In-Life Testing

When all units have failed, the result is complete data. Singly-censored data result in life testing when testing is terminated before all units fail. And multiply-censored data result from ... 

Wearable Devices and Wireless Networks Tools for Pervasive Health Care In-Life Testing... 

Vertical media with very high coercivities can be produced by plating into alumina pores [112], Some of these media are too hard to be easily written with present heads. Tailoring of the pore size can be used to obtain structures with the desired Hc [115, 116], however. Recording characteristics of disks have been determined [112-114, 116] such media show excellent promise as vertical recording media. In addition, structures with electrodeposited Fe in the pores were tested in life-tests at elevated temperatures and humidity and in corrosive atmospheres. They were found to perform satisfactorily. 

Balakrishnan, N., Ed., Recent Advances in Life-Testing and Reliability. A Volume in Honor of Alonzo Clifford Cohen, Jr., CRC Press, Boca Raton, FL, 1995. 

In life test experiments and in the stacks, the cell is run under fixed total current (galvanostatic regime). In this regime, the degradation manifests itself... 

Liu JG, Zhou ZH, Zhao XX, Xin Q, Sun GQ, Yi BL. Studies on performance degradation of a direct methanol fuel cell (DMFC) in life test. Phys Chem Chem Ph5rs 2004 6 134. 

The expected life is sometimes used as an iadicator of system rehabihty however, it can be a false iadication and should be used with caution. In most test situations the chance of surviving the expected life is not 50% and depends on the undedyiag failure pattern. For example, considering the exponential as used ia equation 10, the expected life would be... 

Confidence-Interval Estimates. Confidence-interval estimates for the expected hfe or rehabihty can be obtained easily in the case of the exponential. Here only the limits for failure-censored (Type II) and time-censored (Type I) life testing are given. It is possible to specify a test as either time- or failure-tmncated, whichever occurs first. The theory for such tests is explained in References 16 and 17. 

Time-Censored Life Tests. In this case the total test time T is specified. From the test, r failures are observed. The 100(1 — a)% two-sided confidence interval for the expected life is... 

Tool life tests are used to evaluate the effects of changes in tool materials, cutting variables, processing history, workpiece composition, or workpiece microstmcture. Tool life, T, and cutting speed, can be related by the following equation ... 

The accident at the Three Mile Island (TMI) plant in Pennsylvania in 1979 led to many safety and environmental improvements (4—6). No harm from radiation resulted to TMI workers, to the pubHc, or to the environment (7,8), although the accident caused the loss of a 2 x 10 investment. The accident at the Chernobyl plant in the Ukraine in 1986, on the other hand, caused the deaths of 31 workers from high doses of radiation, increased the chance of cancer later in life for thousands of people, and led to radioactive contamination of large areas. This latter accident was unique to Soviet-sponsored nuclear power. The Soviet-designed Chemobyl-type reactors did not have the intrinsic protection against a mnaway power excursion that is requited in the test of the world, not was there a containment building (9—11). 

The invertebrate phyla are often neglected in ecotoxicological testing protocols. A token invertebrate species such as the copepod Daphnia may be used to evaluate the effects on extremely diverse phyla. This neglects the diversity of biochemical and physiological functions that may render different phyla vulnerable to different classes of compound at different stages of their life cycles. 

Pump tests are needed to establish the performance of a machine before delivery to the user so that contract conditions may be satisfied. They are also required to establish the health of the pump at intervals in its service life. When a new pump is delivered, the pump manufacturer will supply data required either as a set of performance points or a plot as a certificate of suitability. Ideally, the pump should be tested in the system configuration that it is intended to supply, but usually tests are performed in the test bay in a standardized manner laid down by national and international codes. When a pump is installed, a simple test may be performed to establish a performance point in a similar way to periodic tests to establish how the machine s performance is being affected. 

In some life-testing work, units are put on test at various times but are all taken off together this is done to terminate testing by some chosen time to meet a schedule. 

During the first trials with synthetic separators around 1940 it had already been observed that some of the desired battery characteristics were affected detrimentally. The cold crank performance decreased and there was a tendency towards increased sulfation and thus shorter battery life. In extended test series, these effects could be traced back to the complete lack of wooden lignin, which had leached from the wooden veneer and interacted with the crystallization process at the negative electrode. By a dedicated addition of lignin sulfonates — so called organic expanders -— to the negative mass, not only were these disadvantages removed, but an improvement in performance was even achieved. 

The battery system has reached more than 1700 cycles in life cycle tests. The calendar life of the /zebra battery has been proven to be close to five years in a continuing life test. In practical operation in cars the ZEBRA battery exceeded 110000 km within a three year period. This excellent result proves the ZEBRA battery to be a reliable system. 

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