Detection Detonation

The ability to detect detonable masses of high explosives, such as TNT, in scrap collected from firing ranges is of extreme interest to the US military. During normal use, firing ranges accumulate enormous piles of scrap... 

The team was funded by the Strategic Environmental Research and Development Program (SERDP) to determine if the Nomadics Fido sensor could address this problem by detecting detonable masses of HE within piles of scrap materials. 

Two holes that are limiting the measured distance are made in the explosive charge. The velocity probes capable of detecting detonation wave arrival are inserted into the holes. Velocity probes may be of various types, but depending on their operating principle they are divided into... 

CAUTION. Ethers that have been stored for long periods, particularly in partly-filled bottles, frequently contain small quantities of highly explosive peroxides. The presence of peroxides may be detected either by the per-chromic acid test of qualitative inorganic analysis (addition of an acidified solution of potassium dichromate) or by the liberation of iodine from acidified potassium iodide solution (compare Section 11,47,7). The peroxides are nonvolatile and may accumulate in the flask during the distillation of the ether the residue is explosive and may detonate, when distilled, with sufficient violence to shatter the apparatus and cause serious personal injury. If peroxides are found, they must first be removed by treatment with acidified ferrous sulphate solution (Section 11,47,7) or with sodium sulphite solution or with stannous chloride solution (Section VI, 12). The common extraction solvents diethyl ether and di-tso-propyl ether are particularly prone to the formation of peroxides. 

Peroxide Formation. Except for the methyl alkyl ethers, most ethers tend to absorb and react with oxygen from the air to form unstable peroxides that may detonate with extreme violence when concentrated by evaporation or distillation, when combined with other compounds that give a detonable mixture, or when disturbed by heat, shock, or friction. Appreciable quantities of crystalline soHds have been observed as gross evidence for the formation of peroxides, and peroxides may form a viscous Hquid in the bottom of ether-fiHed containers. If viscous Hquids or crystalline soHds are observed in ethers, no further tests for the detection of peroxides are recommended. Several chemical and physical methods for detecting and estimating peroxide concentrations have been described. Most of the quaHtative tests for peroxides are readily performed and strongly recommended when any doubt is present (20). 

It is emphasized that the system shown in Figure 5-13 represents only a simplification of actual plant installations, which may he more complex. If it is not obvious at which point ignition is likely to occur, a flame arrester installed in an actual plant may have to he selected to face a comhination of the conditions shown in Figure 5-13. Therefore, for manifolded vent systems, the arrester should he a hidirectional, detonation type, and hoth sides of the arrester element should he provided with thermocouples to detect a stable flame. 

An interlock system (sensors and valves) which isolates offgas flow to die process heater firebox and routes the offgas to atmosphere on detection of low nitrogen flow or high temperature at the detonation flame arrester outlet. 

If the outlet or discharge pressure is lowered further, the pressure upstream at the origin wtill not detect it because the pressure wave can only travel at sonic velocity. Therefore, the change in pressure downstream will not be detected upstream. The excess pressure drop obtained by lowering the outlet pressure after the maximum discharge has been reached takes place beyond the end of the pipe [3]. This pressure is lost in shock waves and turbulence of the jetting fluid. See References 12,13, 24, and 15 for further expansion of shock waves and detonation waves through compressible fluids. 

Toxicity and Hazards. The odor cf ozone can be detected in concn as low as several parts per hundred million by vol (pphm). The threshold limit value (TLV) is O.lppmor 0.2mg/m3 its toxic dose level (TDL), 50% kill concn is 2ppm (Ref 6) Pure 100% liq ozone may be kept safely at 90°K (cooled by liq oxygen) for indefinite periods of time, but the smallest provocation, such as a spark or fast warming, even only up to bp (161°K), causes detonation. The evapn of liq ozone, for example, in the process of the prepn of pure gaseous ozone is, therefore, a dangerous procedure (Ref 3, p 224)... 

Urea was treated with oxalic acid and carbon. The operation was carried out in the presence of anhydrous copper sulphate in order to detect the water formed, and gases were expected to bubble through a barium hydroxide solution to be able to see carbon dioxide. Unfortunately, the apparatus was closed by mistake. It detonated due to the large quantity of gases formed in the reaction ... 

Early in the program, critical components (e.g.,the turbomolecular pump) and circuit boards were tested for their ability to survive neutron and gamma irradiation rates and doses similar to those that would be received from exposure to the detonation of a tactical nuclear device. All components were powered up at the start of the gamma irradiation tests but not during the neutron irradiation tests. Circuit boards were protected by circumvention circuits that powered down critical circuits in 10 to lOOps upon detecting radiation. All components survived the nuclear radiation tests. This unusual performance was noted with positive commendations by the staff at the White Sands Missile Range, where the tests were performed. Tests of the fully integrated CBMS II system, installed in a reconnaissance vehicle, will be conducted in the future. 

The Detonator Module is a control unit that is used with the UV and/or IR detection system to activate the water deluge system. 

When dealing with an entire fire detection system that utilizes more than one type of detector, a Detonator Module greatly expands the flexibility and capability of the system. An individual Detonator Module can accept multiple inputs from UV and IR controllers, other Detonator Modules, manual alarm stations, heat sensors, smoke detectors or any contact closure device. In the event of a fire, any of these devices will cause the internal fire circuitry of the module to activate the detonator circuit, sound alarms, and identify the zone that detected the fire. When properly used, a Detonator Module will add only one millisecond to the total system response time. See Figure 8 for an illustration of a fire detection system with a Detonator Module. 

Figure 8. Fire Detection System with Detonator Module...

The functional components of a bomb are a control system, detonator, booster, and a main charge. Such threats can often be recognized from their shape. These can be viewed as bulk detection issues, historically addressed by imaging techniques such as sight or touch. Other threats may take no particular physical form and can only be recognized by their chemical composition. These are often trace detection issues, historically detected by the sense of taste or smell. 

A bomb can be considered to contain four functional blocks, namely, a control system, a detonator, a booster, and a main charge. Although a simple ignition fuse can be used as a control system and timing device, the control system is usually more mechanical or electrical in nature. The detection of control systems may be visual, or by magnetometry, or by X-ray. It must be remembered that many of the items involved in the ignition system, that is, clockwork, batteries, or electronic circuitry, are commonplace in ordinary items, such as cameras, mobile telephones, and personal stereos, and are not unique indicators of the presence of a bomb. In fact, it is the presence of explosives that is the key indicator of a bomb. 

Primary explosives are sensitive to modest stimuli such as heat, spark, or friction application of the correct stimulus will lead to a detonation. The primary explosives used in detonators are typically extremely sensitive but not particularly powerful common examples are mercury fulminate, lead azide, and lead styphnate. In principle, the heavy metals present in most primary explosives should be a good cue for detection however, there are primary explosives that do not contain such elements. 

Quadrupole ion trap, time of flight, mass spectrometer Quantum yield Research and development Reversal electron attachment detection Remote environmental monitoring units Remote explosive scent tracking Radio frequency Ragnar s Homemade Detonators Receiver operator characteristics (a graphical portrayal of Pd and Pfp)... 

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