Major technological problem

For at least three decades, long before the recent widespread initiation of field projects, adverse mobility ratio has been recognized as a major technological problem -- perhaps "the major problem" -- of gas-flood EOR (7-9). Adverse mobility ratios produce "viscous fingering," a displacement phenomenon that has been known and studied both experimentally and theoretically for many years (9-14). This phenomenon was a principal reason for the failure of many of the liquified petroleum gas (LPG) floods of the 1950 s and early 1960 s (15). 

What are the major advantages and disadvantages of fusion as a potential energy source compared with fission What is the major technological problem that must be solved to permit development of a fusion reactor ... 

The major technological problem in the use of polymer blends concerns determining correlations between composition, processing, structure and properties. Each variable has inherent characterization problems, e.g., of the preparation process, of the chemistry and morphology, and of what are meaningful properties. None of these correlations or characterizations are easy to make or particularly well understood. 

Adhesion is due to van der Waals interaction with the surface, and, while polyparylene films exhibit excellent chemical stability, poor adhesion continues to be a major technological problem and limitation. Surface modification techniques, which result in covalent interaction between the polymer film and the surface, might greatly improve adhesion and hence render polyparylene films more protective. 

Studies of simple hydrocarbon models suggest that polymers should not oxidize significantly at service temperatures and this led to a widespread belief that polymers do not degrade in normal use. In fact, oxidation is a major technological problem and rather few polymers can be processed or used without stabilization. The reason is the presence of impurities and structural defects in polymers, especially after processing. 

It Is now a relatively straightforward matter to analyze commercial pesticide mixtures for nitrosamlne contamination as part of the normal quality control process (2.18). and, as Illustrated above, some of the major contamination problems have begun to be solved by means of technological Improvements. If further research brings about the circumstance In which there Is no detectable N-nItroso compound In any pesticide sold an here, will that mean that pesticide use Is safe from nitrosamlne-formatlon problems I believe that considerably more research must be done before a responsible answer to this question can be given. To elaborate on this position, let me focus on the herbicides for a moment. 

It is clear from the discussion in Section 10.4 that the advancements in biochemistry, molecular cloning, random and site-directed mutagenesis, directed evolution of biocatalysts, metabolic engineering and fermentation technology can circumvent the major technical problems... 

Thus the study of surfaces has emerged as an important focus in the chemical sciences, and the relationship between surfaces of small systems and their performance has emerged as a major technological issue. Flow in microfluidic systems—for example, in micromechanical systems with potential problems of stiction (sticking and adhesion) and for chemistry on gene chips—depends on the properties of system surfaces. Complex heterogeneous phases with high surface areas—suspensions of colloids and liquid crystals—have developed substantial... 

Resolution of major technical problems of current surface mining technology. 

This book does not offer solutions to major industrial problems, it does not discuss bioinorganic systems in any great detail, it does not do more than offer the promise of a future technology. What this book does try to do is present an array of organic reactions promoted, catalysed or initiated by metal ions. I hope that the reader is as fascinated as I am by the many and varied reactions that proceed in the presence of metal ions. If it stimulates any reader to delve deeper into this subject, it has served its purpose. 

Triazine herbicides are applied world-wide and in important agricultural sectors. They are, evidently, able to resolve major weed problems in such a way and to such a degree that they are quantity-wise the top herbicides used today. Although there is no technology which will not be confronted at some time with a superior technology there is strong evidence for the future utility of this class of compounds. 

The deactivation of catalysts, especially zeolites, during cracking, hydrocracking, methanol conversion, etc, is one of the major technological and economic problems of the chemical industry (1). The interest of these materials lies not only in their high catalytic activity and selectivity but also in the possibility of regenerating them several times so that their Lifetime" is compatible with the cost of their production. Consequently, it is necessary to understand the manner and the rate of catalyst deactivation as well as the nature of the carbonaceous residues formed, commonly called coke". 

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