Powder density modification

The (3-modification is a yellow powder density 5.45 g/cm converts to the a-form when heated to 400°C absorbs moisture from air, the yellow powder becoming green droplets dissolves readily in water forming a colorless solution which turns pink on heating. 

Excipients and/or modification of powder density or flow characteristics... 

Tantalum Oxides. Tantalum pentoxide [1314-61 -0] Ta20, (mp = 1880°C, density = 8.73 g/cm ) is a white powder existing in two thermodynamically stable modifications. The orthorombic P-phase changes at 1360°C into the tetragonal a-modiftcation. The existence of an S-modiftcation has also been reported (70). Tantalum pentoxide reacts slowly with hot hydrofluoric acid but is insoluble in water and in most solutions of acids and alkalies. For analytical purposes, it can be dissolved by fusion with alkali hydroxides, alkali carbonates, and potassium pyrosulfate. 

The determination of precise physical properties for elemental boron is bedevilled by the twin difficulties of complex polymorphism and contamination by irremovable impurities. Boron is an extremely hard refractory solid of high mp, low density and very low electrical conductivity. Crystalline forms are dark red in transmitted light and powdered forms are black. The most stable ()3-rhombohedral) modification has mp 2092°C (exceeded only by C among the non-metals), bp 4000°C, d 2.35 gcm (a-rhombohedral form 2.45gcm ), A77sublimation 570kJ per mol of B, electrical conductivity at room temperature 1.5 x 10 ohm cm- . 

Field Pea Flour in Other Baked Products. When McWatters (44) substituted 8% field pea flour and 4.6% field pea concentrate for milk protein (6%) in baking powder biscuits, sensory attributes, crumb color, and density of the resulting biscuits were adversely affected. No modifications were made in recipe formulation when pea products were incorporated. The doughs were slightly less sticky than control biscuits that contained whole milk. This might be due to lack of lactose or to the different water absorption properties of pea protein or starch. Panelists described the aroma and flavor of these biscuits as harsh, beany and strong. Steam heating the field pea flour improved the sensory evaluation scores, but they were never equivalent to those for the controls. 

The crystallinity of organic pigment powders makes X-ray diffraction analysis the single most important technique to determine crystal modifications. The reflexions that are recorded at various angles from the direction of the incident beam are a function of the unit cell dimensions and are expected to reflect the symmetry and the geometry of the crystal lattice. The intensity of the reflected beam, on the other hand, is largely controlled by the content of the unit cell in other words, since it is indicative of the structural amplitudes and parameters and the electron density distribution, it provides the basis for true structural determination [32],... 

The hyperbranched grafting chemistry used with polyolefin films and wafers was also extended to modification of 200 p.m diameter high density PE powder substrates [19]. However, because of the relatively high surface area of the 200 pm-diameter polyethylene powder (the measured BET surface area was... 

Silvery-white, brittle metallic element crystal system-hexagonal, rhombo-hedral also, exists in two unstable allotropic forms— a yellow modification and a dark-grey lustrous amorphous powder—both of which revert to crystalline form hardness 3.0 to 3.5 Mohs density 6.697g/cm3 melting point 630.5°C boiling point 1635°C electrical resistivity 39.1 microhm-cm at 0°C magnetic susceptibifity —0.87 x 10 emu/g. 

Natural stibnite is black orthorhombic crystal or grayish-black powder the compound also exists as an amorphous substance in yeUow-red modification distorted octahedral arrangement density 4.64 g/cm for the natural stibnite and 4.12 g/cm for the red modification melts at 550°C vaporizes around 1150°C insoluble in water (1.75mg/L at 18°C) and acetic acid soluble in hydrochloric acid and caustic soda solution also, soluble in alcohol, ammonium hydrosulfide and potassium sulfide. 

YeUow or orange monoclinic crystal or powder a red aUotrope modification also known density 3.46 g/cm melts at 310°C bods at 707°C insoluble in water soluble in liquid ammonia and alkalies. 

The oxide exhibits two crystalline modifications, the reddish or orange-red alpha form, known as litharge, and the yellow beta form, massicot. The alpha form constitutes tetragonal crystals while the beta modification is a yellow amorphous powder of orthorhombic crystal structure. The alpha form is stable at ordinary temperatures, converting to the beta form when heated at 489°C density 9.35 g/cm (beta form) Moh s hardness 2 (alpha form) the oxide melts at 888°C vaporizes at 1,472°C with decomposition vapor pressure 1 torr at 943° C and 5 torr at 1,039°C practically insoluble in water (the solubdity of alpha form is 17 mg/L at 20°C and that of beta form 23 mg/L at 22°C) insoluble in ethanol soluble in dilute nitric acid and aUtahes. 

Trigonal crystalline solid or amorphous powder mineral millerite has a yellow metallic luster color varies from yellow to brownish black density 5.30 to 6.65 g/cm3 exhibits three allotropic modifications (1) the acid-soluble amorphous alpha form obtained from nickel salt solution by precipitation with ammonium sulfide, (2) the alpha form rapidly transforms to a crystalline beta form as a brown colloidal dispersion upon exposure to air, and (3) a rhombo-hedral gamma modification found native as mineral millerite, which also can be prepared artificially under certain conditions. 

Exists in two adotropic modifications. Crystalline sihcon is made up of grayish-black lustrous needle-hke crystals or octahedral platelets cubic structure Amorphous sdicon is a brown powder. Other physical properties are density 2.33g/cm3 at 25°C melts at 1,414°C high purity liquid silicon has density 2.533 g/cm at its melting point vaporizes at 3,265°C vapor pressure 0.76 torr at 2,067°C Mohs hardness 6.5. Brinell hardness 250 poor conductor of electricity dielectiric constant 13 critical temperature 4°C calculated critical pressure 530 atm magnetic susceptibility (containing 0.085%Fe) 0.13x10 insoluble in water dissolves in hydrofluoric acid or a mixture of hydrofluoric and nitric acids soluble in molten alkalies. 

V. Nitroglycerine low-density powder. This is a modification of Group IV. Low density (ca. 0.7) is obtained by incorporating vegetable fibre or peat. A low density form of ammonium nitrate and sodium chloride may also be used. A 1 Roun-kol is an example of an explosive of this group. Sheathed Rounkol has been replaced by Unikol. They are used for soft coal, for maximum lump production. Their water resistance is the same as that of Group IV. 

Amorphous Selenium.—(1) Vitreous Selenium.—When molten selenium is cooled in not too protracted a manner, no definite solidification or crystallisation ensues, but the mass gradually hardens and the product really represents a strongly undercooled liquid like glass. Vitreous selenium is a brittle reddish-brown substance, exhibiting a conchoidal fracture. When finely powdered and viewed in thin layers it has a deep red colour. This form has an average density of 4-28 5 the value varies slightly, possibly owing to the presence of other allotropic modifications of the element. 

CSP 2 (Chilworth Smokeless Powder, No 2). This is a tubular double-base proplnt which may be considered as a modification of Cordite (qv). It consists of NC (N content 12.70 0.15%) 70.5, NG 23-5, petroleum jelly 5 Na bicarbonate 1% (Ref 3). The density of the proplnt is 1-56 g/cc. Some other props are calcd by Alvaro Alberto (Ref 2) and applied to the problem of erosion of proplnts. CSP 2 has been known since ca 1902 and has been manufd or adopted by several countries, including Germany, Gt Britain, Brazil (1908), Italy (1910) Spain. It was manufd in Italy by the Societa Italians Dinamite Nobel, Avigliana under the name CZPolvere) (Refs 4 5) and in Spain at the Fabrica de Galdacano of the Union Espanola de Explosivos under the name Polvora sin Humo de Chilworth (Ref 3). This proplnt has been used in various cannons such as cal 76.2mm, 101.6mm, 15 cm, 30.5cm others See also C-2 (Polvere), Vol 2, p Cl-L Refs l)Marshall, Diet (1920), 26 2)Alvaro... 

The primary carbonate is known, in the form of powder, as rhombic crystals,16 and in a monodinic modification.17 Its density is given as... 

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