powder

(redirected from powdery)
Also found in: Dictionary, Thesaurus, Medical.
Related to powdery: powdery mildew

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
..... Click the link for more information.
.

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 periodicals archive ?
Total weight of recovered pouches containing white powdery substance was about 20.8 kgs.
They found that while bunch rot actually led to more positive aroma ratings due to the increased levels of fruity- and vanilla-like notes, powdery mildew decreased the level of pleasant notes in the wine, so that it received more negative ratings from the test panel, who found the infected wine to be less interesting than the healthy sample.
To date, they have identified markers for at least 13 loci for powdery mildew resistance and 27 for downy mildew resistance (Figure 1).
Fungicides can help control powdery mildew if applied before the infection becomes severe, but they are generally not worth applying.
A The paint is powdery because it's damp or was damp.
The powdery mildew occurs throughout the year under favorable conditions and it is more severe in late sown kharif crop.
Moreover, the classification and regression tree (CRT) was utilized to develop the prediction model of wheat powdery mildew.
Carol: It sounds to me like powdery mildew, which can appear if a plant is very dry or has had uneven watering.
It's inexpensive, safe, easy to use, and effective for the prevention and removal of aphids, spider mites and powdery mildew.
Guizhou University has been awarded a patent for a gradient bioceramic coating, wherein the gradient bioceramic coating is prepared with powdery titanium, and powdery composite ceramics, wherein the powdery composite ceramics is composed of powdery ceramics obtained by mixing CaHPO4.2H2O and CaCO3 and a rare earth oxide, wherein the gradient bioceramic coating comprises a first gradient layer, a second gradient layer and a third gradient layer and wherein the first gradient layer and the second gradient layer are composed of powdery titanium and powdery composite ceramics, and the third gradient layer consists of powdery composite ceramics.
The main foliar fungal diseases are brown spot (Bipolaris sorokiniana (Sacc.) Shoemaker), net blotch (Drechslera teres (Sacc.) Shoem.) and powdery mildew (Blumeria graminis DC.