Spray layered materials

For detecting the presence of organochlorine compounds, an acetone solution of silver nitrate is used as a spray reagent (8). Silver nitrate also can be incorporated into the thin-layer material (39) and seems to give better results. However, the thin-layer media must have a low chlorine content or else the background may turn brown or gray. The spots... 

Muzzarelli et al. (2000) described a method for coating prosthetic articles with chitosan-oxychitin. Plates of titanium (Ti) and its alloys were plasma sprayed with hydroxyapatite and glass layers, and subsequently a chitosan coat was deposited on the plasma-sprayed layers using chitosan acetate. These layers were treated with 6-oxychitin to form a polyelectrolytic complex. This complex was optionally contacted with l-ethyl-3-(3-dimethylami-nopropyl) carbodiimide at 4°C for 2 hours to form amide links between the two polysaccharides, or acetylation with acetic anhydride in methanol to obtain a chitin film. In all cases, the modified coats were insoluble, uniformly flat, and smooth. Prosthetic materials coated with chitosan-oxychitin were capable of provoking colonization by cells, osteogenesis, and osteointegration. 

However, the lowest category, <1.0%, includes the overwhelming percentage of the spray-treated material. The 1.0-9.9% category outnumbers it by 3 or 4 times for layers 2 and 4 or about equals it for layer 3 of the tank-treated material (Figures 4 and 5). 

Moisture ratios of the pine core after preservation are much higher than those of the oak core. This contrast may point to differences in wood qualities of the oak and pine pieces. The maximum water contents of the two pieces of wood are deduced from the core samples taken at the beginning of the preservation. This investigation revealed that the maximum water contents of the surface layers of the oak and pine pieces are 200 and 240%, respectively. The layers beneath the surface layers have 150% maximum water ratios in both cases. The next question to be considered is whether the differences in preservation results depend upon the method of treatment used. To get some spray-treated material for comparison, the orlop deck of the Wasa was chosen because the sternmost third of that deck is made of oak and the other two thirds are made of pine planks. The PEG and HgO ratios of the cores from the two different parts of that deck after the automatic spray treatment was stopped (samples 33 and 34) were compared. 

The application of thermosensitive microbiological materials in product recirculation may influence a risk of thermal inactivation if part of the substance being dried stays too long in the heating zone during recirculation. In the case of spraying the material onto the bed of inert material, its particles are covered with a thin layer of wet material. With... 

Zinc arc spraying is an inexpensive process in terms of equipment and raw materials. Only 55—110 g/m is required for a standard 0.05—0.10 mm Zn thickness. It is more labor intensive, however. Grit blasting is a slow process, at a rate of 4.5 m /h. AppHcation of an adhesive paint layer is much quicker, 24 m /h, although the painted part must be baked or allowed to air dry. Arc sprayed 2inc is appHed at a rate of 9—36 m /h to maintain the plastic temperature below 65°C. The actual price of the product depends on part complexity, number of parts, and part size. A typical price in 1994 was in the range of 10—32/m. ... 

Flame spraying is no longer the most widely used melt-spraying process. In the power-feed method, powders of relatively uniform size (<44 fim (325 mesh)) are fed at a controlled rate into the flame. The torch, which can be held by hand, is aimed a few cm from the surface. The particles remain in the flame envelope until impingement. Particle velocity is typically 46 m/s, and the particles become at least partially molten. Upon impingement, the particles cool rapidly and soHdify to form a relatively porous, but coherent, polycrystalline layer. In the rod-feed system, the flame impinges on the tip of a rod made of the material to be sprayed. As the rod becomes molten, droplets of material leave the rod with the flame. The rod is fed into the flame at a rate commensurate with melt removal. The torch is held at a distance of ca 8 cm from the object to be coated particle velocities are ca 185 m/s. 

Some materials that are prepared in the molten state are converted advantageously to flake form by cooling a thin layer continuously on the surface of a rotating drum. Another way is to spray cool from the melt, using a spray diyer with cold air. Thus, massive cooling and subsequent pulverizing are avoided. See the Index for details of these other methods. 

Continuous production ol charcoal is typically performed in multiple hearth furnaces, as illustrated in the Herreshoff patent shown in Figure 2. Raw material is carried by a screw conveyor to the uppermost of a series of hearths, /kir is supplied counter-currently and burns some of the wood to supply process heat. As the layers of wood carbonize, they are transported to the lower (hotter) hearths by rakes. The hot charcoal product is discharged onto a conveyor belt and cooled with a water spray. 

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