Only about three percent of Earth’s water is freshwater. Of that, only about 1.2 percent can be used as drinking water; the rest is locked up in glaciers, ice caps, and permafrost, or buried deep in the ground.

Which zones are together called zone of aeration? Explanation: The intermediate zone is generally of small thickness and may be even absent in many cases. The soil water and intermediate zones are sometimes collectively referred to as the zone of aeration.

Porous means having void spaces between grains. In an unconfined aquifer the zone of saturation (all voids filled with water) lies above an aquiclude; the top of the zone of saturation is the water table. Above this is the zone of aeration (voids filled with air, though grains may be wet – coated with water).

Sands, sandstones, gravels, and conglomerates are good examples of aquifers. 2. A sediment or rock in which rock tends to move slowly is an aquitard. Shales, clay, and many crystalline rocks are good examples of aquitards.

Sandstones generally have good porosity and permeability, making a good well. Shales have poorer permeability and well yields are poorer. The more porous and permeable the rock, the smaller the radius of influence of the well at a given rate of pumping.

Effective permeability of rock to a fluid phase (oil, gas, or water) in porous medium is a measure of the ability of that phase to flow in the presence of other fluid phases.

Magnetic permeability μ (Greek mu) is thus defined as μ = B/H. Magnetic flux density B is a measure of the actual magnetic field within a material considered as a concentration of magnetic field lines, or flux, per unit cross-sectional area.

Reference

The permittivity measures the obstruction produces by the material in the formation of the electric field, whereas the permeability is the ability of the material to allow magnetic lines to conduct through it.

1 : the quality or state of being permeable. 2 : the property of a magnetizable substance that determines the degree in which it modifies the magnetic flux in the region occupied by it in a magnetic field.

The absolute permittivity or simply permittivity of a medium can be defined as the property of the medium which determines certain electric field intensity at a point in the field creates how much flux density at that point. The absolute permittivity of vacuum is taken as the base value of the permittivity.

1. n. [Geology] The measurement of the permeability, or ability to flow or transmit fluids through a rock, conducted when a single fluid, or phase, is present in the rock. The symbol most commonly used for permeability is k, which is measured in units of darcies or millidarcies.

Example 18-12. Force Between Two Parallel Wires Carrying a Current

Permeability of a space in a ship is the percentage of empty volume in that space. Permeability is used in ship survivability and damaged stability calculations in ship design. The permeability of a space is the percentage of volume of the space which may be occupied by seawater if the space is flooded.

To identify the extent of damage that can be considered safe for the ship.

1. Concept of Subdivision of a Ship:
2. Step 1: The floodable length curve is plotted.
3. Step 2: Watertight bulkheads are placed at random, but known positions along the length of the ship, thus dividing it into a number of watertight compartments.

To keep from sinking, the cruise ship has to displace its weight in water before it’s submerged. Large ships such as freighters, naval vessels and transport and cruise ships commonly utilize displacement hulls, or hulls that push water out of the way, to stay afloat.

Why the Ship Floats Archimedes’ buoyancy principle states that buoyant force — what keeps the ship afloat — is equal to the weight of water that is displaced when the ship enters the ocean. The displaced water around a coin weighs less than the coin, so the coin will sink.