Explosives laboratory methods

Hydrogen can be prepared by the reaction of water or dilute acids on electropositive metals such as the alkali metals, alkaline earth metals, the metals of Groups 3, 4 and the lanthanoids. The reaction can be explosively violent. Convenient laboratory methods employ sodium amalgam or calcium with water, or zinc with hydrochloric acid. The reaction of aluminium or ferrosilicon with aqueous sodium hydroxide has also been used. For small-scale preparations the hydrolysis of metal hydrides is convenient, and this generates twice the amount of hydrogen as contained in the hydride, e.g. ... 

The question that arises next is how automated laboratory methods can be applied in and/or should be adapted to plant control. In principle those methods can be devoted to this role191 193 provided that some additional field effects (see Table 5.1) are taken into account, viz., special sampling and measuring requirements we shall confine ourselves to these aspects and not consider extra safety measures against hazards such as contact explosions in plants. 

These methods correlate well with laboratory methods, as well as detecting the presence of other explosives (e.g. DNT s) and need only little technical expertise. Using on-site analysis ... 

Field tests are analytical tests that are normally carried out outside the laboratory (in the field ). Field tests for explosives are usually performed when a rapid, on-site diagnostic detection of explosive materials is required. Thus, they are often carried out on suspects hands and belongings, in post-explosion sites, or in border stations, seaports, and airports. It should be emphasized that they constitute only prehminary examinations, and positive results should not be presented to court unless confirmed by reliable laboratory methods. Because field tests are usually carried out by individuals with no scientific background, their application must be easy, involving simple equipment and methodology. 

The standard industrial and laboratory method for the synthesis of the high explosive known as hexyl (12) (2,2, 4,4, 6,6 -hexanitrodiphenylamine) involves treating 2,4-dinitrochlorobenzene (95) with aniline to produce 2,4-dinitrodiphenylamine (96), followed by a two-stage nitration. - ... 

A complete description of methods used during WWII at the Keystone Ordnance Works, Meadville,Pa was given in Ref Ref G.D.Cliff B.T.Fedoroff, "A Manual of Explosives Laboratories , Lefax,Philadelphia, Vol 3, Chapter 2(1944),pp 19,21,23,24 28... 

V.I. Zenin B.I. Vaynshtein, Laboratory Method of Determining the Stability of Detonation of Explosives Intended for Group Blasting with Delay in Mines , Ibid, No 63/20 (1967)... 

A review including fluid mechanical considerations and useful applications among other aspects of dust explosions [7], and a collection of abstracts covering 20 years to 1977 [8] have been published. In a comparative study of laboratory methods available... 

Small quantities of explosive laboratory chemicals can be destroyed following known methods. By adopting standard methods, it is possible to destroy or reduce the dangerous nature of laboratory chemicals and check their reaction. Hydrocarbons (e.g., alkanes, alkenes, alkynes, arenas) bum well and can be disposed of by incineration or as fuel supplants. Also, many hydrocarbons commonly used in chemical laboratories may be easily ignited. Some cyclic compounds such as alkanes and cyclohexane may form explosive peroxides. Personnel trained in handling explosives should destroy these compounds using detonation. Many poly(nitro) aromatic compounds are explosive, and their disposal requires the services of an expert. 

Although the compound possesses very good explosive properties an application could not be found for it owing to the difficulty of making it, A new laboratory method was given by Olah and tin 112] of nitrating m-dinitro-benzene to s> m-trinitrobenzene with nitronium tetraHuoroborate in fluoro-sulphuric acid solution. A short description of the method is given below. 

Apart from such a practical method of determining the strength of explosives the following are the laboratory methods of examining the strength of explosives... 

The most eommonly used explosives ean be elassified into nitroaromatics (TNT, DNT, TNB), nitramines (RDX, HMX), and nitrate esters (PETN). Of these, TNT is the most widely used explosive. Currently, the laboratory method of TNT analysis is SW-846 Method 8330, whieh is performed in a high performanee liquid chromatography system (HPLC) in an off-site laboratory [2]. This method is a highly seleetive method and sensitive to parts per billion eoncentrations (ppb) however the average turnaround times for the results of a single test are 3 days and 1 month with eosts of 1,000 and 250, respeetively [3]. 

A wide variety of procedures have been developed to evaluate the performance of explosives. These include experimental methods as well as calculations based on available energy of the explosives and the reactions that take place on initiation. Both experimental and calculational procedures utilize electronic instmmentation and computer codes to provide estimates of performance in the laboratory and the field. 

This reaction has often reached explosive proportions in the laboratory. Several methods were devised for controlling it between 1940 and 1965. For fluorination of hydrocarbons of low (1—6 carbon atoms) molecular weight at room temperature or below by these methods, yields as high as 80% of perfluorinated products were reported together with partially fluorinated species (9—11). However, fluorination reactions in that eta involving elemental fluorine with complex hydrocarbons at elevated temperatures led to appreciable cleavage of the carbon—carbon bonds and the yields invariably were only a few percent. 

Samples are most frequently shock deformed under laboratory conditions utilizing either explosive or gun-launched flyer (driver) plates. Given sufficient lateral extent and assembly thickness, a sample may be shocked in a onedimensional strain manner such that the sample experiences concurrently uniaxial-strain loading and unloading. Based on the reproducibility of projectile launch velocity and impact planarity, convenience of use, and ability to perform controlled oblique impact (such as for pressure-shear studies) guns have become the method of choice for many material equation-of-state and shock-recovery studies [21], [22]. 

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