STRUCTURAL QUALIFICATION

The objective of this part of the program is to identify mechanisms of failure in structural ceramics subjected to mechanical, loads at elevated test temperatures. Of particular interest is the damage that accumulates in structural ceramics as a consequence of high temperature exposure to stresses normally present in heat engines. 

The bulk of the results obtained in this study were obtained by analytical transmission electron microscopy. Observations were made on both grades of material in the as-received, untested condition and after tensile testing at 1250°C. Test samples selected for examination covered the range of observed creep behavior, and included samples that failed after times ranging from -10 to -200 hours depending on applied stress and also samples from interrupted tests that survived for up to 2000 hours under lower applied stresses. In addition, a comparison was made of non-reinforced samples tested with and without a 500 hour pre-anneal at the test temperature. In all cases, the gauge sections of crept samples were cut parallel to the stress axis to obtain both near-surface and raid-plane sections. Prior to final TEM specimen preparation, these sections were examined optically for evidence of distributed creep cavitation or crack damage. 

Microstructural analyses of the effect of tensile creep on both grades of GTE hot pressed silicon nitride, i.e., whisker reinforced and non-reinforced, has essentially been completed, and a paper entitled Tensile Creep of Whisker-Reinforced Silicon Nitride is currently in preparation. The following provides a summary description of the results. 

In contrast, the non-reinforced material predominantly exhibited the formation of orthorhombic, 6-phase Y2S1207, although evidence for the monoclinic, X2-phase of Y2SiO , was also found within the interior regions of some creep samples (in particular, non-preannealed samples that failed rapidly). In comparing the main products of devitrification, it should be noted that the orthorhombic 6-phase found in the non-reinforced material corresponds the most stable, high temperature phase of Y2Si20y, while the monoclinic y-phase found in the whisker reinforced material represents a low temperature variant phase, which is conceivably metastable at temperatures above 1200°C. 

Observations on the cavitation damage produced during tensile creep indicate that at stresses sufficient for strain rates exceeding 1 X 10 s full fact cavitation occurs and leads to the development of creep cracks which grow stability or unstably, depending the applied stress. 

---

This portion of the project is identified as project element 3 within the work breakdown structure (WBS). It contains five subelements, including (1) Structural Qualification, (2) Time-Dependent Behavior,... 

Qualification by testing is primarily used to verify the seismic adequacy of equipment components and, in some cases, the seismic adequacy of specific building structures. Qualification by testing may also be used as a special investigative tool to verify the real capacity of structures and equipment when they are subjected to other external events. 

Finally FACTORED LOADS need to be compared against FACTORED RESISTANCES to ensure structural qualification. 

In this text, partnerships include alliances. Some companies prefer the alternate name. Partnerships are structured in many different ways. They may be project specific, commodity specific, or even company specific. Each company has its own qualification criteria. It is beyond the scope ol this book to go into detail on these because that is material for a text of its own. The intent here is to introduce the reader to the concept if it is not known and meld in the negotiarion modifiers for both neophyte and veteran... 

The responsibilities of personnel and the laboratory s management structure must be clearly defined, by means of organizational charts, job descriptions and curriculum vitae for the personnel who are carrying out the study. There must also be up-to-date records of qualifications and of the training that the staff have received, including any records necessary to show their competence to carry out their work. 

The main elements of the used input output model ISIS are described in the following. At the core of ISIS is a statistical input output model (IO model) used to examine the structural impacts of the various strategies. Other modules for employment effects, qualification structure and job conditions, regional effects and environmental effects were developed or added to analyse other dimensions of sustainability. The results of the scenario calculations from the IO model, i.e., production changes as a result of the different strategies, serve as inputs for the other modules. 

The Norwegian company Borregaard makes vanillin by chemo-oxidation of cheap natural lignin. In view of the complexity of the lignin structure this is a remarkable achievement. This semi-synthetic vanillin is, however, not allowed to carry the qualification of natural . Borregaard is the only global producer of lignin-vanillin or wood-sourced vanillin , with a volume of about 2000 t a-1. They obtain 4 kg vanillin from one ton of wood. This vanillin is more expensive than synthetic vanillin, but the flavorist needs lower doses of the extra round flavor . 

For the first time in the history of chemical sciences, theoretical predictions have achieved the level of reliability that allows them to rival experimental measurements in accuracy on a routine basis. Only a decade ago, such a statement would be valid only with severe qualifications as high-level quantum-chemical calculations were feasible only for molecules composed of a few atoms. Improvements in both hardware performance and the level of sophistication of electronic structure methods have contributed equally to this impressive progress that has taken place only recently. 

There is a fundamental question concerning the nature of the self-motion of protons in glass-forming polymers. In Sect. 4.1 we have shown that the existing neutron scattering results on the self-correlation function at times close to the structural relaxation time r (Q-region 0.2t) with a KWW-like functional form and stretching exponents close to jSsO.5. 

Attempts at structural identification of the compound are expected for impurities above the identification threshold. The evaluation of biological safety is expected above the qualification threshold. 

In order to present clear concepts it is necessary that idealized definitions be adopted but it is reeognized that the realities of polymer science must be faced. Deviations from ideality arise with polymers at both molecular and bulk levels in ways that have no parallel with the ordinary small molecules of organic or inorganic chemistry. Although such deviations are not explicitly taken into account in the definitions below, the terms recommended can usefully be applied to the predominant structural features of real polymer molecules, if necessary with self-explanatory, if imprecise, qualifications such as essentially. , almost completely. , or highly. . Although such expressions lack the rigour beloved by the purist, every experienced polymer scientist knows that communication in this discipline is impossible without them. 

Figure 17.3 Tier 1 myeloid assay (Ml cell line) evaluate in-house were compared to IC50 qualification using known hematotoxicants of from level 1 myeloid cell assay, n — 3 different chemical pharmacology and structure, experiments with triplicate wells within each Fifteen compounds with either known colony- experiment. The linear regression line is forming unit granulocyte-macrophage plotted showing the correlation between the...

Figure 17.5 Tier 1 erythroid assay qualification using compounds of similar chemical pharmacology and structure. Fifteen compounds from a single pharmacological class were evaluated in the tier 1 erythroid assay and in vivo measuring absolute number of...

The standard of any facility of operation is highly dependent upon the quality of the design and, therefore, the staff employed to undertake the work. A design qualification protocol, or report document, should detail and record the disciplined, structured approach followed. This will provide a useful lead into the installation qualification (IQ) stage. 

The installation qualification of automatic control systems shall consist of a logical panoply of tests. The tests are carried out step-by-step on each component. The structure of the installation qualihcation shall be standardized for all installation qualihcations of computerized pharmaceutical systems as follows. 

The performance qualification of computerized control systems consists of a group of tests pooled in functional checks. The tests shall be carried out on the integrated system. The structure of the performance qualification shall be standardized for all performance qualification of computerized pharmaceutical equipment. 

---