COjEt COjEt COjEt  [c.95]

CHjCOjEt COjEt Cl, heat 35 298  [c.178]

Style Permalloy Ferrite Gapped Shielding Cost Cost  [c.239]

Fillers may be broadly defined as solid particulates or fibrous materials, substantially inert chemically, incorporated in polymer compositions to modify the properties and/or to reduce cost. Cost reduction is not the primary reason to incorporate fillers in adhesives but they are used to impart specific properties such as flow, improved adhesion, mechanical, thermal, electrical and optical properties, chemical and weather resistance, and rheological behaviour.  [c.628]

Coupled Cluster methods, including doubles (energies and optimizations) or singles and doubles (energies only), and optional triples terms (CCD, CCSD, CCSD(T)).  [c.114]

The lower value of scaling for methods involving electron correlation arises from the transformation of the two-electron integrals from the AO to MO basis, but if the transformation is carried out with one of the indices belonging to an occupied MO hrst, the scaling is actually the number of occupied orbitals (O) times If we consider making the system larger by doubling the fundamental unit (for example calculations on a series of increasingly larger water clusters), keeping the basis set per atom constant, O scales linearly with M, and we arrive at die scaling. This assumption (increasing system size) is the basis for Table 4.5. More often, however, a series of calculations are performed on the same system with increasingly larger basis sets. In this case die number of electrons (occupied orbitals) are constant and the scaling is Many of the commonly employed methods for electron correlation (including for example MP2, MP3, MP4, CISD, CCSD and CCSD(T)) scale in fact as when the number of occupied orbitals is constant.  [c.145]

Isomer HE MP2 MP3 MP4 CCSD CCSD(T) CISD Exp.  [c.292]

Fuel cost = cost of electricity (in /kWh),  [c.433]

System cost Cost should not be the primary deciding factor in system selection. The capabilities of the various systems vary greatly and so does the cost. Care should be taken to ensure a fair comparison of the total system capability and price is made before selection of your system.  [c.805]

Cost Cost of any task of project may exceed budget. When purchase agreements are made. First, seek alternative suppliers, then, consider alternative materials.  [c.827]

Once the problem is formulated mathematically, its solution is carried out through implementation of an optimization algorithm. Economic potential is maximized or cost is minimized (see App. A) in a structural and parameter optimization. Should an integer variable be optimized to zero, the corresponding feature is deleted from the structure and the structure is reduced in complexity. In effect, the discrete decision-making aspects of process design are replaced by a discrete/continuous optimization. Thus the initial structure in Fig. 1.7 is optimized to reduce the structure to the final design shown in Fig. 1.8. In Fig. 1.8, the membrane separator on the hydrogen feed has been removed by optimization, as have the isothermal reactor and many other features of the initial structure shown in Fig. 1.7.  [c.11]

Single reactions. In a single reaction such as Eq. (2.2) which produces a byproduct, there can be no influence on the relative amount of product and byproduct formed. Thus, with single reactions such as Eqs. (2.1) to (2.3), the goal is to minimize the reactor capital cost (which usually means minimizing reactor volume) for a given reactor conversion. Increasing the reactor conversion increases size and hence cost of the reactor but, as we shall see later.  [c.25]

If k-2 increases faster than kx, operate at low temperature (but beware of capital cost, since low temperature, although increasing selectivity, also increases reactor size). Here there is an economic tradeoff between decreasing byproduct formation and increasing capital cost.  [c.42]

The rate at which the catalyst is lost or degrades has a major influence on the design. If degradation is rapid, the catalyst needs to be regenerated or replaced on a continuous basis. In addition to the cost implications, there are also environmental implications, since the lost or degraded catalyst represents waste. While it is often possible to recover useful materials from degraded catalyst and to recycle those materials in the manufacture of new catalyst, this still inevitably creates waste, since the recovery of material can never be complete.  [c.49]

An initial guess for the reactor conversion is very difficult to make. A high conversion increases the concentration of monoethanolamine and increases the rates of the secondary reactions. As we shall see later, a low conversion has the effect of decreasing the reactor capital cost but increasing the capital cost of many other items of equipment in the flowsheet. Thus an initial value of 50 percent conversion is probably as good as a guess as can be made at this stage.  [c.51]

Even though choices of separators must be made at this stage in the design, it must be borne in mind that the assessment of separation processes ideally should be done in the context of the total system. As is discussed later, separators which use an input of heat to carry out the separation often can be run at effectively zero energy cost if they are appropriately heat integrated with the rest of the process. This includes the three most common types of separators, i.e., distillation columns, evaporators, and dryers. Although they are energy intensive, they also can be energy efficient in terms of the overall process if they are properly heat integrated (see Chaps. 14 and 15).  [c.76]

Both vacuum operation and the use of refrigeration incur capital and operating cost penalties and increase the complexity of the design. They should be avoided if possible. For a first pass through  [c.76]

Another variable that needs to be set for distillation is refiux ratio. For a stand-alone distillation column, there is a capital-energy tradeoff, as illustrated in Fig. 3.7. As the refiux ratio is increased from its minimum, the capital cost decreases initially as the number of plates reduces from infinity, but the utility costs increase as more reboiling and condensation are required (see Fig. 3.7). If the capital  [c.77]

When separating azeotropic mixtures, if possible, changes in the azeotropic composition with pressure should be exploited rather than using an extraneous mass-separating agent. When using an extraneous mass-separating agent, there are inevitably losses from the process. Even if these losses are not significant in terms of the cost of the material, they create environmental problems somewhere later in the design. As discussed in detail in Chap. 10, the best way to solve effluent problems is to deal with them at the source. The best way to solve the effluent problems caused by loss of the extraneous mass-separating agent is to eliminate it from the design. However, clearly in many instances practical difficulties and excessive cost might force its use. Occasionally, a component that already exists in the process can be used as the entrainer or solvent, thus avoiding the introduction of extraneous materials for azeotropic and extractive distillation.  [c.83]

Figure B3.1.9 [83] displays the errors (in pieometres eompared to experimental findings) in the equilibrium bond lengths for a series of 28 moleeules obtained at the FIF, MP2-4, CCSD, CCSD(T), and CISD levels of theory using three polarized eorrelation-eonsistent basis sets (valenee DZ tlu-ough to QZ). Figure B3.1.9 [83] displays the errors (in pieometres eompared to experimental findings) in the equilibrium bond lengths for a series of 28 moleeules obtained at the FIF, MP2-4, CCSD, CCSD(T), and CISD levels of theory using three polarized eorrelation-eonsistent basis sets (valenee DZ tlu-ough to QZ).
Coupled cluster calculations are similar to conhguration interaction calculations in that the wave function is a linear combination of many determinants. However, the means for choosing the determinants in a coupled cluster calculation is more complex than the choice of determinants in a Cl. Like Cl, there are various orders of the CC expansion, called CCSD, CCSDT, and so on. A calculation denoted CCSD(T) is one in which the triple excitations are included perturbatively rather than exactly.  [c.25]

The factor estimate, if based on tested actual data, gives good results in the study estimate and often proves adequate at the prehm-inary estimate stage. It is essential to accumulate from past experience data showing actual electrical costs (1) as a percentage of total installed plant cost and (2) as a percentage of installed equipment costs. Studies of electrical instaUations for more than 100 plants (H. C. Bauman, Fundamentals of Cost Engineering in the Chemical Jndus-tiy, Van Nostrand Reinhold, New York, 1964, p. 134) showed electri-c u costs ranging from about 4 to 11 percent or total plant cost, with a median for batteiy-limit process plants of 7.5 percent. The corresponding range based on installed equipment costs was 15 to 40 percent, with a median of 26 percent. Thus, it appears that there is a better correlation between electrical costs and total installed plant cost than with installed equipment costs. Table 9-59, taken from Ban-man s data, gives typical values of electrical costs as a percentage of total installed plant cost. Cost ranges for installed instrumentation costs are also included in Table 9-59, as these would form part of electrical costs. The ranges of values are rather wide, depending on the degree of automatic control required.  [c.872]

The objective of this case study is to synthesize a CHARMEN which has a minimum operating cost (cost of MSAs + cost of cooling utilities).  [c.236]

Schrein, tn. case, cabinet, chest, casket, press.  [c.396]

See pages that mention the term CISDT, CISD : [c.95]    [c.95]    [c.27]    [c.260]    [c.259]    [c.178]    [c.203]    [c.203]    [c.416]    [c.146]    [c.91]    [c.71]    [c.71]    [c.223]    [c.1243]    [c.138]    [c.288]    [c.92]    [c.6]    [c.651]    [c.26]    [c.75]    [c.78]   
Computational chemistry (2001) -- [ c.24 ]