DESIGN FORMULAE

For cathodicaUy protecting an offshore structure, use the current densities given in Table 8.3. Valuable formulae are given in Table 8.4 for coatings and anodes. The reader should consult the cited references for additional details. 

Tidal Zone (TZ) Immersed Zone IZ) Soil Zone SZ) 

Installation 10% coating damage 15% coating damage 50% coating damage 

Ac = Fraction of coating damage per year Axone — Surface area per zone per uncoated or coated steel one = Current density from Table 8.3 or predicted (nA/cm) 

Anode Resistance. The impressed-current system permits variability of the current out and monitor-control instmmentation. However, interactions with nearby stmctures may cause detrimental results. On the other hand, sacrificial anode systems do not require a power source and are easily installed, but large numbers of anodes are needed to protect stmctures. In addition, offshore stmctures are cathodicaUy protected by hybrid systems [13]. 

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Pipe-Wall Thickness. Once the design pressure and temperature have been established and the pipe material and size selected, the wall thickness is calculated using the appropriate section of the code. In rare cases, a thin pipe must be made thicker to withstand handling. Occasionally the thickness is affected by external loads or vibrations. All codes prescribe essentially the same design formula for metallic hoUow circular cylinders under internal pressure ... 

Quite a few years ago, Dr. Azbel and I analyzed the operational requirements for these machines and developed some design formulae. You can find this analysis on pages 646 through 665 in Fluid Mechanics and Unit Operations, David S. Azbel and Nicholas P. Cheremisinoff, Ann Arbor Science Publishers, 1983. There are some sample calculations and sizing criteria that you can follow for some practical exercises in this publication. 

Rao, N.S., Design Formulas for Plastics Engineers, Hanser, Munich (1991). 

Design formulas for plastics engineers , Natti S. Rao Hanser Gardner Pubis (1991) ISBN 1569900841. The formulas in this book are classified for specific areas, including rheology, thermodynamic properties, heat transfer, plastic and part type. 

In operation the tube sheets are subjected to the differential pressure between shell and tube sides. The design of tube sheets as pressure-vessel components is covered by BS 5500 and is discussed in Chapter 13. Design formulae for calculating tube sheet thicknesses are also given in the TEMA standards. 

Cleary, M.P. "Comprehensive Design Formulae for Hydraulic Fracturing," SPE paper 9259, 1980 SPE Annual Technical Conference and Exhibition, Dallas, September 21-24. 

Meyer, B.R. "Design Formulae for 2-D and 3-D Vertical Hydraulic Fractures Model Comparison and Parametric Studies," SPE paper 15240, 1986 SPE Unconventional Gas Technology Symposium, Louisville, May 18-21. 

Designation Formula Molecular Weight Melting Point... 

After the (1 x) laboratory batch is determined to be both physically and chemically stable based on accelerated, elevated temperature testing (e.g., 1 month at 45°C or 3 months at 40°C or 40°C/80% RH), the next step in the scale-up process is the preparation of the (10 x) laboratory pilot batch. The (10 x) laboratory pilot batch represents the first replicated scale-up of the designated formula. The size of the laboratory pilot batch is usually 30-100 kg, 30-100 liters, or 30,000 to 100,000 units. 

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