Roughness average value

Miscellaneous Direct Costs Estimates for the cost of maintenance and repairs, operating supplies, royalties, and patents are best based on company records for similar processes. A rough average value for the annual cost of maintenance is 6 percent of the capital cost of the plant. This percentage can vaiy from 2 to 10 percent, depending on the severity of plant operation. Approximately half of the maintenance costs are for materials and half for labor. Royalty and patents costs are in the order of 1 to 5 percent of the sales price of the product. 

Values with a star,, are rough average values from measurement. A star in parentheses, ( ), points to a typical value from one or a few measurements. AU other values have been calculated from starred values, under the assumption that at 2 km 50% and at 12 km 90% of the columnar resistance is reached. Voltage drop along one of the partial columns can be calculated by subtracting the value for the lower column from that of the upper one. Columnar resistances, conductances, and capacitances are valid for that particular part of the column which is indicated at the left. Capacitances are calculated with the formula for plate capacitors, and this fact must be considered also for the time constants for columns. 

It thus appears to follow from these same experiments first, that the sensible radius of activity of molecular attraction does not vary much with various substances, and that one can adopt, for its rough average value, 1/20000 millimetre in the second place, that the upper limit found by me, being 1/17000 millimetre, is very near the true value in the third place finally, that, in my experiments, as opposed to what Dupre thought, it was indeed half the thickness of the film which had to be taken. 

For commercial pipe with roughness e = 0.046 mm, the friction factor is about 0.0043. Approaching the last hole, the flow rate, velocity and Reynolds number are about one-tenth their inlet values. At Re = 16,400 the friction factor/is about 0.0070. Using an average value of/ = 0.0057 over the length of the pipe, 4/Z73D is 0.068 and may reasonably be neglected so that Eq. (6-151) may be used. With C, = 0.62,... 

The hardness of wood varies markedly from soft balsa to hard ironwood with pine, oak, and maple in between. It is measured either by determining the force needed to push a hard ball (diameter = 0.444 in) into the wood to a depth equal to half the ball s diameter (Janka hardness) or by the initial slope of the force vs. penetration-depth curve (Hardness modulus). Average values of Janka hardnesses for typical woods are listed in Table 13.1. The data are from Green et al., (2006), and are for penetration transverse to the tree axis. The values are for moisture contents of about ten percent. The first set of five items are hardwoods, while the second set are softwoods. To roughly convert Janka hardnesses to VHN multiply by 0.0045. 

Amongst the ash elements the most abundant in biomass is calcium, which is accumulated in leaves, in trunk wood, and in twigs. Potassium is dominant in annual NPP. The masses of trace metals in biogeochemical cycling of this Oak Forest ecosystem are roughly in correspondence to their respective average values for the... 

Surface roughness was measured according to ANSI standard 1346.1-(1978) using a Tencor Instruments Alpha-Step 200 stylus profilometer located at the National Nanofabrication Facility of Cornell. Five surface roughness measurements were made for each sample and their average values recorded. Details of the experimental apparatus set-up and its operation are given elsewhere (Dems, B. C. et. al. Inti. Polvm. Proc.. in press.). 

A rough titration is usually carried out, followed by more accurate titrations until concordant results are obtained. Concordant results are within either 0-1 or 0-2 cm of each other, depending on the accuracy required. The mean or average value of the concordant results is used in the calculations. 

Hints and Help Assume, as a first approximation, that water temperature is a conservative, nonretarded parameter. You can then interpret the fw value calculated for PCE as a retardation factor relative to water temperature. Then you may try to estimate the retardation of water temperature. To do so it may be helpful to assume, as a rough estimate, an average value for the specific heat of the solids in the aquifer, cp, of 1 J g- K-. ... 

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