Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Feasibility physical

The term inversion is used here to refer to a feasible physical phenomenon, whioh in this case is similar to an umbrella that turns inside-out in the wind. The word has already been used twice in different senses (i) the inversion of coordinates, e.g. the passage from a right-handed system to a left-handed one and (ii) a traditional symmetry operation applied to a molecule with a center of invmioa. Accordingly, this term must be used with care ... [Pg.124]

The temperature-entropy diagram in fig. 1 clearly shows that fluids of low molar specific heat, e.g. water, can only partly be evaporated or condensed by reversible adiabatic processes. Fluids of high molar specific heat, e.g. perfluoro-n-hexane (C6F14), however, make complete adiabatic phase changes feasible. Physically, the difference between... [Pg.103]

The design process utilized published information on the General Atomics MHTGR to the extent feasible. Physics analysis to confirm the characteristics of the Lead (208),and other lead and lead alloy coolants, and the fundamental neutronic and thermohydraulic core behaviour was completed. [Pg.93]

Calculate Apj, ATf, ATj, and n for solutions which are 1% by weight in benzene of solutes for which M = 10 and 10 . Assume that these solutions are adequately described by dilute ideal solution expressions. Consult a handbook for the physical properties of benzene. Comment on the significance of the results with respect to the feasibility of these various methods for the determination of M for solutes of high and low molecular weight. [Pg.547]

The third characteristic of interest grows directly from the first, ie, the high thermal conductance of the heat pipe can make possible the physical separation of the heat source and the heat consumer (heat sink). Heat pipes >100 m in length have been constmcted and shown to behave predictably (3). Separation of source and sink is especially important in those appHcations in which chemical incompatibilities exist. For example, it may be necessary to inject heat into a reaction vessel. The lowest cost source of heat may be combustion of hydrocarbon fuels. However, contact with an open flame or with the combustion products might jeopardize the desired reaction process. In such a case it might be feasible to carry heat from the flame through the wall of the reaction vessel by use of a heat pipe. [Pg.512]

Nylon-6 [25038-54-4] was first made in 1899 by heating 6-aminohexanoic acid (143), but its commercially feasible synthesis from caprolactam was discovered by Paul Schlack at 1. G. Farbenindustrie in 1938. Like nylon-6,6, it is a tough, white translucent, semicrystalline sofld, but melts at a lower temperature (T = 230° C. The physical properties and primary producers of nylon-6 are Hsted in Tables 9 and 10, respectively. [Pg.233]

The unsaturation present at the end of the polyether chain acts as a chain terminator ia the polyurethane reaction and reduces some of the desired physical properties. Much work has been done ia iadustry to reduce unsaturation while continuing to use the same reactors and hoi ding down the cost. In a study (102) usiag 18-crown-6 ether with potassium hydroxide to polymerise PO, a rate enhancement of approximately 10 was found at 110°C and slightly higher at lower temperature. The activation energy for this process was found to be 65 kj/mol (mol ratio, r = 1.5 crown ether/KOH) compared to 78 kj/mol for the KOH-catalysed polymerisation of PO. It was also feasible to prepare a PPO with 10, 000 having narrow distribution at 40°C with added crown ether (r = 1.5) (103). The polymerisation rate under these conditions is about the same as that without crown ether at 80°C. [Pg.352]

The quantity of sample required comprises two parts the volume and the statistical sample size. The sample volume is selected to permit completion of all required analytical procedures. The sample size is the necessary number of samples taken from a stream to characterize the lot. Sound statistical practices are not always feasible either physically or economically in industry because of cost or accessibiUty. In most sampling procedures, samples are taken at different levels and locations to form a composite sample. If some prior estimate of the population mean, and population standard deviation. O, are known or may be estimated, then the difference between that mean and the mean, x, in a sample of n items is given by the following ... [Pg.298]

The physical form of the thermocouples varies significantly according to appHcations. Most spacecraft power suppHes utilize separate thermocouples that can be checked for performance at successive stages of manufacturing and be replaced if necessary. This approach fits in very well with the extremely high rehabihty requirements imposed on such systems. In terrestrial systems where such individualized attention is not economically feasible, modular assembhes are generally used, which can contain tens to hundreds of couples in a single unit. [Pg.508]

Dynamic meteorological models, much like air pollution models, strive to describe the physics and thermodynamics of atmospheric motions as accurately as is feasible. Besides being used in conjunction with air quaHty models, they ate also used for weather forecasting. Like air quaHty models, dynamic meteorological models solve a set of partial differential equations (also called primitive equations). This set of equations, which ate fundamental to the fluid mechanics of the atmosphere, ate referred to as the Navier-Stokes equations, and describe the conservation of mass and momentum. They ate combined with equations describing energy conservation and thermodynamics in a moving fluid (72) ... [Pg.383]

The preparation of molecular composites by electropolymeriza tion of heterocycles in solution with polyelectrolytes is an extremely versatile technique, and many polyelectrolyte systems have been studied. The advantages of this method include the use of aqueous systems for the polymerization. Also, the physical and mechanical properties of the overall composite depend on the properties of the polyelectrolyte, so material tailorabiUty is feasible by selection of a polyelectrolyte with desirable properties. [Pg.39]

The treatment of waste is the third element of the hierarchy and should be utilized only in the absence of feasible source reduction or recychng opportunities. Waste treatment involves the use of chemical, biological, or physical processes to reduce or eliminate waste material. The incineration of wastes is included in this categoiy and is considered preferable to other treatment methods (i.e., chemical, biological, and physical) because incineration can permanently destroy the hazardous components in waste materials (Ref. 4). It can also be employed to reduce the volume of waste to be treated. [Pg.2165]

Basic to establishing whether power recovery is even feasible, let alone economical, are considerations of the flowing-fluid capacity available, the differential pressure available for the power recovery, and corrosive or erosive properties of the fluid stream. A further important consideration in feasibihty and economics is the probable physical location, with respect to each other, of fluid source, power-production point, and final fluid destination. In general, the tendency has been to locate the power-recoveiy driver and its driven unit where dictated by the driven-unit requirement and pipe the power-recoveiy fluid to and away from the driver. While early installations were in noncorrosive, nonerosive services such as rich-hydrocarbon absorption oil, the trend has been to put units into mildly severe seiwices such as amine plants, hot-carbonate units, and hydrocracker letdown. [Pg.2524]

It can be seen that other intermediate isomers are feasible but in the above cases they have not been isolated. Substantial differences in both physical and chemical properties are to be expected between coordination isomers. [Pg.920]

A wide variety of physical properties are important in the evaluation of ionic liquids (ILs) for potential use in industrial processes. These include pure component properties such as density, isothermal compressibility, volume expansivity, viscosity, heat capacity, and thermal conductivity. However, a wide variety of mixture properties are also important, the most vital of these being the phase behavior of ionic liquids with other compounds. Knowledge of the phase behavior of ionic liquids with gases, liquids, and solids is necessary to assess the feasibility of their use for reactions, separations, and materials processing. Even from the limited data currently available, it is clear that the cation, the substituents on the cation, and the anion can be chosen to enhance or suppress the solubility of ionic liquids in other compounds and the solubility of other compounds in the ionic liquids. For instance, an increase in allcyl chain length decreases the mutual solubility with water, but some anions ([BFJ , for example) can increase mutual solubility with water (compared to [PFg] , for instance) [1-3]. While many mixture properties and many types of phase behavior are important, we focus here on the solubility of gases in room temperature IFs. [Pg.81]

Physical foundations of SAH application seem more or less clear and have been confirmed experimentally. As for the biological efficiency in solving plant growth problems and, especially, the economic feasibility of their application, the available... [Pg.130]

The main reasons for this lie in feasibility. Conducting fillers are rather expensive and their use increases the cost of an article. Besides, filled polymers have worse physical-mechanical properties, especially impact strength and flexural modulus. The use of fillers is also detrimental to the articles appearance and calls for additional treatment. The continuous development of electronics has also contributed to a loss of interest to conducting composites as screening materials the improvement of components and circuits of devices made it possible to reduce currents consumed and, thereby, noise level a so called can method is practised on a wide scale in order to cover the most sensitive or noisy sections of a circuit with metal housings [14]. [Pg.144]


See other pages where Feasibility physical is mentioned: [Pg.93]    [Pg.263]    [Pg.157]    [Pg.93]    [Pg.263]    [Pg.157]    [Pg.2804]    [Pg.568]    [Pg.366]    [Pg.370]    [Pg.655]    [Pg.586]    [Pg.95]    [Pg.423]    [Pg.249]    [Pg.18]    [Pg.162]    [Pg.170]    [Pg.466]    [Pg.296]    [Pg.50]    [Pg.451]    [Pg.172]    [Pg.195]    [Pg.738]    [Pg.33]    [Pg.91]    [Pg.481]    [Pg.774]    [Pg.76]    [Pg.195]    [Pg.200]    [Pg.202]    [Pg.52]    [Pg.410]    [Pg.23]    [Pg.447]   
See also in sourсe #XX -- [ Pg.8 , Pg.29 , Pg.38 , Pg.39 ]




SEARCH



Feasible

© 2024 chempedia.info