Significant Quantity

To set a target for the quantification of the inspection goal, the IAEA currently adopts the following quantities (O Table 63.1) called significant quantities (SQs) as estimates of the amount of material that would be sufficient to manufacture a nuclear explosive device. 

---

Given that the objective is to manufacture a certain product, there are often a number of alternative reaction paths to that product. Reaction paths which use the cheapest raw materials and produce the smallest quantities of byproducts are to be preferred. Reaction paths which produce significant quantities of unwanted byproducts should especially be avoided, since they create significant environmental problems. 

Can the useful material lost in the purge streams be reduced by additional reaction If the purge stream contains significant quantities of reactants, then placing a reactor and additional separation on the purge can sometimes be justified. This technique is used in some designs of ethylene oxide processes. 

Antioxidant additives can not totally prevent the oxidation phenomenon, especially with the modern trend in oil-change intervals at the end of the interval, oil contains a significant quantity of insoluble oxidized material. 

The progressive cavity pump consists of a rotating cork-screw like sub-surface assembly which is driven by a surface mounted motor. Beam pump rods are used to connect the two. The flowrate achieved is mainly a function of the rotational speed of the subsurface assembly. There Is in principle very little that can go wrong with progressive cavity pumps. Progressive cavity pumps excel in low productivity shallow wells with viscous crude oils and can also handle significant quantities of produced solids. 

Amines like ammonia are weak bases They are however the strongest uncharged bases found m significant quantities under physiological conditions Amines are usually the bases involved m biological acid-base reactions they are often the nucleophiles m biological nucleophilic substitutions... 

Phenol was first isolated m the early nineteenth century from coal tar and a small por tion of the more than 4 billion lb of phenol produced m the United States each year comes from this source Although significant quantities of phenol are used to prepare aspirin and dyes most of it is converted to phenolic resins used m adhesives and plastics... 

Although EXo /ATcd is standard-state potential for the analyte s half-reaction, a matrix-dependent formal potential is used in its place. After the equivalence point, the potential is easiest to calculate using the Nernst equation for the titrant s half-reaction, since significant quantities of its oxidized and reduced forms are present. 

Hard red winter (HRW) is an important bread wheat that accounts for more than 40% of the United States wheat crop and wheat exports. This fall-seeded wheat is produced in the Great Plains, which extend from the Mississippi River west to the Rocky Mountains, and from the Dakotas and Montana south to Texas. Significant quantities are also produced in California. HRW has moderately high protein content, usually averaging 11—12%, and good milling and baking characteristics. 

Economic Aspects. In 1994, there were 16 operating hardboard and hardboard siding mills in the United States. Production was 1.535 x (2) in standard hardboard products. These figures do not include the significant quantities of door skin products made, for which production quantities are not tabulated. Production of hardboards has been relatively stable in recent years, considering them as a group. There have been a few new mill closings and a few mill start-ups. In addition, imports of hardboard have also become more common in recent years. 

At the completion of adsorption, the less selectively adsorbed components have been recovered as product. However, a significant quantity of the weaMy adsorbed species are held up in the bed, especially in the void spaces. A cocurrent depressurization step reduces the bed pressure by allowing dow out of the bed cocurrendy to feed dow and thus reduces the amount of product retained in the voids (holdup), improving product recovery, and increases the concentration of the more strongly adsorbed components in the bed. The purity of the more selectively adsorbed species has been shown to depend strongly on the cocurrent depressurization step for some appHcations (66). A cocurrent depressurization step is optional because a countercurrent one always exists. Criteria have been developed to indicate when the use of both is justified (67). 

Anesthesia. Materials that have unquestionable anesthetic properties are chloral hydrate [302-17-0] paraldehyde, dimethoxymethane [109-87-5] and acetaldehyde diethyl acetal. In iadustrial exposures, however, any action as an anesthesia is overshadowed by effects as a primary irritant, which prevent voluntary inhalation of any significant quantities. The small quantities which can be tolerated by inhalation are usually metabolized so rapidly that no anesthetic symptoms occur. 

Anhydrous Acetic Acid. In the manufacture of acetic acid by direct oxidation of a petroleum-based feedstock, solvent extraction has been used to separate acetic acid [64-19-7] from the aqueous reaction Hquor containing significant quantities of formic and propionic acids. Isoamyl acetate [123-92-2] is used as solvent to extract nearly all the acetic acid, and some water, from the aqueous feed (236). The extract is then dehydrated by azeotropic distillation using isoamyl acetate as water entrainer (see DISTILLATION, AZEOTROPIC AND EXTRACTIVE). It is claimed that the extraction step in this process affords substantial savings in plant capital investment and operating cost (see Acetic acid and derivatives). A detailed description of various extraction processes is available (237). 

Because of the ovedapping roles of coal in industry, many of the technologies covered here have been developed for synthetic fuel appHcations, but they also have been used or have demonstrated potential for production of significant quantities of chemicals. The scope of an article on coal as a chemical source would not be complete without coverage of synfuel processes, but the focus will be on the chemical production potential of the processes, looking toward a future when coal again may become the principal feedstock for chemical production. 

Fig. 3. Routes for making synthetic ammonia into fertilizers. The consumption data are for the year ended June 30, 1990 (5). Significant quantities are...

A large number of by-products are formed in this process, mostly in trace amounts more significant quantities are obtained of hexafluoropropylene, perfluorocyclobutane, l-chloro-l,l,2,2-tetrafluoroethane, and 2-chloro-l,l,l,2,3,3-hexafluoropropane. Small amounts of highly toxic perfluoroisobutylene, CF2=C(CF2)2, are formed by the pyrolysis of chlorodifluoromethane. 

Latex mbber foams are generally prepared in slab or molded forms in the density range 64—128 kg/m (4—8 lbs/fT). Synthetic SBR latexes have replaced natural mbber latexes as the largest volume raw material for latex foam mbber. Other elastomers used in significant quantities are polychloroprene, nitrile mbbers, and synthetic i j -polyisoprene (115). 

Products prepared in this manner typically contain significant quantities of coagulation Factors II, VII, and X and other proteins as well as Factor... 

Proof of the existence of benzene in the light oil derived from coal tar (8) first estabHshed coal tar and coal as chemical raw materials (see Eeedstocks, COAL chemicals). Soon thereafter the separation of coal-tar light oil into substantially pure fractions produced a number of the aromatic components now known to be present in significant quantities in petroleum-derived Hquid fuels. Indeed, these separation procedures were for the recovery of benzene—toluene—xylene (BTX) and related substances, ie, benzol or motor benzol, from coke-oven operations (8) (see BTX processing). 

Hydrogen atoms can be produced in significant quantities in the gas phase by the action of radiation on or by extreme heating of H2 (3000 K). Although hydrogen atoms are very reactive, these atoms can persist in the pure state for significant periods of time because of the inabiUty to recombine without a third body to absorb the energy of bond formation. 

Hydrogen chloride in air can also be a phytotoxicant (88). Tomatoes, sugar beets, and fmit trees of the Pmnus family are sensitive to HCl in air. Exposure of concentrated hydrochloric acid to the skin can cause chemical bums or dermatitis. Whereas the irritation is noticed readily, the acid can be water flushed from the exposed area. Copious use of miming water is the only recommended safety procedure for any external exposure. Ingestion is seldom a problem because hydrochloric acid is a normal constituent of the stomach juices. If significant quantities are accidentally swallowed, it can be neutrali2ed by antacids. 

Minerals and Metals. HCl is consumed in many mining operations for ore treatment, extraction, separation, purification, and water treatment (see Mineral recovery and processing). Significant quantities are also used in the recovery ofmolybdenum (see Molybdenum and molybdenum alloys) and gold (see Gold and gold compounds). This market consumed about 36 thousand metric tons in 1993. 

---