Upstream transport

The truncation error of this approach is also Aa." (Ref. 106). The third approach uses an upstream transport coefficient. 

Scrudato, R.J. and W.H. McDowell. 1989. Upstream transport of mirex by migrating salmonids. Canad. Jour. Fish. Aquatic Sci. 46 1484-1488. 

Tidal trapping when parcels of water are advected into lateral traps during one phase of the tidal cycle and then moved out in another results in an overall upstream transport. 

River downstream of the sewage discharge has been estimated to be attributable to the treatment plant (19). More recent data (28) suggest that 20 to 40% of the trace metal content at Site 4 results from sewage inputs under normal flow conditions, with the remaining amount contributed from upstream transport or from the Minnesota River. 

One-equation models relax the assumption that production and dissipation of turbulence are equal at all points of the flow field. Some effects of the upstream turbulence are incorporated by introducing a transport equation for the turbulence kinetic energy k (20) given by... 

This approach is used when the transport coefficients vary over several orders of magnitude, and the upstream direction is defined as the one in which the transport coefficient is larger. The truncation error of this approach is only Aa. (Refs. 106 and 107), but this approach is useful if the numerical solutions show unrealistic oscillations. 

The concentration profile is steeper for the MacCormack method than for the upstream derivatives, but oscillations can still be present. The flux-corrected transport method can be added to the MacCormack method. A solution is obtained both with the upstream algorithm and the MacCormack method and then they are combinea to add just enough diffusion to ehminate the oscillations without smoothing the solution too much. The algorithm is comphcated and lengthy but well worth the effort (Refs. 37, 107, and 270). 

Galvanic corrosion may also occur by transport of relatively noble metals, either as particulate or as ions, to the surface of an active metal. For example, ions of copper, perhaps resulting from corrosion or erosion-corrosion at an upstream site, may be carried by cooling water to the surfaces of aluminum, steel, or even stainless steel components. If the ions are reduced and deposit on the component surfaces, localized galvanic corrosion may result. 

Economizers are not usually designed to generate steam, and any deposits found in them therefore are not likely to be a result of carbonic acid corrosion or contamination from steam. Rather, the transport and buildup of corrosion debris within an economizer tends to originate from corrosion processes occurring either in the economizer itself or in some upstream part of the pre-boiler system. Economizer deposits typically develop in the presence of oxygen and possess a high iron content. 

Component Transport Transport through membranes can be considered as mass transfer in series (1) transport through a polarization layer above the membrane that may include static or dynamic cake layers, (2) partitioning between the upstream polarization layer and membrane phases at the membrane surface, (3) transport through the membrane, and (4) partitioning between the membrane and downstream fluid. 

Kim, C. H., Kim, H. S., Cubells, J. F., 8c Kim, K. S. (1999). A previously undescribed intron and extensive 5 upstream sequence, but not Phox2a-mediated transactivation, are necessary for high level cell type-specific expression of the human norepinephrine transporter gene. /. Biol. Chem., 274, 6507-18. 

Two-dimensional distributions of ground-state NO were detected by planar laser-induced fluorescence during the process of NO removal in a corona radical shower system in NO/dry air mixtures [57,58], The authors observed that the density of NO molecules decreased not only in the plasma region formed by the corona streamers and the downstream region of the reactor, but also in the upstream region of the reactor. They explained this behaviour by oxidation with ozone, which is transported upstream by electrohydrodynamic flow. 

You must determine the specifications for a pump to transport water at 60°C from one tank to another at a rate of 200 gpm. The pressure in the upstream tank is 1 atm, and the water level in this tank is 2 ft above the level of the pump. The pressure in the downstream tank is 10 psig, and the water level in this tank is 32 ft above the pump. The pipeline contains 250 ft of 2 in. sch 40 pipe, with 10 standard 90° flanged elbows and six gate valves. 

---