Maximum-step conventional

Once it has been determined that acid-removable formation damage is present and that treatment is mechanically feasible, the proper acid type, acid volume, and acid concentrations must be determined. As mentioned earlier, the maximum-step conventional HF treatment design should be the starting point for design, eliminating those steps that are not necessary. The maximum-step procedure is given in table 6-2, with typical volumes per foot... 

Table 6-2. Maximum-step conventional HF treatment design...

Other possible applications of smart elastomers are in the area of polymer engine which can produce maximum power density (4 W/g) and output both in terms of electrical and mechanical power without any noise. These features are superior compared to conventional electrical generator, fuel cell, and conventional IC engine. Many DoD applications (e.g., robotics, MAV) require both mechanical and electrical (hybrid) power, and polymer engine can eliminate entire transducer steps and can also save engine parts, weight, and is more efficient. 

Major advantages of LVI methods are higher sensitivity (compare the 100-1000 iL volume in LVI to the maximum injection volume of about 1 iL in conventional splitless or on-column injection), elimination of sample preparation steps (such as solvent evaporation) and use in hyphenated techniques (e.g. SPE-GC, LC-GC, GC-MS), which gives opportunities for greater automation, faster sample throughput, better data quality, improved quantitation, lower cost per analysis and fewer samples re-analysed. At-column is a very good reference technique for rapid LVI. Characteristics of LVI methods are summarised in Tables 4.19 and 4.20. Han-kemeier [100] has discussed automated sample preparation and LVI for GC with spectrometric detection. 

Solvent extraction can be automated in continuous-flow analysis. For both conventional AutoAnalyzer and flow-injection techniques, analytical methods have been devised incorporating a solvent extraction step. In these methods, a peristaltic pump dehvers the hquid streams, and these are mixed in a mixing coil, often filled with glass ballotini the phases are subsequently separated in a simple separator which allows the aqueous and organic phases to stratify. One or both of these phases can then be resampled into the analyser manifold for further reaction and/or measurement. The sample-to-extractant ratio can be varied within the limits normally applying to such operations, but the maximum concentration factor consistent with good operation is normally about 3 1. 

The above sequence of steps is what enters a so called conventional MR-CI calculation. This is still a widely used method to solve the MR-CI equations and during the past decades many tricks have been developed to circumvent some of the inherent problems with this approach. These problems are mainly due to the storage of large data sets, in particular the storage of the Hamiltonian matrix elements or even worse the storage of the formula tape. Therefore, if this approach is used the MR-CI expansion has to be drastically truncated. The maximum number of configurations which can be handled is in practice 10 to 20 thousand terms. The Hamiltonian matrix will then contain on the order of a few million non-zero terms. Since an MR-CI expansion without truncation in normal applications is 10s to 107 configurations the adopted truncation scheme has to be extremely efficient if the final result should still be accurate. In the next section we will discuss an alternative approach by which it is possible to handle the non-truncated MR-CI expansion without approximations. 

Based on the conventional analysis of the mechanism of decarboxylation of thiamin-derived intermediates, there is no role for a catalyst in the carbon-carbon bond-breaking step of this reaction. The thiazolium nitrogen is at its maximum electron deficiency with no available coordination sites. Ultimately, there is no place for a proton or other cation to position itself in order to promote the reaction by stabilizing a transition state that resembles the product of the reaction. Since there is no role for an acid, base, or metal to accelerate the decarboxylation of these intermediates by stabilizing the transition state for C-C bond-breaking, the means by which this could be achieved became a source of interest and speculation. 

One of the most important variables in the TPD of CO from a supported Pt catalyst is the sample pretreatment. Calcination at 500°C for one hour followed by reduction is the conventional method to obtain the maximum exposed Pt and this follows closely to refinery practice for start-up and regeneration of commercial catalysts. The final step in our case was a 600°C He sweep for 30 minutes to ensure a fully dehydrated catalyst up to this temperature so that no water evolved during the subsequent TPD. We had previously observed that a high temperature He sweep could reduce the Pt catalyst without a prior H reduction presumably by the decomposition of the Pt oxide. 

The hydroisomerization step features complete C4 acetylenes and butadiene conversion to butenes, maximum 2-butenes production, flexibility to process different feeds, polymer-free product and no residual hydrogen. The second step separates isobutylene either by conventional distillation, or by reacting the isobutylene with methanol to produce MTBE. 

While inorganic membrane reactors perform more efficiemly than conventional reactors in most cases, there are situations calling for the combined usage of these two types of reactors for reasons to be discussed. The conventional reactors in these special cases serve as either the pre-processing or post-processing step for the inorganic membrane reactor system to derive a maximum overall reaction conversion. These hybrid types of reactors consist of conventional reactors at the front end or tail end or both of the membrane reactor. 

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