Advisers

Standard-state fugacities at zero pressure are evaluated using the Equation (A-2) for both condensable and noncondensable components. The Rackett Equation (B-2) is evaluated to determine the liquid molar volumes as a function of temperature. Standard-state fugacities at system temperature and pressure are given by the product of the standard-state fugacity at zero pressure and the Poynting correction shown in Equation (4-1). Double precision is advisable. 

Using this concept, Burdett developed a method in 1955 to obtain the concentrations in mono-, di- and polynuclear aromatics in gas oils from the absorbances measured at 197, 220 and 260 nm, with the condition that sulfur content be less than 1%. Knowledge of the average molecular weight enables the calculation of weight per cent from mole per cent. As with all methods based on statistical sampling from a population, this method is applicable only in the region used in the study extrapolation is not advised and usually leads to erroneous results. 

Incidentally, it is advisable to compare the results of several methods to uncover possible anomalies and to analyze the results very carefully. 

It is advisable to provide re-sectioning between these two types of curves so that the properties of any cut can be deduced. 

Petroleum economics provides the tools with which to quantify and assess the financial risks involved in field exploration, appraisal and development, and allows a consistent approach with which alternative investments can be compared. The techniques are applied to advise management on the attractiveness of such investment opportunities, to assist in selecting the best options, and to determine how to maximise the value of existing assets. 

At the same time advisability of designing the instrument taken into consideration cracks length 1 and object thickness T and of defining the instrument application sphere can be only determined after research work. 

Unfortunately, the supennolecule approach [81, 82] is full of teclmical diflSculties, which stem chiefly from the very small magnitude of the interaction energy relative to the energy of the supennolecule. Even today, a novice would be ill-advised to attempt such a computation using one of the black-box computer programs available for perfonning ab initio calculations. 

In the ideal case for REMPI, the efficiency of ion production is proportional to the line strength factors for 2-photon excitation [M], since the ionization step can be taken to have a wavelength- and state-mdependent efficiency. In actual practice, fragment ions can be produced upon absorption of a fouitli photon, or the ionization efficiency can be reduced tinough predissociation of the electronically excited state. It is advisable to employ experimentally measured ionization efficiency line strengdi factors to calibrate the detection sensitivity. With sufficient knowledge of the excited molecular electronic states, it is possible to understand the state dependence of these intensity factors [65]. 

So as to make the individual sections self-contained, we have found it advisable to give some definitions and statements more than once. 

If the task is multivariate calibration, for example, the proper choice of a pre-processing method will essentially aflFect the quality of the resultant model. For more details about the use of these techniques together with PCA and PLS, readers are advised to consider the fundamental monograph by Erikson et al [8]. 

How can we apply molecular dynamics simulations practically. This section gives a brief outline of a typical MD scenario. Imagine that you are interested in the response of a protein to changes in the amino add sequence, i.e., to point mutations. In this case, it is appropriate to divide the analysis into a static and a dynamic part. What we need first is a reference system, because it is advisable to base the interpretation of the calculated data on changes compared with other simulations. By taking this relative point of view, one hopes that possible errors introduced due to the assumptions and simplifications within the potential energy function may cancel out. All kinds of simulations, analyses, etc., should always be carried out for the reference and the model systems, applying the same simulation protocols. 

This book was carefidly produced. Nevertheless, editors, authors and publisher do not warrant the information contained therein to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or otiier items may inadvertently be inaccurate. 

Caution During a sininlation, solvent temperature may increase wh ile th e so In te cools. This is particii larly true of sm all solven t molecules, such as water, that can acquire high translational and rotational energies. In contrast, a macromolecule, such as a peptide, retains most of its kinetic energy in vibrational modes. This problem rem ains un solved, an d this n ote of cau tion is provided to advise you to give special care to simulations using solvent. 

Cannot be used for alcohols, phenols or amines, with all of which it combines. Not advisable for acidic liquids, as ordinary calcium chloride always contains some calcium hydroxide owing to partial hydrolysis during preparation. Usually used for alcohols (see p. 88). Cannot be used for acidic compounds, nor for esters, which it would hydrolyse. 

It is often advisable to lubricate ground-glass joint surfaces with an extremely thin film of vaseline. This applies particularly to joints employed in assemblies for distillation under reduced pressure. For distillations under greatly reduced pressures or at very high temperatures it is essential to employ a special lubricant, e.g., silicone grease. 

Care must be used when employing alkalis. In these circumstances joints tend to stick unless a lubricant is used. In addition it is advisable to rotate the units comprising the joint at frequent intervals. Apparatus in which alkalis have been used should be dismantled immediately after use. 

The preparation of ether is described here because this is chemically its logical position. It is advisable, however, for students to defer its preparation... 

Pour the mixture into a separating-funnel. Owing to the density of the acetate being only slightly greater than that of water, a sharp separation is usually not rapidly obtained. It is advisable therefore to add about 8 ml. of carbon tetrachloride, when, after shaking, a sharp and rapid separation of the heavy solution of the phenyl acetate in the... 

It is advisable in any case before an experiment to place the weighed aluminium isopropoxide overnight in a shallow dish in a vacuum desiccator over sodium hydroxide. The isopropanol should be dried over anhydrous sodium sulphate, and the clear liquid decanted off before use. 

With paraldehyde and the aromatic aldehydes (being insoluble in water), it is advisable to warm the mixture gently on a water-bath, shaking the tube vigorously from time to time to break up the oily globules of the aldehyde. 

Students arc strongly advised not to attempt identification of the soluble carbohydrates by taste—quite apart from the fact that other compounds (c.g., saccharin] also have a sweet taste, the tasting of an imperfectly identified organic compound u too dangerous an operation. 

In the separations (2) and (3) above, it is often advisable to dissolve the original mixture in a water-insoluble solvent. Select a solvent which will dissolve the entire mixture, and then shake the solution with either (i) dil. NaOH or (ii) dil. HCl. Separate the aqueous layer, and to it add either (i) dil. HCl or (ii) dil. NaOH to liberate the organic acid or the organic base, as the case may be. The non-aqueous layer now contains the neutral component. Reextract this layer with either (i) dil. NaOH or (ii) dil. HCl to ensure removal of traces of the non-neutral component. 

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