Conditions necessary for

Introduction and Commercial Application This section will firstly examine the conditions necessary for the existence of a hydrocarbon accumulation. Secondly, we will see which techniques are employed by the industry to locate oil and gas deposits. 

A furtlier problem is tire influence of tire ratlier unusual—from tire physiological viewpoint—salt conditions necessary for crystallization. It should not be presumed tliat proteins embedded in a crystal are in tlieir most common native stmcture. It is well known tliat, witli tire exception of sodium or potassium chloride, which are not very useful for inducing crystallization, salts change key protein parameters such as tire melting temperature [19]. 

The experimental conditions necessary for the preparation of a solution of a diazonium salt, diazotisation of a primary amine, are as follows. The amine is dissolved in a suitable volume of water containing 2 5-3 equivalents of hydrochloric acid (or of sulphuric acid) by the application of heat if necessary, and the solution is cooled in ice when the amine hydrochloride (or sulphate) usually crystallises. The temperature is maintained at 0-5°, an aqueous solution of sodium nitrite is added portion-wise until, after allowing 3-4 minutes for reaction, the solution gives an immediate positive test for excess of nitrous acid with an external indicator—moist potassium iodide - starch paper f ... 

High temperature is an important requirement for the attainment of fusion reactions in a plasma. The conditions necessary for extracting as much energy from the plasma as went into it is the Lawson criterion, which states that the product of the ion density and the confinement or reaction time must exceed 10 s/cm in the most favorable cases (173). If the coUisions are sufficiently violent, the Lawson criterion specifies how many of them must occur to break even. Conventional magnetic confinement involves fields of as much as 10 T (10 G) with large (1 m ) plasmas of low densities (<10 particles/cm ) and volumes and reaction times of about 1 s. If the magnetic flux can be compressed to values above 100 T (10 G), then a few cm ... 

Dry methylene chloride does not react with the common metals under normal conditions however, a reaction with aluminum can be initiated, sometimes explosively, by the addition of small amounts of other halogenated solvents or an aromatic solvent (7). Iron catalyzes the reaction, and this can be significant in the handling and storage of methylene chloride and in the formulation of products, eg, in aluminum aerosol containers of pigmented paints, where the conditions necessary for the reaction are commonly found. A typical reaction in this process is shown in equation 2. 

Chloroisothiazoles and 3-chloro-l,2-benzisothiazoles are less reactive, and the more vigorous conditions necessary for replacement often cause ring cleavage. Halogens at all positions can be replaced by cyano groups (see Section 4.02.3.9). 

The Fire Triangle The well-known/i/ g triangle (see Fig. 26-33) is used to represent the three conditions necessary for a fire (1) fuel, (2) oxygen or other oxidizer (a gaseous oxidizer such as chlorine, a liquid oxidizer such as bromine, or a solid oxidizer such as sodium bro-mate), and (3) heat (energy). 

Avoid the common tendency to attribute to galvanic corrosion the deterioration of one metal simply because another metal is nearby. The conditions necessary for galvanic corrosion are specific, and all must be operating simultaneously for it to occur. These conditions are outlined in the General Description section of this chapter. 

Consider voltages and Ei being equal and in phase, a condition necessary for running the two generators in parallel, i.e. 

In general, when a person is thermally comfortable, the person s thermal sensation for the whole body is at or near neutral as depicted in Fig. 5.7a. As we have seen, the thermal conditions necessary for comfort are affected by clothing insulation. Figure 5.7b shows the range of temperatures and humidities... 

The purpose of a hazard tree is to identify potential hazards, define the conditions necessary for each hazard, and identify the source for each condition. Thus, a chain of events can be established that forms a necessary series of required steps that results in the identified hazard. This is called a hazard tree. If any of the events leading to the hazard can be eliminated with absolute certainty, the hazard itself can be avoided. 

A hazard tree is constructed by first identifying potential hazards. Starting with the hazard itself, it is possible to determine the conditions necessary for this hazard to exist. For these conditions to exist, a source that creates that condition must exist and so forth. Using this reasoning, a hierarchy of events can be drawn, which becomes the hazard tree. In a hazard analysis an attempt is made, starting at the lowest level in the tree, to see if it is possible to break the chain leading to the hazard by elimi-... 

Figure 2.1 identifies the conditions necessary for the occurrence of a flash fire. Only combustion rate differentiates flash fires from vapor cloud explosions. Combustion rate determines whether blast effects will be present (as in vapor cloud explosions) or not (as in flash fires). 

Because the major causes of blast generation in vapor cloud explosions are reasonably well understood today, we can approach the overview of experimental research more systematically by treating and interpreting the experiments in groups of roughly similar arrangements. Furthermore, some attention is given to experimental research into the conditions necessary for direct initiation of a detonation of a vapor cloud and the conditions necessary to sustain such a detonation. 

A detailed study performed by McKay et al. (1989) revealed some of the conditions necessary for a turbulent jet to initiate a detonation directly. These experiments are covered in more detail in Section 4.1.5. 

Platinum, palladium, and rhodium will function well under milder conditions and are especially useful when other reducible functions are present. Freifelder (23) considers rhodium-ammonia the system of choice when reducing -amino nitriles and certain )5-cyano ethers, compounds that undergo extensive hydrogenolysis under conditions necessary for base-metal catalysis. 

Conditions necessary for the onset of corrosion are quite often provided by heterogeneities. These heterogeneities may very well exist within the metal or alloy or may be imposed by external factors. These heterogeneities can give rise to variations in potential on a metal surface immersed in an electrolytic fluid. The galvanic cell thus formed gives rise to flow of current that accompanies corrosion [188]. 

The potentiostat has supplied an experimental tool for the study of anodic protection. The elucidation of passive behaviour made possible by poten-tiostatic anode polarisation curves allowed investigators to determine the conditions necessary for maintaining a metal in a stable passive condition by provision of a suitable environment, addition of cathodic alloying elementsand/or maintenance of the required potential by means of external anodic polarisation - . ... 

Now consider the conditions necessary for the practically complete precipitation of magnesium hydroxide from a 0.1M solution of, say, magnesium chloride. A pOH slightly in excess of4.9(i.e. pH = 9.1) might fail to precipitate the hydroxide owing to supersaturation. Let us suppose the hydroxide ion concentration is increased ten-fold, i.e. to pOH 3.9 or pH 10.1, then, provided no supersaturation is present ... 

The penetration theory has been used to calculate the rate of mass transfer across an interface for conditions where the concentration CAi of solute A in the interfacial layers (y = 0) remained constant throughout the process. When there is no resistance to mass transfer in the other phase, for instance when this consists of pure solute A, there will be no concentration gradient in that phase and the composition at the interface will therefore at all Limes lie the same as the bulk composition. Since the composition of the interfacial layers of the penetration phase is determined by the phase equilibrium relationship, it, too. will remain constant anil the conditions necessary for the penetration theory to apply will hold. If, however, the other phase offers a significant resistance to transfer this condition will not, in general, be fulfilled. 

The purpose of this final chapter is to provide the analyst with a background of practical examples to aid in the selection of, firstly, the best chromatographic method and, secondly, the best phase system when faced with an hitherto unknown sample for analysis. The literature is rich with LC applications and frequently publications are available for the separation of closely similar mixtures to that of the sample. It is unlikely, however, that the chromatographic conditions for the actual separation required will be available and, even if they are, the conditions reported may well not be optimum. This is more likely to be true for those applications that are described in earlier publications. Nevertheless, conditions that have be successfully employed for related separations may certainly help to identify those conditions necessary for the sample supplied for assay. 

Ancient civilizations were bom in environments which provided the challenge to which humans responded by action and achievements. The optimum conditions necessary for birth of civilizations were provided in the valleys of the world s great rivers, among them, the Nile, the Yellow, the Ganges, the Indus,... 

The distinguishing feature of such a mechanism occurs in the fact that the growth of all polymer molecules proceeds simultaneously under conditions affording equal opportunities for all. (This will hold provided the addition of monomer to the initiator is not much slower than succeeding additions.) These circumstances are unique in providing conditions necessary for the formation of a remarkably narrow molecular weight distribution—much narrower than may be obtained by polymer fractionation, for example. Specifically, they are the conditions which lead to a Poisson distribution of the number and mole fraction, i.e. ... 

In recent years the need has arisen for very thin glass windows capable of withstanding a vacuum yet thin enough to transmit a and jS particles. S. Rosenblum and R. Walen (1945) have described the following method for putting very thin windows into capillary tubing of up to 2 mm bore. The process is very simple but may require some practice before the precise conditions necessary for a satisfactory window are achieved. 

Flash Fires. The same materials that can create a VCE can result in a flash fire if the conditions necessary for a VCE are not present, as discussed in 3.2.1.1. 

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