Alternate Processing Techniques

Properties of copolymers and composites are derived from the combination of the characteristics of parent constituents. Accordingly, copolymerization and fabrication of composites of CPs with biofunctional nonconducting polymers have been studied to combine the electrical properties of the former with the processibility, bioactivity, and biostability of the latter. 

Similarly, PPy was electrodeposited on an UV-polymerized poly(2-hydroxyethyl methacrylate) (pHEMA) matrix [80-82]. The addition of PPy in the pHEMA hydrogel reduced the electrical resistivity of pHEMA from 350 Q to 52 Q. The overall impedance of the composite was constantly low at less than 100 Q across the frequency range of 1 mHz-60 kHz. Again, no mechanical properties or the CP content of the composite were reported. 

CP composites of both poly(vinyl alcohol) (PVA) [83-88] and poly(ethylene glycol) (PEG) [87,89,90] have been fabricated by both chemical and electrochemical polymerization of either monomer solution loaded or dispersed into hydrogel networks. Li et al. reported that tetraethylammonium perchlorate (TEAP) doped PPy-PVA composite was more hydrophilic than PPy/TEAP film and showed less fibrinogen adsorption on the surface than the CP control film. The PPY-PVA composite maintained intrinsic conductivity of PPy/TEAP film (7 S cm ) and the porous structure of the composite promoted neural cell attachment and spreading in the model clonal line, PC 12 [86]. 

PPY-PVA and PPY-PEG composites were fabricated by vapor polymerization of pyrrole onto EeCls-loaded hydrogel matrices [87]. FeCl3-loaded PVA and PEG matrices were freeze-dried to form microstructures. The resulting composites have fine foam-like lattice structure with low weight density. The tensile strength and conductivity of 20 wt% PPy-PVA were 2.0 0.2 MPa and 0.1 S cm , respectively. 

The unique combination of high mechanical stability, electrical conductivity, and surface area make carbon nanotubes (CNTs) a popular material for a wide range of biomedical applications, from microbial fuel cells to biochemical sensors [91-94]. Accordingly, CP composites have been investigated to synergize both mechanical and electrical properties of CNTs. 

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In modern microwave synthesis, a variety of different processing techniques can be utilized, aided by the availability of diverse types of dedicated microwave reactors. While in the past much interest was focused on, for example, solvent-free reactions under open-vessel conditions [1], it appears that nowadays most of the published examples in the area of controlled microwave-assisted organic synthesis (MAOS) involve the use of organic solvents under sealed-vessel conditions [2] (see Chapters 6 and 7). Despite this fact, a brief summary of alternative processing techniques is presented in the following sections. 

SWCNT/PS composites prepared using three processing techniques are addressed. For one series, the latex-based route, described in Chapter 2, was strictly followed. For two other series of composites, alternative processing techniques were used [see Table 4.2), namely, film casting/compression moulding and spin coating. 

R. Bond, Shaft Seal Manufacture—Alternate Molding Techniques. Polymer Processing Society European Regional Meeting, Prague, Czechoslovakia, September 21-24 (1992). 

In this chapter the various components that make up the capital cost of a plant and the components of the operating costs are discussed, and the techniques used for estimating reviewed briefly. Simple costing methods and some cost data are given, which can be used to make preliminary estimates of capital and operating costs at the flow-sheet stage. They can also be used to cost out alternative processing schemes and equipment. 

For small projects, and for simple choices between alternative processing schemes and equipment, the decisions can usually be made by comparing the capital and operating costs. More sophisticated evaluation techniques and economic criteria are needed when decisions have to be made between large, complex projects, particularly when the projects differ widely in scope, time scale and type of product. Some of the more commonly used techniques of economic evaluation and the criteria used to judge economic performance are outlined in this section. For a full discussion of the subject one of the many specialist texts that have been published should be consulted Brennan (1998), Chauvel et al. (2003) and Vale-Riestra (1983). The booklet published by the Institution of Chemical Engineers, Allen (1991), is particularly recommended to students. 

In this chapter, the general problem of joint parameter estimation and data reconciliation was discussed. First, the typical parameter estimation problem was analyzed, in which the independent variables are error-free, and aspects related to the sequential processing of the information were considered. Later, the more general formulation in terms of the error-in-variable method (EVM), where measurement errors in all variables are considered in the parameter estimation problem, was stated. Alternative solution techniques were briefly discussed. Finally, joint parameter-state estimation in dynamic processes was considered and two different approaches, based on filtering techniques and nonlinear programming techniques, were discussed. 

Kessler et al. developed the Difference and Sums of Traces within Cosy Spectra (DISCO) technique for the extraction of couplings from the crosspeaks of two-dimensional (COSY) spectra. This post-processing technique combined selected cross-sections of these peaks in order to extract the active coupling , i.e., /ab from the cross-peak of A and B. After such combination, the active coupling was the separation of the in-phase and anti-phase DISCO peaks. DISCO requires accurate scaling of the constituent spectra and resolved cross-peaks. An alternative and simpler method for the accurate measurement of vicinal couplings from COSY spectra has been presented by Kim and Prestergard. ... 

Industries have developed alternate pulping techniques that do not use the conventional cooking methods. Some of these techniques are described briefly in the following subsections. Readers may note that some of these processes have not yet reached commercial stages. 

Fermentation and alternative production techniques, such as roller bottles, can be carried out in four different ways. They are (1) batch process, (2) fed-batch process, (3) chemostat process, and (4) perfusion process. Batch and fed-batch processes require termination of cell growth while chemostat and perfusion processes allow continuous cell cultivation. 

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