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Economy, principle

Not only mechanics but all of physics can be derived from the principle of least action. There are appropriate Lagrangian functions for electrodynamics, quantum mechanics, hydrodynamics, etc., which all allow us to derive the basic equations of the respective discipline from the principle of least action. In this sense, the principle of least action is the most powerful economy principle known in physics since it is sufficient to know the principle of least action, and the rest can be derived. Nature as a whole seems to be organized according to this principle. The principle of least action can be found under various names in nearly every branch of science. For instance the principle of least cost in economy or Fermat s principle of least time in optics. [Pg.66]

Nowadays, a chemical process for the production of a desired product has to be evaluated considering its conversion, chemical yield and selectivity, but also its atom efficiency, according to the atom economy principle established by Trost in 1991. ... [Pg.192]

Early pioneers in green chemistry included Trost (who developed the atom economy principle) and Sheldon (who developed the E-Factor). These measures were introduced to encourage the use of more sustainable chemistry and to provide some benchmarking data to encourage scientists to aspire to more benign synthesis. [Pg.306]

According to the atom-economy principle included in the 12 principles of Green Chemistry, protocols where all the materials used in the process are incorporated in the end product are highly desirable. In this context, multicomponent reactions, which perform with good atom economy, are interesting reactions. Gold-catalysed multicomponent reactions under solvent-free conditions have been extensively studied. [Pg.57]

The book opens with a chapter on the theory underlying the technique of the chief operations of practical organic chemistry it is considered that a proper understanding of these operations cannot be achieved without a knowledge of the appropriate theoretical principles. Chapter II is devoted to a detailed discussion of experimental technique the inclusion of this subject in one chapter leads to economy of space, par ticularly in the description of advanced preparations. It is not expected that the student will employ even the major proportion of the operations described, but a knowledge of their existence is thought desirable for the advanced student so that he may apply them when occasion demands. [Pg.1193]

The industrial economy depends heavily on electrochemical processes. Electrochemical systems have inherent advantages such as ambient temperature operation, easily controlled reaction rates, and minimal environmental impact (qv). Electrosynthesis is used in a number of commercial processes. Batteries and fuel cells, used for the interconversion and storage of energy, are not limited by the Carnot efficiency of thermal devices. Corrosion, another electrochemical process, is estimated to cost hundreds of millions of dollars aimuaUy in the United States alone (see Corrosion and CORROSION control). Electrochemical systems can be described using the fundamental principles of thermodynamics, kinetics, and transport phenomena. [Pg.62]

In developing theoretical problems he always thought about practical uses of results in the national economy. His theoretical and experimental results were applied to developing numerous methods of analytical determination of elements in complex natural and technical situations, and also he also used the principles for improving the university curriculum and to generate new special courses. [Pg.6]

Tolling operations should be held to the same principles of public openness and communication espoused by forward thinking companies in the chemical industry. In 1988, the Chemical Manufacturers Association (CMA) initiated the Responsible Care initiative to assist in making this possible. Its goal is to lead the chemical industry in ethical practices that increasingly benefit society, the economy and the environment. [Pg.8]

Two basic principles govern the arrangement of protein subunits within the shells of spherical viruses. The first is specificity subunits must recognize each other with precision to form an exact interface of noncovalent interactions because virus particles assemble spontaneously from their individual components. The second principle is genetic economy the shell is built up from many copies of a few kinds of subunits. These principles together imply symmetry specific, repeated bonding patterns of identical building blocks lead to a symmetric final structure. [Pg.327]

A synthetically powerful method, an approach based on cycloaddition chemistry, allows one to assemble the pyridine ring in one step. Not only is this method efficient, atom economy, but also its convergency allows for the preparation for highly substituted systems in which one can, in principle, control all five positions on the pyridine ring. A versatile example of this methodology is the Boger reaction. It has been applied to the synthesis of a very diverse set of targets. [Pg.323]

The centrifugal compressor is well established for the compression of gases and vapors. It has proven its economy and uniqueness in many applications, particularly in which large volumes are handled at medium pressures. This compressor is particularly adaptable to steam turbine or other continuous speed change drives, as the two principles of operation and control are quite compatible. It is also adaptable to the electric motor, gas engine, and gas turbine with each installation being specific to a particular problem or process. Installation as well as operating costs can be quite reasonable. [Pg.455]

The polymer field is versatile and fast growing, and many new polymers are continually being produced or improved. The basic chemistry principles involved in polymer synthesis have not changed much since the beginning of polymer production. Major changes in the last 70 years have occurred in the catalyst field and in process development. These improvements have a great impact on the economy. In the elastomer field, for example, improvements influenced the automobile industry and also related fields such as mechanical goods and wire and cable insulation. [Pg.323]

While it is impossible to describe a system of storekeeping and distribution suitable for every site, there are certain essential principles which should be adhered to if cleanliness, order and economy are to be maintained. How these principles should be applied is for individual management to decide. The keynote, however, should be simplicity. A storekeeper familiar with both grades and needs should control distribution. While the lubrication schedule for any particular unit is generally the concern of the operator, the storekeeper must equally be aware of it and have a comprehensive list of the different grades, their applications, quantities, daily and other periodic needs. On such a basis he will be able to requisition and store the necessary lubricants in the most convenient and economic quantities and packages, and ensure that supplies are used on a first in, first out basis. [Pg.885]

Another favorable aspect of these polymers is their conformity with the principles of green chemistry. The latter sets guidehnes for the chemical industry in order to secure sustainable development, while increasing process economy [3,4]. Briefly, green chemistry, and the related green engineering [5] call for an increase in, and/or upgrading of ... [Pg.105]

One of the fundamental and most important principles of Green Chemistry is that of atom economy. This essentially is a measure of how many atoms of reactants end up in the final product and how many end up in byproducts or waste. The percentage atom economy can be calculated as 100 times the relative molecular mass (RMM) of all atoms used to make wanted product divided by the RMM of all reactants. Box 1.2. The real benefit of atom economy is that it can be calculated at the reaction planning stage from a balanced reaction equation. Taking the following theoretical reaction ... [Pg.19]

Yield and other mass-related metrics such as atom economy, reaction mass efficiency and mass intensity have been examined by Constable et al with regard to their significance concerning greenness and costs. The importance of using a (product) concentration term, which can be mass intensity or mass index, is additionally emphasized by Laird et al This is in compliance with Winterton, who in his twelve more green chemistry principles demands the establishment of full mass balances. [Pg.200]


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See also in sourсe #XX -- [ Pg.66 ]




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