Polyethylene Sheeting as a Water Surface Cover in Sub-zero Temperatures

The occurrence of temperatures below -20°C in central Alaska produces a situation conducive to the formation of ice fog. By far the largest source of ice fog in the Fairbanks area is the evaporation of water in the cooling ponds of power plants. In an attempt to find methods to reduce this evaporation and subsequent fogging, a study was conducted during the winter of 1973 in order to examine the feasibility of using po1yethylene sheeting as a water surface cover. An uncovered insulated tank of water was placed on the roof of the Engineering Building of the University of Alaska. The water was circulated to prevent stratification and kept from freezing by a thermostatically controlled heater. From January 23 through February 2, the water surface was 1eft uncovered. Evaporation rates were measured daily by maintaining the water surface at a constant level. During the period of February 2 through 11, the water surface was covered with a sheet of clear polyethylene, thereby eliminating evaporation. Throughout the period of study, daily readings were made of the power consumption of the heater and pump. Temperatures within and above the tank were also frequently measured with copper-constantine thermocouples. From the data co11ected, a daily energy balance for the tank was calculated. Taken into consideration were the net short-wave and long-wave energy exchange, heat loss due to evaporation and sensible heat transfer, heat loss through the sides of the tank, change in stored energy, and energy input from heater and pump. Results indicate that polyethylene is an effective water surface cover that could be used to virtually eliminate evaporation from cooling ponds.The authors wish to acknowledge the assistance of the Institute of Water Resources, University of Alaska, who provided the funds for the construction of the tank and the instrumentation used in the study, and M. Gavin and B. Strickler, who helped in its construction

A Computer Model of the Tidal Phenomena in Cook Inlet, Alaska

The work upon which this report is based was supported by funds (Project A-028-ALAS) provided by the United States Department of the Interior, Office of Water Resources Research, as authorized under the Water Resources Act of 1964, as amended

Arctic Engineering for the Seventies: A Philosophy

The Naval Arctic Research Lab at Barrow has been the base for productive studies of sea ice and pipelines in permafrost. It can offer the engineer a chance to do his fieldwork in the Arctic to solve challenging problems of housing design and construction, structural and power requirements, routings and oil spill difficulties of ships operating through the Northwest Passage, and basic work on physical and chemical properties of sea ice and its significance to shipping

A Program for the Collection, Storage, and Analysis of Baseline Environmental Data for Cook Inlet, Alaska

The scope of this report is to provide a general, yet comprehensive, description of the Cook Inlet System which will serve as a basis for understanding the interrelated natural and man-made factors governing its future; to present a program of field research studies for the estuarine environment that will describe the existing state of the Inlet with respect to the water quality and biota; to provide a framework whereby the program of studies can be evaluated and redirected in light of the preliminary results; and, to provide a method of storing and analyzing the data from the investigations so that it can be made available to interested parties in the most efficient manner possible.This report was prepared by the Institute of Water Resources of the University of Alaska for the Alaska Water Laboratory, Federal Water Pollution Control Administration under Contract No. 14-12-449

Solution-state structure of a fully alternately 2′-F/2′-OMe modified 42-nt dimeric siRNA construct

A high-resolution solution structure of a stable 42-nt RNA dimeric construct has been derived based on a high number of NMR observables including nuclear overhauser effects (NOEs), J-coupling constants and residual dipolar couplings (RDCs), which were all obtained with isotopically unlabeled molecules. Two 21-nt siRNA that efficiently hybridize consist of ribose units that were alternately substituted by 2′-fluoro or 2′-methoxy groups. Structure calculations utilized a set of H-F RDC values for all 21 2′-fluoro modified nucleotides under conditions of weak alignment achieved by Pf1 phages. A completely 2′-F/2′-OMe modified dimeric RNA construct adopts an antiparallel double-helical structure consisting of 19 Watson–Crick base pairs with additional 3′ UU overhangs and a 5′ phosphate group on the antisense strand. NMR data suggest that the stability of individual base pairs is not uniform throughout the construct. While most of the double helical segment exhibits well dispersed imino resonances, the last three base pairs either display uncharacteristic chemical shifts of imino protons or absence of imino resonances even at lower temperatures. Accessibility of imino protons to solvent exchange suggests a difference in stability of duplex ends, which might be of importance for incorporation of the guide siRNA strand into a RISC

IWR; no. 3

Project Number: A-006-ALAS Agreement Number: 14-01-0001-722 Project Duration : November 15, 1965 - June 30, 1966The water resource research requirements for Alaska revolve around the needs of a rapidly expanding population and industrial growth in an unpopulated country. It appears that many of the problems which have been researched elsewhere must be restudied in Alaska because of the extremes of climate which Alaska exhibits . Most of the southern coastal areas of the State exhibit from 70 to 350 inches of runoff per year and in much of the northern part of the State permafrost to great depths and seasonal frost lock virtually all of the water in the solid state for a major part of the year. Alaska Is proving to be an area with vast petroleum reserves. These reserves are being brought into production and are resulting in the development of previously unpopulated areas. The proper management of previously untouched waters requires knowledge of the nature of the existing resources and then an evaluation of the probable effects of alternative water uses in order to optimize the desirable use of Alaskan water resources. This evaluation of present conditions and the analysis of future possible uses provide vast amounts of required research.The work upon which this report is based was supported by funds provided by the U .S . Department of the Interior , Office of Water Resources Research, as authorized under the Water Resources Research Act of 1964