Ability-performance relationship

Two general problems relate to the role of interfaces in advanced materials. The first is simply that we do not have the theory or the computational or experimental ability to understand the interatomic and microscopic interactions at the interfaces between components of an advanced material, on which its properties are critically dependent. There is a general need for research on processes at interfaces and on the stracture-property-performance relationships of interfaces. 

Our goal is to develop a property-performance relationship for different types of demulsifiers. The important interfacial properties governing water-in-oil emulsion stability are shear viscosity, dynamic tension and dilational elasticity. We have studied the relative importance of these parameters in demulsification. In this paper, some of the results of our study are presented. In particular, we have found that to be effective, a demulsifier must lower the dynamic interfacial tension gradient and its ability to do so depends on the rate of unclustering of the ethylene oxide groups at the oil-water interface. 

Compaction Rate Processes The performance of compac tion techniques is controlled by the ability of the particulate phase to uniformly transmit stress and the relationship between apphed stress and the compaction and strength characteristics of the final compacted particulate phase. The general area of study relating compac tion and stress transmission is referred to as powder mechanics (Brown Richards, Principles of Powder Mechanics, Pergamon Press Ltd., Oxford, 1970). 

Traditionally, column efficiency or plate counts in column chromatography were used to quantify how well a column was performing. This does not tell the entire story for GPC, however, because the ability of a column set to separate peaks is dependent on the molecular weight of the molecules one is trying to separate. We, therefore, chose both column efficiency and a parameter that we simply refer to as D a, where Di is the slope of the relationship between the log of the molecular weight of the narrow molecular weight polystyrene standards and the elution volume, and tris simply the band-broadening parameter (4), i.e., the square root of the peak variance. 

In the earliest SFG experiments [Tadjeddine, 2000 Guyot-Sionnest et al., 1987 Hunt et al., 1987 Zhu et al., 1987], a first-generation data acquisition method was used, and, because of the limited signal-to-noise ratios, IR attenuation by the electrolyte solution was a substantial handicap. So, in earlier SFG studies, as in IRAS studies, measurements were performed with the electrode pressed directly against the optical window [Baldelli et al., 1999 Dederichs et al., 2000]. With the in-contact geometry, the electrolyte was a thin film of uncertain and variable depth, probably of the order of 1 p.m. However, the thin nonuniform electrolyte layers can strongly distort the potential/coverage relationship and hinder the ability to study fast kinetics. 

The most serious problem with input analysis methods such as PCA that are designed for dimension reduction is the fact that they focus only on pattern representation rather than on discrimination. Good generalization from a pattern recognition standpoint requires the ability to identify characteristics that both define and discriminate between pattern classes. Methods that do one or the other are insufficient. Consequently, methods such as PLS that simultaneously attempt to reduce the input and output dimensionality while finding the best input-output model may perform better than methods such as PCA that ignore the input-output relationship, or OLS that does not emphasize input dimensionality reduction. 

For the evaluation of a possible relationship between the molecular structure of a potential candidate and its transport abilities to cross the epithelial membrane of the gut, the mechanism or route of transport must be known [1,4]. This is due to the structural requirements for the transcellular route being different from the paracellular route. During the lead optimization phase - when many mechanistically based studies are performed - the cell culture-based models can also be used with great confidence. 

Some quality factors, especially secondary ones, depend directly on material or structural attributes of the product. These product quality factors are often arbitrary and can only be qualitatively evaluated by panels of consumers or experts. Convenience for use, product stability, and ability for human skin protection are all examples of these quality factors. Each arbitrary performance index has specific relationships with the material/structural attributes. In such cases, the desirable quality factor can be realized by directly changing the formulation without concerning any of the performance indices. An example can be that to make a laundry detergent product more convenient to use, the product form can be changed from powder to tablet. Another example is that to make a highly biodegradable product, surfactants with less branching should be used. 

The linear equilibrium isotherm adsorption relationship (Eq. 11) requires a constant rate of adsorption, and is most often not physically valid because the ability of clay solid particles to absorb pollutants decreases as the adsorbed amount of pollutant increases, contrary to expectations from the liner model. If the rate of adsorption decreases rapidly as the concentration in the pore fluid increases, the simple Freundlich type model (Eqs. 8 and 9) must be extended to properly portray the adsorption relationship. Few models can faithfully portray the adsorption relationship for multicomponent COM-pollutant systems where some of the components are adsorbed and others are desorbed. It is therefore necessary to perform initial tests with the natural system to choose the adsorption model specific to the problem at hand. From leaching-column experimental data, using field materials (soil solids and COMs solutions), and model calibration, the following general function can be successfully applied [155] ... 

We tested a variety of military skills in this pilot study. Motion picture documentation of performance was provided and used to produce a film (Soldier s Predicament). The aim of this pilot study was to examine the relationship between performance of military tasks such as rifle assembly and map reading, to cognitive measures such as NF, SC and VITA As expected, the performance ability of well-trained soldiers was grossly inadequate and completely impossible during periods of incapacitation, as indicated by their cognitive test scores. The relevance of laboratory measures to simulated military performance was reinforced by these results. 

Principal Component Analysis (PCA) is performed on a human monitoring data base to assess its ability to identify relationships between variables and to assess the overall quality of the data. The analysis uncovers two unusual events that led to further investigation of the data. One, unusually high levels of chlordane related compounds were observed at one specific collection site. Two, a programming error is uncovered. Both events had gone unnoticed after conventional univariate statistical techniques were applied. These results Illustrate the usefulness of PCA in the reduction of multi-dimensioned data bases to allow for the visual inspection of data in a two dimensional plot. 

---