Terrain

Hydrostatic drives allow for selection of any travel speed up to the maximum without a concurrent variance in engine speed. The engine can be operated at the governed speed to provide proper operating speeds for auxiliary elements, eg, the threshing section of a combine. A frill range of travel speeds is available to adjust to terrain or crop conditions. Industrial applications for hydraulic systems and hydrostatic transmissions include the following (16) ... 

Less mechanization is used on smaller tracts of individually owned land, where the terrain is mountainous or otherwise difficult to reach, or where thinning as opposed to clear-cutting is the preferred silvicultural practice. The harvesting operation maybe done by the landowner or small contractor using chainsaws and tractors. In some operations where minimal damage to the forest is critical, horses may be used. Sale of pulpwood to the mill operation is usually through dealers. 

Its primary military appHcation is to restrict the use of terrain or lower the mobiHty of opposing personnel in a contaminated area. It is volatile enough to be effective as a vapor in warm weather. Relatively modest expenditures of munitions yield severely incapacitating vapor dosages within less than an hour (6). 

One such decontaminant is supertropical bleach (STB). STB is a mixture of chlorinated lime and calcium oxide containing about 30% available chlorine. It can be used either as a dry mix or as a slurry to decontaminate some equipment surfaces and terrain. The dry mix is prepared with two parts bleach to three parts earth by volume. A slurry typically consists of 40 parts STB to 60 parts by weight of water. This material is then sprayed or swabbed on the contaminated surface (see Bleaching agents). STB is an effective decontaminant for mustard, lewisite, and VX. It is less effective against nerve agents other than VX. 

Solar Evaporation. Recovery of salts by solar evaporation (1 3) is favored in hot dry climates. Solar evaporation is also used in temperate 2ones where evaporation exceeds rainfall and in areas where seasons of hot and dry weather occur. Other factors (4,5) affecting solar pond selection are wind, humidity, cloud cover, and land terrain. 

The economics of some mines frequentiy depend heavily on the revenues derived from leaching the waste to recover additional copper. This waste material, which has to be removed to uncover the ore, may be hauled to specially constmeted dumps, where the sulfides, the most common form of copper mineral, are oxidized and the leach solution can contact the waste material uniformly. Economics sometimes precludes optimization of dumps for leaching operations because of such factors as compaction, size distribution, and terrain (16). 

Vat Dyes. AppUed to ceUulosic fibers, vat dyes yield prints with exceUent fastness properties. They are used to print furnishings, drapes, and camouflage where their iafrared reflectance resembles natural terrain and foUage. Their appUcation can foUow two different procedures. 

CTDMPFUS Complex terrain dispersion model plus algorithms for unstable situations SARA Superfund Amendments and Reauthorization Act... 

Building Downwash A review must be conducted for each stack to determine if building downwash effec ts need to be considered. Atmospheric flow is disrupted by aerodynamic forces in the immediate vicinity of structures or terrain obstacles. The disrupted flow near either building structures or terrain obstacles can both enhance the vertical dispersion of emissions from the source and reduce the effective height of the emissions from the source, resulting in an increase in the maximum GLC. 

Design Landfilling method Selection of method will vary with terrain... 

Cell design and construction Will vary depending on terrain, landfilling per month or as required. 

Printing Office, vol. 2, November 1990, Figs. 2-7 and 2-15, or Kingery and PanniU, Memorandum Report No. 1518, Ballistic Research Laboratories, Aberdeen Proving Ground, U.S., April 1964) can then be used to determine the blast parameters of interest (Fig. 26-9). This method has hmitations in the far field where the peak incident overpressure is less than 4 kN/m" (0.5 psi). In this region, local terrain and weather effects become significant. 

FIG. 26-31 Estimated maximum downwind distance to lower flammable limit L, percent by volume at ground level in centerline of vapor cloud, vs. continuous dense vapor release rate at ground level. E atmospheric stability. Level terrain. Momentary concentrations for L. Moles are gram moles u is wind speed. (From Bodmtha, 1980, p. 105, by permission.)... 

Parameters Affeeting Gas Dispersion A wide variety of parameters affect the dispersion of gases. These include (1) wind speed, (2) atmospheric stability, (3) local terrain characteristics, (4) height of the release above the ground, (5) release geometry, i.e. from a point, line, or area source, ( momentum of the material released, and (7) buoyancy of the material released. 

Terrain characteristics affect the mechanical mixing of the air as it flows over the ground. Thus, the dispersion over a lake is different from the dispersion over a forest or a city of tall buildings. 

The Britter and McQiiaid model was developed by performing a dimensional analysis and correlating existing data on dense cloud dispersion. The model is best suited for instantaneous or continuous ground-level area or volume source releases of dense gases. Atmospheric stability was found to have little effect on the results and is not a part of the model. Most of the data came from dispersion tests in remote, rural areas, on mostly flat terrain. Thus, the results would not be apphcable to urban areas or highly mountainous areas. 

A more economical alternative is found in a submersible pump where the pump, directly coupled with the prime mover, is slid into the tubewell through narrow pipes. Narrow pipes are easy to sink into rocky terrain or very deep water levels. They are less expensive and are easy to install due to the elimination of the need for a pump house. Once the unit is slid into the well it requires little maintenance. (See Figures 7.5-7.7.) Such pumps have a standard centrifugal multistage arrangement, and the motors are required to work under water or any other liquid. These motors have an exclusive application for submersible pumps. 

One of the major effects of acidic deposition is felt by aquatic ecosystems in mountainous terrain, where considerable precipitation occurs due to orographic lifting. The maximum effect is felt where there is little buffering of the acid by soil or rock structures and where steep lakeshore slopes allow little time for precipitation to remain on the ground surface before entering the lake. Maximum fish kills occur in the early spring due to the "acid shock" of the first meltwater, which releases the pollution accumulated in the winter snowpack. This first melt may be 5-10 times more acidic than rainfall. 

Vertical air motions affect both weather and the mixing processes of importance to air pollution. Upward vertical motions can be caused by lifting over terrain, lifting over weather fronts, and convergence toward low-pressure centers. Downward vertical motions can be caused by sinking to make up for divergence near high-pressure centers. One must know whether the atmosphere enhances or suppresses these vertical motions to... 

Complicated terrain such as a major canyon with numerous side canyons will produce complicated and unique flows, especially when side canyon drainage flows reinforce the drainage flow in the main valley. 

The Offshore and Coastal Dispersion (OCD) model (26) was developed to simulate plume dispersion and transport from offshore point sources to receptors on land or water. The model estimates the overwater dispersion by use of wind fluctuation statistics in the horizontal and the vertical measured at the overwater point of release. Lacking these measurements the model can make overwater estimates of dispersion using the temperature difference between water and air. Changes taking place in the dispersion are considered at the shoreline and at any points where elevated terrain is encountered. 

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