The Poor

The principle of the photothermal camera is known for decades (see ref. 1) but did not offer sufficient performances to permit this instrument to find an industrial issue. The main reason of that lack of success Is the poor efficiency of the previous configurations when applied on industrial products (figures 3, 4, 5) ... 

A further indication of the poor standard of information in a reaction equation is that the plus +) symbol is used in a reaction equation for two entirely different purposes (Figure 3-2). 

Chemists usually learn about reactions according to fiinctional groups for example, How can I make an aldehyde and what reactions are known for aldehydes " This is clearly not a very good starting point for classifying reactions. The poor state of affairs in the definition of reaction types is further quite vividly illustrated by the fact that many chemical reactions are identified by being named after their inventor Diels-Alder reaction, Michael addition, Lobry-de Bruyn-van Ekenstein rear-... 

The disadvantages associated with the Clemmensen reduction of carbonyl compounds (see 3 above), viz., (a) the production of small amounts of carbinols and unsaturated compounds as by-products, (h) the poor results obtained with many compounds of high molecular weight, (c) the non-appUcability to furan and pyrrole compounds (owing to their sensitivity to acids), and (d) the sensitivity to steric hindrance, are absent in the modified Wolff-Kishner reduction. 

Surprisingly, the highest catalytic activity is observed in TFE. One mi t envisage this to be a result of the poor interaction between TFE and the copper(II) cation, so that the cation will retain most of its Lewis-acidity. In the other solvents the interaction between their electron-rich hetero atoms and the cation is likely to be stronger, thus diminishing the efficiency of the Lewis-acid catalysis. The observation that Cu(N03)2 is only poorly soluble in TFE and much better in the other solvents used, is in line with this reasoning. 

STO—nG n = 2—6) n primitives per shell per occupied angular momentum s,p,d). STO—3G is heavily used for large systems and qualitative results. The STO—3G functions have been made for H with three primitives (3.v) through Xe(15.vl2/i6r/). STO—2G is seldom used due to the poor quality of its results. The larger STO—nG sets are seldom used because they have too little flexibility. 

The first nitration to be reported was that of beri2ene itself. Mitscher-lich in 1834 prepared nitrobenzene by treating benzene with fuming nitric acid. Not long afterwards the important method of effecting nitration with a mixture of nitric and sulphuric acids ( mixed acid ) was introduced, evidently in a patent by Mansfield the poor quality of early nitric acid was probably the reason why the method was developed. Since these beginnings, nitration has been the subject of continuous study. 

The synthesis of MMDA in Pihkal is one of the longest and most tedious in the book. If one is going the route via myristicin, the Sisifos work of isolating the tiny amount of essential oil present in nutmeg, followed by fractional distillation to purify the myristicin fraction is also added to the labor of the poor chemist. Therefore I propose a new route to this "essential amphetamine". 

Cumulenic anions, C=C=C and C=C=C=C, without strongly electron-withdrawing substituents are much stronger bases than acetylides, "CsC- and are therefore also stronger nucleophiles. In view of the poor stability of the cumulenic anions at normal temperatures this is a fortunate circumstance the usual functionalization reactions such as alkylation, trimethylsilylation and carboxylation in most cases proceed at a sufficient rate at low temperatures, provided that the... 

Dimethyl acetylenedicarboxylate (DMAD) (125) is a very special alkyne and undergoes interesting cyclotrimerization and co-cyclization reactions of its own using the poorly soluble polymeric palladacyclopentadiene complex (TCPC) 75 and its diazadiene stabilized complex 123 as precursors of Pd(0) catalysts, Cyclotrimerization of DMAD is catalyzed by 123[60], In addition to the hexa-substituted benzene 126, the cyclooctatetraene derivative 127 was obtained by the co-cyclization of trimethylsilylpropargyl alcohol with an excess of DMAD (125)[6l], Co-cyclization is possible with various alkenes. The naphthalene-tetracarboxylate 129 was obtained by the reaction of methoxyallene (128) with an excess of DMAD using the catalyst 123[62],... 

The poor results obtained in some cases were attributed to the formation of resins and by-products as a result of ring closure by another route leading to the formation of 2-imino-3-oxa-4-thiolenes (187) (Scheme 96). (7,221,294). 

A novel synthesis of 2-thiazolecarboxaldehyde uses the reaction of 2-thiazolyUithium with N-methylformanilide with a yield of 46% (99). Similarly, 5-thiazolecarboxaldehyde was obtained in 5% yield, the poor yield probably being a result of the low stability of 5-thiazolyllithium. These unsatisfactory yields led Iversen and Lund to investigate four new methods (97). 

In media such as water and alcohols fluoride ion is strongly solvated by hydro gen bonding and is neither very basic nor very nucleophilic On the other hand the poorly solvated or naked fluoride 10ns that are present when potassium fluoride dis solves m benzene m the presence of a crown ether are better able to express their anionic reactivity Thus alkyl halides react with potassium fluoride m benzene containing 18 crown 6 thereby providing a method for the preparation of otherwise difficultly acces sible alkyl fluorides... 

Spike recoveries for samples are used to detect systematic errors due to the sample matrix or the stability of the sample after its collection. Ideally, samples should be spiked in the field at a concentration between 1 and 10 times the expected concentration of the analyte or 5 to 50 times the method s detection limit, whichever is larger. If the recovery for a field spike is unacceptable, then a sample is spiked in the laboratory and analyzed immediately. If the recovery for the laboratory spike is acceptable, then the poor recovery for the field spike may be due to the sample s deterioration during storage. When the recovery for the laboratory spike also is unacceptable, the most probable cause is a matrix-dependent relationship between the analytical signal and the concentration of the analyte. In this case the samples should be analyzed by the method of standard additions. Typical limits for acceptable spike recoveries for the analysis of waters and wastewaters are shown in Table 15.1. ... 

The thermospray inlet/ion source does not produce a good percentage yield of ions from the original sample, even with added salts (Figure 11.2). Often the original sample is present in very tiny amounts in the solution going into the thermospray, and the poor ion yield makes the thermo-spray/mass spectrometer a relatively insensitive combination when compared with the sensitivity attainable by even quite a modest mass spectrometer alone. Various attempts have been made to increase the ion yield. One popular method is described here. 

That state of affairs in which the poorness of the solvent exactly compensates for the excluded volume effect is called a 0 condition or Flory condition, after... 

Models are open to revision. Ideally, the good ones get better and the poor ones are abandoned. 

Monsanto s SEE modacryhc is the only remaining U.S. produced modacryhc flame-tesistant fiber. This fiber is a combination of halogen monomers and a dye receptor to offset the poor dye penetration characteristic of acrylonitrile-vinyl halogen copolymers. 

Manufacture. One commercial process features a three-stage saturation—rearomatization technique using benzene and fluorine gas as raw materials (73). Principal problems with this method are the complex nature of the process, its dependence on fluorine gas which is cosdy to produce, and the poor overall utilization of fluorine, because nearly one-half of the input fluorine is removed during the process. 

Polymer Flooding. Even in the absence of fractures and thief 2ones, the volumetric sweep efficiency of injected fluids can be quite low. The poor volumetric sweep efficiency exhibited in waterfloods is related to the mobiUty ratio, Af, the mobiUty of the injected water in the highly flooded (low oil saturation) rock, divided by the mobiUty of the oil in oil-bearing portions of the reservoir, (72,73). The mobiUty ratio is related to the rock permeabihty to oil, and injected water, and to the viscosity of these fluids by the following equation ... 

Aquatic Toxicity. The standard tests to measure the effect of substances on the aquatic environment are designed to deal with those that are reasonably soluble ia water. Unfortunately this is a disadvantage for the primary phthalates because they have a very low water solubiUty (ca 50 p.g/L) and this can lead to erroneous test results. The most common problem is seen ia toxicity tests on daphnia where the poorly water-soluble substance forms a thin film on the water surface within which the daphnia become entrapped and die. These deaths are clearly not due to the toxicity of the substance but due to unsuitable test design. 

Although performance varies with the isotopes for which they are intended, and with the balance in the design between resolution and efficiency, the overall sensitivity of a y-camera collimator is on the order of 5000 counts/(MBqmin) (several hundred counts/(/iCi-min)). In terms of photons detected per photon emitted, this is equivalent to about 2 x lO ". In other words, about two photons out of 10,000 emitted arrives at the crystal. This necessitates exposure times that range from several minutes to the better part of an hour. Fortunately, the large number of photons available from a modest injected radioactive dose more than offsets the poor detector sensitivity. The camera s abiUty to resolve small objects, however, is ultimately limited by the collimator inefficiency. 

Reclaimed mbber, which is widely used in dry mbber, has Htde use in latex compounding. A dispersion or artificial latex of the red aim must be made by a rather expensive process of milling in dispersing agents, eg, soaps and casein, and water. Some reclaim dispersions are used in latex compounds for such things as spread mbber goods and adhesives and fiber binders to reduce cost. However, for most latex compounds, it is not desirable because of the poor physical properties it imparts and the resultant darkening of the compound. 

Single-crystal siHcon can also be grown from various fluxes and by a combination of electrolysis and fluxes at temperatures weU below the melting point of pure siHcon (16). The main disadvantages are the inclusion of the flux in the crystal and the poor crystal quaHty. Potential advantages are a decrease in growth temperature and purification during electrolysis. 

Toxicology. Inorganic tin and its compounds are generally of a low order of toxicity, largely because of the poor absorption and rapid excretion from the tissues of the metal (42—49). The acidity and alkalinity of their solutions make assessment of their parenteral toxicity difficult. The oral LD q values for selected inorganic tin compounds are Hsted in Table 2. It is estimated that the average U.S. daily intake of tin, which is mostly from processed foods, is 4 mg (see Food processing). 

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