Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

REALIZATION OF THE PROBLEM

It is interesting that one of the possible realizations of the problem described corresponds to the situation when the potential of a system is defined as V(r) for r < a and a constant U for r > a. This situation (for the case, when U > V (r) for any r) is similar to the one described above, but for small a the potential well may be too small to have any bound states. This condition defines some critical value aCrit for the existence of the bounded states there are no bound states for a < aCrit see e.g. [85] for numerical examples. [Pg.56]

Of course, there is no problem at all in principle. Structure is itself an electronic property, in that it must be determined by the Coulomb forces of the electrons (and nuclei) of the system and should be derivable from the Hamiltonian. The troublesome needle-inhaystack aspect of structure determination is often a nuisance here, but even if we are lucky enough to be faced with a choice between a few reasonable structures (as in the impurity problem), the fact is that the description of the cohesive forces of solids is a difficult and delicate business. Perhaps the stumbling-block of structure determination has been overemphasized here, but there does not seem to be a wide realization of the problem and its importance to future progress. [Pg.44]

Step 3. The set of fracture properties G(t) are related to the interfaee structure H(t) through suitable deformation mechanisms deduced from the micromechanics of fracture. This is the most difficult part of the problem but the analysis of the fracture process in situ can lead to valuable information on the microscopic deformation mechanisms. SEM, optical and XPS analysis of the fractured interface usually determine the mode of fracture (cohesive, adhesive or mixed) and details of the fracture micromechanics. However, considerable modeling may be required with entanglement and chain fracture mechanisms to realize useful solutions since most of the important events occur within the deformation zone before new fracture surfaces are created. We then obtain a solution to the problem. [Pg.355]

The [nimary objective of the VOC-condensation system is to meet mass-recovery objectives. However, heat is a key element in realizing the mass objectives. Hence, the mass and heat interactions of the problem have to be identified and reconciled. This can be achieved by converting the VOC-recovery task from a mass-transfer problem to a heat-transfer duty. This can be accomplished by relating the... [Pg.250]

The problems with eomputer generation of random surfaees are mostly eonneeted with small sizes of systems we ean use. Eaeh sueh a small system has somewhat different realization of the spatial distribution of heterogeneities. Only at the thermodynamie limit of a truly maeroseopie system does the self-averaging of extensive thermodynamie quantities oeeur. It means that, when using small systems, it is neeessary to generate several (often of... [Pg.253]

It is a characteristic feature of all these relativistic equations that in addition to positive energy solutions, they admit of negative energy solutions. The clarification of the problems connected with the interpretation of these negative energy solutions led to the realization that in the presence of interaction, a one particle interpretation of these equations is difficult and that in a consistent quantum mechanical formulation of the dynamics of relativistic systems it is convenient to deal from the start with an indefinite number of particles. In technical language this is the statement that one is to deal with quantized fields. [Pg.485]

It is generally agreed that the causes and effects of poor water chemistry, mechanical problems, boiler section corrosion, metal failure, and poor boiler plant operation are all closely interrelated. Thus, effective control over the various corrosion processes that may occur in a boiler and its auxiliary equipment is fundamental to the realization of the full life expectancy and safe operation of the plant. Corroded and wasted metal cannot be replaced easily, and the failure of a boiler in service is both potentially dangerous and expensive. [Pg.238]

Most patients are usually aware of displacement of the pilocarpine ocular system, but some patients, the elderly in particular, may not realize that the system has come out of the eye. If displacement does occur, the nurse inserts a new astern and informs the primary health care provider of the problem. [Pg.225]

In this paper we have endeavored to show some of the statistical principles underlying wavefront sensing. It is important to realize that the problem is inherently one of parameter estimation because as such it is part of a significant literature beyond traditional wavefront sensing. [Pg.394]

Inverse problems are very common in experimental and observational sciences. Typically, they are encountered when a large number of parameters (as many as or more than measurements) are to be retrieved from measured data assuming a model of the data - also called the direct model. Such problems are ill-conditioned in the sense that a simple inversion of the direct model applied directly to the data yields a solution which exhibits significant, or even dominant, features which are completely different for a small change of the input data (for instance due to a different realization of the noise). Since the objective constraints set by the data alone are not sufficient to provide a unique and... [Pg.419]

In both cases 1 — rS < 1 and, therefore, for a solution of problem (15)-(16) estimate (14) is valid, but r > 2/A. Because of rounding errors, the computational process is unstable for large j the growth of its solution causes abnormal termination in the computer realization of the algorithm. [Pg.94]

For most applications the makespan criterion is applied. For a very heavy load of the plant, the tardiness might be the most appropriate criterion that will enable to keep delivery dates undue. No matter which criterion is used, scheduling is always a problem of combinatorial character a large number of sequences must be simulated and the best combination chosen. Contrary to production planning, the problem of optimal scheduling is considered to be deterministic and static. This means that all problem parameters are known in advance and remain unchanged during the realization of the schedule. [Pg.473]

The realization of the reasons for poor biocompatibility of general alkoxides with biopolymers led to the development of approaches to minimize or eliminate the problem of the detrimental effect of alcohols. This can be done in two ways modification of the sol-gel processing or the silica precursor. This is considered in some detail below. [Pg.84]

The above classification and the following description of some of the properties of the carbohydrate constituents of these substances are not exhaustive but are intended primarily to focus attention on them and to illustrate the nature of the problems awaiting study. It is rather remarkable that comparatively few investigations have yet been carried out on their protein constituents, but on attempting structural studies it must be realized that one encounters all the difficulties inherent in protein chemistry with the added complication of the presence of complex carbohydrate molecules. [Pg.183]

A stochastic program is a mathematical program (optimization model) in which some of the problem data is uncertain. More precisely, it is assumed that the uncertain data can be described by a random variable (probability distribution) with sufficient accuracy. Here, it is further assumed that the random variable has a countable number of realizations that is modeled by a discrete set of scenarios co = 1,..., 2. [Pg.195]

Maybe our ambitions to gain health in general and mental health in particular have failed because we have not realized the importance of the problems that result as the psychosocial stress and our escalating feelings of discontent and annoyance carry an increasing risk to the health of our modem societies. To maintain our goals of physical and mental health throughout life, stress at these levels must be understood and treated. [Pg.322]


See other pages where REALIZATION OF THE PROBLEM is mentioned: [Pg.76]    [Pg.67]    [Pg.45]    [Pg.812]    [Pg.76]    [Pg.67]    [Pg.45]    [Pg.812]    [Pg.807]    [Pg.503]    [Pg.409]    [Pg.346]    [Pg.424]    [Pg.125]    [Pg.259]    [Pg.6]    [Pg.93]    [Pg.95]    [Pg.320]    [Pg.101]    [Pg.19]    [Pg.58]    [Pg.82]    [Pg.216]    [Pg.194]    [Pg.219]    [Pg.612]    [Pg.38]    [Pg.166]    [Pg.7]    [Pg.309]    [Pg.151]    [Pg.611]    [Pg.237]    [Pg.708]    [Pg.513]    [Pg.210]    [Pg.445]   


SEARCH



Realizability

Realizable

Realization

Realizers

© 2024 chempedia.info