Arrow Project Cofferdam

1968 ◽  
Vol 5 (3) ◽  
pp. 127-141
Author(s):  
J W Gadsby ◽  
F A Bares
Keyword(s):  
British Columbia ◽  
Concrete Structures ◽  
Columbia River ◽  
Hydraulic Head ◽  
Production Rates ◽  
The Core ◽  
The Earth ◽  
Slurry Trench ◽  
Sand And Gravel ◽  
Earth Fill

The Arrow project is located on the Columbia river in south-east British Columbia. The earth-fill cofferdam, required for the construction of the concrete structures, was completed early in 1966 and removed late in 1967. The cofferdam consisted of a sand and gravel fill with a central impervious core. The core was in two parts: the lower core consisted of a concrete cut-off wall formed by the slurry trench process; the upper core was a compacted impervious till. The cofferdam withstood a maximum hydraulic head of 115 ft.Design, construction, performance and removal of the cofferdam are described. Production rates for the concrete cut-off wall are given together with an estimate of costs.

Ups and Downs

2018 ◽  
Author(s):  
Roy Livermore
Keyword(s):  
Mantle Convection ◽  
Laboratory Experiments ◽  
Inner Core ◽  
Computer Modelling ◽  
Great Depth ◽  
New Horizons ◽  
The Core ◽  
The Earth ◽  
The World ◽  
The 1960S

Despite the dumbing-down of education in recent years, it would be unusual to find a ten-year-old who could not name the major continents on a map of the world. Yet how many adults have the faintest idea of the structures that exist within the Earth? Understandably, knowledge is limited by the fact that the Earth’s interior is less accessible than the surface of Pluto, mapped in 2016 by the NASA New Horizons spacecraft. Indeed, Pluto, 7.5 billion kilometres from Earth, was discovered six years earlier than the similar-sized inner core of our planet. Fortunately, modern seismic techniques enable us to image the mantle right down to the core, while laboratory experiments simulating the pressures and temperatures at great depth, combined with computer modelling of mantle convection, help identify its mineral and chemical composition. The results are providing the most rapid advances in our understanding of how this planet works since the great revolution of the 1960s.

Ecotypic variation affects the conservation of North American badgers endangered along their northern range extent

2018 ◽  
Author(s):  
Richard D. Weir ◽  
Trevor A. Kinley ◽  
Richard W. Klafki ◽  
Clayton D. Apps
Keyword(s):  
British Columbia ◽  
Cause Of Death ◽  
Conservation Strategies ◽  
High Fecundity ◽  
Ecological Information ◽  
The Core ◽  
Ecotypic Variation ◽  
Sufficient Energy ◽  
Soil Deposits ◽  
Regional Conservation

This chapter is based on ecological information on 82 radio-tagged badgers (39 F, 43 M) among three study populations in British Columbia, Canada between 1996 and 2010, data that were collected to learn more about the ecology of badgers and consider how variation in their ecology might inform regional conservation strategies. The widely spaced, lower density prey and distribution of soil deposits suitable for digging in British Columbia likely required badgers to use substantially larger areas, relative to the core range, in which to acquire sufficient energy to survive and reproduce. Strikes from automobiles were the primary cause of death among all radio-tagged badgers and this source of mortality is pervasive throughout the limited distribution of badgers in British Columbia. Despite their potential for high fecundity, populations of badgers in British Columbia likely remain at considerable risk compared to those in the core of the species’ range.

A mammoth (Mammuthus primigenius) tooth from late Wisconsin deposits near Embden, North Dakota, and comments on the distribution of woolly mammoths south of the Wisconsin ice sheets

1986 ◽  
Vol 23 (7) ◽  
pp. 909-918 ◽  
Author(s):  
C. R. Harington ◽  
Allan C. Ashworth
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
North Dakota ◽  
Third Molar ◽  
Ice Sheets ◽  
Lake Agassiz ◽  
Mammuthus Primigenius ◽  
Sand And Gravel ◽  
Woolly Mammoth ◽  
Cass County

A well-preserved third molar of a woolly mammoth (Mammuthus primigenius) was recovered from sand and gravel forming the highest (Herman) prominent strandline of Lake Agassiz near Embden in western Cass County, North Dakota. The Herman strandline is estimated to have formed about 11 500 years BP, and presumably the tooth is of similar age. Perhaps the animal lived in a tundra-like area near the Lake Agassiz shoreline.Additional evidence suggests that woolly mammoths occupied a tundra-like range south of the Wisconsin ice sheets extending from southern British Columbia to the Atlantic continental shelf off Virginia.

Dead-Ends and New Directions

2021 ◽  
Vol 15 (4) ◽  
pp. 327-347
Author(s):  
Jean Francesco A.L. Gomes
Keyword(s):  
Natural History ◽  
Scientific Theory ◽  
Good Science ◽  
Orthodox Christian ◽  
The Core ◽  
The Earth ◽  
New Directions ◽  
History Of ◽  
Evolutionary Science ◽  
Doctrine Of Creation

Abstract The aim of this article is to investigate how Abraham Kuyper and some late neo-Calvinists have addressed the doctrine of creation in light of the challenges posed by evolutionary scientific theory. I argue that most neo-Calvinists today, particularly scholars from the Vrije Universiteit Amsterdam (VU), continue Kuyper’s legacy by holding the core principles of a creationist worldview. Yet, they have taken a new direction by explaining the natural history of the earth in evolutionary terms. In my analysis, Kuyper’s heirs at the VU today offer judicious parameters to guide Christians in conversation with evolutionary science, precisely because of their high appreciation of good science and awareness of the nonnegotiable elements that make up the orthodox Christian narrative.

The density variation of the earth's central core*

1942 ◽  
Vol 32 (1) ◽  
pp. 19-29
Author(s):  
K. E. Bullen
Keyword(s):  
Pure Iron ◽  
Outer Boundary ◽  
Density Variation ◽  
Central Core ◽  
Good Precision ◽  
Wide Margin ◽  
The Core ◽  
The Earth ◽  
The Mean ◽  
Published Paper

ABSTRACT A detailed analysis of the problem of the earth's density variation has been extended to the earth's central core. It is shown that in the region between the outer boundary of the core and a distance of about 1400 km. from the earth's center the density ranges from 9.4 gm/cm.3 to 11.5 gm/cm.3 within an uncertainty which, if certain general assumptions are true, does not exceed 3 per cent. The density and pressure figures are, moreover, compatible with the existence of fairly pure iron in this part of the earth. The result for the earth's outer mantle as given in a previously published paper, together with those in the present paper, are found to give with good precision the density distribution in a region occupying 99 per cent of the earth's volume. Values of the density within 1400 km. of the earth's center are subject, however, to a wide margin of uncertainty, and there appears to be no means of resolving this uncertainty for the present. The most that can be said is that the mean density in the latter region is greater than 12.3 gm/cm.3 and may quite possibly be several gm/cm.3 in excess of this figure. In the present paper figures are also included for the variation of gravity and the distribution of pressure within the central core. The gravity results are shown to be subject to an appreciable uncertainty except within about 1000 km. of the outer boundary of the core, but the pressure results are expected to be closely accurate at all depths.

Free spheroidal vibrations of the earth at very long periods, Part I— Calculation of periods for several earth models

1963 ◽  
Vol 53 (3) ◽  
pp. 483-501 ◽  
Author(s):  
Leonard E. Alsop
Keyword(s):  
Inner Core ◽  
Computer Programs ◽  
Free Vibrations ◽  
Stoneley Waves ◽  
The Core ◽  
The Earth ◽  
Earth Models ◽  
Shear Modes ◽  
Phase And Group Velocities ◽  
Group Velocities

Abstract Periods of free vibrations of the spheroidal type have been calculated numerically on an IBM 7090 for the fundamental and first two shear modes for periods greater than about two hundred seconds. Calculations were made for four different earth models. Phase and group velocities were also computed and are tabulated herein for the first two shear modes. The behavior of particle motions for different modes is discussed. In particular, particle motions for the two shear modes indicate that they behave in some period ranges like Stoneley waves tied to the core-mantle interface. Calculations have been made also for a model which presumes a solid inner core and will be discussed in Part II. The two computer programs which were made for these calculations are described briefly.

Development of Web-based Technology for Environmental Engineering Education System

2020 ◽  
Vol 50 (4) ◽  
pp. 04-05
Author(s):  
Procopio Cocci
Keyword(s):  
Engineering Education ◽  
Education System ◽  
Environmental Engineering ◽  
Web Based ◽  
The Core ◽  
The Earth ◽  
Training Mode ◽  
Natural Information ◽  
Good For ◽  
Ecological Building

The objective of the ecological building instruction ought not just train understudies' natural information, the more significant thing is that it prepares understudies' natural ethics and structures the conduct which is good for the earth, and these must be shaped by training, in actuality. In the customary showing model of training, one instructor can just guide one practice simultaneously. With the improvement of organization innovation, instructor can control the distinctive practice exercises firing up in various areas or in various occasions by network. In light of the incorporation of viable need and intuitive qualities of condition instruction, the creator set forward an online domain training mode named "practice-intelligent partake in". The Core of this mode is to prepare understudies' natural ethics by training and to understand educators' guidance through organization.

Epicentral intensities and damage in the Hebgen Lake, Montana, earthquake of August 17, 1959

1962 ◽  
Vol 52 (2) ◽  
pp. 181-234
Author(s):  
Karl V. Steinbrugge ◽  
William K. Cloud
Keyword(s):  
Ground Motions ◽  
Strong Motion ◽  
Fault Scarp ◽  
Rock Falls ◽  
Small Unit ◽  
The Earth ◽  
Major Fault ◽  
Seismograph Station ◽  
Fault Scarps ◽  
Earth Fill

ABSTRACT An extensive fault scarp system was formed during the Hebgen Lake earthquake of August 17, 1959 (11:37:15 p.m., M.S.T., Gutenberg-Richter magnitude 7.1). Bedrock beneath Hebgen Lake warped, rotated, and caused a seiche in the lake. A major landslide dammed Madison Canyon, causing a lake to form above the slide. An estimated 19 persons were buried by the slide. Other slides and rock falls took out sections of the main highway north of Hebgen Lake and closed many roads in Yellowstone Park. Small unit masonry structures as well as wooden buildings along the major fault scarps usually survived with little damage when subjected only to vibratory forces. The unit masonry buildings, in particular, had little or no earthquake bracing. Intensity at the major scarp has been given a Modified Mercalli Scale rating of X. However, the maximum intensity ratings based on vibratory motion even a few feet away from the scarps were VII or VIII. Within the limits of observation there was little or no reduction in vibratory intensity 5 to 10 miles away compared to that at the fault. This is not to say that the ground motions were similar. At the closest strong-motion seismograph station (Bozeman, 58 miles from the epicenter) maximum recorded acceleration was about 7 per cent gravity. The earthquake was generally felt in about a 600,000 square mile area, mostly north of the instrumental epicenter. The earth-fill Hebgen Dam was within 1000 feet of a major scarp. The dam was significantly damaged, but it continued to be an effective structure.

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