As organizing concepts

Closed-Mill Concept. The closed-mill concept, or water circuit closure, has been studied by the pulp and paper industry for many years. In some parts of the paper manufacturing process, up to 98% of the water is recycled within the process, eg, the wet end of the paper machine. However, in the pulp mill, especiaUy kraft mills, effluents are produced owing to the need to purge from the system various metals that come in with the wood, as weU as organic by-products from the pulping process, additives, and especially chloride ions that originate in the bleach plant. 

Straightforward analytical models, however, receive particular attention in the present book, as they are of unique significance in the comprehension of physical phenomena and, moreover, provide the very language to describe them. To exemplify, recall the effect caused on the phase transition theory by the exactly soluble two-dimensional Ising model. Nor can one overestimate the role of the quasiparticle concept in the theory of electronic and vibrational excitations in crystals. As new experimental evidence becomes available, a simplistic physical picture gets complicated until a novel organizing concept is created which covers the facts known from the unified standpoint (thus underlying the aesthetic appeal of science). 

The facts noted in the four subsections of this chapter suggest that chemists ought to keep an open mind concerning the concept of chemical bonding. Useful as this concept is the field of organic chemistry, it becomes more and more meaningless and inadequate as we move toward inorganic, nonmetallic and, above all, metallic chemistry. 

We wish to emphasise that the formation of esters (E) from alkenes (M) and acids (HA), the catalysis of the reactions of E by HA or MtXn, and the activation of E, such as organic chlorides, by the co-ordination of a Lewis acid, such as A1C13, are all very familiar chapters in conventional organic chemistry. It follows that the pseudo-cationic theory is nothing more than a generalisation of conventional organic-chemical ideas and a revival of some pre-Whitmore interpretations which had become occulted by the usefulness and novelty of the carbenium ion concept. 

All the above reactions of PVC were performed homogeneously in DA-solvents such as HMPA, DMF and dimethylsulfoxide (DMSO). For the practical modification of PVC, the reaction must be conducted under more commercial conditions as in slurry water. As mentioned before, azidation of PVC did not occur in water. However, the reaction proceeded feasibly in water by addition of some cationic surfactant to give, e.g. 8-20% (DS) of azidated PVC at 80°C by use of tetra-n-butyl ammonium chloride (1 ). The use of cationic surfactant was also effective in organic solvents and attracted increased attention as the conception of "phase transfer catalyst" in organic chemistry developed. 

The method detection limit is, in reality, a statistical concept that is applicable only in trace analysis of certain types of substances, such as organic pollutants by gas chromatographic methods. The method detection limit measures the minimum detection limit of the method and involves all analytical steps, including sample extraction, concentration, and determination by an analytical instrument. Unlike the instrument detection limit, the method detection limit is not confined only to the detection limit of the instrument. 

Intense efforts within the last decade to boost the acquisition of organic chemicals from the sugars listed in Table 2.1 have, so far, failed to bridge the conceptional, technological, and economic gap between hydrocarbons and carbohydrates as organic raw materials. 

Senacs book could be seen as organized more on the mechanical doctrine of affinity than on a phlogistic viewpoint. It provides a most explicitly clear statement how the concept of differential affinity can be applied in the design of experimental procedures. 

To help answer these questions I start this chapter with an examination of the various meanings of responsibility and discuss the nature of our responsibilities for things. I then examine how decisions about technology are currently made and point out the ways in which this leads to organized irresponsibility , particularly in the case of synthetic chemicals. Finally, I consider the limitations of risk assessment as a conception of responsible decision making. 

In this chapter and the one that follows, we will review the research concerning the uses of polyurethanes in biomedical applications. Such uses range from topical application of hydrophilic polyurethane pads to the implantation of scaffolds of reticulated foam as organ-assist devices. The range of applications is broad and each use requires that specific problems associated be addressed. This chapter begins with a discussion of biocompatibility — a broad concept ranging from the simple nonir-ritating characteristics required for topical applications to the complex type of compatibility (hemocompatibility) that allows use with whole blood. 

When organic farming was conceived as a concept and a practice, in the 1920s-1930s, our socie-... 

As a branch of chemistry, the activities of nuclear chemists frequentiy span several traditional areas of chemistry such as organic, analytical, inorganic, and physical chemistry. Nuclear chemistry has ties to all branches of chemistry. For example, nuclear chemists are frequently involved with the synthesis and preparation of radiolabeled molecules for use in research or medicine. Nuclear analytical techniques are an important part of the arsenal of the modem analytical chemist. The study of the actinide and transactinide elements has involved the joint efforts of nuclear and inorganic chemists in extending knowledge of the periodic table. Certainly, the physical concepts and reasoning at the heart of modem nuclear chemistry are familiar to physical chemists. In this book we will touch on many of these interdisciplinary topics and attempt to bring in familiar chemical concepts. 

This controversy has been instrumental in the development of important structural methods in physical organic chemistry with respect to critical evaluation of results as well as to concepts behind the methods. 

The brain can no longer be seen as a vast piece of organic clockwork, but as a subtle device amplifying quantum events. If we trace a nerve impulse down to its root, there lies a quantum uncertainty, a sea of probability. So just how is it that this sea of probability can cast up such ordered structures and systems as the conception of a cello concerto or abstract mathematical entities Perhaps here we may glimpse a way in which "spirit" can return into our... 

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