General practices

Never climb onto or stand on chairs and stools. 

Never place bottles, beakers, flasks, etc., containing solutions or chemicals precariously close to the edge of a bench, etc., where they can be knocked off easily. 

If toxic, dangerous, or unpleasant gases become present in the lab at unsafe levels, all personnel should vacate the lab immediately and the plant supervisor notified. Examples include natural gas leaks, an experiment gone awry, etc. 

Avoid raising chemicals or solutions above eye level. 

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For general practical instructions concerning reactions in liquid ammonia one should consult "Preparative Acetylenic Chemistry", Elsevier, Amsterdam, 1971. 

Resist the temptation to use curved arrows to show the movement of atoms Not only is this con trary to general practice but it is also less reasonable Electrons are much more mobile than atoms so it makes sense to focus on them... 

The goal of a collaborative test is to determine the expected magnitude of ah three sources of error when a method is placed into general practice. When several analysts each analyze the same sample one time, the variation in their collective results (Figure 14.16b) includes contributions from random errors and those systematic errors (biases) unique to the analysts. Without additional information, the standard deviation for the pooled data cannot be used to separate the precision of the analysis from the systematic errors of the analysts. The position of the distribution, however, can be used to detect the presence of a systematic error in the method. 

Slimes Treatment. After the corroded anodes are washed, and the adhering slimes scraped off, filtered, and dried, approximately 8% moisture is left to prevent dusting. The general practice is to smelt the slimes in a small reverberatory furnace, which produces a slag 10—12% by weight of the slimes (Eig. 

For by-product coke ovens, it is general practice to blend two or more types of coals that have complimentary technical as well as economic characteristics. Because most by-product coke plants are located near the large industrial users of the coke and by-products, coals usually have to be transported from the coal mines to the coke plants. Thus coal blends are designed on integration of coke quaUty needs, by-product quaUty needs, coal costs, transportation costs, impacts of productivity, and impacts on the coke ovens themselves. The physical behavior of coal blends during coking can damage coke ovens. 

Frinciples of Double-Entry Accounting Many of the accounts involve both income and expenditure. The general practice is to keep accounts by the double-entry system, which may be summarized by... 

Two variations of the technique exists isocratic elution, when the mobile phase composition is kept constant, and gradient elution, when the mobile phase composition is varied during the separation. Isocratic elution is often the method of choice for analysis and in process apphcations when the retention characteristics of the solutes to be separated are similar and not dramaticallv sensitive to vei y small changes in operating conditions. Isocratic elution is also generally practical for systems where the equilibrium isotherm is linear or nearly hnear. In all cases, isocratic elution results in a dilution of the separated produces. 

To have a modular construction with a wide choice of module sizes for optimum utilization of the usable area in each vertical panel, which is normally 1800 mm as illustrated in Figure 13,32, The general practice is to have the module sizes in the ratio of 1/6 (300 mm), 1/4 (450 mm), 1/3 (600 mm) and 1/2 (900 mm), etc. Some manufacturers, however, supply 1/8 (225 mm) and 1/9 (200 mm) size of modules when the sizes and number of components for a module are less and can be accommodated in such a small module size. For critical installations, however, such as for a refinery or a petrochemical plant or for the essential services of a powergenerating station or installations that are in humid conditions or are contaminated, it is advisable to have a module size no smaller than 1/6 (300 mm)... 

However, due to the minor variations in the phase impedances, all the phases may not be subjected to identical severity of faults. For instance, in the above test each phase has recorded a different fault cunent. To evaluate the fault level from these test data, the general practice has been to consider the phase that has recorded the highest fault current as the base, which may occur in any of the phases. In the above test, it has occurred in phase Y. For this fault current, the test duration is adjusted to achieve the required severity of fault in terms of thermal effect (50 x 1 in the above case). 

The general practice to express an overvoltage is in p.u. This abbreviation will be used frequently in our discussions. One p.u. is the maximum voltage between the phase and the neutral, i.e. 

Considerable alterations have been made in the chapters concerned with technical applications which are the result of advances in electrochemical corrosion protection in general practice. Here also, abbreviation and omission of less relevant parts of the older editions have had to be made to create space for more recent information. Recent applications in the chemical industry have necessitated a complete rewriting of the industrial chapter. A new chapter is included on the cathodic protection of steel reinforcement in concrete. 

In summary, equation (13) accurately describes longitudinal dispersion in the stationary phase of capillary columns, but it will only be significant compared with other dispersion mechanisms in LC capillary columns, should they ever become generally practical and available. Dispersion due to longitudinal diffusion in the stationary phase in packed columns is not significant due to the discontinuous nature of the stationary phase and, compared to other dispersion processes, can be ignored in practice. 

Generally, practice would be to select a colunm allotving a few extra trays, making column total trays = 45. 

The general practice is to deliver the oil-base mud ready mixed to the rig, although some oil-base muds can be prepared at the rig. In the latter case, the most important principles are (1) to ensure that ample energy in the form of shear is applied to the fluid, and (2) to strictly follow a definite order of mixing. The following mixing procedure is recommended ... 

Line packing is generally practiced by building up the pressure during the night and reducing it during the day. 

Viscosity is a measurement of resistance to flow. Although the unit of absolute viscosity is poise, its measurement is difficult. Instead, kinematic (flowing) viscosity is determined by measuring the time for a given flow through a capillary tube of specific diameter and length. The unit of kinematic viscosity is the stoke. However, in general practice, centistoke is used. Poise is related to stoke by the equation ... 

Most fish is still caught at sea and must be cooled soon after it is taken on board, and kept cold until it can be sold, frozen or otherwise processed [45]. The general practice is to put the fish into refrigerated sea water tanks, kept down to 0°C by direct expansion coils or a remote shell-and-tube evaporator. The sea water must be clean and maybe chlorine dosed. At this condition, fish can be kept for up to four days. 

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