powder


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powder,

any mass of fine particles or dust prepared by various mechanical means, e.g., grinding of solid substances, or by chemical means, e.g., precipitation from solutions. In a special sense, the word is applied to powdered propellant explosives, e.g., gunpowder, and to powdered substances that produce a bright light when ignited. See explosiveexplosive,
substance that undergoes decomposition or combustion with great rapidity, evolving much heat and producing a large volume of gas. The reaction products fill a much greater volume than that occupied by the original material and exert an enormous pressure, which can be
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.

Powder

 

a finely ground solid, a dispersed free-flowing material.

Powder is formed by dispersion of solids and by separation of the solid dispersed phase from supersaturated solutions or vapors. The manufacture of highly dispersed powders usually involves such substances as softening solutions, dispersing agents, and stabilizers. These facilitate pulverizing and prevent the agglutination of fine particles. Particle size in powders may vary from 10-4 to 10-1 mm. Powders with particles of identical size are called monodisperse powders, and those with particles of varying size are known as polydisperse powders. Fine powders, especially hygroscopic types, are subject to lumping and caking. Highly dispersed dry powder carried off by a gas or air flow becomes dust. Powder moistened with a liquid forms a paste or dough, and when powder is rapidly agitated in a sufficiently large volume of liquid, a suspension is produced.

Many types of commercial products are manufactured and used in powder form. They include materials used in metallurgy and silicate technology; mineral binders, fillers, and pigments; ingredients for plastics, rubbers, paints, and explosives; fertilizers and pesticides; detergents; food products; and medications. Products in powder form are often granulated or compressed into tablets to ensure convenience in handling and to reduce loss and improve sanitation.

REFERENCE

Voiutskii, S. S. Kurs kolloidnoi khimii. Moscow, 1964. Page 374.

L. A. SHITS


Powder

 

a friable solid form of medicine used internally or externally. Various synthetic preparations, antibiotics, and substances of plant and animal origin are used in powder form. The following substances are not prescribed as a powder: hygroscopic substances, such as calcium chloride and sodium bromide; mixtures of substances that are fluidized upon exposure to the air, such as phenylsalicylate and bromo-camphor or antipyrine and quinine; substances that easily decompose, such as silver nitrate mixed with organic matter; or substances that form explosive mixtures. Powders may be simple (consisting of a single substance) or compound; they can be divided or not divided into individual doses.

powder

[′pau̇d·ər]
(materials)
A general term for explosives.
A loose grouping or aggregation of solid particles, usually smaller than 1000 micrometers.

powder

1. a solid substance in the form of tiny loose particles
2. any of various preparations in this form, such as gunpowder, face powder, or soap powder
3. fresh loose snow, esp when considered as skiing terrain
References in classic literature ?
I only keep to statistical facts when I say that, during the war, and for the very largest guns, the weight of the powder was reduced, as the result of experience, to a tenth part of the weight of the shot.
Perfectly correct," said Morgan; "but before deciding the quantity of powder necessary to give the impulse, I think it would be as well "
Well," continued the Tin Woodman, "the old woman had an idea that the Powder in the bottle must be moth-powder, because it smelled something like moth-powder; so one day she sprinkled it on her bear rug to keep the moths out of it.
Therefore I believe it is a good thing that all the Magic Powder of Life is now used up, as it can not cause any more trouble.
I thought," went on Chunk hopefully, "that if I had one of them powders to give Rosy when I see her at supper to-night it might brace her up and keep her from reneging on the proposition to skip.
But tell me, please, what you intend to do with this new lot of the Powder of Life, which Dr.
No servant will come here because the place is so lonely and out-of-the-way, so my clever husband, the Crooked Magician, proposed that I make a girl out of some sort of material and he would make her live by sprinkling over her the Powder of Life.
What do you think a mother would feel like if she found her child tattooed over with a baking powder advertisement?
We're a-changing of the powder, Jack," answers one.
I came into Oxford Street by the Marble Arch, and here again were black powder and several bodies, and an evil, ominous smell from the gratings of the cellars of some of the houses.
As for Porthos, after having hurled the barrel of powder amidst his enemies, he had fled, as Aramis had directed him to do, and had gained the last compartment, into which air, light, and sunshine penetrated through the opening.
However, I said no more to the boy, but bade him lie still, and I took our biggest gun, which was almost musket-bore, and loaded it with a good charge of powder, and with two slugs, and laid it down; then I loaded another gun with two bullets; and the third (for we had three pieces) I loaded with five smaller bullets.