The spatial aspects of sea ice pressure ridge statistics have been examined by a census of all ridges in each of three small areas in the arctic basin. A model that predicts random orientation of ridges can be rejected at the 0.05 level of significance in each study area. Measurements of ridge spacings generally confirm the usefulness and validity of the probability density function P(x) dx = μe−μx dx. The estimator trueμˆ varies as a function of direction within the study areas, but a mean value 〈μ〉 is shown to be related to the ridge density (total length of ridges per unit area) by the simple equation 〈μ〉 = (2/π)RD.

Four main genetic coastal types are proposed to classify the shoreline of northern Alaska bordering the Chukchi and Beaufort Seas, which extends for more than 2,150 km. from Cape Thompson eastward to the Canadian border: Land erosion-coast marked by subaerial erosion of terrestrially shaped land forms and partly drowned by rise in sea level (8.9 per cent of coastline); River deposition-coast formed by fluvial deposition (19.9 per cent); Wave erosioncoast shaped primarily by marine agencies and exposed to the open ocean, being marked by coastal retreat and negligible nearshore deposition (37.5 per cent); Marine depositionsimilar to preceding except nearshore sediment deposition is pronounced (33.7 per cent). Four categories of coastal relief or sea cliff height associated with these coastal types are proposed: Low reliefless than about 2 m.; Moderafe reliefabout 2-5 m.; High reliefabout 5-8 m.; Very high reliefgreater than about 8 m. About 1,590 km. or 74 per cent of the coast has relief of 5 m. or less whereas mean relief or scarp height for the entire coast is about 4 m. In gzneral mean scarp heights decrease to the east along the coastal plain.

/ Using specially designed temperature profiling equipment, two surveys were conducted during thermal backwashing operations at Pilgrim Nuclear Power Station to determine the spatial and temporal extent of temperature rises above ambient. Thermal backwashing is a process where biofouling is combated by a heat treatment procedure. Backwashing formed a thermal plume about 5-to 6-ft thick (1.5-to 1.8-m) in front of the intake screenwall. Maximum observed surface temperatures were 101.0~ (38.3~ representing a rise (AT) of about 43.4~ (24.1~ above ambient. The frontal zone of the plume spread gradually seaward at about 0.2 kn. Its outer edge became thinner and rapidly cooled, presumably by advection and turbulent diffusion associated with currents from the reverse pumping and local changes from dissipation to the atmosphere. Along the intake shoreline, the plume was often less than 1 ft (0.3 m) thick. Most of the hot water was dissipated within several hundred feet of the intake with ~Ts of about 10.0 to 15.0~ (5.6 to 8.3~ above ambient. Under the influence of 15 mph southwesterly winds during the second survey, some warmed water was apparently carried beyond the outer breakwaters into Cape Cod Bay. These surveys provided real-time data indicating that the backwashing operation caused a relatively thin thermal plume, which spread rapidly from the intake out across the study area and along the seaward breakwater. Within a few hours these backwash thermal plumes were completely dissipated.The electric utility industry places emphasis on improving the efficiency of electrical generation. One area that is receiving significant attention is the control of biofouling within operating condensers. Biofouling, which occurs on the water side of operating condensers, contributes to the decrease in circulating (cooling) water flow rate and decreases the heat transfer efficiency of the condenser. These problems lead to an overall decrease in operating efficiency of the entire energy production system.Biofouling is a process which goes through various stages. There are two major types of biofouling: macrofouling (associated wiih setting and growth of shellfish within the condenser tubes) and microfouling (associated with the growth ofa bio-film). Cooling water flowing past the tube surface represents a nearly endless supply of a large variety of seed organisms (for example, mussel larvae), nutrients, and constituents for the growth process. The entire biofouling process is quite complex and involves physical, chemical, and biological reactions.The control of biofouling is quite site-specific. At Pilgrim Station, biofouling control is based upon the use of chlorine and thermal backwashes. The efficiency of chemical use is typically low because of the short residence time and the tendency toward secondary chemical