Example 5.2 Advanced selection procedure

For batch plants where several products are manufactured in small to medium quantities the same piece of equipment may be required to perform several different separations. In such circumstances a good deal of heuristic information and detailed knowledge of a wide variety of separators is needed in order to produce a shortlist of equipment. However, a sophisticated selection is readily performed using FDS without a need for user expert knowledge. 

Consider a plant which is required to process five separate feeds in batches at rates equivalent to 15 m h At the current stage of process specification it is not clear whether the prime objective for the separation of two of the feeds is solids dewatering or washing. Sedimentation and filtration tests have been performed on small samples of the slurries and analysed using 

Filtration time (s) Cumulative filtrate volume (m ) Filtrate flow rate (m s ) (t-t V-Vi) (s m 5) 

Settling specifications Settling rate Supernatant clarity Sludge proportion  

Selected equipment Selection warnings (1) (2) Index (3) (4) (5) Particle size ( im) Feed cone. (% w/w) 

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In this volume procedures are documented for selective oxidations and reductions that represent the advances in these fields since Volume 1 of this series was published (in 2002). This introduction highlights some examples from the literature that demonstrates the needs of industry and identifies how some of these requirements were met and illustrates a number of the challenging problems that are still to be overcome. 

Nuclear reactions producing exotic nuclei at the limits of stability are usually very non-specific. For the fast and efficient removal of typically several tens of interfering elements with several hundreds of isotopes from the nuclides selected for study mainly mass separation [Han 79, Rav 79] and rapid chemical procedures [Her 82] are applied. The use of conventional mass separators is limited to elements for which suitable ion sources are available. There exists a number of elements, such as niobium, the noble metals etc., which create problems in mass separation due to restrictions in the diffusion-, evaporation- or ionization process. Such limitations do not exist for chemical methods. Although rapid off-line chemical methods are still valuable for some applications, continuously operated chemical procedures have been advanced recently since they deliver a steady source of activity needed for measurements with low counting efficiencies and for studies of rare decay modes. The present paper presents several examples for such techniques and reports briefly actual applications of these methods for the study of exotic nuclei. 

The current review is of necessity selective. Over the two year period covered, there has been impressive advances in several areas of P(V) chemistry. For example, biological aspects of quinquevalent phosphorus acids chemistry continue to increase in importance. A wide variety of natural and unnatural phosphates including inositols, lipids, some carbohydrates and their phospho-nates, phosphinates and fluorinated analogues has been synthesized. Special attention has been paid to the synthesis of phosphorus analogues of all types of amino acids and some peptides. Numerous investigations of phosphate ester hydrolysis and related reactions continue to be reported. Interest in approaches to easier detoxification of insecticides continues. A number of new and improved stereoselective synthetic procedures have been elaborated. The importance of enantioselective and dynamic kinetic asymmetric transformations is illustrated in many publications. 

The development of techniques and methods for protein purification has been an essential pre-requisite for many of the advancements made in biotechnology. This booklet provides advice and examples for a smooth path to protein purification. Protein purification varies from simple one-step precipitation procedures to large scale validated production processes. Often more than one purification step is necessary to reach the desired purity. The key to successful and efficient protein purification is to select the most appropriate techniques, optimise their performance to suit the requirements and combine them in a logical way to maximise yield and minimise the number of steps required. 

In the discussions above and in the examples previously described, it has been assumed that the variables to be included in the multivariate regression equation were known in advance. Either some theoretical considerations determine the variables or, as in many spectroscopic examples, visual inspection of the data provides an intuitive feel for the greater relevance of some variables compared with others. In such cases, serious problems associated with the selection of appropriate variables may not arise. The situation is not so simple where no sound theory exists and variable selection is not obvious. Then some formal procedure for choosing which variables to include in a regression analysis is important and the task may be far from trivial. 

In the final example, we will continue with the subject of selective oxidation of propene to PO, but this time using advanced CaCOs supported Ag catalysts. The focus is directed towards a novel synthesis procedure, in which La incorporation is shown to have a significant effect on the alkali content of the catalyst and thus on the resulting catalyst performance. 

The choice of reference spectra is carried out, on one hand, manually from real (deterministic) spectra, with the consideration of determined spectra (nitrate, nitrite, surfactants). It is completed automatically, on the other hand, with a mathematical procedure [15] allowing the selection of the more relevant spectra for the model, able to explain by a linear combination, the shape of UV spectra of water or wastewater. This last procedure can be replaced by any advanced statistical algorithms (PCA or PLS, for example) or by commercial software (such as UVPro from Secomam). 

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