Object-Based Model

One of the simplest ways to model polymers is as a continuum with various properties. These types of calculations are usually done by engineers for determining the stress and strain on an object made of that material. This is usually a numerical finite element or finite difference calculation, a subject that will not be discussed further in this book.  [c.307]

A useful method of traciag the origins of molecular modeling is to examine how its offshoot, computer-assisted molecular modeling (CAMM), came to be developed. Molecular modeling today represents a convergence of a number of techniques from different disciplines. Basic techniques used to accomplish modeling objectives necessarily draw on these. Specific software systems today importandy assist the researcher ia the study of molecular systems and provide help ia deriving a rigorous and consistent explanation for the chemical or biological behavior observed or help the researcher to develop a model for predictions.  [c.157]

Holography involves the recording of the mutual interference pattern due to two mutually coherent optical fields. A generic holographic recording experiment is shown in Figure 2 an expanded and collimated laser beam is spHt into two paths, with one falling directiy on the holographic material and the other scattering off an object to be collected on the same material. The first is called the reference and the second the object. Although variations of this basic arrangement exist, its simplicity is most suitable for the present discussion. The intensity distribution falling on the film is given by equation 1, where S is the object wave ampHtude and R represents the plane wave reference.  [c.158]

If a metal wand plus a short length of tubing is used for manual sampling inside tanks or other enclosures, the tubing should be antistatic or conductive to avoid isolating the metal wand, and the analyzer should be either grounded or hand-held by a grounded operator. The hazard of long, nonconductive sample lines charged by slipping through gloved hands is analogous to that of synthetic cord, except that owing to the larger typical diameter of sample tubing the ignition risk is greater (5-5.1). When sampling large tanks for gas-free status, it may be required to sample near the base of the tank. In this case it is especially important that if a metal object is used to create a plumb bob it is not isolated from ground by a nonconductive sample line. In both these cases, antistatic or conductive sample tubing should be used tubing approved by the American Bureau of Shipping and the US Coast Guard is commercially available. ABS/CG requirements are based on a Safety of Life at Sea (SOLAS) regulation calling for Anti-Static, Electrically Conductive tubing. However, for portable analyzer applications the tubing does not need to be conductive. Antistatic tubing is sufficient to dissipate charge accumulated on the tubing itself. When using antistatic tubing with a molded-in wire, the wire should be bonded to the analyzer and to any metal probe (wand or plumb bob) inserted into a potentially flammable atmosphere.  [c.144]

The oldest-established of the powder processes is fluidised-bed coating. In the process a metal object which is to be coated with polyethylene is heated to about 160-250°C and then suspended in a fluidised bed of powdered polymer. Fluidisation is brought about by blowing air through a porous base in the powder container so that in effect the individual particles are lubricated with a thin film of air. Particles coming into contact with the hot metal fuse and adhere to the metal part. This, together with the adhering particles, is then transferred to a second oven where the particles fuse together to give an even coating. In a variation of this process the fluidised powder particles are electrically charged whilst the object to be coated is earthed. This can then attract the charged particles without the need for preheating the part.  [c.237]

Larger objects may be coated by spraying techniques of which there are two basic variants, flame spraying and electrostatic spraying. In the first process the powder is sprayed on to preheated metal with a flame spray gun and the coating is then heated to fuse the particles. With electrostatic spraying the particles are charged as they leave the spray gun and are attracted to the object to be coated, which is earthed. It is claimed that thinner coatings are possible using electrostatic spraying techniques so that the method may in future years become a serious competitor of present-day techniques of applying surface coatings.  [c.237]

Borate-Promoted Oxidation. Another alternative to the basic cyclohexane oxidation process is one which maximizes only the yield of A. This process uses boric acid as an additive to the cyclohexane stream as both a promoter and an esterilying agent for the A that is produced. Metaboric acid [10043-35-3] is fed to the first series oxidizer as a slurry ia cyclohexane to give a molar ratio of boron cyclohexane of around 1.5 100. No other metal catalyst is used. Ksterilying the A effectively shields it from overoxidation and thus allows the attainment of very high yields (ca 90%) (65). The ratio A K ia the final product can exceed 10 1. The process was developed ia the mid-1960s by a number of companies, including Halcon/Scientific Design (79,80), Institute Francais Petrole (68,81), and Stamicarbon (82). The process was ticensed and commercialized by several companies ia the decade foUowiag its development, including Monsanto, ICl, and Bayer. The major drawback to the process is the need to hydrolyze the borate ester ia order to recover A. This is an energy-iatensive step and can be quite a mechanical nuisance because of the requirement for handling boric acid sotids. Without careful attention to energy conservation and engineering, the savings that accme from the high yield can be mote than offset. The process does, because of its high yield, offer advantages in waste minimization and product purity. It does, however, introduce boron into the waste streams.  [c.242]

Supply and demand of scrap is affected by a variety of factors, including technological advances ia iroa- and steelmaking and scrap processiag, war-time effects such as price controls and export restrictions, economic depressions, and foreign trade ia scrap. The opea-hearth furnace, which was oace a primary part of steelmaking ia an iategrated plant, was capable of melting up to 100% scrap or any combination of hot metal (molten pig iron) and scrap. Open-hearth steelmaking declined rapidly ia the 1980s and was phased out ia 1991 ia the United States. The lost demand for scrap by this process has been offset by advances ia electric arc furnace (EAF) and basic oxygen furnace (BOF) processes. Developments impacting scrap iaclude minimills, coatiauous castiag, and minimill thin-slab casting.  [c.552]

Incandescence means to heat an object to the point of producing light. The incandescent lamp, then, is a lamp with a filament heated to the point of glowing. The trick accomplished by Thomas Edison and his team at Menlo Park, New Jersey, in 1879 was to produce an inexpensive lamp with a carbon filament that would glow for several hundred hours. After more than a year of experimenting, Edison was able to demonstrate an incandescent lamp producing approximately 2 lumens per watt and lasting several hundred hours. Incremental improvements in that basic design, especially the use of the metal tungsten in filaments, have increased the efficacy of commercially available incandescent lamps to between 10 and 15 lumens per watt. More significantly, perhaps, these lamps are easy to install and cost as little as tifty cents each.  [c.716]

See pages that mention the term Object-Based Model : [c.42]    [c.67]    [c.447]    [c.28]    [c.7]    [c.596]   
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Chemoinformatics  -> Object-Based Model