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Light and Color Production
Published in John A. Conkling, Christopher J. Mocella, Chemistry of Pyrotechnics, 2019
John A. Conkling, Christopher J. Mocella
To produce color in a pyrotechnic flame, heat (from the reaction between an oxidizer and a fuel) and a color-emitting species are required. Sodium compounds added to a heat mixture will impart a yellow–orange color to the flame. Strontium salts and lithium will yield red, barium and certain boron or copper compounds can give green, and certain other copper-compounds will produce blue. Color can be produced by emission of a narrow band of light (e.g., light in the range 435–480 nm is perceived as blue) or by the emission of several ranges of light that combine to yield a particular color. For example, the mixing of blue and red light in the proper proportions will produce a purple–violet flame effect, while mixing red and green light in the proper proportions will produce a yellow flame effect (recall these are emissive or additive colors and do not mix like paint). While all children learn their basic colors early in life, Color Theory is a complex topic, but it is one that should be studied by anyone desiring to produce colored flames (Kosanke and Kosanke 2004).
Integrated Pest Management
Published in L.B. (Bert) McCarty, Golf Turf Management, 2018
The distance a particular pyrotechnic device will travel varies from 50 to several hundred yards (>46 m) depending on manufacturer and type. Check with the manufacturer to be sure a particular device fits your needs. They can be very effective when used as soon as the flock begins to use the pond or property. But if the flock become established, their effectiveness is lessened or may be only temporary. Individuals using pyrotechnics should be trained in their use and should wear eye and ear protection.
Facile synthesis of CuO nanobricks for high combustion characteristics with nanoaluminum and catalytic thermal decomposition of lithium perchlorate
Published in Particulate Science and Technology, 2021
Vinay Kumar Patel, Ankur Gupta
In pyrotechnics, the alkali metal nitrates and perchlorates are most common oxidizers used. Among them, nitrates of sodium or potassium and potassium perchlorate are quite often used for flares and smoke ammunitions. The perchlorate is naturally occurring anion consisting one chlorine and four oxygen atoms bonded together along with alkali metals like sodium, and potassium. Among various alkali metal perchlorates, a little work had been done on Lithium perchlorate, yet Lithium is lightest alkali metal. The lithium perchlorate (LiClO4) is a white colored crystalline substance having density of 2.428 g/cc. The decomposition of anhydrous LiClO4 starts at 439 °C with a maximum at 470 °C [26]. In this article, we have studied the exothermic reactivity of nanoaluminum with surface CuO nanobricks and the catalytic activity of copper nanobricks were examined by decomposition of lithium perchlorate by adding 2 wt% of CuOnb.
Development and Parametric Study of B/BaCrO4/FG Pyrotechnic Delay Composition
Published in Combustion Science and Technology, 2018
Azizullah Khan, Abdul Qadeer Malik, Zulfiqar Hameed Lodhi, Syed Ammar Hussain
A pyrotechnic composition consists of fuels, oxidizing agents, and sometimes additives. Pyrotechnics are a special class of energetic material; when suitably initiated, they give a special effect as reported in Bailey and Murray (1989). Delayed pyrotechnic compositions are materials that rapidly burn when ignited, thus creating a time delay. A pyrotechnic delay composition must produce enough heat to compensate the heat loss through the rigid delay body, especially in a low-temperature environment in order to sustain reliable burning propagation in the delay body (Aube, 2008). There are two types of pyrotechnic delay compositions, a gassy delay composition, which generates gases relatively greater than 20 cc/gram on combustion at standard temperature and rressure, and a gasless delay composition, which generates a little less than 5 cc/gram of gas on combustion. A pyrotechnic delay composition is developed to perform some function after a predetermined delay time. Therefore, reproducibility in the delay time and burning rate/charge consumption are critical outcomes of any pyrotechnic delay composition for some special applications. Factors that may affect reproducibility of the delay time and burning rate/charge consumption of pyrotechnics delay composition include: confinement, particles size, percentage of fuels, diameter of the tube, thickness of delay body, conductivity of delay body, geometry of the delay body, ingredients, ingredients ratios, initial temperature, ambient temperature, ambient pressure, consolidation pressure, moisture, terminal charge, ignition composition, delay body material, storage condition, charge increment, binders, intimate contacts of ingredients, and so on (Beck and Brown, 1986; Danali et al., 2010; Eller and Valenta, 1974; Fathollahi et al., 2004; Khan et al., 2011; Li et al., 2010; Morgan et al., 2009; Ren et al., 2010). The consistency and accuracy of delay time is very important in a delay device especially in short pyrotechnic delay cartridges and detonators used to function after a predetermined delay time. Modern pyrotechnic devices are required to be consistent and precise in delay time (Jakubko and Indet, 1997; Li et al., 2010; Ricco et al., 2004; Wei et al., 2005; Youcheng and Song, 2000). A delay device is normally vented, obturated, or confined. In the case of a confined delay device, the pyrotechnic composition is required to be gasless in order to avoid development of pressure inside the devices. Boron-Barium chromate is a gasless delay composition. The propagative burning of the pressed delay column of this gasless delay composition is a combustion reaction in which B and BaCrO4 react to give solid products. The Differential Thermal Analysis (DTA) and Thermal Gravimetric Analysis (TGA) studies of the fuel/oxidizer in B/BaCrO4 delay mixture do not indicate the formation of a gaseous phase (Pamplet, 1967). The reported reaction between B and BaCrO4 is given below (McLain, 1980; Conkling, 1985):