Economic and product quality

The revolutionary discoveries by Ziegler and Natta, relating to the low pressure polymerization, respectively, of ethylene and of propylene and other a-olefins onto the previously unknown crystalline polymers, opened a new era in science and technology. Since then, remarkable progress has been made in the fields of coordination catalysis, macromolecular science and stereochemistry. With the discovery and development of the new generation catalytic systems for polyethylene in the late 1960 s, and more recently for polypropylene, enormous progress was made in terms of polymerization process as to economics and product quality Further process simplification and, above all, ever more accurate product quality control by taylor made catalytic systems is the aim of the 1980 s. 

Contemporary Attempts to Enhance PHA Production in Terms of Economics and Product Quality... 

In some liquid-phase processes, catalyst components are slowly leached from the catalyst bed and eventually the catalyst must be replaced. The feasibility of this type of process involves economics, ie, the costs of catalyst maintenance and keeping a unit out of service for catalyst replacement, and product quality and safety, ie, the effects of having catalyst components in the product and their ease of removal. 

The development of commercial continuous processes involves the consideration of many factors associated with process design and product quality. Most of the factors discussed in this paper will be important. Other, equally significant parameters, may be important for specific polymer products. Failure to deal with any of these problems may mean failure to develop an economical process. 

P cycling, pre chain emissions, animal welfare, economics, biodiversity, product quality, soil quality, and landscape aesthetics [60]. Whole farm model (WFM) uses pasture growth and cow metabolism for predicting CH4 emissions in dairy farms. Also included in the WFM is climate and management information. However, recent reports also suggests that WFMs may incorrectly estimate CH4 emission levels as they do not take into account the DMI and diet composition while predicting the enteric CH4 emission. This low prediction efficiency of WFMs may lead to substantial error in GHG inventories [10,11],... 

An important issue to be addressed in industrial applications of two-phase polymer systems for enzyme recovery is the economic or product quality requirement that the phase-forming polymers and salts be recycled. 

A wide variety of size-reduction equipment is available. The chief reasons for lack of standardization are the variety of products to be ground and product qualities demanded, the limited amount of useful grinding theory, and the requirements by different industries in the economic balance between investment cost and operating cost. Some differences exist for the sake of difference sometimes similarities are advertised as differences [Rumpf, Chem. Ing. Tech., 37(3), f87-202 (f965)]. 

The development of simpler, more economic processes for the production of polyethylene and polypropylene did not signify the end of MgCl2 catalyst research, but rather constituted the first phase. New, ever more sophisticated requirements, both in terms of process and product quality, have been emerging, steadily increasing the performance range required for the catalyst control of the polymer molecular structure (MWD, branching, steric purity), of its morphological properties (shape and particle size distribution), and supply of copolymers with controlled structures. 

This success was only possible by using recombinant DNA technology for the enzyme production. Of course, the development of a biocatalytic process is very complex. It is not only the biocatalytic steps that have to be developed. A lot of effort is necessary to gain access to the enzymes in the desired quality and at acceptable costs. The economics are mainly determined by the stability of the biocatalysts and product quality by the enzymatic activities in the cells of the producing organisms and an effective downstream process. As one can imagine the different... 

Several other applications of electiodialysis in the pharmaceutical industry have been studied on a laboratory scale [51]. Most of these applications are concerned with desalting solutions containing active agents which have to be separated, purified, or isolated from certain substrates [52]. Here, electrodialysis is often in competition with other separation procedures such as dialysis, solvent extraction, etc. In many cases, electrodialysis is the superior process as far as economics and the quality of the product is concerned. Especially the separation of amino acids and other organic acids by electrodialysis seems to be of interest to the pharmaceutical and chemical industry [53]. However, the deionization of cheese whey with an installed capacity of more than 35,000 square meters of membrane area for the production of more than 150,000 tons of desalted lactose per year is economically by far the most important application of electrodialysis in the food industry today. 

Among the key variables in strategic alkylphenol planning are feedstock quality and availabiUty, equipment capability, environmental needs, and product quality. In the past decade, environmental needs have grown enormously in their effect on economic decisions. The manufacturing cost of alkjiphenols includes raw-material cost, nonraw-material variable cost, fixed cost, and depreciation. 

Surface foam and entrained air can indeed be a serious hindrance to operations and quality in a paper miU. This can be a major economic problem recently it was estimated that the use of defoamers in the US paper industry alone in 2001 was over US 250 million and growing at over 5% annually. That is not the only cost of the problem - a much more significant impact to the papermaker would be the lost production and product quality problems that require the use of these products to control foam. 

The driving force for the introduction of new processes are economic considerations, which are largely influenced by the production costs of the product and product quality. The optimal exploitation of raw materials, energy saving, and the environmental friendliness of processes will still take presidence in futnre. Selectivity is becoming more and more the decisive factor in industrial processes, mainly as a result of increasing purity demands, for example, in polymer chemistry and in the pharmaceutical sector. Higher selectivity means that better use is made of raw materials and therefore lower formation of side products, which must be removed in expensive separation processes or pollute the environment. 

At the national level, stmcture is defined by the share the different economic sectors have in gross domestic product, for exampale, the share of manufacturing versus the share of the service sector. At a lower level of aggregation, stmcture is defined by the mix of products and those aspects that influence product mix and product quality (such as feedstock). 

Nancy L. Rose (1990), Profitability and Product Quality Economic Determinants of Airline Safety Performance, Journal of Political Economy, Vol. 98, No. 5, Part I, pp. 944-964. 

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