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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Ice conditions and ice forecasting in the Beaufort sea

Swenson, Paul B. January 1958 (has links)
Thesis (M.A.)--Boston University / Introduction The purpose of the thesis is; to develop and explain the location and extent of sea ice in the Beaufort Sea, and to describe methods in use and proposed by the science of ice forecasting to aid ship movements in the area. Much of the data in the thesis camas from unpublished or widely scattered papers, and the thesis is an attempt to assimilate such data into cohesive form. Chapter I. The Newly Acquired Importance of the Beaufort Sea Region and the Status of Ice Forecasting. Prior to World War II the area of the Beaufort Sea was little known or exploited. A few explorers occasionally had joined the native eskimos as inhabitants of the area. After the war, a program of oil exploration was undertaken on the southern shores of the Sea by the U.S. Navy. Discovery of oil and the newly feasible means of making trans-polar flights across the Arctic waters suddenly catipulated the area into a position of strategic importance to our national defense. Research programs devoted to gathering data on how to live in such a hostile climate bacame a natural outgrowth of this new importance. With the construction and resupply of the DEW line a vital necessity, methods of coping with sea ice had to be developed. In this respect, the Russians were far advanced over the Western Allies, having devoted much time and effort on the problem since the 1920's. Nonetheless, U.S. and Canadian scientists, under an accelerating research program, are well on the way to equality in the fields surrounding sea ice research. [TRUNCATED]
2

The Relationship Between Meteorological Factors and Ice Conditions in Hudson Bay

Silis, Arvids 04 1900 (has links)
<p> This study focuses on the relations hip between ice cover and wind frequency, wind speed and air temperature. Results showed that there are four distinct MELT periods along the west coast of Hudson Bay. With a standardized MELT period, stations are generally higher correlated with their southern neighbours. Onshore wind frequencies increased signficantly from the NOMELT to the MELT period, and were associated with air temperatures 3 to 4 degrees Celsius colder than those of offshore winds. </p> <p> Mean air temperature was most highly correlated with percent ice cover. Ice cover was most strongly correlated with mean air temperature at Chesterfield Inlet and least so at Churchill. Thus, freeze-up and melt at Chesterfield Inlet are most strongly influenced by air temperature whereas at Churchill, other factors, presumably wind direction and currents, strongly influence the ice cover. Ice cover was most strongly influenced by air temperature during the NOMELT period. This shows that cold temperatures hasten freezeback more than warm temperatures hasten MELT. </p> / Thesis / Bachelor of Arts (BA)
3

Coastal Enviroments And Processes In The Canadian Artic Archipelago

Taylor, Robert 05 1900 (has links)
<p> The prime objective is to define and characterize the various coastal environments in the Canadian Arctic Archipelago. The research, Hhich utilizes both secondary source information and actual field observations, takes into account coastal morphology, beach profile, sediment types, sea ice conditions, tidal range, depth of the frost table and wave energy. From a total of twelve coastal divisions based on the criteria of coastal morphology, tidal conditions and length of open water season, five have been chosen as t he basic coastal environ ments of the Arctic Archipelago. They are as follows: the Arctic Coastal Plain, the Ice Shelf, the Fiord environment, the High Straight coastal environment, and the Ridge and Valley coastal environment. Field observations within the last three environments provided additional evidence for the divisions and observations on the beach and nearshore characteristics at five selected locations. </p> / Thesis / Master of Science (MSc)
4

Ice load prediction for design of ice-going ships for inland waterways

Zhang, Meng January 2019 (has links)
With increasing interest in utilizing the inland waterways (IWW) in European countries, the design of IWW vessels gains attention both from a transport efficiency and an emission control point of view. However, unlike in western and central European countries, in Nordic countries, e.g. Sweden, IWW ships must deal with ice on the fairway during every winter. Usually, IWW ships are designed without ice concerns and are structurally weaker compared to ships designed according to ice class notification from the classification societies. Developing such ships requires particular concerns since there is no strict requirements regarding ice class notifications for IWW ships. A primary challenge is to estimate both the global and local ice loads acting on the ship hull structure. To consolidate the design problems for IWW ice-going ships, Lake Mälaren is selected. Ice conditions, i.e. ice type and concentration, and ice data, e.g. ice thickness and ice flexural strength, are extracted and analysed for the ice load estimation. The ice mechanical properties have great influence on the ice load. Ice characteristics are studied based on empirical formulae and properties are calibrated by reference data. The deterministic approach is widely used to predict the ice loads. It is suitable when all variables, i.e. ship geometry and ice properties, are known and refers to rule-based design hereby. For first year light ice conditions in Lake Mälaren, the Finnish Swedish Ice Class Rule (FSICR) is widely used. The thesis uses guidelines from the Finnish Swedish Ice Class Rules as a reference and compare the results with other methods. The probabilistic approach, on contrary, is useful when certain variables are unknow, which are interpreted as random variables, for instance ice breaking pattern. Here the probabilistic method and ice-hull interaction mechanism are studied. The probabilistic method simplifies the ice pressure in relation to the contact area between the ice and the ship hull. It predicts maximum ice pressure acting on the ship hull based on field ice test data and ice exposure conditions. Such semi-empirical method can be used regardless of ship type and size. For this, a numerical model is introduced based on ice-hull collision mechanisms and the essential ice breaking characteristics. The physical mechanism is studied for idealizing ship-ice impact model. The idealization model includes the ice failure process, ice conditions and ship geometry. The ice failure is assumed to be initiated by crushing ice and followed by breaking due to bending failure. Ice properties are set as constant values without any variations. The stochasticity in interact process is represented by randomness in collision location and number of pieces of ice floe formed after breaking. An energy method is used to calculate the ice crushing force, indentation displacement and contact area. The ice bending scenario is simplified as an infinite plate resting on an elastic foundation under a concentrated load. Ice impact load and critical load can be obtained for global and local structural assessment respectively. The structural responses and structural strength of a representative panel at linear and nonlinear contexts are investigated as well. Ship structure is commonly designed with material yield strength as limit. However, the study shows a lighter structure can be achieved if plastic deformation is allowed without causing failure. Therefore, the design can be optimized with regards to ice loading capacity and weight control.

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