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

Saline Conversion and Ice Structures from Artificially Grown Sea Ice

The environment of cold regions is generally viewed as inhospitable, primarily due to application of ideal processes and techniques suitable to temperate zones. The work herein is a step toward solving two environmental problems. The first involves the supply of inexpensive, potable water in Arctic regions, the lack of which is a severe detriment to development. Although water does exist in the Arctic, it is neither available in potable form during many months of the year nor does it occur in sufficient quantity near the point of use. Principally, this lack is caused by the aridness of the Arctic and the shallowness of fresh water sources which, for all practical purposes, do not exist but freeze completely each winter season. The remaining liquid water source is the sea. Arctic problems are then similar to other arid regions where the conversion of sea water to potable water or the transmission of potable water to desired locations is necessary. Cold temperatures generally preclude transmission except over very short distances. Desalination by freezing sea water is a much reported process and has been included among the desalination processes under study worldwide. The advantage of this method in the Arctic is the cold winter-time temperature for freezing and the existence of adequate solar energy in the summer for melting self purified ice. Power requirements are greatly reduced using these natural phenomena. The second aspect of this study concerns the use of artificially grown sea ice as a structural material, thinking primarily in terms of coastal facilities such as docks, jetties, islands, platforms, etc. At sufficiently high latitudes, the summer ablation can be controlled to the point where major structures can be maintained intact during the summer. The unit cost of material is quite low because of low energy requirements. The results of this study show that each of these sea water uses have considerable promise. Desalination to potable level was accomplished. Ice growth rates were obtained which indicate that ice structures of substantial size can be built.This project was accomplished under a matching grant between the Office of Water Resources Research, Department of the Interior, and the University of Alaska, Arctic Environmental Engineering Laboratory. Funds available under this grant purposefully did not anticipate the heavy logistic expense in moving the project and equipment from Fairbanks to Kotzebue, Alaska. Therefore, a major third contributor was the Alaska Air National Guard, Kulis Air Force Base, Alaska. The support offered by the officers and men of the Alaska Air National Guard was excellent and greatly appreciated

How do emerging technologies for collision avoidance in Earth’s orbit impact risk management processes?

Human society is strongly dependent on satellite-based services such as communication, Earth observation, navigation etc. A by-product of satellite operations is the generation of space debris which consists amongst others of launch stages, defunct satellites, tools or debris resulting from collisions. A collision between an operating spacecraft and space debris can severely damage the operating spacecraft, render it inoperable or in the worst lead to its destruction and many thousands of new pieces of debris. The commercialization of space operations has led to the introduction of thousands of new spacecraft into orbit which provides challenges for collision avoidance operations. Earlier, these have been manual operations, but the sheer number of objects in orbit around the Earth questions if human operators can handle this. Thus, autonomous collision avoidance systems including emerging technologies such as Artificial intelligence have been utilized. Earlier, for manual collision avoidance operations, classical risk management procedures could be adopted, since the space environment resembled a rather static problem. Now, the orbital picture is much more dynamic with constant manoeuvrers and the change from human to AI operators. Thus, the question arises if the introduction of AI into collision avoidance requires risk management procedures to be revised and the inherent risk of AI operations to be addressed. This thesis discusses these two issues and concludes that, although AI operations can significantly support collision avoidance features, emerging technologies require modernised risk management approaches with human feedback in order to quality-check the deliveries of the AI and to address the highly dynamic system the AI operates in. Otherwise, AI operations can lead to situations which should have been prevented from the beginning, namely collisions that created even more space debris. This could in the worst case render the orbit around the Earth inoperable

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

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

Dder einfluss von liganden auf den assoziationsgrad des desoxy-hämoglobins der flussneunaugen (lampetra fluviatilis L.)

AbstractIn alkaline aqueous solution, the sedimentation coefficients of DeoxyHb, HbO2 and HbCO of Lampetra fluviatilis L. are 1.9 ± 0.1 S. This value corresponds to a molecular weight of about 17,000, i.e. the value of a single haem polypeptide chain. In weak acidic conditions, both the non-liganded DeoxyHb and the liganded forms, HbO2 and HbCO, associate to form dimers and oligomers. The monomer-oligomer transitions of these compounds take place at different pH values: DeoxyHb pHO.5 ∼ 6.7; HbO2 and HbCO pHO.5 ∼ 5.9. With respect to the association modus, the equilibrium: 4 Hb ⇌ 2 Hb2⇌Hb4 may be preferred

Core compressor exit stage study, 2

A total of two three-stage compressors were designed and tested to determine the effects of aspect ratio on compressor performance. The first compressor was designed with an aspect ratio of 0.81; the other, with an aspect ratio of 1.22. Both compressors had a hub-tip ratio of 0.915, representative of the rear stages of a core compressor, and both were designed to achieve a 15.0% surge margin at design pressure ratios of 1.357 and 1.324, respectively, at a mean wheel speed of 167 m/sec. At design speed the 0.81 aspect ratio compressor achieved a pressure ratio of 1.346 at a corrected flow of 4.28 kg/sec and an adiabatic efficiency of 86.1%. The 1.22 aspect ratio design achieved a pressure ratio of 1.314 at 4.35 kg/sec flow and 87.0% adiabatic efficiency. Surge margin to peak efficiency was 24.0% with the lower aspect ratio blading, compared with 12.4% with the higher aspect ratio blading

Efficient cytosolic delivery of molecular beacon conjugates and flow cytometric analysis of target RNA

Fluorescent microscopy experiments show that when 2′-O-methyl-modified molecular beacons (MBs) are introduced into NIH/3T3 cells, they elicit a nonspecific signal in the nucleus. This false-positive signal can be avoided by conjugating MBs to macromolecules (e.g. NeutrAvidin) that prevent nuclear sequestration, but the presence of a macromolecule makes efficient cytosolic delivery of these probes challenging. In this study, we explored various methods including TAT peptide, Streptolysin O and microporation for delivering NeutrAvidin-conjugates into the cytosol of living cells. Surprisingly, all of these strategies led to entrapment of the conjugates within lysosomes within 24 h. When the conjugates were pegylated, to help prevent intracellular recognition, only microporation led to a uniform cytosolic distribution. Microporation also yielded a transfection efficiency of 93% and an average viability of 86%. When cells microporated with MB–NeutrAvidin conjugates were examined via flow cytometry, the signal-to-background was found to be more than 3 times higher and the sensitivity nearly five times higher than unconjugated MBs. Overall, the present study introduces an improved methodology for the high-throughput detection of RNA at the single cell level

Sub-cellular trafficking and functionality of 2\u27-O-methyl and 2\u27-O-methyl-phosphorothioate molecular beacons

Molecular beacons (MBs) have shown great potential for the imaging of RNAs within single living cells; however, the ability to perform accurate measurements of RNA expression can be hampered by false-positives resulting from nonspecific interactions and/or nuclease degradation. These false-positives could potentially be avoided by introducing chemically modified oligonucleotides into the MB design. In this study, fluorescence microscopy experiments were performed to elucidate the subcellular trafficking, false-positive signal generation, and functionality of 2\u27-O-methyl (2Me) and 2\u27-O-methyl-phosphorothioate (2MePS) MBs. The 2Me MBs exhibited rapid nuclear sequestration and a gradual increase in fluorescence over time, with nearly 50% of the MBs being opened nonspecifically within 24 h. In contrast, the 2MePS MBs elicited an instantaneous increase in false-positives, corresponding to ~5–10% of the MBs being open, but little increase was observed over the next 24 h. Moreover, trafficking to the nucleus was slower. After 24 h, both MBs were localized in the nucleus and lysosomal compartments, but only the 2MePS MBs were still functional. When the MBs were retained in the cytoplasm, via conjugation to NeutrAvidin, a significant reduction in false-positives and improvement in functionality was observed. Overall, these results have significant implications for the design and applications of MBs for intracellular RNA measurement