Colored sparks

Metal particles - especially aluminum, titanium, and "mag-nalium" alloy - produce good sparks that are white in appearance. Charcoal of sufficiently large particle size also works well, producing sparks with a characteristic orange color. Sparks from iron particles vary from gold to white, depending on the... 

The luminous phenomena in these ozonizers occur in the shape of more or less wide, colored bands of light, mostly in a horizontal and radial direction. Non-luminous vapors either remain wholly dark or become,—this is oftener the case,— interspersed with green-colored sparks. The sparks very rapidly decompose the vapors, precipitating carbonaceous substances the luminosity itself, on the contrary, produces only extremely trifling changes in the substances. 

The focus of this section is the emission of ultraviolet and visible radiation following thermal or electrical excitation of atoms. Atomic emission spectroscopy has a long history. Qualitative applications based on the color of flames were used in the smelting of ores as early as 1550 and were more fully developed around 1830 with the observation of atomic spectra generated by flame emission and spark emission.Quantitative applications based on the atomic emission from electrical sparks were developed by Norman Lockyer (1836-1920) in the early 1870s, and quantitative applications based on flame emission were pioneered by IT. G. Lunde-gardh in 1930. Atomic emission based on emission from a plasma was introduced in 1964. 

Wire sparklers are wires coated with pyrotechnic composition which are hand-held and produce a gende spray of gold sparks from iron filings. Fountains are cardboard tubes filled with chemical mixtures that produce a spray of color and sparks extending 2—5 m into the air. Roman candles are cylindrical tubes which repeatedly fire colored stars distances of 5—20 m into the air. These items typically contain 5—12 stars. 

Electro discharge (spark erosion) techniques rely heavily on the ability of EDM oil to act as an electrical insu-lant, to dissipate heat from the electrode, and to flush away erosion debris from the workpiece. EDM oils also are suitable for all die-sinking spark erosion operations. They should have low aromatic levels, good filterability, low fuming, high dielectric strength, excellent oxidation resistance and low color level. 

Images of the flame propagation process in an HCSI engine. Color scale qualitatively represents burning intensity. The presence of the spark is highlighted in the first image. 

The glow was blue in color and changed to the ordinary yellow-green glow with continuous spectrum if the spark gap was excluded. The spectrum of the glow was photographed with a small Hilger quartz spectro-... 

The basis for the claim of discovery of an element has varied over the centuries. The method of discovery of the chemical elements in the late eightenth and the early nineteenth centuries used the properties of the new sustances, their separability, the colors of their compounds, the shapes of their crystals and their reactivity to determine the existence of new elements. In those early days, atomic weight values were not available, and there was no spectral analysis that would later be supplied by arc, spark, absorption, phosphorescent or x-ray spectra. Also in those days, there were many claims, e.g., the discovery of certain rare earth elements of the lanthanide series, which involved the discovery of a mineral ore, from which an element was later extracted. The honor of discovery has often been accorded not to the person who first isolated the element but to the person who discovered the original mineral itself, even when the ore was impure and that ore actually contained many elements. The reason for this is that in the case of these rare earth elements, the earth now refers to oxides of a metal not to the metal itself This fact was not realized at the time of their discovery, until the English chemist Humphry Davy showed that earths were compounds of oxygen and metals in 1808. 

Arai,Y. Sparks, D.L. (2001) ATR-ETIR spectroscopic investigation on phosphate adsorption mechanisms at the ferrihydrite-water interface. J. Coll. Int. Sd. 241 317—326 Araki, S. Hirai, H. Kyuma, K. (1986) Phosphate absorption of red and/or yellow colored soil materials in relation to the characteristics of free oxides. Soil Sd. Plant Nutr. 32 609-616... 

Example 10-2 Everyone has poked a campfire at night and watched the sparks fly up. They glow a bright red, which indicates that they are emitting blackbody radiation from a source with a surface temperature of -1200°C. You have also noticed (if you were thinking about scientific matters at the time) that their color does not change until they suddenly disappear. The time for this reaction varies, but they seem to glow for a few SdC and then suddenly disappear. 

The use of pyrotechnic mixtures for military purposes in rifles, rockets, and cannons developed simultaneously with the civilian applications such as fireworks. Progress in both areas followed advances in modern chemistry, as new compounds were isolated and synthesized and became available to the pyrotechnician. Berthollet s discovery of potassium chlorate in the 1780 s resulted in the ability to produce brilliant flame colors using pyrotechnic compositions, and color was added to the effects of sparks, noise, and motion previously available using potassium nitrate-based compositions. Chlorate -containing color-producing formulas were known by the 1830 s in some pyrotechnicians arsenals. 

FIGURE 19 Flint tools. Axes, scrapers, and knives. Flint is a hydrated form of ciyp-tociystalline silica that occurs naturally as irregular nodules in chalk deposits. It is colorless and translucent when pure, but opaque and often colored when it contains impurities. When struck, flint breaks with a conchoidal fracture and the fragments formed have smooth, sharp edges. It is for this reason that prehistoric humans used flint to make tools. Since it also sparks when struck, flint was also used, until the eighteenth century, for lighting Are. 

Iron, Powder for Pyrotechnics. Sidorov et al claim a spark-forming composition for ppg fireworks which forms bright sparks of different colors, containing a thermal mixt a metal powder, eg (%wt) . NFLtClC 55 5, urotopine 14 2, iditol 8 2, metal powder (Fe or steel chips, powdered Al or its alloy with Mg) 23 5 (Ref 2)... 

Pyrites is described by Dioscorides as a land of stone from which copper is made. It resembles brass in color, and strikes sparks easily. There is no evidence that any discrimination was made by Dioscorides between iron and copper pyrites. 

Another important discovery by Cavendish is based upon an observation of Priestley. Priestley had experimented by passing the electric spark through air confined over water colored with litmus, and found that the air was diminished in volume and that the litmus was reddened. As Priestley believed that electricity was another form of phlogiston, his results were puzzling to him. His curiosity excited by Priestley s observations, Cavendish also attacked the problem. This resulted in his proof that, by this means, practically all the phlogisticated air could by a sufficient... 

The accurate measurement of chlorophylls has importance for numerous reasons ranging from simple color considerations to medical research. The most practical of these is the assessment of fruit and vegetable color quality, as chlorophylls are known to degrade rapidly when subjected to thermal processing (Schwartz et al., 1981). However, interest has also been sparked by recent literature reports that point to the possible health benefits associated with chlorophyll consumption (Hartig and Bailey, 1998). 

Roman candles are repeating guns which shoot projectiles of colored fire and send out showers of glowing sparks between the shots. To the pyrotechnists of the seventeenth century they were known as star pumps or pumps with stars. ... 

Neither No. 128 nor 129 is bright enough to make much of a show if the colored fire is also burning. When they bum to an end, the fire is communicated to the colored composition at the same time the bright diamond composition, either No. 149 or 152, commences to bum. No. 149 produces a splendid aureole of silver-white flowers. These flowers are less developed than those produced by steel wool and make a different effect from the latter. 40 No. 152 produces a splendid effect—no inflamed disc, no reddish sparks—numerous jasmine flowers of all dimensions forming a vast aureole of a striking white. 41... 

Mercury fulminate is usually stored under water, or, where there is danger of freezing, under a mixture of water and alcohol. When wet it is not exploded by a spark or by ordinary shock, but care must be taken that no part of the individual sample is allowed to dry out, for wet fulminate is exploded by the explosion of dry fulminate. It is not appreciably affected by long storage, either wet or dry, at moderate temperatures. At the temperature of the tropics it slowly deteriorates and loses its ability to explode. At 35°C. (95°F.) it becomes completely inert after about 3 years, at 50°C. (122°F.) after about 10 months. The heavy, dark-colored product of the deterioration of fulminate is insoluble in sodium thiosulfate solution. 

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