Ignition of samples

Measurements recorded 3 minutes after ignition of sample. 

Measurements recorded at end of experiment, i.e. 10 minutes after ignition of sample. (Reproduced with permission from Ref. 34, Copyright 1989 John Wiley Sons Ltd.)... 

Determination of total phosphorus in lake sediments by ignition of samples in a muffle furnace at 550°C, boiling of the residue from ignition in lmol L 1 hydrochloric acid, and subsequent determination of orthophosphate gave approximately the same values as the perchloric acid digestion. 

The calcium salt of the principal product, d/-tartaric acid, crystallizes with four molecules of water, while the secondary product, meso-tartaric acid, forms a calcium salt which crystallizes with three molecules of water. The amount of sulfuric acid actually required may readily be calculated from the percentage of calcium found on analysis in the regular way or it may be estimated by igniting a sample, and titrating the residue with standard acid. 

One of the most stringent and most widely accepted test is UL 94 that concerns electrical devices. This test, which involves burning a specimen, is the one used for most flame-retardant plastics. In this test the best rating is UL 94 V-0, which identifies a flame with a duration of 0 to 5 s, an afterglow of 0 to 25 s, and the presence of no flaming drips to ignite a sample of dry, absorbent cotton located below the specimen. Tlie ratings go from V-0, V-l, V-2, and V-5 to HB, based on specific specimen thicknesses. 

Fig. 5. Gas-phase ignition of propellant samples in shock tube (P8).

Portions of a 20 g sample of the oxidant salt, prepared exactly as the published description [1], had been used uneventfully dining a few days. Subsequently, as a 2 g portion was tipped out onto glazed paper, it ignited and burned violently, leading also to ignition of the bottled material [2],... 

The flammability of solids may be considered to be a function of the heat release rate and critical ignition energy of the material being studied. Flammability is an inverse function of the actual ignition energy of the material in question, and it is directly related to the rate of heat liberated after ignition of the sample. 

Table VI. Effect of Sample Configuration on the Minimum Ignition Temperature (in Oxygen) of Cottonwood Chars...

Dry-ashing Ignition of organic matter in a furnace. Resulting ash dissolved in acid for further analysis Metals in organic solid samples (e.g. metals in foodstuffs)... 

For quantitative analysis, the amount of sample taken is usually measured by mass or volume. Where a homogeneous sample already exists, it may be subdivided without further treatment. With many solids such as ores, however, crushing and mixing are prior requirements. The sample often needs additional preparation for analysis, such as drying, ignition and dissolution. 

What is the percent loss on ignition of a sample given the following data ... 

The mineral particles and ash that remain after the ignition of a sample as described above may be important to calculate and report. The mineral and ash are known as the residue. In pharmaceutical... 

This would be expected since any change in the onset of decomposition or initial rate of decomposition would affect the oxygen concentration for ignition of the sample. As mentioned... 

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