Functional units

Not all the properties of alkenes are revealed by focusing exclusively on the func tional group behavior of the double bond A double bond can affect the proper ties of a second functional unit to which it is directly attached It can be a sub stituent for example on a positively charged carbon in an allylic carbocation, or on a carbon that bears an unpaired electron in an allylic free radical, or it can be a substituent on a second double bond in a conjugated diene... 

Conjugare is a Latin verb meaning to link or yoke together and allylic carbocations allylic free radicals and conjugated dienes are all examples of conjugated systems In this chapter we 11 see how conjugation permits two functional units within a molecule to display a kind of reactivity that is qualitatively different from that of either unit alone... 

The second family of reactions are those in which the aryl group acts as a sub stituent and affects the reactivity of a functional unit to which it is attached... 

The aromatic ring of a phenol like that of an arylamine is seen as an electron rich functional unit and is capable of a variety of reactions In some cases however it IS the hydroxyl oxygen that reacts instead An example of this kind of chemical reac tivity IS described m the following section... 

As CPU performance increases, the gap between CPU and disk and memory speeds will continue to widen. As limits of technology are approached, other techniques will be needed to gain performance advantages more functional units, multiple processors, and so on. These approaches are discussed in the sections on minisupercomputers and parallel processing. 

Because the Multiflow had multiple functional units, it would simultaneously perform both A = B + C and D = E + F storing both results in registers. If the result of the comparison turned out to be false, then it would not store the result D back into memory, and the calculation would be discarded. Because the two operations were done in parallel, this method took no extra time. The integer operation, 7 = 7 -H 1, as well as four other operations, could also be performed simultaneously. 

Loops that could not be vectorized on conventional vector computers often performed very well under the Multiflow architecture and, unlike vector machines, for which a person could spend a great deal of time optimizing programs, substantially less could be done on the Multiflow, as most of the work fell to the compiler anyway. All the usual optimizations for memory utilization and cache usage also appHed to the Microflow. There were, of course, programs for which the compiler could not make good use of the multiple functional units, and the computer would mn at the speed of just one or two iadividually quite slow functional units. 

A recent victim of the killer micros was Evans and Sutherland s parallel computer development effort, halted ia 1990. Their architecture combiaed a small number of approximately 1-MFLOPS processors iato semi-iadependent functional units. Several of these units could, ia turn, be combiaed to form a processor hierarchy, building up to systems that were expected to cost between 1 and 8 million dollars. With the advent of lO-MFLOPS uniprocessor killer micros, such an architecture became irrelevant and the project was halted. The RISC killer micro could deUver the same level of performance as could the combiaed efforts of 10 of the 1-MFLOPS processors, evea with the unlikely assumptioa that the problem could be perfectiy parallelized across 10 processors. 

Step Count Methods These methods, used for order-of-magnitude estimates, are based on the definition of the functional units required to carry out the process. A functional unit is a signifi-... 

Pumping and heat exchange form part of a functional unit. Tn-process storage is ignored, but large storage requirements for raw materials, intermediates, or products are usually estimated separately. Sometimes there are difficiilties in the identification and definition of the functional units involved in a process. 

For a particular process, the capital cost per functional unit is given by... 

Typical methods are those of F. C. Zevnik and R. L. Buchanan [Chem. Eng. Progi , 59, 70-77 (Feb. 1963)] and J. H. Taylor Eng. 6-Proc. Econ., 2, 259-267, 1977). The former is mainly a graphical method of estimating the cost per functional unit (Cp) based on the capacity, the maximum pressure, the maximum temperature, and the materials of construction. The Taylor method requires the determination of the costliness index, which is dependent on the complexity of the process. A simpler method was suggested by S. R. Timms (M.Phil. thesis, Aston University, England, 1980) to give the battery hmits cost for gas phase processes only in U.S. dollars with a Marshall and Swift index of 1000. The simple equation is... 

Figure 2.19 Organization of polypeptide chains into domains. Small protein molecules like the epidermal growth factor, EGF, comprise only one domain. Others, like the serine proteinase chymotrypsin, are arranged in two domains that are required to form a functional unit (see Chapter 11). Many of the proteins that are involved in blood coagulation and fibrinolysis, such as urokinase, factor IX, and plasminogen, have long polypeptide chains that comprise different combinations of domains homologous to EGF and serine proteinases and, in addition, calcium-binding domains and Kringle domains.

It also specifies data requirements, assumptions, limitations, eventual type of critical review, and the report requirements. For example, a study could be done to select between one of two materials when developing a dust transport container for a baghouse filter. The intended audience may be the designers, the results being used to indicate which one of the two materials provides the lowest environmental impact. The system function may be to transport dust from the baghouse filter to a landfill site, and the functional unit may be one metric ton or m of dust. The system boundaries may be described by considering which processes are included and which are outside the system limits. 

Reference flow and the functional unit are defined for the entire product system, and the elementary flows are calculated in relation to these. The flow figures are normally aggregated, and the total flow of each substance recorded and used for impact assessment. 

A unit of an organization which may perform one or more functions. Units of organization regardless of their names are also referred to as functions (see Functions). 

The oxetane functional unit is a rare but occurring group in natural products and appears both as end products as well as synthetic intermediates. Patemo-Buchi reactions can be used to insert oxetanes directly into biologically active compounds, as in the example... 

Note in Figure 12-103A that the various operational sections of the functioning unit are indicated however, these sections may vary mechanically between the competing manufacturers, but the general concept is the same. 

The Summary Drug Table Diuretics lists examples of die different types of diuretic drugp. Most diuretics act on die tubules of die kidney nephron (Pig. 46-1), the functional unit of the kidney. Each kidney contains about one million nephrons, which filter die bloodstream to remove waste products. During diis process,... 

Figure 46-1. The nephron is the functional unit of the kidney. Note the various tubules, the site of most diuretic activity. The loop of Henle is the site of action for the loop diuretics. Thiazide diuretics ad at the ascending portion of the loop of Henle and the distal tube of the nephron.

Depending on the types of unsaturated functional units involved in the metathesis process, the reactions can be classified into three major categories diene, enyne, and diyne metathesis (Figs. 1-3). Another mode of classification... 

The ST-100 is not a typical array processor. Figure 1 shows the data flow through the functional units of the machine for a routine application. There are seven main functional units (1)... 

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