Natural disadvantage

So far we have considered memory from the point of view of recognition and identification. There is yet another side to memory that is concerned with recall and mental imagery. Here the perfumer is at a natural disadvantage when compared to the artist or musician. Most of us have more or less well developed senses of visual and auditory recall. The ability to see familiar objects in our mind s eye is one that we put to constant use, and the trained artist can reproduce on paper realistic images from memory. Similarly a musician can be trained to know precisely the sound that will be produced from the notes of a musical score, as might be heard in an actual performance. However, the ability to recall smell is usually much less developed. Can we really recall the smell of a rose in the same way that we can recall a color or a melody We may be able to describe the smell and recapture all the associations that go with it, but can we experience a concrete olfactory image of it in our minds ... 

Underestimation of cost and obsolescence. Looking back on history, it appears that rather few complex computer applications have paid their way in commercial enterprises until the particular development came into widespread use. The normal development scenario is that of a gross underestimation of development and application costs, and an overestimation of effectiveness by everybody. .. especially the salesman. Projects, as opposed to continuous-product organizations, are at a natural disadvantage here. Each project has its different needs, and there is no time for system development on the job. 

The use of Henry s constant for a standard-state fugacity means that the standard-state fugacity for a noncondensable component depends not only on the temperature but also on the nature of the solvent. It is this feature of the unsymmetric convention which is its greatest disadvantage. As a result of this disadvantage special care must be exercised in the use of the unsymmetric convention for multicomponent solutions, as discussed in Chapter 4. 

Since arsenic is often found in nature associated with sulphide ores, sulphur dioxide obtained by this method may contain some arsenic(III) oxide as impurity, and in certain processes this is a distinct disadvantage. 

The process can be operated in two modes co-fed and redox. The co-fed mode employs addition of O2 to the methane/natural gas feed and subsequent conversion over a metal oxide catalyst. The redox mode requires the oxidant to be from the lattice oxygen of a reducible metal oxide in the reactor bed. After methane oxidation has consumed nearly all the lattice oxygen, the reduced metal oxide is reoxidized using an air stream. Both methods have processing advantages and disadvantages. In all cases, however, the process is mn to maximize production of the more desired ethylene product. 

If possible comparisons are focused on energy systems, nuclear power safety is also estimated to be superior to all electricity generation methods except for natural gas (30). Figure 3 is a plot of that comparison in terms of estimated total deaths to workers and the pubHc and includes deaths associated with secondary processes in the entire fuel cycle. The poorer safety record of the alternatives to nuclear power can be attributed to fataUties in transportation, where comparatively enormous amounts of fossil fuel transport are involved. Continuous or daily refueling of fossil fuel plants is required as compared to refueling a nuclear plant from a few tmckloads only once over a period of one to two years. This disadvantage appHes to solar and wind as well because of the necessary assumption that their backup power in periods of no or Httie wind or sun is from fossil-fuel generation. Now death or serious injury has resulted from radiation exposure from commercial nuclear power plants in the United States (31). 

Insect Cells. In this system the cDNA is inserted into the genome of an insect vims, baculovims. Insect cells, or Hve insect larvae, are then infected with the vims. In this way advantage is taken of the vims s natural machinery for repHcation utilizing the insect cell. This is one of the best systems available for high level production of native protein having post-translational modifications similar to those seen in mammalian cells. Disadvantages of this system include lytic—batch variations, comparatively slow growth, and cosdy scale-up. 

Such compacting presses are not suited to larger tonnages when a small briquette is required. Their reciprocating nature is a disadvantage since this produces nonuniform loads on the drive motors. 

Fibers have been used by humans for thousands of years, but only in the twentieth century has there been such an explosion in fiber types available to the textile manufacturer. The advent of synthetic fibers possessing improved resiliency and dimensional stability has placed natural fibers, particularly cotton (qv), at an ostensible disadvantage. Before synthetics, various means to control the shrinkage, dimensional stability, and smooth-dry performance of cotton had been investigated, but the appearance of synthetics such as polyester has placed a greater sense of urgency on cotton interests to focus on the perceived deficiencies of natural fibers. 

After removal of the unreacted ammonia and recovery of hydrogen cyanide, the waste gas is essentially all hydrogen suitable for other chemical use. The advantages of the BMA process are the high ammonia and natural gas yields and the usehil hydrogen waste gas, but the high investment and maintenance for the converter is a decided disadvantage. 

The conditions for surfactants to be useful to form Hquid crystals exist when the cross-sectional areas of the polar group and the hydrocarbon chain are similar. This means that double-chain surfactants are eminently suited, and lecithin (qv) is a natural choice. Combiaations of a monochain ionic surfactant with a long-chain carboxyHc acid or alcohol yield lamellar Hquid crystals at low concentrations, but suffer the disadvantage of the alcohol being too soluble ia the oil phase. A combination of long-chain carboxyHc acid plus an amine of equal chain length suffers less from this problem because of extensive ionisa tion of both amphiphiles. 

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