Download or read book Ice Tunnel Closure Phenomena written by John F. Abel and published by . This book was released on 1961 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanics of closure, exhibited by ice tunnels, can be understood by considering the ice as a viscous solid. The viscous solid will flow, when subjected to a force, at a rate dependent on the magnitude of the force, the area of relief open for flow, and the apparent viscosity of the viscous solid. In the case of the ice tunnels, the force inducing the flow is the weight of the overburden; the area of relief open for flow is the tunnel opening; and apparent viscosity is the resistance to flow exhibited by the ice. The closure of a rectangular opening made in ice was measured. Maximum closure occurs at the center of unsupported roof, wall, or floor spans. The vertical closure rate decreases negligibly approximately 2% from the center of a room to approximately 6 ft from the wall. From the point about 6 ft from the wall to the wall, the closure rate decreases about 30%. Approximately 30% of vertical closure at the center of the span is due to flexure of the floor and roof. The remaining 70% is due to shortening of the wall height; the major portion of this wall closure occurs at the bottom of the wall. Over 80% of closure due to flexure of the floor and roof results from flexure of the floor. (Author).
Download or read book Ice Tunnel Closure Phenomena written by John F. Abel and published by . This book was released on 1959 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Special Report Corps of Engineers U S Army Cold Regions Research and Engineering Laboratory written by Cold Regions Research and Engineering Laboratory (U.S.) and published by . This book was released on 1972 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book USA CRREL Technical Publications written by Cold Regions Research and Engineering Laboratory (U.S.) and published by . This book was released on 1972 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book SIPRE Report written by and published by . This book was released on with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book CRREL Technical Publications 1950 1975 written by Cold Regions Research and Engineering Laboratory (U.S.) and published by . This book was released on 1992 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Keywords Index to U S Government Technical Reports written by United States. Department of Commerce. Office of Technical Services and published by . This book was released on 1962 with total page 990 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Environment of the Greenland Ice Cap written by Donald W. Hogue and published by . This book was released on 1964 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Under ice Mining Techniques written by John F. Abel and published by . This book was released on 1961 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods of excavating in the Greenland Ice Cap, and the planning required, equipment employed, and problems encountered are described individually for each of 5 operating seasons (1955-1959), and relative cost evaluations of the different methods are given. Three basic methods were used: hand-picking and manual haulage; explosives and manual haulage (drill-blast-muck cycle); and mechanized mining and haulage. Manual methods, which are of low capacity and limited to widths under 12 ft, are justified only when small openings are required, and in remote, inaccessible regions. The drill-blast-muck cycle of mining has a slightly higher capacity than manual methods, but requires power to operate the drills and to ventilate after blasting. Explosives can be used for room spans not exceeding 12 ft; when greater spans are excavated by blasting, the resulting roof is unstable. The machine method using mechanized coal mining equipment has the highest capacity and the lowest unit cost. Openings with roof spans in excess of 36 ft have been made with coal mining machines without dangerous roof conditions developing.
Download or read book Permafrost Tunnel Camp TUTO Greenland written by John F. Abel and published by . This book was released on 1960 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental tunnel, 300 x 9 ft. was driven into a glacial till hillside near Camp TUTO during the summer of 1959 for the purposes of determining the feasibility of excavating subsurface openings in frozen glacial till, developing efficient methods for excavating this material, and determining the characteristics of the glacial till at depth. Excavation of frozen glacial till by conventional hard-rock mining methods, modified slightly to allow for low temperatures, was found to be feasible. The employment, effectiveness, and possible improvement of the mining methods and equipment are discussed and problems for future study are suggested.
Download or read book When the Ice Is Gone What a Greenland Ice Core Reveals About Earth s Tumultuous History and Perilous Future written by Paul Bierman and published by W. W. Norton & Company. This book was released on 2024-08-20 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Paul Bierman’s realization that Greenland’s ice sheet melted when Earth was no warmer than today sounds an alarm for our planet. In 2018, lumps of frozen soil, collected from the bottom of the world’s first deep ice core and lost for decades, reappeared in Denmark. When geologist Paul Bierman and his team first melted a piece of this unique material, they were shocked to find perfectly preserved leaves, twigs, and moss. That observation led them to a startling discovery: Greenland’s ice sheet had melted naturally before, about 400,000 years ago. The remote island’s ice was far more fragile than scientists had realized—unstable even without human interference. In When the Ice Is Gone, Bierman traces the story of this extraordinary finding, revealing how it radically changes our understanding of the Earth and its climate. A longtime researcher in Greenland, he begins with a brief history of the island, both human and geological, explaining how over the last century scientists have learned to read the historical record in ice, deciphering when volcanoes exploded and humans started driving cars fueled by leaded gasoline. For the origins of ice coring, Bierman brings us to Camp Century, a U.S. military base built inside Greenland’s ice sheet, where engineers first drilled through mile-thick ice and into the frozen soil beneath. Decades later, a few feet of that long-frozen earth would reveal its secrets—ancient warmth and melted ice. Changes in Greenland reverberate around the world, with ice melting high in the arctic affecting people everywhere. Bierman explores how losing Greenland’s ice will catalyze devastating events if we don’t change course and address climate change now.
Download or read book USA SIPRE List of Publications written by U.S. Army Snow, Ice, and Permafrost Research Establishment and published by . This book was released on 1958 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bulletin of the U S Antarctic Projects Officer written by and published by . This book was released on 1962 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bulletin of the U S Antarctic Projects Officer written by United States. Antarctic Projects Office and published by . This book was released on 1962 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Report ES written by and published by . This book was released on 1961 with total page 660 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Keywords Index to U S Government Technical Reports permuted Title Index written by United States. Department of Commerce. Office of Technical Services and published by . This book was released on 1962 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Report written by and published by . This book was released on 1963 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt:
