Centerpiece

The Fossil Power Plants of the 1990s and into the early part of the new millennium will be the Combined Cycle Power Plants, with the gas turbine as being the centerpiece of the plant. It is estimated that between 1997-2006 there will be an addition of 147.7 GW of power. These plants have replaced the large Steam Turbine Plants, which were the main fossil power plants through the 1980s. The Combined Cycle Power Plant is not new in concept, since some have been in operation since the midl950s. These plants came into their own with the new high capacity and efficiency gas turbines. 

The goal of the basic infrared experiment is to determine changes in the intensity of a beam of infrared radiation as a function of wavelength or frequency (2.5-50 im or 4000—200 cm respectively) after it interacts with the sample. The centerpiece of most equipment configurations is the infrared spectrophotometer. Its function is to disperse the light from a broadband infrared source and to measure its intensity at each frequency. The ratio of the intensity before and after the light interacts with the sample is determined. The plot of this ratio versus frequency is the infrared spectrum. 

A coconut-infused rum, which was the centerpiece of a chocolate cream dessert cocktail, tasted superb, but when you mixed the drink, it looked like a curdled custard, with a sheen, he said. The coconut oil just rose to the top. It was disgusting. ... 

Centerpieces of combinatorial concepts include the synthesis of compound libraries instead of the preparation of single target compounds. Library synthesis is supplemented by approaches to optimize the diversity of a compound collection (diversity-oriented synthesis) and by efforts to create powerful interfaces between combinatorial synthesis and bioassays. 

These conceptual goals are attained by several combinatorial methods and tools. Characteristic for combinatorial chemistry is the synthesis on solid support or by polymer-supported synthesis, allowing for much higher efficiency in library production. Synthesis can be conducted either in automated parallel synthesis or by split-and-recombine synthesis. Centerpieces of combinatorial methods further include specific analytical methods for combinatorial... 

A search for stacked erosion surfaces became the centerpiece of work by King (1967), who compiled spectacular continental-scale examples from South America, Africa, India, and Australia. In a sense, these surfaces are rather like super-terraces, occurring within a narrow... 

This nonequilibrium Second Law provides a basis for a theory for nonequilibrium thermodynamics. The physical identification of the second entropy in terms of molecular configurations allows the development of the nonequilibrium probability distribution, which in turn is the centerpiece for nonequilibrium statistical mechanics. The two theories span the very large and the very small. The aim of this chapter is to present a coherent and self-contained account of these theories, which have been developed by the author and presented in a series of papers [1-7]. The theory up to the fifth paper has been reviewed previously [8], and the present chapter consolidates some of this material and adds the more recent developments. 

Innovative Lives Patsy Sherman and the Invention of Scotchgard. Smithsonian Institution, http //www.si.edu/lemelson/centerpieces/ilives/ lecturel 1. html... 

Figure 1. Top Original "tennis ball" monomer 1, its syn- the guests and 129Xe-NMR spectrum of a solution of 1 1 thesis, and analogs 2 and 3. Bottom left X-ray structure of with Xe added. Due to the aromatic centerpieces of the cap-...

Figure 2. Left Family of softball" monomers 4-7. Different spacers between the centerpiece and the glycoluril binding sites permit assembly of dimers with cavity volumes between 186 A3 and 313 A3. Right Computer-minimized...

Because this area is not too well known, the authors have taken pains to describe, in some detail, experimental monolayer chemistry. The centerpiece of the chapter is enantiomer and diastereomer discrimination in monolayers. It concludes with a discussion of surface properties, in particular energetics, which are quite sensitive to stereochemistry. We call attention to the fact that this chapter is of potential interest to biochemists, notably those concerned with lipids and with cell membrane organization. 

Selected entries from Methods in Enzymology [vol, page(s)] Association constant determination, 259, 444-445 buoyant mass determination, 259, 432-433, 438, 441, 443, 444 cell handling, 259, 436-437 centerpiece selection, 259, 433-434, 436 centrifuge operation, 259, 437-438 concentration distribution, 259, 431 equilibration time, estimation, 259, 438-439 molecular weight calculation, 259, 431-432, 444 nonlinear least-squares analysis of primary data, 259, 449-451 oligomerization state of proteins [determination, 259, 439-441, 443 heterogeneous association, 259, 447-448 reversibility of association, 259, 445-447] optical systems, 259, 434-435 protein denaturants, 259, 439-440 retroviral protease, analysis, 241, 123-124 sample preparation, 259, 435-436 second virial coefficient [determination, 259, 443, 448-449 nonideality contribution, 259, 448-449] sensitivity, 259, 427 stoichiometry of reaction, determination, 259, 444-445 terms and symbols, 259, 429-431 thermodynamic parameter determination, 259, 427, 443-444, 449-451. 

Typically, for batch processes such as blending or drying, this entails the determination of process end-point attributes. The PAT method then becomes the centerpiece of the scale-up effort. Process scale-up can be undertaken under the assumption that the relationships between observables and performance are independent of scale, and if this assumption is verified in practice, the manufacturing process in full scale can be monitored (typically, to completion) providing a higher level of assurance that the product is likely to be within compliance. 

The Introduction to Physical Chemistry course is the centerpiece of the physical chemistry curriculum. It is named as such only because, by college rules, we needed to distinguish it from the previously offered Physical Chemistry I and Physical Chemistry II courses. We do believe, however, that it is aptly named because it provides an introduction to three of the four major areas of physical chemistry and our students are required to take an additional elective course covering one topic in greater detail. 

A more quantitative measure of stability, known as the stability ratio, can be obtained by setting up and solving the equation for diffusive collisions between the particles. Quantitative formulations of stability, known as the Smoluchowski and Fuchs theories of colloid stability, are the centerpieces of classical colloid science. These and related issues are covered in Section 13.4. 

The method of equilibrium ultracentrifugation described by Yphantis (28) was used in these studies. A double-sector centerpiece with two 2 1/2° sectors 12 mm. in length was used with standard Schlieren optics. Apparent molecular weights, M, were determined from the equation ... 

Carnot s prescient pamphlet, apparently distributed only among a small circle of friends, remained unknown in the scientific literature for about a decade. Fortunately, its content and value were recognized by fellow French engineer Emile Clapeyron, who built on its concepts and extended its methods, including, for example, the first graphical PV representation of the Carnot cycle. Clapeyron s 1834 paper was the means by which Carnot s discoveries first became known to William Thomson, who made them the centerpiece of his own later work on thermodynamic theory. 

There are numerous issues relating to science and society. In the Spotlight is a special feature of Conceptual Chemistry that highlights these issues and prods you to consider implications. These features can also sewe as a centerpiece foT potentially heated discussions with youT classmates and others. To inform youTself further on the issues, be sure to explore the related web sites listed on the last page of each preceding chapter. 

In the Spotlight essays appear after each of the first 12 chapters. These essays focus on chemistry-related issues that lend themselves to controversy. A Spotlight essay can serve as a starring point for a student project or as a centerpiece for in-class student discussion groups. 

A conceptual model which is the centerpiece of this chapter is developed in Section III. This is preceded (Section II) by a brief introduction to various organized media. The validity and generality of the model is examined by two approaches. In the first (Sections IV-VI), selected photochemical reactions belonging to various classes and chromophores are presented as supporting examples. In the second (Sections VII and VIII), a critical reevaluation of the results reported on Norrish II reactions in a number of organized media is made on the basis of the model. However, although we examined the literature examples on the basis of our model, we often have deviated from the initial explanations offered by the authors. 

Here A is the wavelength of the light being used (546 nm for the green line of mercury), and h is the thickness of the centerpiece (12 mm is most common). 

So far the equations that have been developed are independent of the shape of the cell. In order to make Equation 17 more useful, it is necessary to relate Ci( — 0) to the initial concentration of component i, Coi. To do this one applies conservation of mass, which states that in a closed system (the solution column in the ultracentrifuge cell) the total amount of solute is constant at all times. Since mass equals concentration times volume, it is necessary to know the volume of the centerpiece, and this depends on the shape of the centerpiece. Two types of centerpieces are currently used. One is a sector-shaped centerpiece, and the other is a six-channel, equilibrium [or Yphantis (24)] centerpiece. Top views of both centerpieces are shown in Figure 1. In either centerpiece, one side is reserved for solvent and the other for solution. 

For the sector-shaped centerpiece the conservation of mass equation can be expressed as (for 6 in radians)... 

Figure 1. Top view of double-sector (left) and Yphantis (right) centerpieces...

Figure 2. Plot of the cross-sectional width f(r) vs. radial distance r for an Yphantis centerpiece...

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