Three Cautions

Analyze and Design Behavior through the Eyes of Others The last 

Although it is impossible to capture the complexity of all human interaction in a few short words, learning and using the three principles can often lead to useful guidance in new or unanticipated situations. 

Engineering teaches us to apply models in an almost promiscuous fashion. Engineers model structures. Engineers model circuits and control systems. Engineers model manufacturing workstations, assembly lines, even whole factories. But when it comes to modeling creative activity and human interaction, we need to be somewhat more cautious in our modeling. Specifically, three cautions must be exercised. 

One should be sensibly realistic in applying ideals. It may be all right to press for your own top performance or that of an organization that reports to you, but applying ideals to others who do not share your vision is a prescription for unhappiness and disappointment. Moreover, as pointed out elsewhere (Fritz, 1991), you should select ideals with considerable care, as it is possible to become paralyzed by conflict between what the ideals promise and what is actually possible. 

Mastering the Obvious Isn t Easy Engineering students often think of 

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In conclusion of this section, three cautions will be listed to point out errors into which those not familiar with free energy often fall. First, AF depends on concentrations, and therefore one must not use AF values in place of AF values. Second, AF is not related to the rate of a reaction, and therefore reactions do not necessarily occur at a measurable rate, even though AF is negative. Third, the maximum heat that a reaction can evolve is not equal to the maximum possible useful work, i.e., AH is not equal to AF. 

In a 500 ml. flask, fitted with a reflux condenser, place 53 g. of 1-chloro-methylnaphthalene (Section IV.23), 84 g, of hexamethylenetetramine and 250 ml. of 1 1 acetic acid [CAUTION 1-Chloromethylnaphtha-lene and, to a lesser degree, a-naphthaldehyde have lachrymatory and vesicant properties adequate precautions should therefore be taken to avoid contact with these substances.] Heat the mixture under reflux for 2 hours it becomes homogeneous after about 15 minutes and then an oil commences to separate. Add 100 ml. of concentrated hydrochloric acid and reflux for a further 15 minutes this will hydrolyse any SchifiF s bases which may be formed from amine and aldehyde present and will also convert any amines into the ether-insoluble hydrochlorides. Cool, and extract the mixture with 150 ml. of ether. Wash the ether layer with three 50 ml. portions of water, then cautiously with 50 ml. of 10 per cent, sodium carbonate solution, followed by 50 ml. of water. Dry the ethereal solution with anhydrous magnesium sulphate, remove the ether by distillation on a steam bath, and distil the residue under reduced pressure. Collect the a-naphthaldehyde at 160-162718 mm. the yield is 38 g. 

Equip a 500 ml. three-necked flask with a dropping funnel, a mechanical stirrer and a reflux condenser. Place a solution of 72 g. (65 ml.) of redistilled phenylhydrazine (Section IV,89) CAUTION poisonous) in 300 ml. of ether in the flask, stir vigorously, and add 33 g. (26 ml.) of A.R. carbon disulphide slowly during about 30 minutes. A precipitate is formed immediately upon the addition of the carbon disulphide, the mixture becomes warm and the temperature soon approaches the boiling point maintain the temperature just below the b.p. by cooling with ice water if necessary. When the addition is complete, stir for a further 30 minutes, then filter the precipitate at the pump, wash it with about 25 ml. of ether, and spread it upon filter paper for 20 minutes to permit of the evaporation of the ether. The yield of the salt (I) is 92 g. 

B. 3-Chlorothietane 1,1-dioxide. Thietane 1,1-dioxide (14.0 g, 0.132 mol) is placed in a three-necked, 500-mL, round-bottomed flask fitted with a magnetic stirrer, reflux condenser and a chlorine bubbler, caution sinae ahtovine is poisonous, the reaation involving it should be done in a good hood.) Carbon tetrachloride (300 mL) is added to the flask (Note 4) and the suspension is irradiated by a 250-watt sunlamp positioned as close as possible to the reaction flask without touching it (Note 5) while chlorine is bubbled through the solution for 15 min at a moderate rate (Note 6). A copious white precipitate forms and irradiation and addition of chlorine must be stopped at... 

The solid is separated by filtration and the filtrate is extracted with three 150-ml. portions of ether. Caution Gloves should be worn when handling this solution because of the large amount of cyanide it contains.) The solid is dissolved in ether and this solution is combined with the extracts. The combined ethereal solutions are washed with water and dried over 5 g. of sodium sulfate. Removal of the solvent by distillation leaves crude ferrocenyl-acetonitrile as a solid or as an oil that crystalli/.es on being scratched. I he nitrile is dissolved in about 200 ml. of boiling... 

Three reports have been issued containing IPRDS failure data. Information on pumps, valves, and major components in NPP electrical distribution systems has been encoded and analyzed. All three reports provide introductions to the IPRDS, explain failure data collections, discuss the type of failure data in the data base, and summarize the findings. They all contain comprehensive breakdowns of failure rates by failure modes with the results compared with WASH-1400 and the corresponding LER summaries. Statistical tables and plant-specific data are found in the appendixes. Because the data base was developed from only four nuclear power stations, caution should be used for other than generic application. 

There are three main methods for calculating electron correlation Configuration Interaction (Cl), Many Body Perturbation Theory (MBPT) and Coupled Cluster (CC). A word of caution before we describe these methods in more details. The Slater determinants are composed of spin-MOs, but since the Hamilton operator is independent of spin, the spin dependence can be factored out. Furthermore, to facilitate notation, it is often assumed that the HF determinant is of the RHF type. Finally, many of the expressions below involve double summations over identical sets of functions. To ensure only the unique terms are included, one of the summation indices must be restricted. Alternatively, both indices can be allowed to run over all values, and the overcounting corrected by a factor of 1/2. Various combinations of these assumptions result in final expressions which differ by factors of 1 /2, 1/4 etc. from those given here. In the present book the MOs are always spin-MOs, and conversion of a restricted summation to an unrestricted is always noted explicitly. 

Aluminium anodes comprise essentially three generic types Al-Zn-In, Al-Zn-Hg and Al-Zn-Sn. Since Al-Zn-Sn alloys have largely been superseded, they will not be discussed further. Indium and mercury are added to aluminium to act as activators, i.e. to overcome the natural passivation of aluminium. Despite this, aluminium anodes are not suitable for low chloride environments which would lead to passivation. These anodes are therefore not used for land-based applications (although examples of use in environments such as swamps do exist). Similarly their use in low chloride aqueous environments such as estuaries must be viewed with caution. 

The spectral characteristics of the source, photocells, and the three filters are such that approximate I.C.I. tristimulus values may be calculated (5) and from these a specification in terms of luminous reflectance, dominant wave length, and purity can be obtained. Hardy has cautioned (3), however, that the usefulness of such an instrument as a tristimulus colorimeter depends upon the standardization and constancy of the spectral characteristics of the light source, cell, and filters. 

Occurrence of the temperature inhomogeneity along a film during its heating was reported recently (45f). Different results were obtained when temperature measurement and control were effected only in one point, and in three points of the desorption cell, which illustrates that caution should be observed in this respect when studying thermodesorption from the films. This caution is obviously yet more essential when working with powdered materials. 

For a calculation of d. see R- H. Fowler. Statistical Thermodynamics. Second Edition, Cambridge University Press. 1956. p. 127. In Section 1.5a of Chapter 1 we defined the compressibility and cautioned that this compressibility can be applied rigorously only for gases, liquids, and isotropic solids. For anisotropic solids where the effect of pressure on the volume would not be the same in the three perpendicular directions, more sophisticated relationships are required. Poisson s ratio is the ratio of the strain of the transverse contraction to the strain of the parallel elongation when a rod is stretched by forces applied at the end of the rod in parallel with its axis. 

B. N-Nitromorpholine. Morpholine (34.8 g., 0.40 mole) and 26 g. (0.20 mole) of acetone cyanohydrin nitrate are mixed in a 50-ml. round-bottomed flask equipped with a thermometer well. A condenser is attached, and the mixture is heated slowly. At about 60° an exotherm ensues that raises the temperature of the mixture to 110°. The mixture is allowed to cool to 80° and maintained there for 1 hour. It is poured into 200 ml. of 10% hydrochloric acid (Caution Do in a hood Note 8) and extracted with three 100-ml. portions of methylene chloride (Note 9). The extracts are combined, washed successively with two 100-ml. portions of water, 100 ml. of 10% hydrochloric acid, and 100 ml. of water, and dried over anhydrous magnesium sulfate. The solvent is removed by evaporation on a water aspirator at room temperature to yield a pale-yellow oil (Note 10). 

Sometimes the atomic arrangement of a crystal is such as not to permit the formulation of a covalent structure. This is the case for the sodium chloride arrangement, as the alkali halides do not contain enough electrons to form bonds between each atom and its six equivalent nearest neighbors. This criterion must be applied with caution, however, for in some cases electron pairs may jump around in the crystal, giving more bonds than there are electron pairs, each bond being of an intermediate type. It must also be mentioned that determinations of the atomic arrangement are sometimes not sufficiently accurate to provide evidence on this point an atom reported equidistant from six others may be somewhat closer to three, say, than to the other three. 

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