Strength Studies on Antarctic Sea Ice PDF Download

Author: George Hendrickson
Publisher:
ISBN:
Category : Sea ice
Languages : en
Pages : 32

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Author: W. F. Weeks
Publisher:
ISBN:
Category : Ice mechanics
Languages : en
Pages : 100

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Book Description
The review discusses the state of thinking of each of the main national groups investigating sea ice and gives an overall appraisal of the field as a whole. Emphasis is placed on (1) the physical basis for interpreting sea ice strength (phase relations, air volume, and structural considerations), (2) theoretical considerations (strength models, air bubbles and salt reinforcement, and interrelations between growth conditions and strength), (3) experimental results (tensile, flexural, shear, and compressive strength, elastic modulus, shear modulus and Poisson's ratio, time dependent effects, and creep), and (4) plate characteristics. The paper includes a review of problems in sea ice investigations, relates the chemical, crystallographic, mechanical, and physical aspects involved, and concludes by showing how to utilize this knowledge to solve practical problems. (Author).

Author: Theodore R. Butkovich
Publisher:
ISBN:
Category : Sea ice
Languages : en
Pages : 28

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Author: A. Assur
Publisher:
ISBN:
Category : Salt
Languages : en
Pages : 68

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Part of the salts contained in sea water are trapped in sea ice upon freezing. They form liquid and solid inclusions in a systematic pattern. The amount depends upon temperature and salinity. A detailed table of phase relations is given and a general theory is derived to show how the internal cavities may affect the strength of sea ice. The general theory leads to specific models. The principle of ring tensile strength tests is explained and a series for evaluation is given. Test data lead to a substantiation of theoretical principles and to an illustration of several hypotheses concerning the effect of solid salt inclusions upon strength. Observed sea ice phenomena are explained on the basis of internal structure. (Author).

Author: George Hendrickson
Publisher:
ISBN:
Category :
Languages : en
Pages : 26

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The strength of sea ice was studied at McMurdo, Antarctica, during two successive field seasons. Three hundred tensile tests were made on continuous core samples taken at various locations on ice aged 1 year, 2 years, and more than 5 years. Salinity profiles were obtained for each core. A relationship between strength sigma (kg/sq cm) and volume of brine cavities v (%0), as suggested by Assur, adequately represents the data for brine volumes less than 0.400: sigma = 29.1 - 48.0 v to the 1/2 power. The constants agree satisfactorily with values obtained previously for Arctic sea ice, the value of sigma for very low brine volume approaching the value for fresh-water ice. The model on which the above expression is based apparently breaks down at high brine volumes. (Author).

Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
ISBN: 0309456002
Category : Science
Languages : en
Pages : 83

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The sea ice surrounding Antarctica has increased in extent and concentration from the late 1970s, when satellite-based measurements began, until 2015. Although this increasing trend is modest, it is surprising given the overall warming of the global climate and the region. Indeed, climate models, which incorporate our best understanding of the processes affecting the region, generally simulate a decrease in sea ice. Moreover, sea ice in the Arctic has exhibited pronounced declines over the same period, consistent with global climate model simulations. For these reasons, the behavior of Antarctic sea ice has presented a conundrum for global climate change science. The National Academies of Sciences, Engineering, and Medicine held a workshop in January 2016, to bring together scientists with different sets of expertise and perspectives to further explore potential mechanisms driving the evolution of recent Antarctic sea ice variability and to discuss ways to advance understanding of Antarctic sea ice and its relationship to the broader ocean-climate system. This publication summarizes the presentations and discussions from the workshop.

Author: United States. Naval Civil Engineering Laboratory
Publisher:
ISBN:
Category : Antarctica
Languages : en
Pages : 23

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Author: R. A. Paige
Publisher:
ISBN:
Category : Antarctica
Languages : en
Pages : 27

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Book Description
During the austral summer of 1964-65, a study of some of the physical properties of sea ice was made near McMurdo Station, Antarctica, where the sea ice is used extensively for aircraft operations, travel, freight hauling, and docking facilities. Tests of specimens showed that both shear and ring-tensile strengths increased almost linearly as specimen temperature decreased; the strength decreased as the ice sheet became warmer and more nearly isothermal. Average shear strength decreased from 140 psi in late October to a low of 90 psi in late January and then increased to 115 psi by 10 February just before breakup; average ring-tensile strength similarly decreased from 190 psi in mid-December to a low of 145 psi in early February, and then increased to 170 psi by 10 February. Internal deterioration and decrease in strength, thickness, salinity of brine, and temperature gradient are all related to rising temperatures and increased solar radiation during the summer. Development of a reliable method of predicting the bearing capacity of sea ice depends upon more detailed knowledge of the effects of loads, the history of the ice, danger zones and safety factors, and other features to insure safe operation on the ice. (Author).

Author: Guenther E. Frankenstein
Publisher:
ISBN:
Category : Sea ice
Languages : en
Pages : 24

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The report describes the results of tests made to determine the dynamic Young's modulus E of young sea ice. The ice samples were mainly parallelepipeds but a few were 7.62-cm-diam cores. The longitudinal wave velocity was determined by measuring the time required for a sound wave to travel the length of the sample. The flexural strength of the ice was determined by conducting a number of simple beam tests. The average value for the flexural strength was 11.3 kg/sq cm. (Author).

Author: Guriĭ Nikolaevich I︠A︡kovlev
Publisher:
ISBN:
Category : Ice
Languages : en
Pages : 210

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Book Description
"The results of recent investigations of ice, including the structure of the ice cap, its resilient features, methods of forecasting its stable characteristics, ice breaking methods, and experimental laboratory work are presented in this collection of articles. The book is designed for ice technologists, and engineers whose work brings them into contact with questions deriving from the science of ice."--Jacket.