Recovery Flats

The wrinkle recovery angle provides a measure of the degree of chemical modification. This is calculated by blending a small sample and measuring the recovery to the flat configuration (180°). Whereas the untreated cotton recovers approximately 90°, the cross-linked cotton sample recovers 120—140°. If this is measured on dry fabric, it is termed conditional wrinkle recovery angle if on wet fabric, it is termed wet wrinkle recovery. At one point, wet wrinkle recovery was important, particularly in Europe. In the United States, the widespread use of clothes dryers has made conditional wrinkle recovery important. 

A final note is with regard to flat bottom cyclones which have gained acceptance in recent years. The installation of a flat bottom in place of the conical section will coarsen the separation by more than twofold. Additionally, the sharpness of the recovery curve will decrease significantly. As such, flat bottom cyclones should be restricted to those applications in which coarse separations are required. The flat bottom cyclone does produce a very clean underflow but at the expense of a large amount of misplace coarse solids in the overflow. An illustration of a flat bottom cyclone is shown in Figure 58. The reader should refer to the reference section of this chapter for citations that provide more in-depth coverage of this equipment, as well as design case studies and example. 

A typical ozone system consists of 100 g/hr at a concentration of 1.0 percent to 1.5 percent in air fed to the bottom of bleach collection tanks through ceramic spargers (pore size of approximately 100 t). The system contains air compression and drying equipment, automatic control features, and a flat-plate, air-cooled ozone generator. Regeneration of bleach wastes totaling about 10,000 gallons a year, and recovery of other chemicals can also be cost effective. 

An overview is given of plutonium process chemistry used at the U. S. Department of Energy Hanford, Los Alamos National Laboratory, Rocky Flats, and Savannah River sites, with particular emphasis on solution chemistry involved in recovery, purification, and waste treatment operations. By extrapolating from the present system of processes, this paper also attempts to chart the future direction of plutonium process development and operation. Areas where a better understanding of basic plutonium chemistry will contribute to development of improved processing are indicated. 

Large-scale plutonium recovery/processing facilities originated at Los Alamos and Hanford as part of the Manhattan Project in 1943. Hanford Operations separated plutonium from irradiated reactor fuel, whereas Los Alamos purified plutonium, as well as recovered the plutonium from scrap and residues. In the 1950 s, similar processing facilities were constructed at Rocky Flats and Savannah River. 

Chemical processing activities involve the recovery of plutonium from Rocky Flats Plant scrap, waste materials and residues, and effluent streams. The final product of this recovery and purification effort is high-purity plutonium metal for use in foundry operations. 

The original plutonium recovery and purification processes were adopted from Los Alamos processes in 1950. The processes at Rocky Flats are still similar today, in many respects, to the Los Alamos processes. 

Figure 3. Plutonium Recovery Processes at Rocky Flats...

Figure 1 shows a simplified flow sheet for plutonium-239 recovery operations at Rocky Flats. Impure plutonium metal is sent through a pyrochemical process, called molten salt extraction (MSE), to remove the elemental impurity americium. The product plutonium metal, if it meets plant purity requirements, is sent to the foundry. Metal that does not meet foundry requirements is processed further, either through an aqueous process using ion exchange, or through a pyrochemical electrorefining process. The waste chloride salt from MSE is... 

The NaCl-KCl eutectic is used when the pregnant extraction salt is to be processed by aqueous recovery (this is the salt currently used at Rocky Flats because calcium follows americium in the present aqueous recovery process). The NaCl-CaCl system is used when the salt is processed by pyrochemical means to recover the americium and residual plutonium. When the pyrochemical recovery technique is used, the NaCl-CaCl2-MgCl2 salt is contacted with liquid calcium metal at approximately 850°C in a batch extractor. The calcium reduces A111CI3,... 

Fig. 22 (a-f) Time series photographs showing recovery of shape-memory tube from start to finish of the process total time 10 s, at 50 °C. The tube was made of PCL-dimethacrylate polymer network that had been programmed to form a flat helix. Reprinted from [323] with permission... 

Each object has the ability to serialize itself and also to initialize itself from a serialized representation. If the programming language has a reflective facility, you can write a single piece of code to determine the structure of the object and perform serialization and initialization. Java serialization works this way. Of course, flat files do not provide any of the multi-user, concurrency, meta-data, schema evolution, transaction, and recovery facilities that a database provides. 

Membrane extraction offers attractive alternatives to conventional solvent extraction through the use of dialysis or ultrafiltration procedures (41). The choice of the right membrane depends on a number of parameters such as tlie degree of retention of the analyte, flow rate, some environmental characteristics, and tlie analyte recovery. Many early methods used flat, supported membranes, but recent membrane technology has focused on the use of hollow fibers (42-45). Although most membranes are made of inert polymers, undesired adsorption of analytes onto the membrane surface may be observed, especially in dilute solutions and when certain buffer systems are applied. 

The effects of type of vinyl monomer on the properties of copolymer fabrics are shown in Table VII. Two different fabric constructions, print cloth and twill, were used. After the copolymer fabrics were prepared, they were given the usual treatment with dimethyloldihydroxyethylene urea to crosslink the cellulose. The wash-wear appearance ratings, flat abrasion resistances, and, in most cases, wrinkle-recovery angles of copolymer twill fabrics were improved over fabric controls. For copolymer... 

Polymer DMDHEU4 Wash-Wear Flat Abrasion Wrinkle Recovery Angle,... 

Experiments with zearalenone standards show that the linear fluorimeter response covers four orders of magnitude with a detection limit of 300 pg zearalenone injected onto a Ci8 reverse-phase column. The corn samples are first purified using a small silica gel column. The recovery from this step is 86% over the range from 5ppb to 2.5 ppm. Based on the magnitude of the zearalenone signals compared to the flatness of the baseline for zearalenone-free corn samples, a limit of 5 ppb is placed on the detection of zearalenone by this procedure. 

Table V. Recoveries of Bacillus thuringiensis (Thuricide 16B) and carbaryl (Sevin 4-oil) on Kromekote cards over flat open terrain.

Gas Continuous Gas trapped in microporous by external liquid Flat sheet, hollow fiber Formed-in-place Recovery of volatile substances from liquids... 

FIGURE 15.4 Scanning electron microscopic observation of two different forms of barium sulfate. In (a) flat board structures are observed (bar = 20 /im). This type has a negative f -potential and accelerates skin barrier recovery, (b) shows disordered structure (bar = 20 gm). This type has a positive potential and does not accelerate barrier repair. 

Biological tissues The electrode was constructed from a slice of pig muscle (0.9-1 mm thick), stuck over the flat end of a glass pH electrode and covered with a nylon net fixed with a rubber ring. The calibration graph of potential versus concentration was rectilinear from 20 to 600 pg/mL of acetylcholine in 1 mM. KC1 at 30°C. There was no interference from a wide range of biological compounds. Recovery was 98.2% and the coefficient of variation was less than 8% (n = 8). [111]... 

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