Problems to Be Solved

Hybrid systems. Depending on the problem to be solved, use can also be made of a combination of techniques leading to a hybrid system. For example, a rule-based system may use neural networks for solving classification subproblems (as is described in [Hopgood, 1993]), or a combination of a rule-based and a CBR system can be used as in the system for URS data interpretation described later in this paper. 

From the viewpoint of biophysical chemistry, the main problems to be solved are (i) what is the submolecular basis of... 

Further prerequisites depend on the chemical problem to be solved. Some chemical effects have an undesired influence on the structure descriptor if the experimental data to be processed do not account for them. A typical example is the conformational flexibility of a molecule, which has a profound influence on a 3D descriptor based on Cartesian coordinates. In particular, for the application of structure descriptors with structure-spectrum correlation problems in... 

In this section assume a mathematical model is possible for the problem to be solved. The model may be encoded in a subroutine and be known only imphcitly, or the equations may be known explicitly. A general form for such an optimization problem is... 

Example 1 Sample Quantity for Composition Quality Control Testing An example is sampling for quality control of a 1,000 metric ton (VFg) trainload of-Ks in (9.4 mm) nominal top-size bentonite. The specification requires silica to be determined with an accuracy of plus or minus three percent for two standard errors (s.e.). With one s.e. of 1.5 percent, V is 0.000225 (one s.e. weight fraction of 0.015 squared). The problem to be solved is thus calculating weight of sample to determine sihca with the specified error variance. 

In classical examples of kinetics, such as the hydrolysis of cane sugar by acids in water solution, the reaction takes hours to approach completion. Therefore Whilhelmy (1850) could study it successfially one and a half centuries ago. Gone are those days. What is left to study now are the fast and strongly exothermic or endothermic reactions. These frequently require pressure equipment, some products are toxic, and some conditions are explosive, so the problems to be solved will be more difficult. All of them require better experimental equipment and techniques. 

X-ray absorption spectroscopy is an important part of the armory of techniques for examining pure and applied problems in surface physics and chemistry. The basic physical principles are well understood, and the experimental methods and data analysis have advanced to sophisticated levels, allowing difficult problems to be solved. For some scientists the inconvenience of having to visit synchrotron radia-... 

Throughout the book there are worked examples to illustrate the use of the theory and at the end of each chapter there are problems to be solved by the reader. These are seen as an important part of the book because in solving the problems the reader is encouraged to develop the subject material beyond the level covered in the text. Answers are given for all the questions. 

The Born-Oppenheimer approximation allows the two parts of the problem to be solved independently, so we can construct an electronic Hamiltonian which neglects the kinetic energy term for the nuclei ... 

The proper combination of plastic and product will result in a good product with good mutual chemistry. With polyethylene and many food products, there are no problems to be solved. With other proposed combinations, a cooperative effort between the food product manufacturer, the container producer, and the resin supplier is needed to produce a high quality product. 

Researchers are facing difficulties in improving the properties and response rates of chemomechanical andelectrochemomechanical systems based on polymer gels or proteins that are intended to be used as actuators in robotics. Lack of mechanical toughness and long-term durability are other problems to be solved. A basic improvement in the low efficiency... 

The discovery of nanotubes and other nanostructures has opened up an exciting new field of research. But just what other shapes are possible and what other materials will form nanotubes To find out, we will need to predict the effect of different configurations. There are also many experimental problems to be solved. For example, how would you form an electrical connection to a nanotube Methods for synthesizing the large amounts of nanotubes needed in large-scale applications of nanotube assemblies also need to be developed. 

There are yet many problems to be solved to build a more realistic model for network formation, and more experimental information will be necessary in order to clarify these complicated phenomena. We do however believe these kinetic models will provide greater insight into the phenomenon of network formation. 

The other problem-dependent boxes in Fig. 8 relate to reading input and writing output - tasks that are clearly application-specific. We view writing post processing files to be part of the output function. It is usually inefficient to force the code that computes the solution to perform simultaneously all the interpretive functions. Moreover, if the solution itself is saved, then any number of post-processing functions can be exercised without requiring the problem to be solved again. 

Electrolyte loss occurring in long-term operation of MCFC is another problem to be solved for practical application of MCFC. For commercialization, the MCFC should show stable performance over 40,000 hours. Electrolyte loss in MCFC is caused by various factors, e.g., corrosion of components, creepage, reaction with cell components and direct evaporation. These... 

The primary reason it is difficult to treat angular momentum rigorously is due to the angular momentum catastrophe [58]. As noted in Section III, cross sections and other experimental observables are sums over all relevant total angular momentum quantum numbers, J. Each J represents a quantum dynamics problem to be solved, and the size of the problem increases dramatically with J. For each J, there are Nk projections of K, where Nts = fmax — min + 1- For a fliree-atom system, the minimum value of K, is a function of both J and p, such that = 0 when J and p are... 

Now, the general formulation of the problem is finished and ready to be applied to real systems without relying on any local coordinates. The next problems to be solved for practical applications are (1) how to find the instanton trajectory qo( t) efficiently in multidimensional space and (2) how to incorporate high level of accurate ab initio quantum chemical calculations that are very time consuming. These problems are discussed in the following Section III. A. 2. 

Eq. (122) represents a set of algebraic constraints for the vector of species concentrations expressing the fact that the fast reactions are in equilibrium. The introduction of constraints reduces the number of degrees of freedom of the problem, which now exclusively lie in the subspace of slow reactions. In such a way the fast degrees of freedom have been eliminated, and the problem is now much better suited for numerical solution methods. It has been shown that, depending on the specific problem to be solved, the use of simplified kinetic models allows one to reduce the computational time by two to three orders of magnitude [161],... 

A major problem to be solved for multiproduct plants is the occurrence of disparities in the cycle times and size requirements for the different stages. In the following it will be assumed that the size factors as well as the cycle times of all units are independent on equipment size. This assumption is usually relaxed in further stages of the design. In case of batch heating and cooling, or reactors operated in semi-continuous mode, this is necessary in order to adopt the cycle times to the capacity of equipment, which is related to batch size. 

In eadi specific case the choice of an adsorbent, electrophysical parameters and the method of registration of its change as well as the choice of various pre-adsorption treatment techniques of the surface of adsorbent is dictated by the type and nature of analytical problem to be solved. For instance, if particles active from the standpoint of the change in electrophysical parameters of semiconductor adsorbent occur on the surface of the latter due to development of a chemical reaction involving active particles, it is natural to use either semiconductor material catalyzing the reaction in question or if this is not possible specific surface dopes accelerating the reaction. Above substances are used as operational element of the sensor. If such particles occur as a result of adsorption from adjacent volume, one can use semiconductor materials with maximum adsorption sensitivity to the chosen electrophysical parameter with respect to a specific gas as operational element. 

Of special importance is the reduction of the consumption of oil and petroleum products. The fluctuation of prices in these products constitutes one of the stabilizing factors in the world economy and could lead to serious conflicts. Direct savings of oilfuel by way of improving oil-consuming devices and the replacements of this fuel with appropriate alternatives present one of the major problems to be solved in the nearfuture. 

Damages to human health and the environment are by economists most often considered as market failures since they are external costs not included in the price when a transaction is taking place on the market. If the damage were to be fully financially compensated in the transaction, the damage would not be an external cost and the market would function properly. A properly functioning market implies that there is no problem to be solved (from the point of view of an economist). Externalities is the term used by economists when exploring non-priced effects of transactions [6]. 

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