Principal areas

Gases used in the manufacture of semiconductor materials fall into three principal areas the inert gases, used to shield the manufacturing processes and prevent impurities from entering the source gases, used to supply the molecules and atoms that stay behind and contribute to the final product, and the reactive gases, used to modify the electronic materials without actually contributing atoms or molecules. 

Methods for the large-scale production of hydrogen must be evaluated in the context of environmental impact and cost. Synthesis gas generation is the principal area requiring environmental controls common to all syngas-based processes. The nature of the controls depends on the feedstock and method of processing. 

Wine Making. Wine making is one of the principal areas of tartaric acid use. There is a relationship between the size of the grape crop and its tartaric acid content when grapes are pressed. In poor harvest years, the tartaric acid content is low in good harvest years, the tartaric acid content is high. Thus, in poor harvest years, tartaric acid often is added to correct acid deficiencies in wine. 

A typical phenol plant based on the cumene hydroperoxide process can be divided into two principal areas. In the reaction area, cumene, formed by alkylation of benzene and propylene, is oxidized to form cumene hydroperoxide (CHP). The cumene hydroperoxide is concentrated and cleaved to produce phenol and acetone. By-products of the oxidation reaction are acetophenone and dimethyl benzyl alcohol (DMBA). DMBA is dehydrated in the cleavage reaction to produce alpha-methylstyrene (AMS). 

Given stringent requirements for effective sensitizers and the desire to use wavelengths further to the red for therapeutic appHcations, definition of newer sensitizers has been a principal area of research since about 1987. Expanded theoretical and experimental understanding of photophysics has been a key element in identifying new classes of potential sensitizers (93—98). Research has focused on cationic derivatives of Nile Blue (93), metaHo-phthalocyanines (94), naphthalocyanines (95), chlorin-type compounds (96), expanded ring porphyrinoids (97), as well as porphyrins other than hematoporphyrin and its derivatives (98). This work has also been reviewed (10,91). Instmmentation for photodynamic therapy has been reviewed (99). 

Efficient integration of the process with the utiUty system involves reducing the two principal areas of irreversibiUty that are inherent in the cycle the... 

Pyridine bases are produced in three principal areas of the world the United States, Western Europe, and Japan. In the United States, there are two... 

The subsequent improvement of the physical and chemical characteristics of these membranes, their incorporation into machines, and the development of procedures to prevent or clean surface-fouling films were the principal areas of significant advancement. By 1990, the industrial ultrafiltration market had grown to an estimated (90-100) x 10 . ... 

The reliability of a product is the measure of its ability to perform its intended function without failure for a specified time in a particular environment. Reliability engineering has developed into two principal areas part and system. Part reliability is concerned with the failure characteristics of the individual part to make inferences about the part population. This area is the focus of Chapter 4 of the book and dominates reliability analysis. System reliability is concerned with the failure characteristics of a group of typically different parts assembled as a system (Sadlon, 1993). 

Indicates an apparent high degree of usefulness for SARA Title III (i.e., includes two or more principal areas of use identified on page 12). 

The principal areas where cooling design is affected by environmental requirements are visual and audible (i.e. aesthetic (plume) and noise). 

Here, selected, more established laser diagnostic techniques will only be briefly named with their principal area of application in combustion measurements, but not further described details on these and other methods can be found in the above-mentioned literature and references cited therein. Workhorse techniques in combustion diagnostics include Raman and Rayleigh... 

Figure 1, Classification of principal areas of colloidal particle chromatography...

Returning to our discussion of benefits, we note that they fell into two principal areas the time-value of information and the improvement in laboratory productivity. As we saw, assessing the benefits from the time-value of information requires examination of the total process through which that information will be used. For example, using data such as the anticipated improvement in laboratory turn around time, the rate at which material Is produced and its value, and the current the financial losses attributable to scrap or rework, one can estimate the savings in dollars to be accrued (each hour of faulty production avoided through faster lab turnaround time yields as a gain to the firm, the revenue that otherwise would have been lost). 

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