation of the performance data necessary for the evaluation of systems for marine structures. It is difficult, if not impossible, to quantitatively predict structure life Grom such tests. Accelerated testing, however, can be useful in screening candidate materials and systems so that the best alternatives can be evaluated in in-situ tests. 

There are available standard accelerated oxidation tests that consist of passing air or oxygen through an oil at elevated temperature. The test is conducted with or without the presence of catalysts or water. 

The routine compositional and functional testing done on the adhesives includes gas chromatographic testing for purity, potentiometric titrations for acid stabilizer concentrations, accelerated thermal stabiUty tests for shelf life, fixture time cure speed tests, and assorted ASTM tests for tensile shear strengths, peel and impact strengths, and hot strengths. 

Gun Propellents. Although the stresses on individual gun propellant grains are less severe because of the small size, these propellants must withstand much higher weapon pressures and accelerations. Formulation options are usually more limited for gun propellants than for rocket propellants because the products of combustion must not foul or corrode a gun, should have a low flame temperature, and should exhibit minimum flash and smoke characteristics. Gun propellants are examined microscopically for porosity, are tested for mechanical characteristics, and fired in closed bombs to determine the burning characteristics. 

The octane number requirement (ONR) of a car is the octane number which causes barely audible, ie, trace knock when driven by a trained rater. The Coordinating Research Council (CRC), a research organi2ation funded joindy by the American Petroleum Institute (API) and the American Automobile Manufacturers Association (AAMA), has defined test procedures for measuring ONR. Each car is driven under a set of light and heavy accelerations until the most sensitive driving mode is determined. Then a series of fuels is mn in the car until trace knock is determined. Each year, CRC members measure ONR of more than 100 cars and pubHsh the results. 

Tests on Cable Constructions. The Association of Edison Illumination Companies (AEIC) has approved an accelerated cable hfe test in which typical underground distribution power cables can be statistically compared based on their resistance to water treeing (number of days to fail). The comparison can be made by varying the type of insulation and/or other cable layers in an environment that contains hot water (90°C) under 8V/fi (200 V/mil) voltage stresses (four times the typical power cables operating voltages). 

The above-mentioned codes contain requirements for accelerated durabiUty tests. In addition, interlayer manufacturers and laminators expose test samples for several years under extreme weather conditions, eg, the Florida coast and Arizona desert. The laminated products weather extremely well, with no change in the plastic interlayer. Occasionally, clouding is noted around the edges when exposed to high humidity for long periods, but this is reversible. Colored areas of PVB laminates may fade while subjected to extensive uv/solar irradiation, which could cause an appearance issue. This has not, however, been shown to alter the laminate s other performance properties. 

Examp/e 8. There are 40 components placed on an accelerated 80-hlife test. A 75% lower confidence limit on the rehabUity is desired. To use equation 51, a value of F must be looked up. In this case, n = 40 and y = 37, and the required value is... 

Liquid Fabric Softeners. The principal functions of fabric softeners are to minimize the problem of static electricity and to keep fabrics soft (see Antistatic agents). In these laundry additives, the fragrance must reinforce the sense of softness that is the desired result of their use. Most fabric softeners have a pH of about 3.5, which limits the materials that can be used in the fragrances. For example, acetals cannot be used because they break down and cause malodor problems in addition, there is the likelihood of discoloration from Schiff bases, oakmoss extracts, and some specialty chemicals. Testing of fragrance materials in product bases should take place under accelerated aging conditions (eg, 40°C in plastic bottles) to check for odor stabiUty and discoloration. 

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