Operational Approach

The opportunity for creative design by viewing many imaginative variations would be blunted if each variation introduced a new set of doubts as to its ability to withstand whatever stress might be applied. From this point of view the development of computer graphics has to be accompanied by an analysis technique capable of determining stress levels, regardless of the shape of the product. This need is met by FEA. 

The FEA computer-based technique determines the stresses and deflections in a 

FEA is applicable in several types of analyses. The most common one is static analysis to solve for deflections, strains, and stresses in a structure that is under a constant set of applied loads. In FEA material is generally assumed to be linear elastic, but nonlinear behavior such as plastic deformation, creep, and large deflections also are capable of being analyzed. The designer must be aware that as the degree of anisotropy increases the number of constants or moduli required to describe the material increases. 

Uncertainty about a material s properties, along with a questionable applicability of the simple analysis techniques generally used, provides justification for extensive end use testing of plastic products before approving them in a particular application. As the use of more FEA methods becomes common in plastic design, the ability of FEAs will be simplified in understanding the behavior and the nature of plastics. 

FEA does not replace prototype testing rather, the two are complementary in nature. Testing supplies only one basic answer about a design that either passed or failed. It does not quantify results, because it is not possible to know from testing alone how close to the point of passing or failing a design actually exists. FEA does, however, provide information with which to quantify performance. 

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Pennycook, W. A., Embrey, D. E. (1993). An Operating Approach to Error Analysis. In Proceedings of the First Biennial Canadian Conference on Process Safety and Loss Management. Edmonton, 24th April. Waterloo, Ontario, Canada Institute for Risk Research, University of Waterloo. 

Product operator A set of orthogonal operators that can be connected together by a product. The product operator approach can be used to analyze pulse sequences by applying simple mathematical rules to weakly coupled spin systems. 

As exergy efficiency approaches 100%, the environmental impact associated with process operation approaches zero, since exergy is only converted from one form to another without loss. Also sustainability approaches infinity because the process approaches reversibility. 

An operational approach to the determination of the acidity of solutions in deuterium oxide (heavy water) was suggested by Glasoe and Long. This quantity, pD, is determined in a cell consisting of an aqueous (H20) glass electrode and a saturated aqueous calomel reference electrode on the basis of the equation... 

Hensley, E.F. The Unit Operations Approach, a paper presented at the American Association of Cost Engineers Annual Meeting, 1%7. 

The significance of the uncertainty concept in analytical chemistry has increased in the last century, notwithstanding that at first some conformity was missed. But inconsistencies have been dispelled (see Thompson [1995] AMC [1995]) and operational approaches have been presented by Hund et al. [2001]. Numerous examples of application have been given in EURACHEM [1995]. 

MCFC components are limited by several technical problems (30), particularly those described in Section 6.1.1. A review of the literature from 1994 to the present shows that research efforts described in a previous issue of this handbook (31) essentially continue. It should be noted that MCFC component designs and operational approaches exist on an individual basis that would result in operation for a 40,000-hour lifetime at atmospheric pressure and with natural gas fuel. 

The operational approach to the definition of fundamental concepts in science has been emphasized by Mach, Poincare, and Einstein and has been expressed in a very clear form by Bridgman [2]. (Operational definitions had been used implicitly much earlier than the twentieth century. Boyle, for example, defined a chemical element in terms of the experiments by which it might be recognized, in order to avoid the futile discussions of his predecessors, who identified elements with qualities or properties.) In this approach, a concept is defined in terms of a set of experimental or mental operations used to measure or to recognize the quantity The concept is synonymous with the corresponding set of operations (Bridgman). An operational definition frequently may fail to satisfy us that we know what the concept really is. The question of scientific reality has been explored by many scientists and philosophers and is one that every student should examine. However, in the operational approach, we are not concerned with whether our definition has told us what the concept really is what we need to know is how to measure it. The operational approach has been stated succinctly by Poincare in the course of a discussion of the concept of force ... 

The power of the operational approach became strikingly evident in Einstein s theory of special relativity, with its analysis of the meaning of presumably absolute, intuitive concepts such as time or space. Newton defined absolute time as... 

Because the vast majority of the sedimentary organic compounds are not amenable to direct study by current analytical techniques, organic geochemists rely on operational approaches to characterize them, such as measuring the %OC, %ON, OC/ON ratio and humin content. Other strategies include molecular analysis of the small fraction of sedimentary organic compounds that are detectable. Some of these compounds make... 

It was not our colorful fantasies alone that were centered on DMT-type hallucinogens. Our operational approach to discovering the secrets of the hallucinogenic dimension was centered on them as well. This was because, of the psychoactive compounds we knew. 

It should be noted that the surface integral on the r.h.s. of Eqs. (34) and (35) depends on the curvature F as well as on the connection A entering the covariant derivatives, which is reminiscent of the path dependence of the curvature 3F in the operator approach. 

Within these broad categories two principal classes may be distinguished, depending on whether current or voltage is the controlled parameter. The individuals in each class are often described by an operational nomenclature consisting of an independent-variable part followed by a dependent-variable part (i.e., volt-ammetry, chrono-potentiometry) with some system-specific modifiers (i.e., rotating disk voltammetry). Unfortunately, the whims of history have left the electrochemical nomenclature in a rather confused state. The operational approach has been only partially adopted but seems to be gaining popularity. 

Product operators can thus be used to predict the behavior of an NMR experiment. The calculations are relatively simple to perform. Computer programs are available that also take into account the effects of phase-cycling to select the desired terms and reject unwanted ones. A drawback of the product operators approach is that, in its simplest version, it does not take into account the effect of relaxation. This is a must when dealing with paramagnetic substances. Exponential decay terms can be introduced to multiply each term and take relaxation into account. The method then becomes more cumbersome, and the effect of relaxation is introduced in a phenomenological way. A more detailed approach is that of using the concept of Redfield density matrix [1,2]. 

Bove R. and Ubertini S., 2006. Modeling solid oxide fuel cell operation Approaches, techniques and results. Journal of Power Sources 159(1), 543-559. 

Extension of the equilibrium model to column or field conditions requires coupling the ion-exchange equations with the transport equations for the 5 aqueous species (Eq. 1). To accomplish this coupling, we have adopted the split-operator approach (e.g., Miller and Rabideau, 1993), which provides considerable flexibility in adjusting the sorption submodel. In addition to the above conceptual model, we are pursuing more complex formulations that couple cation exchange with pore diffusion, surface diffusion, or combined pore/surface diffusion (e.g., Robinson et al., 1994 DePaoli and Perona, 1996 Ma et al., 1996). However, the currently available data are inadequate to parameterize such models, and the need for a kinetic formulation for the low-flow conditions expected for sorbing barriers has not been established. These issues will be addressed in a future publication. 

W. Jaworski and D. M. Wardlaw, Phys. Rev. A, 45, 292 (1992). Sojourn-Time Operator Approach to Interaction Time in Quantum Scattering General Formulation for Arbitrary Scattering Systems. 

Domcke,W. (1991). Theory of resonances in electron molecule collisions The projection operator approach, Phys. Rep. 208, 97-188. 

Considering the volatiles that evolve from hot pressing and heat-treating operations, it is concluded that the major chemical changes occurring in this stage are pyrolytic. Methanol, acetic acid, furfural, and ligneous tars are the common volatiles produced by the slow pyrolysis of wood practiced in destructive-distillation processes. The temperatures used in the board conversion operations approach pyrolysis temperatures of wood and the evidence indicates that pyrolysis is indeed active in board conversion. 

Domcke, W. (1991). Theory of resonance and threshold effects in electron-molecule collisions the projection-operator approach, Phys. Rep. 208, 97-188. [178] Huo, W.M. and Gianturco, F.A., eds. (1995). Computational Methods for Electron-Molecule Collisions (Plenum, New York). 

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