Previous Failures

Both the.se methods have weaknesses. The historical data, implicit in both, may not be appropriate for the component in the assumed environment for the particular circumslances considered and may be irrelevant because of design rectification based on knowledge of previous failure. The broad approach may then be unduly pessimistic. On the other hand, the fault tree may fail to identify a primary cause which may have been missed by the plant designer to underestimate the probability of failure. The fault tree approach also takes credit for the preventative measures which may not be present in practice. The broad approach is likely to overestimate the risks because of insufficient account of preventative measures. The PSA team used the broad approach, recognizing that more accuracy may be attained by detailed industry studies. 

Bechtol in reviewing his clinical experience with 1087 cemented Charnley and Bechtol total hip replacements concluded that prosthetic stem failure is actually the final sequence of previous failures of bony and cement support. His suggested sequence of events leading to prosthetic stem failure have been substantiated in the literature and are as follows ... 

One last comment about pulse widths it is important that we know what the 90° pulse width is for the nuclei that we observe as accurate pulse widths are required for many pulse sequences (as mentioned previously). Failure to set these correctly may give rise to poor signal to noise or even generate artifacts in the spectrum. When instruments are serviced, these pulse widths are measured and entered into a table to ensure that the experiments continue to work in the future. 

We concluded, therefore, that in sufficiently pure alkyl halide solvents the tert-alkyl tetrahaloaluminates are stable electrolytes and that previous failures to produce them, and the consequent legend of the instability of tcrt-alkyl carbenium ions, arose from the use of inappropriate and insufficiently rigorous experimental techniques. On this basis it seems highly probable that in the polymerised solutions the cations R+ partaking in reaction (viii) were also original ions, i.e., 2 at the end of a live chain and 3 and 4 formed by alumination of a terminal double bond, and not derived ions formed by degradative reactions of monomer or polymer. 

I would like to extend Prof. Simon s characterizations of these beautiful new molecules to include a description of the effects on lipid bilayers of his Na+ selective compound number 11, which my post-doctoral student, Kun-Hung Kuo, and I have found to induce an Na+ selective permeation across lipid bilayer membranes [K.-H. Kuo and G. Eisenman, Naf Selective Permeation of Lipid Bilayers, mediated by a Neutral Ionophore, Abstracts 21st Nat. Biophysical Society meeting (Biophys. J., 17, 212a (1977))]. This is the first example, to my knowledge, of the successful reconstitution of an Na+ selective permeation in an artificial bilayer system. (Presumably the previous failure of such well known lipophilic, Na+ complexing molecules as antamanide, perhydroan-tamanide, or Lehn s cryptates to render bilayers selectively permeable to Na+ is due to kinetic limitations on their rate of complexation and decomplexation). 

It was shown that the diene reacted only slowly with tetracyanoethylene, even slower than with maleic anhydride. The reaction of the ortho adduct with maleic anhydride led to the same 1 2 adduct as the photochemical reaction between benzene and maleic anhydride. The previous failure to trap the diene with tetracyanoethylene resulted from an unexpectedly low dienophilic reactivity of this compound toward the ortho adduct in the presence of benzene. Tetracyanoethylene is apparently completely complexed in benzene solution. 

As a result, Syngenta has been fined 375,000 and ordered to sponsor a compliance training conference by USDA [28-30]. However, the regulatory response appears to be subdued at best, especially in light of previous failures by biotechnology companies to implement federal regulations. 

When an individual over-compensates for an underlying EMS, they behave as if the opposite of the EMS were true in an attempt to distance themselves from it. Thus, it is proposed that workaholism is an attempting to undo previous failures (Machlowitz 1980). In childhood, these individuals may have been made to feel fundamentally inadequate relative to their peers in areas of achievement such as academia or sports, and to feel that they were less successful than others. It is postulated that children who have been economically, socially or emotionally deprived, or who have experienced love as being conditional upon success, may be more prone to become workaholics in adulthood (Machlowitz 1980 Oates 1971 Thorne 1987). 

Construction engineering is an activity throughout the development process of human society. We human moved into skyscraper from the cave by accumulating successful experience and we can also prevent the accidents from recurring via the analysis of previous failures to master relevant laws. 

The first technique applies probabilistic methods to historical data from previous failures for a given class of systems. Parameters of probability functions are estimated from collected data. An advantage of probabilistic methods is that no detailed information is needed. However, the determination of parameters that faithfully describes an observed degradation phenomenon requires a significant amount of legacy statistical fault data. If these data are available, confidence limits can be determined that give an indication of the accuracy of a prediction. 

Fluorobis(phenylsulfonyl)methane (139) has been successfully added to benzalde-hyde to give the a-fluorinated carbanion that - on protonation - gives a-fluoroalcohol (140). Previously, failure had been ascribed to unfavourable equilibrium. The new protocol uses a lithium base (LiHDMS) in DCM at -94 °C, followed by protonation with TFA at the same temperature. VT- F-NMR evidence indicates a key role for lithium coordination of the carbinolate and that an equilibrium shift to (PhS02)2CF Li+ and aldehyde readily occurs at, for example, -19°C." °... 

We surmised that our previous failures were caused by the rapid hydrolysis of the phosphorus acid chloride mainly from the following two observations. First, phosphorus acid chlorides are rapidly hydrolyzed in the presence of water. Second, classical interfacial reactions employing fully charged Lewis Bases such as R-0 and RCO are found to occur within the... 

The 1990 Nobel Prize in Physiology or Medicine was awarded to Joseph E. Murray, the surgeon who performed the first-ever kidney transplant between identical twins, which demonstrated that previous failures were due to immunologic incompatibilities rather than surgical methods. The average kidney is about 4.5 inches long and weighs between four and six ounces. 

Retention faults These faults are similar to the open fault for logic (discussed previously). Failures to this fault model do not retain data over an extended period of time. 

Equipment files should also contain repair records. With most equipment, documenting failures, major part replacements, operating time, and other service-related events serves a valuable purpose. Nothing is more useful in troubleshooting than a record of previous failures, configuration, modifications, and—of course—a copy of the original manual. 

Back in the mid-70 s when the polyetherimide chemistry and physical properties were under study, considerable skepticism and prejudice existed. Previous failures to melt process high temperature polyimides were at the roots of our concerns. 

After requesting the teacher s clarification on wheflier the failure of protein synfliesis in bacteria represents a broad problem solved through cDNA cloning, peers develop another test for flie stated hypothesis. F suggests the elimination of the proposed cause in order to examine flie deriving consequences on the cause s potential effect. Thus, she produces the strand the MRT protein is indeed synthesized in bacteria by an mRNA cloned in bacteria but aheady spliced elsewhere, then the cause of the previous failure of its synthesis must have been the inability of the mRNA sphcing in bacteria . So, once more the validity of the hypothesis is predicted upon flie experimental outcomes and not vice versa. 

As discussed previously, failure is most often treated as a separate issue from the determination of modulus properties of materials. In fact, most failure laws are derived empirically from observations related to a catastrophic event such as yielding or rupture. As a result, a great deal of testing and data analysis is necessary to establish an appropriate law. On the other hand, modulus or constitutive laws are derived by more rational means of relating deformations to the forces that produce them. For this reason, often much less testing is necessary to define a constitutive law for a material especially if deformations do not depart from the linear elastic or reversible deformation range of a material. 

Ekanem Mosleh, 2013 Dynamic BBNs to model dependency among HFEs in an accident sequence. Every time an HFE occurs, Bayesian updates are conducted to incorporate the new evidence (in the form of observation of the previous failure and/or of the state of the influencing factor). DA... 

Previous failure mode and effect analysis and fault tree analysis work by the authors has shown that the inherently complex system of a PEMFC assembly can harbor dependencies between multiple failure modes. Therefore in this presented work, Petri-Net simulation has been adopted to develop a more accurate degradation model. Operational parameters such as water content, temperature and current density s effects on the occurrence of failure modes can be modelled through this technique. This work will improve previous fuel cell reliability studies by taking into consideration operating parameters (water content, temperature), ambient weather and fuel cell voltage demand (drive cycles). 

For the case under study, the flat bottom tank has been modeled with a mesh of 262919 elements and 264267 nodes. The FEM analyses have been performed considering the tank behavior both in nominal operating conditions and in conditions of extreme loads, caused by the occurrence of the critical events identified by the previous failure analyses. The loads in ordinary conditions and the material strength have been set according to SOL internal documents. 

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