Mixing with pastes

Pills made with paste Because the herbal ingredients are mixed with paste (made from rice or wheat flour), this type of pill is absorbed slowly and is especially suitable for ingredients that are toxic or have harsh actions which can easily irritate the stomach. This type of pill is also used for chronic conditions when gentle and steady effects are required. 

Figure 10.26 The effect of pitch carbon fibre content on the load-deflection curves in bending of mixes with paste matrix. The fibre is 10 mm long and 14.5 fim in diameter (after Akihama et al. [107]). (a) 0.420 w/c ratio...

The high potential and small radius of curvature at the end of the capillary tube create a strong electric field that causes the emerging liquid to leave the end of the capillary as a mist of fine droplets mixed with vapor. This process is nebulization and occurs at atmospheric pressure. Nebulization can be assisted by use of a gas flow concentric with and past the end of the capillary tube. 

Flame plating (D-gun) employs oxygen and fuel gas. In this method, developed by the Union Carbide Corporation, the gas mixture is detonated by an electric spark at four detonations per second. The powders, mixed with the gas, are fed under control into a chamber from which they are ejected when detonation occurs. The molten, 14—16-pm particles are sprayed at a velocity of 732 m/s at distances of 5.1—10.2 cm from the surface. The substrate is moved past the stationary gun. 

Soda. Ash Roasting. Some of the first processes to recover selenium on a commercial basis were based on roasting of copper slimes with soda ash to convert both selenium and tellurium to the +6 oxidation state. Eigure 1 shows flow sheets for two such processes. Slimes are intensively mixed with sodium carbonate, a binder such as bentonite, and water to form a stiff paste. The paste is extmded or peUetized and allowed to dry. Care in the preparation of the extmdates or pellets is required to ensure that they have sufficient porosity to allow adequate access to the air required for oxidation. 

Prereduced Powders. These are usually made from press cake paste to which a reducing agent has been added, such as sodium sulfide, sodium hydrosulfide, or sodium dithionite, which solubili2e the dye in water. Before drying, the dye paste may be mixed with dispersing and stahi1i2ing agents to aid appHcation. 

Polydimethyl siloxane is of moderately high molecular weight. The siHcone is a viscous Hquid. CoUoidal siHca or micronized metal oxides, 5—10 p.m particle size, are added to prepare a paste that is mixed with a tetraalkyl siHcate containing 50% ethoxy groups, eg, commonly tetraethyl orthosiHcate, and 1—2% of an organic tin activator. This type of catalyst has a limited shelf life because of oxidation. 

Tin oxide is a pure white powder. Mixed with water, glycerol, or alcohol into a paste, it is used for polishing teeth and metallic restorations. 

Over the past decades, advances have been made that reduce environmental impacts of coal burning in large plants. Some arc standard and others experimental. Limestone (mainly calcium carbonate) scrubber smokestacks react with the emitted sulfates from the combustion and contain the chemical products, thereby reducing the release of SO., into the atmosphere by a large factor (of ten or more). Pulverization of coal can also allow for the mechanical separation of some sulfur impurities, notably those in the form of pyrites, prior to combustion. Currently deployed—with more advanced versions in the development stage—are various t yies of fluidized bed reactors, which use coal fuel in a pulverized form, mixed with pulverized limestone or dolomite in a high temperature furnace. This technique reduces sulfate release considerably. There are... 

All AB, alloys are very brittle and are pulverized to fine particles in the hydrid-ing-dehydriding process (see Sec. 7.2.1). Thus electrodes must be designed to accommodate fine powders as the active material. There are several methods of electrode fabrication Sakai et al [35] pulverize the alloy by subjecting it to several hydrogen absorption-desorption cycles, before coating the resulting particles with Ni by chemical plating. The powder is mixed with a Teflon dispersion to obtain a paste which is finally roller-pressed to a sheet and then hot-pressed to an expanded nickel mesh. The fabrication of a simple paste electrode suitable for laboratory studies is reported by Petrov et al. [37],... 

Pittius Explosives. C. vanPittius of Holland obtd a BritP in 1910 on expls consisting of combustible mats and oxidizers. The combustible constituent is prepd by mixing resin (lOp) and stearin (5p) together at 150°, and incorporating paraffin (lOp) and a blend consisting of TNT (25p) and NG (5p) or NC (3p). Molten TNT (50p) is then added and blended while maint the mixt at 85°. The reddish-brnmixt is termed TNT paste . To use this expl the TNT paste is mixed with oxidizers, viz, a) TNT paste 20, K nitrate 30, amm perchlorate 30 and K perchlorate 20% b) TNT paste 8 and amm nitrate 92%... 

Zinc oxide is a white powder that makes a very opaque paste when mixed with water or oils. It is used as a sunblock and as a colorant in toothpastes and cosmetics. Zinc oxide is used in many of the same products as titanium dioxide. 

The paraffin sulfonate melt from the bottoms of the thin film evaporator is mixed with water, cooled, and bleached with hydrogen peroxide (9). After conditioning (10) and defoaming (11), the paraffin sulfonate (alkanesulfonate) is sold as an approximately 65% paste. The specifications are given in Table 6 [7],... 

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