Other Methods of Initiation

Sonication, the apphcation of high-intensity ultrasound at frequencies beyond the range of human hearing (16 kHz), of a monomer results in radical polymerization. Initiation results from the effects of cavitation— the formation and collapse of cavities in the hquid. The collapse (implosion) of the cavities generates very high local temperatures and pressures. This results in the formation of excited states that leads to bond breakage and the formation of 

---

Radiation-induced polymerization can be carried out in bulk, in solution, in emulsion (suspension), in the gas and solid states, and in the glassy state in other words, just as in other methods of initiation (conventional, thermal, photochemical initiation, etc.). 

Other Methods of Initiation. Apart from the above-mentioned methods of initiating free radical polymerizations, there are several more alternatives which can be selected from, if required for the specific application. These techniques include (I) ionizing irradiation, (2) plasma initiation, (3) electroinitiation, and (4) ultrasonic initiation. 

The tetracyclosilane could be expected to have a somewhat strained ring, and hence susceptible to polymerization. It was found that this cyclic material from the polymerization of either hexylmethyl- or propylmethyldichlorosilane in the presence of 15-crown-5 could be polymerized by heating. Other methods of initiation were attempted at lower temperatures, but with no success (Table 2). 

Method 5. Other Methods of Initiation Catalysts were prepared by the interaction of molybdenum or tungsten hexacarbonyl with bicyclo(2.2.1]heptadiene or cycloheptatriene (Si). They were described as being effective for the cyclopolymerization of [9] and [143]. 

A statistical analysis allows us to determine whether our results are significantly different from known values, or from values obtained by other analysts, by other methods of analysis, or for other samples. A f-test is used to compare mean values, and an F-test to compare precisions. Comparisons between two sets of data require an initial evaluation of whether the data... 

Continuous chlorination of benzene at 30—50°C in the presence of a Lewis acid typically yields 85% monochlorobenzene. Temperatures in the range of 150—190°C favor production of the dichlorobenzene products. The para isomer is produced in a ratio of 2—3 to 1 of the ortho isomer. Other methods of aromatic ring chlorination include use of a mixture of hydrogen chloride and air in the presence of a copper—salt catalyst, or sulfuryl chloride in the presence of aluminum chloride at ambient temperatures. Free-radical chlorination of toluene successively yields benzyl chloride, benzal chloride, and benzotrichloride. Related chlorination agents include sulfuryl chloride, tert-huty hypochlorite, and /V-ch1orosuccinimide which yield benzyl chloride under the influence of light, heat, or radical initiators. 

Mechanical effects Corrosion can often be initiated or intensified by the conjoint action of mechanical factors. Typical examples include the presence of inherent or applied stresses, fatigue, fretting or cavitation effects. Inhibitors that are effective in the absence of some or all of these phenomena may not be so in their presence. In fact it may not always be possible to use inhibitors successfully in these situations and other methods of corrosion prevention will be required. 

All known methods of initiation are used for inducing three-dimensional polymerization of AAm, AAc, and their copolymerization [37, 38]. Some special initiating systems have been also elaborated [39]. There is a wide choice of crosslinking agents various A,A -bis-acrylamides (methylene, ethylene, isopro-pylidene) as well as dimethacrylates of oligoethylene glycols and some others. 

Since X + In X is a transcendental function, Eq. (2-67) cannot be solved for [A], Two methods are usually used. The method of initial rates is the more common one, since it converts the differential equation into an algebraic one. Values of v(, determined as a function of [A]o, are fit to the equation given for v. This application to enzyme-catalyzed reactions will be taken up in Chapter 4. The other method regularly used relies on numerical integration these techniques are given in Chapter 5. 

The study of reactions with rates that He outside the time frame of ordinary laboratory operations requires specialized instrumentation and techniques. This chapter presents the wide range of methods currently in use for very fast reactions. Extraordinarily slow reactions, on the other hand, have received very little attention. For them, one may resort to measuring a tiny concentration of product over normal times, as in the method of initial rates. 

Cl is an efficient, and relatively mild, method of ionization which takes place at a relatively high pressure, when compared to other methods of ionization used in mass spectrometry. The kinetics of the ion-molecule reactions involved would suggest that ultimate sensitivity should be obtained when ionization takes place at atmospheric pressure. It is not possible, however, to use the conventional source of electrons, a heated metallic filament, to effect the initial ionization of a reagent gas at such pressures, and an alternative, such as Ni, a emitter, or a corona discharge, must be employed. The corona discharge is used in commercially available APCI systems as it gives greater sensitivity and is less hazardous than the alternative. 

This technique provides a method of initiating primacord—-and thus any explosive charge—if a regular blasting cap is not available. The device may be rigged as a booby trap with trip wire or it can be fired remotely by the operator. Since the technique does require the destruction of a usable rifle it likely would be used only when there is no other alternative. In addition, care should be taken in all phases of the preparation, because when the weapon is fired it will break into many fragments which would severely injure anyone holding the weapon or close to it. 

Other methods of producing the initiating radicals include photochemical and redox reactions.) Initiation is followed by propagation of the radical by the successive additions of very large numbers (usually thousands) of monomer molecules... 

Since the early delipidation procedure was applied initially to the whole serum (815) and later to the isolated serum lipoproteins (818), many other methods of delipidation have been reported [see reference (816) for review], employing mixtures of organic solvents (ethanol-ethyl ether chloroform-methanol, acetone, etc.) or detergents (sodium dodecyl or decyl sulfate, Triton X-100, Nonidet, etc.). Techniques for delipidation have not been standardized, nor is there a comprehensive comparative assessment of the various proposed methods presently avail-... 

PO 6, Hollister, Calif, 95023) consists of a stainless steel, hollow, cylindrical body ca 1.67-inches long, which can be hermetically closed. It contains three charges donor, receptor, and main chge, all of them secondary HE compns. Complete elimination of primary expl compns makes these devices safer to handle than other types of initiators. The main chge generates 3900 to 4500 psi within 0.4 millisecs in a closed volume of 10 cc. The method of initiating the TBI was not reported... 

Initiation by Primers (and Boosters) is the standard method of initiating secondary explosives. Thus hot wires (or other means) are used to initiate the primer charge (Lead Azide, Mercuric Fulminate etc) explosive whose detonation then initiates the main charge of PETN,... 

The explosive decomposition of tetryl, like that of other explosives, depends on the method of initiation, density etc. Haid and Schmidt [45] give the following equation for the decomposition of tetryl, at a density of 1.56 ... 

---