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The Rytz’s axis construction is a basic method of descriptive geometry to find the axes, the semi-major axis and semi-minor axis and the vertices of an ellipse, starting from two conjugated half-diameters. If the center and the semi axis of an ellipse are determined the ellipse can be drawn using an ellipsograph or by hand (see ellipse).
Shotcrete, gunite (/ ˈ ɡ ʌ n aɪ t /), or sprayed concrete is concrete or mortar conveyed through a hose and pneumatically projected at high velocity onto a surface. This construction technique was invented by Carl Akeley and first used in 1907. [1]: 7 The concrete is typically reinforced by conventional steel rods, steel mesh, or fibers.
Portland cement has been used to treat more contaminated material than any other S/S binding agent because of its ability to bind free liquids, reduce permeability, encapsulate hazardous materials, and reduce the toxicity of certain contaminants. Lime can be used to adjust the pH of the substance of drive off water by using high heats of hydration.
Dalecarlia Water Treatment Plant, Washington, D.C. Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment.
Dolphin WaterCare is a brand of environmentally responsible pulsed-power water treatment technology patented by Clearwater Systems Corporation. [3] [4] The system is designed to control scale, corrosion and biological activity in cooling towers without the use of chemicals, chemical tanks or pumps. [5]
Early work by Dry included embedding long, thin glass channels in concrete. [26] This self-healing mechanism was eventually scaled up and used on a sample bridge deck. [27] The difficulty of casting concrete with these very fragile materials was one obstacle preventing this technique's widespread use.
The tremie concrete placement method uses a vertical or nearly vertical pipe, through which concrete is placed by gravity feed below water level. [4]The lower end of the pipe is kept immersed in fresh concrete so that concrete rising from the bottom displaces the water above it, thus limiting washing out of the cement content of the fresh concrete at the exposed upper surface.
Oxidation of pyrite in clay formations in contact with concrete – this produces sulfuric acid which reacts with concrete. Bacterial activity in sewers – anaerobic sulfate reduction at work in the organic-rich sludges accumulated under water in the conduits produces hydrogen sulfide gas (H 2 S).