Emergency examples of water permeability directionality

The water moves in the direction of the agrosolution.

You can do an experiment like this: take half of the radish, dig out part of it, pour in a little thick brine, and after a few hours, you can see that there is more brine in the radish, because the water in the radish seeps out.

Soybeans are soaked in clean water, don't soybeans slowly become "fat"? This is actually also a phenomenon of osmosis.

Because there is very little water in dried soybeans, we can regard it as a concentrated solution, and the outer layer of soybeans is equivalent to a semi-permeable membrane, when soybeans are immersed in clean water to cook, osmosis will occur, and the result is that the water molecules in the clear water pass through the soybean skin into the soybeans, making the soybeans fat. Only after the soybeans are fully soaked and fattened, and then boiled for a period of time, the cells of the soybeans will be burst, making the beans rotten.

If the salt is added too early when boiling the beans, the soybeans are soaked in the brine, because the concentration of the brine is much thicker than that of water, so it is not easy for the water to penetrate into the soybeans. If more salt is added, the concentration of brine may even exceed the concentration in soybeans, so that the water not only cannot enter, but may even "drill" out of the slightly fattened soybeans, and the soybeans do not have enough water, no wonder the soybeans are boiled and boiled.

Selective permeable membranes are not considered.

Water permeates from a dilute solution to a concentrated solution. It can be understood that the number of water molecules in the dilute solution accounts for a high proportion, and at the same time, the number of water molecules moving from the dilute solution to the concentrated solution is more than the number of water molecules moving from the concentrated solution to the dilute solution, so the water penetrates from the dilute solution to the concentrated solution.

1 Inject yourself with saline and find out that you are fine.

2 Inject yourself with too high (low) salt water and find yourself hanging. The cause is cell rupture.

Permeation from low to high concentrations. The first floor is wrong, there is more water with a low concentration than water with a high concentration, that is, more than its volume. Therefore, more water is "replenished" to less water. That's it.

Osmosis principle: osmosis from low concentration to high concentration. For example, if the crops are fertilized too much and the seedlings are burned, the soil concentration is high, and the water in the seedlings penetrates into the soil, resulting in the burning of seedlings.

Penetrate from the high concentration end to the low concentration end.

Yes, water permeates from low to high concentrations.

1.Principal permeability coefficient.

The direction of the strongest and weakest permeability is often referred to as the main direction of infiltration. When it is a two-dimensional flow, KXX is often used to represent the permeability coefficient of the direction with the strongest permeability, and kyy is used to represent the permeability coefficient of the direction with the weakest permeability. KXX and KYY are also known as the main permeability coefficients.

Let the ox of the {o-x,y} coordinate system be consistent with the direction of kxx, which can be obtained by equation (1-20).

Groundwater dynamics.

Groundwater dynamics.

This formula is the homogeneous anisotropic two-dimensional flow seepage formula. Because kxx is not equal to kyy, even if.

The penetration velocity will also be the same along the cardinal direction, i.e., v x ≠ v y.

v′=-kgradh （1-31）

where: k is the permeability coefficient tensor, head gradient.

And groundwater dynamics.

Eq. (1-31) is also a differential form of Darcy's law.

Figure 1-11 Schematic diagram of seepage velocity addition.

Figure 1-12 Geometric diagram of the permeability coefficient.

2.Directional permeability coefficient.

Starting from Eq. (1-31), it can be proved that the permeability coefficient k in the direction satisfies the relation.

Groundwater dynamics.

If you take the point p on v, its vector diameter r can be written as x=r cos and y=r sin, substitute it into the above equation and multiply it at both ends of the equation.

groundwater dynamics.

If r is numerically equal.

Eq. (1-33) can be rewritten as:

Groundwater dynamics.

This equation is a standard elliptic equation, and the denominator is the length and short radius of the ellipse, as shown in Figure 1-12.

Equation (1-34) is the distribution of permeability coefficients at any point in a homogeneous anisotropic medium, and Figure 1-12 is the geometric solution. If kxx and kyy are known, then the permeability coefficient k along the direction can be divided into equations (1-32) and taken from the reciprocal to obtain:

Groundwater dynamics.

where: k is the permeability coefficient in the direction; kxx is the permeability coefficient in the direction of the strongest permeability; kyy is the permeability coefficient in the direction where the permeability is weakest.

The above discussion can be directly generalized to the seepage situation when the groundwater movement is three-dimensional.

The main factors affecting the permeability of sandy soil are the particle size, shape, gradation and density of the permeable fluid and soil. The main influence of permeating fluids is viscosity, which in turn is affected by temperature.

The higher the temperature, the lower the viscosity and the greater the seepage velocity. The effect of soil particles is that the finer the particles, the lower the permeability; Well-graded soils reduce pore size due to fine particles filling the pores of large particles, thereby reducing permeability. As the density of the soil increases, the pores decrease, and the permeability decreases.

The main factors influencing the permeability of cohesive soils are the mineral composition, shape and structure (pore size and distribution) of the particles, as well as the interaction of the soil-water-electrolyte system. The shape of the clay particles is flattened and has a directional arrangement, so the permeability has a significant anisotropic property. The capillary model of permeability shows that the permeable flow rate is proportional to the square of the pore diameter, while the unit flow rate is proportional to the fourth power of the pore diameter.

The permeability of the structure with the same porosity and large voids between the particles accounts for a high proportion is much greater than that of the structure with uniform pore size, and the microstructure and macrostructure of the cohesive soil have a great influence on the permeability, so the measurement results in the real hazard room can not reflect the actual soil situation. The permeability of layered clays in the horizontal direction tends to be much greater than in the vertical direction; In loess and loess-like soil, due to the development of vertical macropores, the permeability in the vertical direction is greater than that in the horizontal direction. Due to the presence of a fracture network, the permeability coefficient of fractured clay is close to that of coarse sand and has strict directionality. When studying the permeability of the actual soil, it is necessary to pay attention to its special laws.

Soil permeability (permeability

ofsoils) the ability of water to permeate and flow in the pores of soil. The permeability index of soil is the permeability coefficient. The water in the soil flows under the influence of water level difference and stress, and the seepage of sand basically obeys Darcy's law.

Because of the viscous resistance of cohesive soil, only when the hydraulic gradient increases to the initial hydraulic gradient and overcomes the viscous resistance of bound water, water can infiltrate and flow in the soil, and the seepage of cohesive soil does not conform to Darcy's law.

Reverse osmosis membrane is used for water treatment, such as seawater desalination, it is used to remove dissolved salts, colloids, microorganisms, organic matter, etc. in water. Theoretically, the reverse osmosis membrane should be able to intercept diesel molecules, but the general reverse osmosis membrane will not be used in the organic solvent system, and the current reverse osmosis membrane is still limited in its resistance to organic solvents.

Molecular sieve membranes can be divided into hydrophilic and hydrophobic (only hydrophilic molecular sieve membranes are taken as an example below). Different from the reverse osmosis membrane, the permeable water component of the molecular sieve membrane must be vaporized, and the osmotic driving force is the pressure difference between the steam transporters of the water components on both sides of the membrane, which is related to temperature, and is mostly used for the dehydration of organic side solvents containing less water components; However, there is no phase change in the infiltration process of reverse osmosis membrane, and the water components are directly permeable under the pressure drive, which is related to the operating pressure and carrying force, and is mostly used for water treatment or brine desalination. For example, Wahaha's water is made by secondary reverse osmosis, which is considered very pure water.

As for the direction of choice that LZ said, I have not heard of this concept, anyway, it is water driven by pressure or vapor pressure through the membrane. Knowing the principles of these two membranes is not a problem.

Reverse osmosis water purifier is a set of water purification system, which is mainly composed of a filter and a reverse osmosis device, as well as a dosing and disinfection device. The filter is mainly pretreated to ensure the quality of the inlet water of reverse osmosis and avoid the occurrence of blockage and scaling of reverse osmosis.

Composition of reverse osmosis:

The filter material in the filter is generally anthracite, manganese sand, quartz sand, activated carbon, etc., and different filter materials are selected according to different water quality.

Membrane elements for reverse osmosis. There are Dow membranes, Hyde membranes, GE membranes and so on.

Reverse osmosis water purifier is also the more mainstream pure water purifier now, reverse osmosis means reverse osmosis filtration through RO membrane, likeClear mountain spring water purifierThe pore size of the RO membrane is so small that even viruses cannot pass through, and the filtration effect is very good.

1. Originally, the low-concentration liquid should flow to the high-concentration liquid, but the high-concentration liquid can penetrate into the low-concentration liquid through high pressure, and the reverse osmosis of the water purifier is this principle;

2. Squeeze the dirty water through several layers of filtration membrane, so that clean and fine water molecules pass through, and the outflow is pure water, this technology is called reverse osmosis technology, and the water purifier in the water purifier operates through reverse osmosis.

Reverse osmosis water purifier is a device that integrates microfiltration, adsorption, ultrafiltration, reverse osmosis, ultraviolet sterilization, ultra-purification and other technologies to directly convert tap water into ultrapure water.

Reverse osmosis (RO) membrane, the core element of the reverse osmosis water purifier group, the pure water produced by the reverse osmosis pure water machine is fresher, more hygienic and safer than the bottled water, it has a wide range of uses, and the film that is selective to the permeable substance becomes a semi-permeable membrane, and the film that can only permeate solvents and cannot permeate solutes is generally regarded as an ideal semi-reverse osmosis water purifier membrane.

The key component of the reverse osmosis water purifier is the RO membrane filter element, that is, the water is passed through a layer of extremely fine reverse osmosis membrane reaching very small microns through pressure, which can only pass through water molecules and a small amount of minerals, so the filtered out is pure water.

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There are many more examples.

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Big data refers to a collection of data whose content cannot be captured, managed, and processed with conventional software tools in a certain period of time. Big data technology refers to the ability to quickly obtain valuable information from a wide variety of types of data.

"Big data.

bai"It is a number dao with a particularly large volume and a particularly large data category

data collection, and such datasets cannot be captured, managed, and processed with traditional database tools. Data comes from a variety of data sources, and the types and formats of data are becoming more and more diverse, breaking through the previously limited category of structured data to include semi-structured and unstructured data.

5V Characteristics: