Crater method

The thickness of the deposits was determined by the ball cratering method or SEM measurement of cross-sections. The elemental composition was determined by electron microprobe analysis with wavelength dispersive spectroscopy (EPMA-WDS) on a Camebax Cameca equipment and by X-ray photoelectron spectroscopy (XPS) on a VG Escalab MK2 apparatus... 

Krater-Methode = crater method 301 Kresylit = trinitrocresol (german) 354 kritischer Durchmesser = critical diameter 66... 

The ball cratering method offers a genuine alternative to transverse and oblique sectioning techniques, because it can be performed with great simplicity, speed, and accuracy. In this method, a concave depression is ground into the sample surface by means of a steel ball rotating on a precisely centered spindle. An abrasive is introduced to the process in the form of a diamond suspension. 

Figure 137. Functional principle of the ball cratering method.

Some wave phenomena, familiar to many people from the human senses, include the easy undulation of water waves from a dropped stone or the sharp shock of the sonic boom from high-speed aircraft. The great power and energy of shock events is apparent to the human observer as he stands on the rim of the Meteor Crater of Arizona. Human senses provide little insight into the transition from these directly sensed phenomena to the high-pressure, shock-compression effects in solids. This transition must come from development of the science of shock compression, based on the usual methods of scientific experimentation, theoretical modeling, and numerical simulation. 

The maximum potential power of an explosive can be calculated, or it can be measured by techniques such as those developed by Cook. A typical method consists of firing the explosive under water and measuring the energy liberated in the various forms, such as shock wave in the water, the work of expansion of the gas bubble, etc. These figures have limited practical value as the methods of application of explosives are of low and variable efficiency. A more practical measurement of strength can be obtained by the measurement of cratering efficiency. This, again, demands considerable expense and also requires the availability of uniform rock. 

This section describes two derailment techniques one, a hasty method and, two, a concealed cratering system. 

The Russian word "rabotosposobnost or "capacity of doing work corresponds to Engl "power , while the word "sila (pronounced sceela) means "force and can also be called "strength (See Ref 20, p 644-45 Ref 21, p 92 Ref 22, p 466). For practical determination of "rabotosposob-nost one uses in Russia Trauzl Test (Ref 20, p 647 Ref 22, p 466), as well as Ballistic Pendulum Test and Ballistic Mortar Test (Ref 22, pp 469-74). One can also use the Cratering Test (Ref 22, p 474) and a method based on the measurement of shock pressure (Ref 22, p 475). In the book of Baum et al (Ref 20, p 645) it is stated that "sila (F) can be calcd from the equation ... 

Ballistic Pendulum Test) 471-74 (Ba llistic Mortar Test) 474-75 (Cratering Test) 475-76 (A method based on measurement of shock wave pressure) 23)... 

Such a product may be prepared by various methods, e.g. by mixing a coarse crystalline substance derived from crystallization in benzene with a fine crystalline one obtained by the precipitation of tetryl with water from an acetone solution. Another method (according to Crater [22]) consists of pouring the benzene solution into water heated to above the boiling point of benzene. Alternatively, crystallization from dichlorethane (according to Rinkenbach and Regad [23]) may produce an acceptable form of tetryl. 

Power is usually defined in terms of one or several of the following experimental methods a Ballistic Mortar Test(qv) b) Ballistic Pendulum Testf qv) c)Cratering Effect Test(q ) d)Mortar Test(qv) e) Quinns Test(qv) )Trauxl or Lead Block Expansion Test(qy), and ita modifications CVP and Kraftzabl. 

Review of literature on nitration, including continuous method .) 29)Kirk Othmer 6 (1951), 29-30 9(1952, 324-27(Continuous methods of Schmid, Schmid Meissner Biazzi) 30)Stettbacher, Polvoras (1952), 81-3 (Continuous method of Biazzi) 31)W. deC. Crater,... 

Methods of analysis of a std cratering chge consisting of AN 65, Na nitrate 20 TNT 15% are given in Refs 2,3,6 7 Refs 1) US Corps of Engineers Rept 999 (1947) (Cratering with expls) 2) F.Pristera S. 

Crater (Ref 106) patented a method whereby RDX, in cryst form, may be recovered from expl compns contg it TNT, NC or Tetryl by use of a solv, (such as acet or chlf) to dissolve the chge, except the RDX... 

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