Combined architectures

Schnall, M., Rosten, S., Englander, S., Orel, S., and Nunes, L. (2001). A combined architectural and kinetic interpretation model for breast MR images, Academic Radiology, 8 591-597. 

The development of the CRP based on the idea of reversible chain termination decrease the disadvantage of the free-radical polymerization and permits the synthesis of defined block copolymer structures. The growing demand for well-defined and ftinctional soft materials in nanoscale applications has led to a dramatic increase in the development of procedures that combine architectural control with flexibility in the incorporation of ftinctional groups. Thus, there is a strong increase in the elucidation of a variety of controlled polymerization strat es in the past years. " These include nitroxide-mediated radical polymerization (NMRP), atom transfer radical polymerization (ATRP), " and reversible addition-fragmentation chain transfer (RAFT) procedures. Such techniques led to well-defined homo and block copolymers of different architectures whose behavior was investigated in solution and on surfaces. ... 

It can be said that these three main strategies have been applied equally and very often in combination. Basically, the first approach implies the use of a faster computer or a parallel architecture. To some extent it sounds like a brute force approach but the exponential increase of the computer power observed since 1970 has made the hardware solution one of the most popular approaches. The Chemical Abstracts Service (CAS) [10] was among first to use the hardware solution by distributing the CAS database onto several machines. 

Other fibrous and porous materials used for sound-absorbing treatments include wood, cellulose, and metal fibers foamed gypsum or Pordand cement combined with other materials and sintered metals. Wood fibers can be combined with binders and dame-retardent chemicals. Metal fibers and sintered metals can be manufactured with finely controlled physical properties. They usually are made for appHcations involving severe chemical or physical environments, although some sintered metal materials have found their way into architectural appHcations. Prior to concerns regarding its carcinogenic properties, asbestos fiber had been used extensively in spray-on acoustical treatments. 

The main benefit of the Dow process was control of the polymer architecture. The polymer from the self-condensation process possessed a linear stmcture, but there were other difficulties. The monomer was cosdy and removal of the cuprous bromide by-product was difficult (17) ultimately, scale-up difficulties terrninated the Dow PPS development. However, there was a growing recognition that PPS was an attractive polymer with an excellent combination of properties. 

A chemical property of silicones is the possibility of building reactivity on the polymer [1,32,33]. This allows the building of cured silicone networks of controlled molecular architectures with specific adhesion properties while maintaining the inherent physical properties of the PDMS chains. The combination of the unique bulk characteristics of the silicone networks, the surface properties of the PDMS segments, and the specificity and controllability of the reactive groups, produces unique materials useful as adhesives, protective encapsulants, coatings and sealants. 

The atmospheric corrosion performance of the newer colour anodised finishes is of interest, and severtil authors have reported testsLongterm weathering of dyed finishes has also been described and this has led to the recommendation of a limited range of special dyes for architectural applications Good performance of the combined anodised and elec-trophoretically deposited clear lacquered finishes, now used very widely in Japan, has also been reported together with details of the vertical lines used to produce them . 

Combining control over architecture with control over the stereochemistry of the propagation process remains a holy grail in the field of radical polymerization. Approaches to this end based on conventional polymerization were described in Chapter 8. The development of living polymerization processes has yet to substantially advance this cause. 

We have developed an approach termed ARBITER (Architecture for Reliable Business Improvement and Technology Evaluation in Research) [25], with associated simulation and visualization capability, that combines... 

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