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The average size of dust particles is 20 microns. The most harmful dust particles are from 2 to 8 microns in size. Once in the upper respiratory tract (the protective properties of which, although very great), dust particles, settling on the tissues of the lungs, contribute to various diseases. Therefore, dust control is given Special attention In particular, special dust removal ventilation is installed and material processing with humidification is introduced.  

The size of dust particles is of great hygienic importance, since the smaller the dust, the deeper it penetrates into the respiratory system. If relatively large dust particles, when inhaled, are retained to a greater extent in the upper respiratory tract and are gradually removed from there with mucus (expectorated), then fine dust, as a rule, passes into the lungs and settles there on long term, causing damage to lung tissue. In addition, fine dust with the same mass has a larger surface of contact with the lung tissue, so it is more active. Highly dispersed dust poses a greater danger than coarse (finely dispersed) dust, since it remains suspended in the air longer.  

The size of the dust particles is very different and varies depending on the quality of the pyrite and the burning method. But even under the same conditions, dust particles ranging in size from 1 to 30/i are carried away. With flotation pyrite the dust is even finer.  

The size of dust particles determines their ability to penetrate more or less deeply into the respiratory tract and linger there. This is important from both preventive and therapeutic points of view. Particles larger than 10 microns are deposited in the respiratory tract and practically do not reach the alveoli of the lungs.  

The average size of dust grains can be taken as 20 microns; there are dust grains measuring 0-1 microns and even smaller. Dust contains organic substances, including mold spores.  

Knowing the size of dust particles that should be deposited in the dust chamber ( smallest size, which is given in the task), using the nomogram, find the deposition rate of dust particles, then introduce a correction for viscosity.  

Reducing the size of dust particles leads to an increase in the relative reaction surface of the fuel, which ensures certain area jets, greater heat absorption, intensifying the heating and ignition of the dust-air mixture. Volatile fuels released during heating, having more low temperature ignitions than the coke residue ignite earlier than it and contribute to the acceleration of the ignition of dust.  

Due to the small size of the dust particle and its rapid heating, an intensive release of volatiles occurs already during the combustion process (see chapter. At first, volatiles, together with carbon monoxide, partially block the access of oxygen to the surface of the particle and inhibit its combustion. But this period, coinciding with the release of volatiles, ends very quickly, within a short period of time compared to the total time the particle burns out.  

As the size of dust particles decreases, their deposition is increasingly influenced by the adhesion force that arises between the dust grain and the droplet upon their collision.  

According to the above, for each size of dust particle, other things being equal, there is a single trajectory. If for this trajectory rmin rvykh, then the speck of dust gets into the fine product, if rmin rvykh - only into the coarse product. Thus, for any values ​​of the determining factors and the presence of a stable equilibrium, ideal separation should take place. However, in practice, even at negligible dust concentrations, when the influence of particles on each other and on the flow can be neglected, ideal separation is practically unattainable. At the same time, there are other, organic reasons for the decrease in efficiency, which are discussed below.  

Calcium carbide, granulated from the size of dust particles to pieces measuring 60 mm, is fed by a plate conveyor / onto a vibrating sieve, where the granulation fraction below 4 mm is screened out. If the carbide grinding is not uniform, the coarse fraction is sent for re-grinding. The carbide crushed in mills is fed by a conveyor to the generator department; a fine fraction of carbide, sifted out on a vibrating sieve, is also supplied here.  

Depending on their size, dust particles have different properties. Larger particles larger than 10 [ l ([ l-mic-ren) gradually settle out of the air under the influence of gravity, forming the so-called temporary air pollution.  

To determine the diameter of a speck of dust, you must first determine what dust is in general. Small solid particles of organic or mineral origin are called dust.

1050; Dust includes very, very small particles from fractions of a micron to huge particles up to 0.1 mm in size. And the particles bigger size already referred to as sand. And under the influence of moisture, all the dust turns into dirt, which is already visible to everyone.

What is the diameter of a speck of dust?

Dust grains are tiny particles that are lighter than air. Everyone has noticed how in the sun there is a lot of dust in the air in the room. But it is almost impossible to see them, only with the help of special magnifying devices. And the size of a speck of dust varies from 0.01 to 0.1 millimeters.




A speck of dust is a tiny, almost invisible particle of matter. The diameter of the dust particle is approximately 0.005 m (+/-). The maximum size of a speck of dust is determined by 0.1 mm. But particles larger than 0.1 mm are called sand, not dust.

The diameter of a speck of dust seems to be 0.0001 m……………..

Here are the sizes of some dust particles. Dimensions are given in micrometers:

• dust 1-10000;
• coal dust 1-100;
• cement dust 3-100;
• insecticidal dust 0.4-10;
• atmospheric dust 0.001-20.

And this astronomical quote: So when we build our model of the Sun and our nearest star, we have two specks of dust, each 1/100 of an inch in diameter, four and a half miles apart.

To determine the diameter of a speck of dust, you must first determine what dust is in general. Small solid particles of organic or mineral origin are called dust. Dust includes very, very small particles from fractions of a micron to huge particles up to 0.1 mm in size. And even larger particles are classified as sand. And under the influence of moisture, all the dust turns into dirt, which is already visible to everyone.




Dust particles larger than 200 microns do not experience significant air resistance and settle quickly enough. Particles less than 200 microns to 0.1 microns already experience air resistance, their settling speed varies depending on the size of the dust particles. If the particle size is less than 0.1 microns, then they are in chaotic movement in the air and almost do not settle.

A speck of dust is considered to be a particle of matter approximately 0.005 mm in size, or a little more or a little less. The maximum size of a speck of dust is determined to be 0.1 mm (tenth of a millimeter). Anything more is already considered sand.

A speck of dust is a tiny, almost invisible particle of some substance. Most often, we can only see fine dust in the rays sunlight. The sizes of dust particles range from 0.1 mm or less, to micron sizes.

speck of dust has a certain diameter.

Those who have conducted such studies claim that the diameter of the dust particle is from 0.01 to 0.1 mm. It all depends on what substance, mineral this dust is from.

There is a table on the Internet that shows dust particle diameter:

Dust particles vary in size. For example, dust particles with a diameter of 1 to 7 - 8 microns, when inhaled, reach the lungs and are exhaled into small quantity, which causes pneumonicosis. Dust grains with a diameter of up to 15 to 100 microns are considered medium, and over 100 microns are considered large.




Dust are called particles that do not exceed 0.1 millimeters in size. But this maximum size, a speck of dust can have a diameter of less than a micrometer (1 micrometer = 0.001 millimeters).

Particles larger than 0.1 mm are no longer called dust, but sand.

Even dust can be different, in rooms we see one kind of dust, on the streets - another, and in factories and enterprises - a third. This is just the basics. It is generally accepted that the diameter of dust is 1 micrometer, that is, one to the minus sixth power of a meter. And it is impossible to see such dimensions with the human eye.

LogoInformation portalInterfaceMain sectionsSearch for information resourcesFederal portal "Russian education"Widely represented news feed, there is a search on the portal, sections of the portal are widely represented; Catalog of educational Internet resources, State educational standards, Institutions, technical schools, universities, Educational CDs, DVDs To search for resources, you need to go to the section “Catalogue”, “Levels of Education”, “Professional”, “Secondary”, select the desired material. Russian educational portal Present: News feed, Search by section, Collections. Preschool education, Primary and general education, Catalog, Education in the regions. To search for resources, you need to go to the “Catalogue” section, “Preschool education”, and select the material you are interested in. A unified collection of digital educational resources. Present: News feed, Electronic publications, Regional collections. TsOR sets for textbooks , Thematic collections, Teaching materials To search for resources you need to go to the section: “Catalogue”, “Level of education”, and the subject you are looking for Analog-to-digital conversion audio signals: Lecture notes Author/creator: Vologdin E.I. Year: 2012 Tutorial in audio engineering for universities. Methods for analog-to-digital conversion of audio signals based on linear pulse code modulation (PCM), sigma-delta modulation, differential PCM, delta modulation, adaptive differential PCM, PCM with non-uniform quantization step, such as instant companding, almost instantaneous companding and PCM are considered. floating point. The basic theory and scope of application are outlined. Much attention is paid to the analysis of quantization errors, their spectrum and sound. Analog-to-digital conversion of audio signals 2012.pdf QuestionAnswer1) indicate the time of approval of the Gregorian calendar, October 4, 15822) what is the diameter of a speck of dust 0.001 m3) indicate the lethal sound level of 200 db4) what is the boiling point of iron 2862 ⁰C5) what is the melting point of iodine 113.5 ⁰C6) indicate the speed Earth's revolution around the Sun≈ 30 km/s7) what is the mass of the Earth5.9736 ▪ 10^24 kg8) what mountain in Australia is the highestMount Kosciuszko (2228 m)9) describe the Campa peopleCampa - one of the peoples of Peru, living in the river basins " Ucayali", "Apurimac", "Pacitea". Traditional social organization- a community of several related families. Marriage is patrilocal, kinship is bilateral. They profess Catholicism and speak Campa. Activities: Manual slashing - fire farming, hunting and fishing.10) indicate the years of the reign of Ivan III1462 - 1505.11) indicate the years of the reign of Catherine II1762 - 1796.12) indicate the years of the reign of Ivan IV1547 - 1574, 1576 - 1584.13) indicate the years of the reign of N.S. Khrushchev. 1953 - 1964.14) in what year was the first wooden bicycle invented? 1817

Getting rid of dust is the dream of every housewife. But as soon as you tidy up the house a little, harmful specks of dust again settle on all surfaces.

For many people, dust is not only unsightly, but also dangerous, since it is a source of allergic reactions.

To lead effective fight with dust formation, you need to, as they say, “know the enemy by sight”, and then develop a killer strategy against him.

Wikipedia gives the following answer to this question: these are solid particles, and the diameter of a dust particle is less than a tenth of a millimeter.

Its sources are plants, rocks and, according to Wikipedia, space. Pets also contribute to dust formation. About a third of the dust particles are nothing more than tiny particles of the skin's epidermis and fur.

Renewal of the skin of people and animals occurs gradually. According to statistics, each person produces about 0.5 kg during the year. such small particles. In general, the composition of dust is quite complex.

The reason for the danger can be understood by examining a speck of dust under a microscope. It turns out that dust particles provide a favorable environment for the proliferation of harmful microorganisms. This is not only dust mites, but also mold fungi.

It is mold and mite waste products that cause allergies. In addition, excessive dust can also cause intoxication, since house dust also contains toxic substances.

How to reduce dust formation in the house

Dust not only spoils the interior and damages the reputation of the owner, but also poses a health hazard.

Especially for children, since it has been established that the highest concentration of particles is located at a distance of 70-150 cm from the floor. How to get rid of dust in an apartment for a long time?

Here are tips to help reduce dust formation in your room.

How to get your apartment in perfect order

The “dust collectors” are more or less dealt with. Now we make the apartment perfectly clean and take measures to get rid of dust in the house.

So, how to properly wipe dust from furniture and surfaces?

The procedure is approximately this.

1. Put clothes in closets and shoes in closed drawers. If you are a lover of interior decor, place it in a glass display case.
2. Vacuum upholstered furniture thoroughly. It is advisable to treat soft toys, furniture and bedding with a steam generator. It kills dust mites and disinfects objects.
3. The steamer is convenient for treating curtains. They will look fresher because the steam kills microorganisms. If you have a lot of windows in your apartment or house, you should purchase a powerful floor-mounted steamer with a large water tank.
4. Spray your house plants regularly with a spray bottle. It is advisable to wipe the dust from the leaves with a piece of soft cloth.
5. Brush your pets periodically. By the way, if you are allergic to pets, consider placing the animal in good hands. The “hypoallergenicity” of hairless breeds of cats, dogs and guinea pigs is a myth. Allergies can also be caused by small particles of the epidermis.
6. For cleaning floor coverings, furniture and floor cleaning, purchase a vacuum cleaner with an aqua filter. After wet cleaning With such a vacuum cleaner, the air becomes noticeably cleaner. Collecting dust in a “classic” dust collector does not solve the problem. It has been established that almost 30% of the dust from the old “Rocket” or “Typhoon” returns back to the room. Don’t be surprised that after cleaning with an old vacuum cleaner, dust appears again.
7. To clean dust in hard-to-reach places, use special attachments for a vacuum cleaner.
8. During cleaning, set all windows to ventilation mode. To avoid dust from the street, use mosquito nets and cover them with moistened gauze.
9. Wipe the dust in the room not only from the surfaces, but also from the ceiling. A piece of clean, dampened cloth placed over a clean mop will help. Don't forget about the walls.
10. Make sure there are no cobwebs in the corners. It is an excellent dust collector.
11. When cleaning floors, don't forget about baseboards. Dust particles settle on them very intensively.

Household chemicals and appliances - to help

Various aids can help you get rid of household dust.

1. Humidifiers. With their help, the struggle for cleanliness is much simpler, since, after moistening, the dust particles settle and are more noticeable. It is enough to rub the surfaces with a microfiber cloth so that they are completely free of dust.
2. Hygrometers. These are devices with which you can control the level of humidity in a room. Excessive dampness encourages mold, and dry air keeps particulate matter suspended.
3. Modern window design. The micro-ventilation function helps prevent dust from entering the room.
4. A good remedy for dust is an “air washing” device. This device passes air through itself, while filters trap dust. This device is especially helpful in a room after renovation or in a new building.
5. Polishes with antistatic effect. Of course, they do not reduce the dustiness of the room, but the surfaces remain clean, since dust does not sit on them for a long time. Such products are not recommended for use in rooms where allergy sufferers live. Dust in suspension can trigger an allergy attack.
6. To prevent dust from settling on furniture longer, use a special “dust spray” made by yourself. Mix a glass of water, 0.25 cups of grape vinegar and 2 tablespoons of olive oil. If you spray the mixture with a spray bottle and wipe with a piece of microfiber, dust will not appear on the surface for longer.

Cleaning the car

A conscientious car owner tries to keep the car clean, but the speed with which dust can appear in the cabin can shock anyone.

How to remove dust and dirt from inside a car and what to wipe surfaces with?

Simple rules for cleaning the interior of the “iron horse” will help maintain perfect cleanliness in the cabin.

1. Do not neglect timely replacement of the cabin filter. The cost of this procedure is low, and the dust content of the air is reduced.
2. Clean the ashtray, wipe with a damp cloth and wipe dry. It's no secret that the ashtray is the main source of dirt in the car. If you remember about it last, you will have to do all the cleaning activities all over again.
3. Remove the rubber mats from the car, rinse thoroughly and dry.
4. Clean the car floor from dirt.
5. Thoroughly vacuum carpets, seats and all interior surfaces. To get rid of dust in hard-to-reach places and crevices, use a regular soft paint brush.
6. Now it's time for wet cleaning. Wash the floor and sides of the machine, wipe off dust with a damp cloth on the front panel and plastic parts.

After cleaning the interior is completed, you can begin washing the external surfaces of the car.

Now your car will shine like new!