Recommended Values

The recommended techniques for measuring the viscosity of high-temperature melts given above have the main difficulties listed in Table 13. 

The recommended viscosity data for NaCl and KNO3 melts are available for calibration, as mentioned in Section II. There still exists appreciable, though small, disagreement between the data obtained by the two groups, that is, 0ye s group and Nagashima s group. Ejima et al.  

Main Difficulties Involved in Typical Methods for Measuring Viscosity 

Oscillating cylinder Difficult for high-vapor pressure fluid 

Falling ball Difficult for nontransparent fluids and for low-viscosity fluids 

---

Recommended values for the force constant are 7.0 kcal/mol A-for an in teratorn ic distari cc. 12,5 kcal/rn ol degree- for an angle, and 16.0 kcal/mol degree- for a dihedral angle. Use the recommended values and then, if the internal coordinate is not sufficiently restrained, try a larger force eonstant. 

Level of enforcement of the incompressibility condition depends on the magnitude of the penalty parameter. If this parameter is chosen to be excessively large then the working equations of the scheme will be dominated by the incompressibility constraint and may become singular. On the other hand, if the selected penalty parameter is too small then the mass conservation will not be assured. In non-Newtonian flow problems, where shear-dependent viscosity varies locally, to enforce the continuity at the right level it is necessary to maintain a balance between the viscosity and the penalty parameter. To achieve this the penalty parameter should be related to the viscosity as A = Xorj (Nakazawa et al, 1982) where Ao is a large dimensionless parameter and tj is the local viscosity. The recommended value for Ao in typical polymer flow problems is about 10. ... 

AMBER, BIO-h and OPLS scale 1 van der Waals and 1 electrostatic interactions. Although the value of the 1 nonbonded scale factors is an option in HyperChem, you should generally use recommended values. This is because during parameterization, the force field developers used particular values for the 1 nonbonded scale factors, and their parameters may not be correct for other scale factors. 

Extrapolation from these two sets of values to C4 gives a (C4H,o) = 40-5 A for n-butane, which may be compared with the figure of 44-4 A (with a standard deviation of 4 A ) given in McClellan and Harnsberger s final list of recommended values and the value of 40 A found by Davis for n-butane on graphitized carbon at 195 K. A contributory factor to the variation in a -values is that the value of c tends to be low, e.g. on CaCOj (p. 251) c for butane is around 25. 

In their review McClellan and Hamsberger arrived at a recommended value of = 43 A with a standard deviation of 3A ... 

Although ASTM specifies certain quaUty levels, there are a number of factors that contribute to other quaUty levels in the marketplace. At times, government regulations are more restrictive than ASTM specifications, especiaHy with respect to environmental issues. Secondly, competitive forces may encourage companies to provide fuel quaUty that is better than that defined by ASTM. Thirdly, ASTM specifications do not have the force of law, and certain companies may decide to exceed or not meet their recommended values. In response to this last factor, some states have adopted ASTM fuel quahty specifications as state regulations, thus forcing a minimum quaUty level in the field. 

The film coefficient h is for the inner wall Dj is the inside diameter of the mixing vessel. The term L N p/ is the Reynolds number for mixing in which L is the diameter and Nr the speed of the agitator. Recommended values of the constants a, b, andm are given in Table 18-2. 

The recommended values for shorl-timc duly are 10, 30. 60 and 90 minutes. The type designation for a particular rating, say for 30 minutes, will be specified as - 30 minutes. Likely applications are operation of lock gales, sirens, windlasses (hoisting) and capstans. 

Motors rated 7500 kW and less must be considered suitable for dielectric tests or operation only when the polarization index or the value of the insulation resistance (at 40°C) is at least the minimum recommended values. 

Motors rated above 7500 kW must have both the polarization index and the insulation resistance above the minimum recommended values. 

The winding insulation resistance to be used for comparison with the recommended minimum value (/, ) is the observed insulation resistance obtained by applying a d.c. voltage to the entire windings for one minute, corrected to 40°C. In practice, motors having insulation resistance readings as high as ten to a hundred times the minimum recommended value R , are not uncommon. 

Table 15.1 Recommended values of minimum creepage distances for a VT or a CT...

The following are the recommended values of the switching transient voltages that may be considered to select the switching device ... 

Consider the scheme of Example 23.4 having an automatic parallel switching. If we assume the closing sequence cycle to be 30 seconds, the recommended value of discharge resistance for each 20 kVAr capacitor bank having a capacitance of 120 fiF can be determined as follows ... 

Use a torque wrench to tighten the fasteners to ensure correct surface-to-surface contact of the current-carrying parts (Figure 29.2(c)). The recommended values of bolt torque are given in Table 29.1. A pressure that is too high may eause relaxation of the joint by cold flow and must be avoided. 

In reality the charging current increases in the smaller diameter dip pipe. Also, small diameter spiral-wound hose can in some cases greatly increase charging current. This effect is presumed due to increased turbulence at the inner wall [8]. Eor overhead filling of road and rail tankers the maximum vd products recommended in this book are respectively 0.38 mVs and 0.50 mVs, which are smaller than the maximum recommended values given in... 

Lightning. Protection is generally provided by earthing with low resistance, e.g. 7 Q, which should be short and direct. The recommended value for protection of plant is <10 Q. 

Mishima, J., 1993, Recommended Values and Tedmical Bases for Airborne Relea.se Fractions (ARFs), Airborne Release Rates (ARRs), and Respirable Fractions (RFs) for Materials from Accidents in DOE Fuel Cycle, Ex-Reactor Facilities, Revision 2, Draft DOE report, April. 

When the heat load even locally exceeds 230 kW m - the target values for drum pressure, 160 bar (except for Si02), should be used for all boiler pressures. For feedwater, the recommended values for >67 bar should be... 

The recommended value of the face velocity has Ireen the subject of much debate and variation over the years. The recommended values have also varied widely with use. For example, CIBSE recommends values as low as 0.2 and 0.25 m s for fume cupboards for teaching and research purposes, respectively, and as high as 2.0 m for radioactive work dependii on grade. Middleton quotes the optimum range for the face velocity of laboratory fume cupboards to lie between... 

The ACGIHi" gives guidelines for the minimum capture velocity, V p, which must be induced to move a contaminant toward an exhaust. The recommended value depends on the industrial process and the local conditions, and Table 10.12 shows the recommendations for typical open-surface-tank processes. 

Note that the recommended value for p is not always conservative. In some cases, heat input may be so high that the safety valve cannot vent all the generated vapor. In such cases, the internal pressure will rise until the bursting overpressure is reached, which may be much higher than the vessel s design pressure. For example, Droste and Schoen (1988) describe an experiment in which an LPG tank failed at 39 bar, or 2.5 times the opening pressure of its safety valve. Note also that this method assumes that the fluid is in thermodynamic equilibrium yet, in practice, stratification of liquid and vapor will occur (Moodie et al. 1988). 

Gaussian also includes a facility for estimating molecular volumes for SCRFsDipole calculations. An energy calculation run with the Volume keyword will produce an estimate value for Uq. For example, here is the output indicating the recommended value for Oq for formaldehyde (RHF/6-31+G ) ... 

The following table lists recommended values of og for the v.irunij jy, ] includes the published frequency (scaled) associated with carbonyl stretch in the gas phase for each compound that we gave in Chapter 4 ... 

A trial calculation shows that /in must be positive, and different authors recommend values ranging from 0.5 to 1.2. The value of kcN is sometimes taken as 0.8,... 

Equation 13 is used to calculate the SMB flow rates. To ensure a throughput of 10 tons/year of the racemic mixture we need a feed flow rate of 1250 L h The y value must fulfill 1 < y < 1.22 with our recommended value of 1.02. 

Wilke-Chang reported the recommended values for i ) as follows water, 2.6 benzene, heptane and ether, 1.0 methanol, 1.9 ethanol, 1.5 una.ssociated solvents, 1.0. I he mixture parameter for the example problem is considered unity. 

All guy line anchors should have a minimum breaking or pull-out strength at least equal to two times the maximum total calculated anchor load in the direction of the resultant load, and in the absence of manufacturer s recommendations, values in Table 4-3 are recommended. 

The maintenance of lime-treated muds consists of monitoring the calcium content, i.e., the proper lime solubility. Since the lime solubility is controlled by the amount of caustic soda present in the mud, the proper alkalinity determination is of great importance. The recommended value of is 5 to 8, and it is maintained with caustic soda the recommended value of P is 25 to 40, and it is maintained with excess lime. The amount of excess lime should be from 5 to 8 Ib/bbl. 

The most frequent mistake in splitless injection is that the initial column temperature is too high. We recommend values shown in Table A.2. 

However when the SF cross-section is analyzed, its composite nature still results in a twofold increase in rigidity, compared to an equivalent amount of solid plastic, since rigidity is a cubic function of wall thickness. This increased rigidity allows large structural products to be designed with only minimal distortion and deflection when stressed within the recommended values for a particular foamable plastic. 

---