The problem of environmental pollution is too complicated and multifaceted to try to learn it quickly.

In funds mass media Noise usually pays little attention, and many do not consider it an atmosphere polluter. But actually it is not? Until now, a huge part of people does not recognize the danger of noise pollution. This is due to the fact that the problems of the noise pollution of the urban environment were at the scientific level relatively recently and became sharply in recent decades. The solutions are chosen by us not by chance. Currently, health problem is very acute, the rapid pace of life leads not only to the growth of cities, urban agglomerations and megalopolises, industry, but also in connection with the following, to the deterioration of ecology, violation of the geographical habitat of a person, and, as a rule, worsens health population

Explore the noise as one of the environmental pollutants;

Reveal the effect of noise on the human body;

Identify human protection measures from noise impact

1. Types of noise and their impact on human feelings.

What is noise? Based on previously gained knowledge from the course of physics, students can give

Noise - a random mixture of sounds of different heights (frequency). Unit of measurement 1 dB \u003d 10 lg.

A man always lived in the world of sounds and noise. Sound is called such mechanical oscillations of the external environment, which are perceived by the human hearing aid (from 16 to 20,000 oscillations per second). The fluctuations of the greater frequency are called ultrasound, smaller - infrasound. Noise - Loud Sounds, Sleeping into Non-Strong Sound.

The noise level is measured in units expressing the degree of sound pressure, - decibels. This pressure is not perceived irrelevant. Noise level in 20-30 decibels (DB) is almost harmless to humans, this is a natural noise background. As for loud sounds, then the permissible border is approximately 80 decibels. The sound in 130 decibels already causes a pain of a painful sensation, and 150 becomes intolerable for him.

For all living organisms, including a person, the sound is one of the environmental impacts.

In nature, the loud sounds are rare, the noise is relatively weak and short. The combination of sound stimuli gives time to animals and a person necessary to assess their nature and the formation of a response. The sounds and noises of high power are striking the auditory apparatus, nervous centers, can cause pain and shock. So there is noise pollution.

Very high level of industrial noise. In many works and noisy production, it reaches 90-100 decibels and more. Not much quieter and we have at home where all new sources of noise appear - the so-called household appliances.

Thus, two types of noise are distinguished:

1. Noise natural origin.

2. Noise of anthropogenic origin.

2. Changes in the hearing apparatus under the influence of loud sounds

What body reacts to excessive noise primarily? Of course this is an hearing body.

Quiet rustling of foliage, murmur stream, bird voices, light water splash and surf's noise are always pleasant to man. They calm him, remove stress. It is used in medicinal institutions in psychological unloading offices. But the natural sounds of the votes of nature are becoming increasingly rare, disappear completely or drown out with industrial, transport and other noises.

Long-term noise adversely affects the hearing body, lowering the sensitivity to the sound. It leads to a disorder of heart activities, liver, to depletion and overvoltage nerve cells. Weak cells of the nervous system cannot clearly coordinate the work of various organism systems. From here there are violations of their activities.

For a long time, the effect of noise on the human body was not specifically studied, although already in ancient times they knew about his dangers.

Currently, scientists in many countries of the world lead various studies in order to determine the effect of noise on human health. Their studies have shown that the noise causes tangible harm to human health, but also the absolute silence scares and oppresses it. Also, scientists have established that the sounds of a certain force stimulate the process of thinking, especially the account process.

Each person perceives the noise in different ways. Much depends on age, temperament, health status, surrounding conditions.

Some people lose their hearing even after a short effect of noise of relatively small intensity.

The constant impact of strong noise can not only adversely affect the rumor, but also cause other harmful effects - ringing in the ears, dizziness, headache, increase fatigue.

The noise has a accumulative effect, that is, acoustic irritation, accumulating in the body, the nervous system is increasing more and more. Therefore, a functional disorder of the central nervous system occurs before the hearing loss of the effects of noise. Especially harmful effects have noise on the nervous psychological activity of the body.

The noise is cunning, its harmful effects on the body is committed invisibly, imperceptibly. Violations in the body are not found immediately. In addition, the human body against noise is almost defenseless.

Table. Sound volume levels from different sources

Sound Sound Level (dB)

Calm breathing is not perceived

Rust of leaves in calm weather 17

Shipping newspapers 20.

Normal noise in the house 40

Surf on the shore 40

Middle Volume Talk 50

Loud conversation 70.

Working vacuum cleaner 80

Train in the metro 80

Rock Music Concert 100

Rasse thunder 110.

Jet engine 110.

Shot of gun 120

Pain threshold 120.

Practical part

1. Determination of hearing acuity at students

Hearing is the minimum sound volume, which can be perceived by the tested ear.

In order to determine the severity of rumors from students, we took the mechanical clock and ruler.

Equipment:

Running mechanical clock

Operating procedure:

1. Close the clock until you hear the sound. Measure the distance from the ear to hours at centimeters.

2. Attach the clock tightly to the ear and assigned from yourself until the sound disappears. Again determine the distance to the clock

3. If the data coincides, it will be approximately the right distance.

4. If the data does not coincide, then to estimate the distance of hearingness, you need to take the arithmetic average of two dimensions.

The experiment participated (50 students) of them:

1. Lovers listen to loud music in headphones;

2. Calm music;

3. Fans of silence

Assessment of test results:

1. Lovers listen to loud music in headphones - 8-9 cm;

2. Calm music-12-13cm;

3. Lovers of silence-15-16 cm.

■ With a constant stretching of the eardrum, its elasticity decreases, so it takes a high sound volume so that it starts to fluctuate, that is, the sensitivity of the auditory analyzer is reduced;

■ Hearing receptors are damaged.

Sociological survey on the detection of noise on the mental processes of students of 8th grades

How does noise affect you?

■ Fast fatigue;

■ Weakening of memory;

■ decline in attention;

■ loss of working capacity;

■ sleep disorder;

■ Total weakness

The effect of noise on teachers

(20 people)

How does noise affect you?

■ annoyance;

■ decrease in functional activities;

■ Difficulties in the family;

■ loss of working capacity;

■ Increased irritability;

■ Loss of sleep;

Conclusions: long-acting noise leads to rapid fatigue, weakening of memory, reduce attention, loss of working capacity, increased irritability, sleep impairment, general weakness. The effect of noise may gradually lead to mental illness.

The effect of noise leading to mental illness

Noise action

Difficulties of mutual understanding

Disuse of attention

Weak focus

Loss of sleep

Irritability

Reduced functional activity

Discontent

Difficulties in the family

Mental diseases

Conclusion

Man's protection measures from noise exposure.

So noise is harmful. "Noise is a slow killer," American experts say so. But is it possible to reduce its impact on living organisms, including a person? What can each of us do?

Like all other species of anthropogenic effects, the problem of pollution of the medium noise has international Character. World Organization Health care, given the global nature of noise pollution, has developed a long-term program to reduce noise in cities and settlements World.

In Russia, protection against noise impact is regulated by law Russian Federation "On Environmental Protection" (2002) (Art. 55), as well as government rulings on noise reduction measures industrial enterprises, in cities and other settlements.

Protection against noise impact - a very difficult problem and to solve it requires a set of measures: legislative, technical and technological, urban planning, architecturally - planning, organizational, and others. To protect the population from the harmful effects of noise regulatory and legislative acts, its intensity is regulated, the time of action and Other parameters. Gosstandart has established unified sanitary and hygienic standards and rules for the limitation of noise at enterprises, cities and other settlements. The norms are based on such levels of noise effects, the action of which for a long time does not cause adverse changes in the human body, namely: 40 dB during the day and 30 - at night. Permissible levels of transport noise are installed within 84-92 dB and will eventually decrease with time.

Technical and technological measures are reduced to noiseing, under which integrated technical measures to reduce noise in production (installation of soundproofing housings of machines, sound absorption, etc.), in transport (emission silencers, replacing the boopred brakes to disc, noise absorbing asphalt, etc.).

At the urban planning level, protection against noise impact can be achieved by the following events:

Zoning with the removal of noise sources beyond the development of the development;

The organization of a transport network that excludes the passage of noisy highways through residential areas;

Removal of noise sources and device for protective zones around and along the sources of noise impact and the organization of green plantings;

Laying triggers in tunnels, a device of shu-regular embankments and other absorbing noise obstacles to noise distribution paths (screens, recesses, bodies);

Architectural and planning measures provide for the creation of noise protection buildings, i.e. such buildings that provide the premises of a normal acoustic regime with the help of constructive, engineering and other measures (sealed windows, double doors with a tambour, cladding of walls with sound-absorbing materials, etc.).

A certain contribution to the protection of the medium from noise infrared is the prohibition of vehicle sound signals, Viapetov over the city, restriction (or prohibition) of take-off and landing aircraft at night and other organizational measures.

However, these measures are unlikely to give a proper environmental effect, if the main thing is not understood: protection against noise exposure - the problem is not only technical, but also social. It is necessary to raise the sound culture and consciously prevent actions that would contribute to increasing the noise pollution of the medium.

Noise as an environmental factor.

Tasks:

1. General Education

• Gain environmental orientation biological knowledge; Message of students with information about the noise pollution of the environment and its impact on a person.
• Acquisition of students in knowledge of an ethical, humanitarian nature, which make up the basis of the worldview.
• Teaching students to independent acquisition of knowledge in the group form of cognitive activity.
• Mastering the foundations of the methodology of scientific knowledge.

2. Developing

• Development of cognitive interest.
• The development of logical thinking (analysis, comparison, generalization, definition and explanation of concepts).
• Different identity development: memory training, observation, incentive of cognitive interest, creative abilities, skills analysis of problems and ways to solve them.
• Development of skills on the use of biological knowledge in practice.

3. Educational tasks

• Education of environmental literacy, feelings of collectivism, formation and development of the moral qualities of schoolchildren.

Teaching methods

• Partial search (performing independent research, business game).
• Sensual (heuristic conversation with elements of independent work).
• Vite-shaped (tables, illustrations, listening to noise entries, passages from literary works).
• Test.

Forms of cognitive activity: Individual and group.

Equipment: audio magnetophone, audio cassette with the record of the work of E.Grieng "Morning", with noises of natural and anthropogenic origin; Information sheets for individual work students; Tables, posters and drawings on the subject of the lesson; Mechanical clock and ruler.
In advance, two students are given a task to conduct a survey of students of 8-9 grades to determine their attitude towards natural noise with the question: "What feelings do you have noises of natural origin?". Before the start of the lesson, the guys are divided into 4 groups; On the table, each student is an information sheet, mechanical clock and a ruler.

Structure occupation

1. The introductory word of the teacher.

Sound music sounds. The teacher reads passages from the Earth poems - the planet of animals, paintings and people, the planet, an integral part and the main enemy of which is a person.

We are small children with one big nature,
We divide good luck and adversity with her,
One fate with us and her.

My Planet is a human house,
But how to live under the smoky cap,
Where is the wastewalk - the ocean,
Where is the whole nature caught in drone?
Where there is neither Aista, nor Lero.
Where the grass moan: "I can't!"

(Conversation with students about the relevance of environmental protection.)

What are we talking about in these passages?

The problem of environmental pollution is too complicated and multifaceted to try to learn it in the lesson. Therefore, we will limit it to her small part and get acquainted with one of the types of environmental pollutants. But with what, try to determine by listening to the passage from the story B.Vasiliev "Do not shoot in the White Swans." (Listening to the joke on the background of the music of E.Grega. Replies of students.)

In the media, nois is usually given little attention, and many do not consider it an atmosphere polluter. But is it true? We will find out in today's lesson. (Summary of the tasks of the lesson, the teacher highlights the corresponding transparencies.)

1. Examine the noise as one of the pollutants of the environment.
2. Reveal the effect of noise on the human body.
3. To establish a link between environmental protection and health.

Let our motto today will be the words of the writer B.Vasiliev: "I need to figure it outself, but to understand myself, it is necessary to think together."

(The motto is written on the board. The teacher explains the rules for working with the information sheet. The information sheet is inserted into workbook, Him students write theme of the lesson, the basic concepts of the theme, fill the table, write tasks).

2. Studying a new material.

Types of noise and their impact on man feelings

During the conversation, the concept of noise as a random mix of sounds of different heights (frequencies) is specified in the course of the knowledge of the physics, the concept of noise (natural and anthropogenic) is specified. When listening to noise and during the front conversation, the impact of noise on the human body (on mental processes) is revealed.

In the course of the work, the columns of the working page table of the information sheet are filled.

Information sheet

The subject of classes.

New term: ___________________________

The field of ecology at the junction of bioacastics and human ecology, which is engaged in natural and technogenic sounds, affecting the psyche and human health, as well as the state and stability of ecosystems.

The teacher summarizes the data obtained and summarizes the conclusion about a favorable, in general, the effect of natural noise to the human body.

What do you think from what sounds there is a noise background in a modern city?

(Audio recording of urban noise). There is a discussion of the following issues:

- Did this noise symphony like you;
- How do you explain your attitude to these noise;
- What noises in the record more and why?

The teacher brings the class to the conclusion that noises act in different ways to humans: their action depends on the origin of noise, the volume, age and the state of human health, the surrounding conditions.

The noise volume depends on the source and is measured in relative units - decibels: 1 dB \u003d 10 LG (P1 / P2), where the ratio of the decimal logarithm is worth the ratio of noise acoustic capacities. The noise can have a volume of 0 dB (the most quiet audible sound) to more than 160 dB. Sounds volume more than 120 dB, i.e. One trillion times more loud than the quietest of hearing sounds, cause pain. Sound perception also depends on the height of the tone. The greatest harness Hearing authorities cause (and cause the greatest stress) loud sounds of high frequency. The table shows typical or maximum noise volumes from different sources.

(With the help posted on the board table, students respond to the following questions).

- Why a whisper and turning of newspapers harmless to humans;
- How would you estimate the level of noise during the school day (lessons and change) in terms of impact on the body;
- What conclusions can be done based on the table data?

Table. Sound volume levels from different sources

Changes in the auditory apparatus under the influence of loud sounds

I suggest you answer the question: "What an organ reacts to excessive noise first?"

According to statistics today, 20 out of 150 million. Russians suffer from hearing loss. A group of scientists examined young people who often listen to loud modern music. In 20% of boys and girls who are exorbitantly fond of rock music, the rumor was reduced in the same way as 85-year-old old people.

(In groups, a test is carried out in the definition of hearing acuity - a task from the information sheet. The teacher pre-identifies as a result of a survey of lovers to listen to loud music in headphones, calm music, fans of silence, and they have a hearing acuity).

TEST

Determination of hearing sharpness

Acuity of hearing - This is the minimum volume of sound, which can be perceived by the ear of the test.

Equipment: mechanical clock, ruler.

Operating procedure

1. Close the clock until you hear the sound. Measure the distance from the ear to hours at centimeters.
2. Attach the clock tightly to the ear and assigned from yourself until the sound disappears. Again, determine the distance to the clock.
3. If the data coincides, it will be approximately the right distance.
4. If the data does not coincide, then to estimate the distance of hearingness, you need to take the arithmetic average of two dimensions.

Assessment of test results

There will be a normal hearing such in which the ticking of the handmade hours of the medium size is heard at a distance of 10-15 cm.

The numbers are recorded on the board, are analyzed, after which students answer the question: "What changes occur in the auditory apparatus under the influence of high-profile sounds?"

Using the "Hearing Analyzer" table, the guys talk about converting sound signals into electrical, indicate the changes occurring in the auditory apparatus during the long-term exposure of loud sounds:

- with constant stretching of the eardrum, its elasticity decreases, so it takes a high volume of sound so that it starts to fluctuate, i.e. The sensitivity of the auditory analyzer is reduced;

- Hearing receptors are damaged.

The effect of noise on the human body

But are hearing organs suffer from noise?

Students are invited to find out, familiarizing themselves with the following statements of prominent scientists about noise.

1. The noise becomes the cause of premature aging. Thirty cases of a hundred noise reduces the life expectancy of people in major cities for 8-12 years.

2. Each third woman and every fourth man suffer from neurosis caused by an increased level of noise.

3. A fairly strong noise after 1 min can cause changes in the electrical activity of the brain, which becomes similar to the electric activity of the brain in patients with epilepsy.

4. Such diseases such as gastritis, stomach and intestines ulcers are most often found in people living and working in a noisy setting. Pop Musicians ulcer stomach - professional disease.

5. Noise inhibits the nervous system, especially with a recurring action.

6. Under the influence of noise, a resistant reduction in frequency and depth of breathing occurs. Sometimes the arrhythmia of the heart, hypertension appear.

7. Under the influence of noise, the carbohydrate, fatty, protein, salt metabolism changes, which is manifested in changing the biochemical composition of blood (the blood sugar level is reduced).

Brief conclusion: from excessive noise (above 80 dB) not only hearing organs, but also other organs and systems (blood, digestive, nervous, etc.) are suffering, violated processes of life, energy exchange begins to prevail over plastic, which leads to premature aging organism.

Discussion of these sociological survey

Two students of your class conducted a study in the form of a sociological survey to identify a long-acting noise on the mental processes of students in ninth grades. I am giving a word.

The first student represents the survey data from which it follows that a long-acting noise leads to complaints of fast fatigue, memory weakening, decline in attention, loss of working capacity, increased irritability, sleep disorder, general weakness. The story is accompanied by a demonstration of a colorful circular chart, where all data are presented as a percentage.

According to the second student, the effect of noise can gradually lead to mental illness. As an illustration on the board, the "staircase", rolled into the harmonica, which during the story gradually unfolds.

Noise action

Difficulties of mutual understanding

Disuse of attention

Weak focus

DOSADE

Loss of sleep

IRRITABILITY

Reduced functional activity

Discontent

Difficulties in the family

QUARRELING

Mental diseases

Man's protection measures from noise impact

So noise is harmful. "Noise is a slow killer," American experts say so. But is it possible to reduce its impact on living organisms, including a person? What can each of us do?

Work in groups is the development of human protection projects from noise impact at different social levels.

• I group. I am a philistine (Multiple Memo).
• II group. I am the mayor of the city.
• III group. I am an architect.
• IV Group. I am the director of the large plant.

Groups draw up projects on Watman sheets, hang them on the board and protect.

3. Conclusion

We will not talk and think about the consequences of human activity for nature and yourself. I would like to hope that today's conversation did not pass for you without a trace. We almost did not affect the impact of noise on the environment, and this problem is as difficult and multifaceted, as well as the problem of the impact of noise per person discussed. Only protecting nature from the harmful effects of their activities, we will be able to preserve themselves.

Kohl is destined to breathe with the air in one,
Let's unite ever in an eyelid,
Let's keep our souls,
Then we are on earth and remain.

N.Starshinov

What conclusions did you do for yourself after today's conversation? (The answers of students are heard.)

4. Checking the assimilation of the new material by the method of self-analysis

In the lesson, we thought together, but everyone worked individually. And now you have to evaluate your activity in the lesson.

The teacher explains how to fill the student's self-esteem sheet, then includes audio recording of the sounds of nature, and students appreciate their work.

Self-assessment sheet of student

Noise as an environmental factor

Purpose of work: Acquaintance with the characteristics of the noise and the peculiarities of its impact on the human body, with the features of measurement and normalization of noise parameters, as well as with noise assessment methods in natural environmental conditions.

Theoretical part

1. Sound and its main characteristics

Any violation of the stationary state of a particular medium generates wave processes. Mechanical oscillations of the particles of the medium in the frequency range 20 - 20000 Hz Perceived by the ear of man and are called sound waves. Medium fluctuations with frequencies below 20 Hz called infrasound, and oscillations with frequencies above 20,000 Hz- ultrasound. Length of sound wave l. associated with frequency f. and sound speed with addiction: l. \u003d C / F . The non-stationary state of the medium during the propagation of the sound wave is characterized by sound pressure ( P. ), under which they understand the mean square value of the pressure deviation in the medium when the sound wave is propagated from the pressure in the unperturbed medium measured in Pascals ( PA). The power of the energy of the flat sound wave through the surface unit perpendicular to the direction of propagation of the sound wave, characterize the intensity of the sound (the density of the flow of sound power), W / m 2: , (1)

where P. - sound pressure, PA; r. - Specific medium density, g / m 3; c. – the speed of propagation of the sound wave in this environment, m / S.. The energy transfer rate is equal to the speed of propagation of the sound wave.

Human hearing organs are able to perceive sound oscillations in very wide ranges of changes in the intensities and sound pressures. For example, at a sound frequency in 1 kgz The averaged threshold of the sensitivity of the human ear (hearing threshold) corresponds to the sound pressure values \u200b\u200band the intensity of the sound: P 0 = 2∙10 -5 PA and I 0. = 10 -12 W / m 2and the threshold of the painful sensation (the excess of which can already lead to physical damage to the hearing organs) corresponds to the values P B. = 20 PA and I B. = 1 W / m 2. Values P 0 and I 0. In sound engineering, adopted as standard (reference) quantities. According to Weber-Fekhner's law, the annoying human ear action is proportional to the sound pressure logarithm, so in practice, instead of absolute intensity and sound pressure values, their relative logarithmic sound levels are used, expressed in decibels ( dB): ; , (2)

where I. 0 = 10 -12 W / m 2 and P. 0 = 2∙10 -5 PA - Standard threshold values \u200b\u200bof intensity and sound pressure. For real atmospheric conditions, we can assume that L I. = L P. = L. .

A real noise field is often determined not one, but several sources of noise. The most simple as an experimentally established rule of the addition of the intensities of the sound of several sources :. (3) The rule of addition of sound pressures created by several sources is easily derived from expressions (1), (3) and is of a quadratic character:

Using expressions (2) - (4), it is easy to obtain a rule of addition of relative logarithmic sound levels. According to the definition of relative logarithmic levels of sound i. -to source and the total sound level are defined as

where do we respectively:

. (5) It can be similar to the total sound level:. Expanding the expression (5) and (4) consistently here, we receive a rule of addition of relative logarithmic sound levels of several sources :. (6) In the case of n identical sound sources (Li \u003d L) of formula (6) simplified: L. å = L. + 10 lG ( n. ) . (7) From formulas (6) and (7) it follows that if the level of one of the sound sources exceeds the level of another by more than 10 dB, then the sound of a weaker source can practically be neglected, since its contribution to the overall level will be less than 0, 5 dB. Thus, when combating noise, first of all it is necessary to drown the most intensive sources of noise. In addition, it should be borne in mind that in the presence of several identical sources of noise, the elimination of one or two of them is very poorly affected by the overall reduction in the noise level. The noise source characteristic is the level of its sound power. Sound power W. , T.- This is the total amount of sound energy emitted by the source of noise per unit of time. . (8) If the energy is emitted in all directions evenly and attenuation of the sound in the air is not enough, then with intensity I. on distance r. From the noise source, its sound power can be determined by the formula: W \u003d 4. p. R2I . By analogy with the logarithmic levels of intensity and sound pressure, logarithmic levels of sound power were introduced ( dB): , (9)

where W. 0 = I. 0 s. 0 = 10 -12 - Standard sound power value, T.; s. 0 = 1 m 2..

The noise distribution in the sound frequency range is characterized by a frequency spectrum. In practical use, the noise spectrum shows the levels of sound pressure or intensity (for sound sources - sound power levels) in octave frequency bands characterized by lower f N. And top f B. boundary frequencies in the ratio f c / fn \u003d 2 and medium meterometric frequency: f SG \u003d (F H · F c) 0.5 . The medium-meter frequencies of adjacent octave bands correspond to the standard binary row, which includes 10 values: 31.5; 63; 125; 250; 500; 1000; 2000; 4000; 8000; 16000. Hz.

2. Features of subjective sound perception

The perception of sound by human ear is very strong and non-linearly depends on its frequency. The features of the subjective perception of sound are illustrated graphically using the curves of equal volume in Fig. 1. Each curve in fig. 1 characterizes sound pressure levels at different frequencies perceived by the ear of a person with the same level of volume ( L N. ).

Fig. 1. Curves equal volume

The relative logarithmic volume level is estimated by special units - background. To determine the volume of an arbitrary point N. In the drawing field in fig. 1 It follows through this point to carry out an equal volume curve (as shown by the dotted line in Fig. 1) and determine the sound pressure level ( L p * ) at which this curve crosses the frequency line in 1000 Hz. The resulting numerical value of the sound pressure level expressed in dBand will determine the numerical value of the volume level expressed in background, i.e.:. Aphysic device for measuring sound pressure levels (objective physical parameter) - " noiseomer"- technically implemented simply. To estimate the volume levels (subjectively perceived by a person parameter), it is necessary, as follows from the drawing in Fig. 1, so correct the measuring process in the noomer, so that when changing the sound pressure level in accordance with one of the curves of equal volume, its readings remained unchanged and equal to the level of sound pressure at 1000 Hz. That is, for an arbitrary curve of an equal volume (for example, shown by the dotted line in Fig. 1), it is necessary that the condition is carried out:. It is not possible to carry out the simple technical means to carry out the exact correction. Therefore, the practically implemented correction is carried out approximated. There are several variations of the noiseomer reading correction to evaluate the volume levels. The greatest distribution was the correction called the type correction BUT . Thus, corrected sound pressure levels obtained using a physical noiseomer (i.e. operating in mode with type correction BUT ) And the volume levels taken as estimates subjectively perceived by the person are determined in the form (10)

and are called sound levels measured in special units dBA.

From the above, you can draw the following conclusion: if any of the curves of equal volume for tonal sound to subjected to corrections BUT , as a result, we obtain the value of the constant level of sound (in dBA), approximately (accurate correction is practically not realized) the corresponding volume level ΔL N. This curve, expressed in volume measurement units ( background), i.e., you can count the levels of sound L A. approximate assessment of subjective noise perception in the form of volume levels L N. : .

3. The effect of noise on the human body

Noise it is considered any sound, adversely acting on the human body. Depending on the intensity and duration of the action of noise on the human body, there is a decrease in the sensitivity of the hearing organs, expressed in the form of a temporary displacement of the threshold of hearingness (lower curve in Fig. 1). As a result of this displacement of the threshold of the hearing aid, a person begins to hear the quiet sounds. As a rule, the sensitivity threshold is restored after some (relatively short) time interval. However, with a large intensity and duration of noise, an irreversible loss of the sensitivity of the human hearing aid (hearing loss) is possible. Regular prolonged impact on a person intensive noise (with a level of output 80 dBA) It is usually sooner or later leads to partial or even complete loss of hearing. Studies show that at present, the hearing loss goes to one of the leading places in a number of occupational diseases and tends to further growth. The effect of noise on the body is not limited to the direct influence on the hearing organs. Sound irritation through the nervous system of hearing agencies is transmitted to central and vegetative nervous systems and by them can affect the internal organs of a person, causing significant changes in their state. Thus, the noise is able to influence the human body as a whole. This fact It is confirmed by the fact that the statistics of the overall morbidity of working noisy industries are 10-15% higher. Activities on a vegetative nervous system manifests even with small sound levels (40 - 70 dBA) and does not depend on the subjective perception of noise by man. Of the vegetative reactions, the most pronounced is a violation of peripheral blood circulation as a result of the narrowing of the capillaries of the skin and mucous membranes, as well as an increase in blood pressure (at sound levels above 85 dBA). The impact on the central nervous system of man causes an increase in the time of visual and engine reactions, disrupts the bioelectric activity of the brain with the possible occurrence of general functional changes in the body (at sound levels above 50 - 60 dBA), as well as biochemical changes in the structures of the brain. Associate effect on a person noise can render, starting from sound levels in 30 dBA. The impact on the human psyche increases with an increase in the intensity of the sound, as well as with a decrease in the width of the frequency spectrum of noise. In impulse and irregular noise, the degree of their exposure increases. Changes in central and vegetative states nerve systems There are much earlier and at lower levels of noise. The symptoms of the "noise disease" include: a decrease in the hearing sensitivity, a change in the functions of digestion (reduced acidity), cardiovascular insufficiency, neuroendocrine disorders. Under the influence of noise, the levels of attention and memory are reduced, increased fatigue occurs, headaches may occur.

4. rationing of noise

By the nature of the spectrum of noises are divided into broadband and tonal. Broadband noise have a continuous frequency spectrum of less than one octave width. In the spectrum of tonal noise, there are pronounced discrete tones, determined by the measurement by measurements in the frequency-tailed bands with an excess of sound pressure level over adjacent strips of at least 10 dB. According to the temporary characteristics of noise, they are divided into permanent, the sound level of which for an 8-hour working day changes no more than 5 dBA In measurements on the time characteristic of "slowly" noiseomer, and non-permanent, not satisfying this condition. Landworthy noises, in turn, are divided into the following types:

• oscillating in the time noise, the sound level of which is continuously changing over time;
• intermittent noises, the sound level of which stepwise changes (on 5 dBA or more), and the duration of the intervals during which the level remains constant, is at least 1 with;
• pulse noiseconsisting of one or more audible signals, each duration of less than 1 with, at the same time, sound levels in dBA and dBA (I.) measured according to the time characteristics " slow"And" pulse"Noiseomer, differ at least 7 dBA.

The concept of equivalent LAE sound (effect of exposure) expressed in dBA and representing the sound level of such constant broadband noise representing the intensity of the time during the time conspicuous broadband noise, was introduced to evaluate non-permanent noise. T. ) It has the same meaning as this time changing noise:,

where L. A. ( t. ) - Current values, respectively, sound pressure and sound level of noise variable in time. Values L. BUT E. can be measured using automatic integrating noiseomers for a specified period T..

The normalized noise parameters are: for permanent noise - sound pressure levels L P. (dB) in octave frequency bands with medium-meter frequencies 31.5; 63; 125; 250; 500; 1000; 2000; 4000 and 8000. Hz; In addition, for the approximate estimate of permanent broadband noise at workplaces, the sound level is allowed. L. A. , expressed B. dBA;for non-permanent noise (except for impulse) - equivalent sound level L AE (on the energy of exposure), expressed in dBAis the sound level of such a constant broadband noise that affects the ear with the same sound energy as a real noise-changing noise for the same period of time; for pulse noise - equivalent sound level L. AE , expressed B. dBA, and maximum sound level L. BUT Max at dBA (I), measured on the temporal characteristic of the "pulse" of the noiseomer. The duplicate values \u200b\u200bof the noise parameters at workplaces are granted GOST 12.1.003-83 * "Noise. General security requirements "and CH 3223-85" Sanitary norms of permissible noise levels in workplaces. " The permissible values \u200b\u200bof noise parameters are set depending on the type of work performed (jobs) and noise nature. For work related to creative, managerial, scientific activities or requiring increased attention, concentration, auditory control, lower noise levels are provided. The following are characteristic types of work, differing in normalization, indicating the sequence number. The Metal, scientific work, training, design , design, development, programming. Administrative and management work, requiring focusing work, analytical work in the laboratory. Dyspeptic work, requiring speech connection by phone, in the halls of processing information on the computer, in the sections of the accurate assembly, in typewritten bureaus. accommodation of noisy computers associated with observation and remote control processes without speech communication by phone; Works in laboratories with noisy equipment. All types of work with the exception of those listed in PP 1 - 4. For broadband noise in Table. 1 shows permissible levels of sound pressure. L P. In octave frequency bands with medium-meter frequencies f SG , sound levels L A. (for subjective volume estimation of constant noise) and equivalent sound levels L AE (To evaluate non-permanent noise). For tonal and impulse noise, as well as for noise created in the premises of air conditioning and ventilation installations, allowable levels should be on 5 dB Below indicated in Table 1 (with measurements on the characteristic "slowly" noiseomer).

Table 1

Permissible levels of noise

type of work	Sound pressure levels L P. (dB) in octave frequency bands with medium-meter frequencies, Hz									Sound levels L A. , dBA

For fluctuating in time and intermittent noise, the maximum sound level should not exceed 110 dBAPulse noise. The maximum sound level measured on the characteristic of the "impulse" of the noiseomer should not exceed 125 dBA (I). According to CH 3077-84, more stringent requirements for noise in residential premises, public buildings and in residential buildings are established. For example, in the audiences educational institutions Levels L A. and L AE should not exceed 40 dBA, and the maximum sound level - 55 dBAEven any case is prohibited even by a short-term stay of people in areas with sound pressure levels Over 135 dB In any octave strip. Zones with sound level Over 85 dB must be indicated by safety signs; Working in such zones should be supplied with personal protective equipment.

5. Features of the propagation of sound in the atmosphere

Sound level ( dB) created by a point source at a distance r. (m.) From it in a homogeneous medium without absorption and away from any obstacles, determined by the formula:, (11)

where L W. - the relative logarithmic level of the sound power of the source (formula (9)); f. - the radiation pattern of sound source relative to the control point (for point sources of sound, considered in this work, f \u003d. 1); Ω - body (spatial) Angle of sound radiation source, cf.; Δ L. at - Additional weakening of the sound level caused by the absorption of the energy of the sound wave of atmospheric air.

The sound pressure level created by the sound source at the observation point removed for a certain distance from the source depends on the characteristics of the source (emitted spectrum, the radiation direction characteristic), from the location of the observation point (control point) relative to the sound source and a number of some other parameters. ( W. ) is a part of the space bounded by the conical surface. The conical surface in the general case is a plurality of direct lines (forming) in three-dimensional space connecting all points of some line (guide) with this point (vertex). The measure of a corporal angle is the ratio of the area of \u200b\u200bthe surface of the sphere s. arbitrary radius r. With a center in the top of a bodily corner, which is cut into the conical surface of this bodily corner, to the square of the sphere radius (Fig. 2): steradian (cf.). (12) The conical surface is represented as a variety of straight lines ( figy) In the space connecting all the points of some, in the general case of arbitrary, line ( guide) With this point ( vertine), as shown in Fig. 2.

If the source of the sound is located in the free space and radiates in all directions (not necessarily the same), the solid angle of radiation will be equal to the full bodily corner (the body angle contains all the space): W. = 4 p. cf..

When the sound source is located on a certain plane, for example, on the earth's surface, the body angle will include a half-space and, therefore, the size of the corporal angle in this case will be 2 p. cf.. For expressions (11), excluding the magnitude Δ L B. , It follows that the level of sound pressure at the control point decreases by 6 dB When doubling the distance to the sound source. Such a decrease in sound pressure is called the "geometric decline of sound level". In the real environment The overwhelming majority of sound sources are located near the earth's surface with a certain recreakable ability. In such cases, the sound level at the control point will be determined by both the direct and reflected sound waves (Fig. 3). In fig. 3 marked: r 1. and r 2. - distances passable by direct and reflected sound waves, m.; h sh and h K.T. - the height of the location above the surface of the sound source and the control point. With regard to the designations in Fig. 3 There is a formula for estimating the sound level spreading near the reflective surface:, (13) where: f 1. and f 2. - the radiation patterns of the radiation of sound by the source in the direction of the control point and in the direction of the point of reflection of the sound wave from the surface (in this work for point sources of noise are taken equal to 1); a OTR - reflection coefficient of sound wave from the surface (0< a OTR < 1, для земной поверхности a OTR \u003d 0.37). h sh £ r 1. / 3 and a Or. ≈ 1 With a minor error, we can assume that the radiation of the sound occurs directly from the surface. In this case, believe r 1. ≈ r 2. ≈ r. (Fig. 4), f \u003d. 0,5(F 1 + F 2) \u003d 1 I. W \u003d. 2p. cf. (radiation of sound in the half-space) and as a calculated formula is used by formula (11) .If h K.T. << r. , h sh << r. and f cf. £ 40/ (h sh h K.T. ) - average frequency emitted frequency bandwidth, Hz, the direct and reflected sound waves are simply folded and the sound pressure level increases by magnitude. D. L add = 3 dB relative to the level determined by the formula (14). Additional attenuation of the sound level caused by the losses of sound energy in atmospheric air is proportional to the distance r. (m.), passing sound waves:, (14)

where b. at - sound absorption coefficient in the air, dB / km.. Value b. at depends on the frequency of sound, as well as on temperature and relative humidity of air (in this paper it is accepted b. at =5,2 dB / km.).

An additional weakening of noise on the path of propagation of sound waves in the environment can cause various obstacles, such as strip of forests. If the height of the forest plantation is at least 5 m., the sound is partially reflected from it, and partially dissipates in crowns of trees and shrub. An additional weakening of the noise of the lane of forests can be taken into account by calculating the negative correction to formulas (11) and (13): D. L L.P. \u003d. b lp b lp , (15) Where: b lp - coefficient of weakening the sound of a lane of frozen dB / M.; b lp - Width of the strip of frisms, m.. The coefficient of weakening the sound of the forest bar is complexly depends on the type of vegetation and the type of its landing, as well as its width. Averaged the value of the coefficient of the sound of the forest belt is considered to be b lp = 0,08 dB / M.. Of course, it should be borne in mind that forest belt, consisting of deciduous plantings, in winter practically does not relax the level of sound wave passing through her. The above formulas make it possible to estimate the noise level at some distance from its point source. However, there are noise sources in the environment, such as extended streets, highways, noisy production trains, etc., which cannot be considered point. Such noise sources are called extended or linear. Sound pressure ( dB) when removing the distance d. From an infinitely long linear noise source in the medium without absorption decreases by 3 dB when doubling distance ( d. , m.) : L K.T. \u003d. L * W - 10. lG ( d) - 3 , (16) where L. * W. – the relative logarithmic level of sound power emitted by the length of the extended source length 1 m.. Sound pressure levels created by individual areas of linear sources or extended sources of finite length in an arbitrarily located control point (Fig. 4) are determined by the formula :. (17) in fig. 4 marked: l Sh - length of the extended source of noise, m.; d. - the shortest distance from the front of the extended noise source to the control point, m.; α - angle under which the extended noise source is seen from this control point, glad; r. - distance from the middle of the extended noise source to the control point, m.. If a r. > 2l Sh then you can use formula (14) with f. \u003d 1 I. Ω \u003d 2p. cf., i.e. the extended source in this case can be considered point.

Fig. 4. To determine the level of sound pressure near the extended noise source of the final length

At a sufficiently large removal from the extended source of noise in formulas (16) and (17), it should be corrected to absorb the sound of the air medium (formula (14)) and, if necessary, to weaken the noise of the forest-protecting strip (formula (14)).

Practical part

1. Get a task option from the teacher.

2. Examine the task received.

3. Classify noise in a given situation.

4. By the corresponding calculations to estimate the noise level in situations defined by the task option.

5. According to the results of the calculations, construct the graphic dependencies indicated in the task.

6. Evaluate the obtained characteristics of noise for compliance with regulatory levels.

1) The report must contain the results of the required calculations and graphic dependencies illustrating the results of calculations.

2) According to the task, classify the noise studied (determine their character).

3) to conclusion about the compliance of the calculated levels of noise at the specified control points with the regulatory levels.

test questions

1. Sound and its characteristics.
2. Features of the subjective perception of sound by human hearing authorities.
3. The effect of noise on the human body.
4. Noise characteristics and their classification.
5. What is the purpose of an idea of \u200b\u200ban equivalent sound level and represents this parameter?
6. The principles of normalization of noise.
7. Features of the perception of noise emanating from several sources.
8. Posted on bodily corner, within which sound radiation occurs.
9. What factors can influence the level of perceived sound when it is propagated in atmospheric air.
10. Features and distinction of point and extended sound sources.
11. Fighting noise in manufacturing: reference book / under total. ed. E. Ya. Yudina. M.: Mechanical Engineering, 1985. P. 11 - 17, 36 - 57.
12. Environmental protection / Ed. S. V. Belova. M.: Higher School, 1991. P. 200 - 234.
13. Denisenko G.F. Occupational Safety and Health. M.: Higher School, 1985. P. 182 - 193.

Bibliographic list

Laboratory work number 4

Determine the conditions for dispersion of emissions by industrial enterprises

Purpose of work: Determine the level of contamination of atmospheric air by industrial emissions and emissions from ventilation devices.

Theoretical part

1. Technogenic emissions and environmental impacts

Technogenic pollution of the medium is the most obvious causal bond in the ecosphere system: "Economics, production, technique, environment." It leads to degradation of environmental systems, global climatic and geochemical changes, to the defeats of people and animals. Figure 1 shows the classification of technogenic OS contaminants.

Fig. 1. Classification of technogenic pollution

In general, by nature and scales, chemical pollution are most significant, and the largest threat is associated with radiation. As for the objects of impact, in the first place, of course, there is a person. Recently, not only the growth of pollution is a special danger, but also their total influence, often exceeding the final effect of simple summation of the consequences. With an environmental point of view, all the products of the technosphere are pollution or potential pollutants, even those that are chemically inert, as they occupy place In the biosphere and become ballast of environmental flows. Most of the production products also become pollutants with time, representing "pending waste". The most part of the pollution of the OS refers to unintentional, albeit obvious, environmental disorders. Many of them are significant, many difficult to control and they are dangerous in unforeseen effects due to the remoteness of the consequences. For example: Technogenic emission of CO 2 or thermal pollution is fundamentally inevitable. While there is a fuel energy. The waste of modern humanity and technosphere products make up almost 160 GT / year, of which about 10 Gt Form a lot of products, i.e. "Deferred waste." On average, one resident of the Earth accounts for about 26 t. All anthropogenic emissions per year. 160. Gt The waste is distributed in approximately as follows: 30% is ejected to the atmosphere, 10% falls into the reservoirs, 60% remains on the surface of the Earth. The chemless of a large scale has reached a chemicalization of the biosphere, which significantly affects the geochemical appearance of the ecosphere. The total weight of the chemicals and active waste of the entire chemical industry has exceeded 1.5 GT / year. Almost all of this amount can be attributed to the pollution of the OS. But it is not only a matter of mass, but also in the diversity and toxicity of most chemicals produced. In the global chemical nomenclature there are more than 10 7 chemical compounds and their number annually increases by several thousand. However, most of the substances used are not estimated in terms of their toxicity and environmental hazards.

2. Sources of man-made emissions

All sources of man-made emissions are divided into organized, stationary and movable. Organized sources are equipped with special devices for the directional output of emissions (pipes, ventilation mines, output channels, gutters, etc.). Emissions from unorganized sources arbitrary. Sources are also divided into geometrical characteristics (point, linear, derivatives) and in terms of operation - continuous, periodic, salvo. The content of the predominant part of chemical and thermal pollution is thermochemical processes in the energy industry - combustion of fuel and associated thermal and chemical processes and leaks. The main reactions that determine the emission of carbon dioxide, water vapor and heat, go as follows:

Carbon: C + O 2 → CO 2;

Hydrocarbons: C n h m + (n + 0.25m) O 2 → NCO 2 + 0.5MH 2 O .

Along the way, they are reactions that determine the issuance of other pollutants, and they are connected with the content of various impurities in the fuel, with the thermal oxidation of air nitrogen and with secondary reactions occurring in the OS. All these reactions accompany the operation of thermal stations, industrial furnaces, internal combustion engines, gas turbine and jet engines, processes in metallurgy, firing mineral raw materials, etc. The highest contribution to the energy-dependent pollution of the medium is made by thermal power and transportation. The general picture of the exposure to the thermal power plant (TPP) on the OS is shown in Fig. 2. Fuel burning All its mass turns into solid, liquid and gaseous waste. Data on emissions of the main air pollutants during the operation of the TPP are given in Table. one.

Table 1

Specific emissions to the atmosphere when operating a TPP with a capacity of 1000 MW. on different types of fuel, g / kt hour

			Natural gas

The amount of emissions depends on the quality of fuel, such as flue aggregates, emission neutralization systems and dravethitors and wastewater treatment devices. On average in fuel power engineering to 1 t. Combined fuel is thrown into OS about 150 kg Pollutants.

Fig. 2. The effect of heat-power plants on the environment

1 - boiler; 2 - pipe; 3 - steam tube; 4Electrosener; 5 - electrical substation; 6 - condenser; 7 - Condenser Cooling Water-Fence; 8 - water power boiler; 9 - power lines; 10 - electricity consumers; 11 - reservoir

Metallurgical processes are based on the restoration of metals from ores, where they are contained mainly in the form of oxides or sulfides, using thermal and electrolytic reactions. The most characteristic total (simplified) reactions:

iron: FE 2 O 3 + 3C + O 2 → 2FE + CO + 2CO 2;

copper: Cu 2 S + O 2 → 2CU + SO 2;

aluminum (electrolysis): Al 2 O 3 + 2O → 2AL + CO + CO 2.

The technological chain in ferrous metallurgy includes the production of pellets and agglomerates, coke-chemical, domain, steel-smelting, rolling, ferroalloy, foundry production and other auxiliary technologies. All metallurgical converters are accompanied by intensive pollution of the medium (Table 2). In coke-chemical production, aromatic hydrocarbons, phenols, ammonia, cyanides and a number of other substances are additionally distinguished. Black metallurgy consumes a large amount of water. Although industrial needs for 80 - 90% are satisfied at the expense of circulating water supply systems, the fence of fresh water and the discharge of contaminated drains achieve very large volumes, respectively, about 25 - 30 m 3. and 10 - 15 m 3. on 1. t. full cycle products. With drainage in the water bodies there are significant amounts of suspended substances, sulfates, chlorides, compounds of heavy metals.

table 2

Gas emissions (before purification) of the main alterations of ferrous metallurgy

(Bez Cockochemical Production), in kg / t relevant product

	Production
	Agglomeration	Domain	Step smelting	Rolling

* kg / m 2 Metal surfaces

Color metallurgy, despite relatively smaller material flows, is not inferior to ferrous metallurgy on the aggregate toxicity of emissions. In addition to a large amount of solid and liquid waste containing such dangerous pollutants, such as lead, mercury, vanadium, copper, chrome, cadmium, thallium, etc., and many airplanes are emitted. With the metallurgical processing of sulphide ores and concentrates, a large mass of sulfur dioxide is formed. Thus, about 95% of all harmful gas emissions of the Norilsk Mining and Metallurgical Plant are at SO 2, and the degree of its disposal at exceeds 8% Industry and other) contain many significantly unlocked material cycles. The main sources of harmful emissions are the processes of production of inorganic acids and alkalis, synthetic rubber, mineral fertilizers, kernels, plastics, dyes, solvents, detergents, oil cracking. The list of solid, liquid and gaseous waste of the chemical industry is huge in the mass of pollutants, and for their toxicity. In the Chemical Complex of the Russian Federation more than 10 is formed annually mul T. Harmful industrial waste. Independent technologies in manufacturing industries, primarily in mechanical engineering, include a large number of different thermal, chemical and mechanical processes (foundry, forge-pressed, machining production, welding and cutting of metals, assembly, galvanic, paintwork, etc. .). They give a large amount of harmful emissions polluting medium. A noticeable contribution to the overall pollution of the medium is also made by various processes accompanying the production and enrichment of mineral raw materials and the construction of the economy and life of people on their own waste - the remnants and products of the vital activity of plants, animals and humans - are essentially not the sources of pollution of the medium, since these Products can be included in the biotic circulation. But, first, for modern agrotechnologies and utilities, a concentrated discharge of most of the waste is characterized, which leads to significant local extensions of the permissible concentrations of organics and such phenomena as eutrophication and infection of water bodies. Secondly, more seriously, agriculture and life of people are intermediaries and participants in the dispersal and distribution of a significant part of industrial pollution in the form of distributed emission flows, petroleum products, fertilizers, dehymicks and various used products, garbage - from toilet paper to abandoned farms and cities.

Fig. 3. Scheme of environmental pollution influences

Each media there is a constant exchange of part of pollutants: a heavy part of aerosols, gas and dust impurities from the atmosphere falls on the ground surface and in water bodies, a part of solid waste from the surface of the Earth is washed off into the reservoirs or dissipated by air flows. The pollution of the medium affects the person directly or through the biological link (Fig. 3). In technogenic streams of pollutants, transporting media - air and water occupy a key place.

3. Pollution of the atmosphere

Composition, quantity and danger of aircraft. Out of 52. Gt Global anthropogenic emissions into the atmosphere more than 90% are accounted for carbon dioxide and water pairs, which are usually not related to pollutants (about a special role of CO 2 emissions is referred to below). Technogenic emissions in the air environment are tens of thousands of individual substances. However, the most common, multi-duct pollutants are relatively few pollutants. These are various solid particles (dust, smoke, soot), carbon monoxide (CO), sulfur dioxide (SO 2), nitrogen oxides (NO and NO 2), various volatile hydrocarbons (CH X), phosphorus compounds, hydrogen sulfide (H 2 S ), ammonia (NH 3), chlorine (CL), hydrogen fluoride (HF). The number of the first five groups of substances from this list, measured by tens of millions of tons and emitted to the overaffled world around the world and Russia are presented in Table. 3.

Table 3.

Emissions into the atmosphere of the five main pollutants in the world and in Russia ( mul T.)

	Stationary sources	Transport	Stationary sources		Transport

The greatest contamination of the atmosphere is observed in industrial regions. About 90% of emissions fall on 10% of the land area and are focused mainly in North America, Europe and East Asia. The air basin of large industrial cities is particularly polluted, where man-made heat and aircraft flow streams, more often with adverse meteo conditions (high atmospheric pressure and thermal conversions), often create dust dome and phenomena of smog - toxic mixtures of fog, smoke, hydrocarbons and harmful oxides. Such situations are accompanied by strong excess of MPC many aircraft. More 200 cities of Russia, whose population is 65 million Man is experiencing constant exceeding the PDC toxic substances. Residents of 70 cities are systematically encountered with PDC exceeding 10 or more times. They include including Moscow, St. Petersburg, Samara, Ekaterinburg, Chelyabinsk, Novosibirsk, Omsk, Kemerovo, Khabarovsk. In the listed cities, the main contribution to the total emissions of harmful substances is accounted for by vehicles, for example, in Moscow, it is 88%, in St. Petersburg - 71%. The ground atmosphere has the ability to self-cleaning against pollutants, due to the physico-chemical and biological processes. However, the power of man-made sources has increased so much that in the lower layer of the troposphere, along with a local increase in the concentration of some gases and aerosols, global changes occur. A person invades a balanced substance cycle, sharply increasing the emission of harmful substances into the atmosphere, but without providing their conclusion. The concentration of a number of anthropogenic substances in the atmosphere (carbon dioxide, methane, nitrogen oxides, etc.) is growing rapidly. This suggests that the assimilation potential of biota is close to exhaustion. Silver precipitation. For a number of indicators, first of all by weight and prevalence of harmful effects, the atmospheric pollutant number one is considered sulfur dioxide. It is formed when the sulfur oxidation contained in the fuel or in the composition of sulfide ores. Due to the increase in the capacity of high-temperature processes, the translating of many TPPs on gas and the growth of the car fleet grow emissions of nitrogen oxides formed during the oxidation of atmospheric nitrogen. Admission to the atmosphere of large amounts of SO and nitrogen oxides leads to a noticeable decrease in the pH of atmospheric precipitation. This is due to the secondary reactions in the atmosphere leading to the formation of strong acids - sulfur and nitric. In these reactions, oxygen and water pairs, as well as particles of technogenic dust as catalysts are involved as catalysts: 2SO 2 + O 2 + 2H 2 O → 2H 2 SO 4; 4NO 2 + O 2 + 2H 2 O → 4HNO 3. In the atmosphere, it turns out and A number of intermediate products of the specified reactions. The dissolution of acids in atmospheric moisture leads to the loss of "acid rain". Acid precipitates are very dangerous in areas with sour soils, the microflora dies, the organic was washed, the reservoirs of rivers, lakes and irreversible changes in ecosystems occur. The occurrence of the ozone layer. In the 70s, there were reports of regional reductions in ozone content in the stratosphere. Especially noticeable seasonally pulsating ozone hole over the Antarctic area of \u200b\u200bmore than 10 million km 2.where the content of O 3 for the 80s decreased by almost 50%. Later, the "wandering ozone holes", the truth, smaller and not with such a significant decline, began to be observed in the winter and in the northern hemisphere, in the areas of persistent anticyclones - over Greenland, Northern Canada and Yakutia. The average rate of global decreases for the period from 1980 to 1995 is estimated at 0.5 - 0.7% per year. Sobelka weakening the ozone screen is extremely dangerous for the entire ground biota and for the health of people, these data attracted close attention of scientists, and then All society. A number of hypotheses were expressed about the causes of the ozone layer impairment. The mining of specialists is inclined to the opinion of the technogenic origin of ozone holes. The most substantiated representation, according to which the main reason is to enter the upper layers of the atmosphere of technogenic chlorine and fluorine, as well as other atoms and radicals capable of extremely actively attaching atomic oxygen, thereby competing with the reaction of O + O 2 → O 3. Transaction of active halogen in The upper layers of the atmosphere are mediated by volatile chlorofluorocarbons (CFCs) of the type of freon (mixed fluorochlorides of methane and ethane, for example, Freon-12 - dichlorodifluoromethane, CF 2 Cl 2), which, under normal conditions, inert and non-toxic, under the action of short-wave ultraviolet rays in the stratosphere are disintegrating. Bringing out "to freedom", each chlorine atom is able to destroy or prevent the formation of a set of molecules of ozone. Chlorofto compounds have a number of useful properties that caused their wide use in refrigeration plants, air conditioners, aerosol cans, fire extinguishers, etc. Since 1950. CFCs annually increased by 7 - 10% and in the 1980s amounted to about 1 mul T.. Subsequently, international agreements were adopted,
Subscribing member countries to reduce the use of CFCs. In 1978, the United States introduced a ban on the use of HFFU-aerosols. But the expansion of other applications of CFCs again led to the growth of their world production. The transition of the industry to new ozone-saving technologies is associated with large financial costs. In the last decades, others appeared, purely technical pathways of active ozone destroyers in the stratosphere: nuclear explosions in the atmosphere, emissions of supersonic aircraft, launching rockets and reusable spacecraft. It is not excluded, however, that part of the observed weakening of the Earth's ozone screen is not related to technogenic emissions, but with centuries-old oscillations of the aerochemical properties of the atmosphere and independent changes in climate, the partitioning effect and climate change. Technogenic pollution of the atmosphere to a certain extent associated with climate change. It is not only about the very obvious dependence of the mesoclimate of industrial centers and their surroundings from thermal, dust and chemical air pollution, but also about the global climate. From the end of the XIX century. to the present, there is a tendency to increase the average temperature of the atmosphere; Over the past 50 years, it has risen approximately 0.7 ° S.. This is not enough, if we consider that at the same time the gross increase in the internal energy of the atmosphere is very large - about 3000 MJ.. It is not associated with an increase in the solar constant and depends on the properties of the atmosphere itself. The main factor is to reduce the spectral transparency of the atmosphere for long-wave reverse radiation from the surface of the Earth, i.e. Strengthening the greenhouse effect. The greenhouse effect is created by an increase in the concentration of a number of gases - CO 2, CO, CH 4, NO X, CFC, etc., called greenhouse gases. According to the data summarized in recently the International Group of Experts on Climate Change (IPCC), there is a fairly high positive correlation between the concentration of greenhouse gases and the deviations of the global atmosphere. Currently, a significant part of the emission of greenhouse gases has man-made origin. The dedication of global warming is given very important. The question of whether it will happen or not, no longer worth it. According to experts of the World Meteorological Service, with the existing level of greenhouse gas emissions, the average global temperature in the next century will increase at a speed of 0.25 ° S. For 10 years. Its growth by the end of the XXI century, in different scenarios, (depending on the adoption of certain measures) can be from 1.5 to 4 ° S.. In the northern and medium latitudes, warming will be stronger than at the equator. It would seem that such an increase in temperature should not cause special concern. Moreover, possible warming in countries with a cold climate, such as Russia, it seems almost welcome. In fact, the effects of climate change may have a catastrophic nature. Global warming will cause a significant redistribution of precipitation on the planet. World Ocean Level During the melting of ice can increase by 2050 by 30 - 40 cm, and by the end of the century - from 60 to 100 cm. This will create a threat of flooding of significant coastal territories. For the territory of Russia, the general trend of climate change is characterized by weak warming, the average annual air temperature from 1891 to 1994. Rose by 0.56. ° S.. During the period of instrumental observations, the warmest were the last 15 years, and the highest possible to the warmth was 1999. In the past three decades, there is also a tendency to reduce precipitation. One of the consequences of climate change consequences can be the destruction of frozen soils. Increase temperature in the permafrost zone by 2 -3 ° S. will lead to a change in the carrier properties of soils, which will threaten the various structures and communications. In addition, the CO 2 stocks and methane reserves contained in the permafrost of the soils will begin to enter the atmosphere, exacerbating the greenhouse effect.

4. Determine the conditions for dispersion of emissions of industrial enterprises

Distribution in the atmosphere of industrial emissions from pipes and ventilation devices is subject to the laws of turbulent diffusion. The process of dispersion of emissions, the state of the atmosphere, the location of enterprises and emission sources, the nature of the area, the chemical properties of the ejected substances, the height of the source, the diameter of the pipe, etc. The horizontal movement of impurities is determined mainly by the velocity and direction of the wind, and the vertical - the temperature distribution in the atmosphere in height. In the basis of the "Methods for calculating the concentrations in the atmospheric air of harmful substances contained in the emissions of enterprises" OND-86, a condition in which the total concentration of each harmful concentration Substances should not exceed the maximum one-time maximum permissible concentration of this substance in atmospheric air. Maximum concentration C M. harmful substances (in mg / m 3) The earth's surface is formed on the ejection axis of the discharge at a distance X MAX From the source of emissions (for a hot gas-air mixture):

A. - the coefficient of stratification of the atmosphere, depending on the temperature gradient and the determining conditions of vertical and horizontal dispersion of emissions (for the center of Russia takes a value within 140 – 200);

M. - Mass of a substance emitted into the atmosphere per unit of time g / s;

V 1. - the volume of the discharged gas-air mixture, m 3 / s;

h. - pipe height, m.;

F. - the coefficient that takes into account the rate of sedimentation of suspended emission particles in the atmosphere (for gases is 1, for dust with purification efficiency of more than 90% - 2, from 75% to 90% - 2.5, less than 75% - 3);

Δ T. - the difference between the temperature of the gasped gas-air mixture and the temperature of the ambient atmospheric air, equal to the average temperature of the hottest month at 13 o'clock;

η - a dimensionless coefficient, taking into account the impact of the terrain;

m. - dimensionless coefficient, taking into account the conditions of gas out of the pipe:

where: f \u003d 10 3 w 0 d / h 3 Δt;

W 0 \u003d 4 V 1 / π D 2. - average gas output from the pipe, m / S.;

D. - pipe diameter, m.;

n. - dimensionless factor depending on the parameter V M. , m / s:

For Vm ≤ 0.3 Accept n. \u003d 3, when Vm \u003e 2 accept n. \u003d 1, at 0.3< Vm < 2 принимают n \u003d [(VM - 0,3.)(4,36 – Vm)] 0,5 .

Expected maximum concentration of pollutants (in mg / m 3) In the emission of a cold gas-air mixture is determined by equation:

The distance to the place where the maximum concentration is expected ( X. Mach ) is defined as follows: ● for gases and fine dust X MAX = dH where d. - dimensionless value depending on the parameter V M. :

for cold emissions

d \u003d 11.4 V M. for V M. ≤ 2;

d \u003d 16.1 ( V m) 0.5 for V M. > 2;

● for large dust ( F. ≥ 2)

X Mach \u003d 0.25 (5 - F) dH ;

● for a hot gas-air mixture:

d \u003d 4,95V M (1 + 0.28f 1/3) for V M. ≤ 2;

d \u003d 7 ( V M) 0.5 (1 + 0.28 f 1/3) for V M. > 2.

The concentration of the pollutant in the surface layer atmosphere at any distance X. from the source of emissions other than X MAX determined by the formula: C. = C M. S. 1 ,

where S 1 - coefficient depending on the value χ = X. / X MAX :

● Ply χ ≤ 1 S 1 \u003d 3 χ 4 - 8 χ 3 + 6 χ 2. ;

● at 1.< χ ≤ 8 s 1 \u003d 1.13 (1 + 0.13 χ 2) -1;

● Ply χ ≤ 8 (F. = 1) S 1 \u003d. χ (3,58. χ 2 +3,52. χ + 120) -1 ;

● Ply χ ≤ 8 (F. = 1) S 1 \u003d (0.1 χ 2 +2.47 χ + 17,8) - 1 .

Practical part

A report on the implementation of laboratory work must contain:

1) source data;

2) the results of all calculations;

3) Conclusions.

test questions

1. What are technogenic emissions?
2. Thermal sources and their role in the pollution of the OS.
3. The effect of metallurgical and chemical processes on the pollution of the OS.
4. What is the reason for the destruction of the ozone layer?
5. What caused acid precipitation?
6. What is a greenhouse effect and what is his danger?
7. What is the reason for the pollution of the atmosphere?
8. Environmental protection / Ed. S.V. Belova. M.: Higher School, 1991. 2. 234 p.
9. Ecology / Ed. Denisova V.V.: Rostov-on-Don, March, 2002, 630 p.
10. Fedorova A.I. Workshop on ecology and environmental protection. M.: Vlados, 2001, 288 p.

Introduction

The concern of modern society about improving the quality of life implies improvement in the environment and the noise caused by transport is one of the areas of work.

Noise from road traffic is a total result:

the noise of the operating engine of the vehicle,

noise from the contact of the tires and the surface of the road surface.

Consequently, the issue of noise reduction capabilities should be considered as part of the work of experts representing:

vehicle manufacturers,

tire manufacturers,

road builders,

oil industry (manufacturers of road bitumen and fuel).

The joint work of experts from various industries to solve the problems of reducing noise is aimed at:

Expanding cooperation of manufacturers of tires and vehicles to ensure a more comprehensive approach in reducing transport noise

Harmonization of various methods of noise measurements on a European scale.

Definition:

An integrated approach is the use of methods to consider objects and phenomena in mutual communication and in combination to obtain a more accurate and correct idea of \u200b\u200bthe problem.

The task of a new integrated approach is to prepare technical norms and unified legislative acts on:

modern methods for determining the noise caused by the interaction of road surface and tires, as well as a vehicle.

rules addressed to the relevant participants

1. Measuring noise level and existing rules

The interaction of the tire and the road produces noise that is perceived at varying degrees inside and outside the car.

From the point of view of the environment, interest causes noise outside the car, which can be determined by:

measuring the overall noise indicator

measuring noise from the movement of a separate car.

The overall noise indicator is a permanent noise level for a certain period of time, which is a result from the actual noise allocation process.

There are several main methods for measuring noise when the car is moving, but none of these methods are not yet standardized.

Car manufacturers measure overall noise levels when accelerating the vehicle's movement by various tests.

Motor noise measurements are necessary for approval of the type of car, since this requires a European standard for accessing the automotive industry to the European market and brutal competition in the industry.

Tire maker measure the noise level from the contact of the tire and the road surface for their purposes, checking the general performance of the tires under different conditions.

Road builders determine the acoustic properties of road surface surfaces, but by their methods that do not give comparable results, which could be linked to the noise produced by a moving vehicle (taking into account the type of tire and engine operation).

Thus, within the framework of these three groups, the results expressed in physical units - decibels (dB) cannot be used in one common mathematical model that could be the basis for decision making.

2. Vehicle

Until now, to assess the noise produced by such a source as a vehicle, a too generalized approach was used.

In fact, this common noise can be decomposed between two main sources:

traction vehicle energy (engine, drive shaft, gears),

contact Tire and coatings.

In the recent models of heavy vehicles, the dominant part of the total noise is noise from the contact of the tire and coating. Since the 60s, manufacturers of truck engines have achieved a decrease of 15 times the noise of traction energy by introducing project improvements.

However, if the overall noise of the motor vehicle is determined by standardized methods, then the standard that would suit for measuring the noise of the contact of the tire and coating the road as a part of the total noise, does not yet exist.

3. Recognition Tire / Road

The contact of the moving tire and coating produces a whole spectrum of sound waves, more or less distinguishable originating due to the rolling effect of the wheel. Knowledge of the mechanism of the occurrence and distribution of these sound waves reduces the degree of their environmental impact.

Special noise measurement methods have been developed for a combination: a car cover-coating.

The components of noise sources have been identified and the effect of each of them is studied on various parameters involved in the generation and distribution of noise.

Reducing the level of rolling noise is to control the processes of its generation, distribution and absorption, which depend:

from vehicle (weight, quantity of wheels, vibration, body forms),

from the tires (pressure / propagation of air under the surface of the tread, its drawing, the contact area and the clutch of the surface of the tire with the surface of the road),

from the rolling condition (speed, torque, ambient temperature),

from the road (surface characteristics of the coating, road clothing design, transverse profile).

When studying different noise levels from contact, the tire / coating is revealed that rolling noise:

significantly increases with increasing speed (3 dB + 0.2 / 0.5 dB for every 15 km / h),

when moving at a constant speed of about 60 km / hour, rolling noise prevails over the noise of the engine,

when measuring on the boundary, the coating varies from 3 dB, depending on whether smooth tires or medium (European types) tread tires are used,

when measuring on the surface of the tire, the noise varies with 6 dB, depending on the design characteristics of the road (measurements were carried out on typical European main roads).

To limit noise, it is required to study the complex contact model Tire / coating, taking into account the characteristics of the coating and tires.

4. Wood coating and layers of wear

The purpose of the coating is to ensure the movement of vehicles with maximum safety, namely the coating should:

withstand moving loads

provide security users and comfort with any weather, both in day and night.

This last double function is achieved mainly using a deterioration layer because:

The user's safety is determined by the degree of confrontation of the drift and roughness of the surface of the coating, especially important in rainy weather.

The driver's comfort is determined by the level of coating and rolling noise, which also creates the inconvenience of residents of houses located near the road.

Porous asphalt concrete represents one of the most modern and cost-effective materials for coatings. This is the only type of wear layer, which gives a good result to reduce noise, at the same time improving road safety.

5. Possibility of further noise reduction

The European Community Commission formed a special working group for the purpose of considering the issue in terms of technical progress. From the report prepared by the Working Group follows the following:

The group concluded that the application of the 1984 directive contributed to the fact that all possible, to date, technical improvements to reduce noise emissions by all sources arising in the process of road traffic, except for the interaction of the tire and the surface of the road surface.

The following starting position was revealed to start solving the problem:

Tests and methods for estimating noise levels are not established by any rules (i.e. it is difficult to assess objectively and compare noise levels).

In some cases, a decrease in the total noise levels cannot be achieved by technical solutions (for example, if an increase in noise emission occurs as a result of sharp braking).

The differences between the methods of assessing noise levels and the conditions of testing and the real conditions of transport movement do not guarantee the effect of measures to reduce discomfort from noise (measures developed under test track conditions may not give proper effect in the actual environment).

In those who are responsible for the state of the environment, there are no relevant technological and economic instruments that contribute to control and taking measures to reduce noise (for example, the levels of restrictions for noise from contact with the tire / coating, reliable levels of levels for imposing a fine for their excess ).

The first stage is to highlight the categories of vehicles where you can not take into account the noise from the contact tire / coating.

The second stage is to further study to develop reproducible methods for determining the results of the interaction of the characteristics of the tire and roads relating to the appearance of noise, to prepare rules and requirements for vehicles, tires and roads.

Definition

The reproducible method is a way to solve specific tasks in a certain area (establishing levels of noise emission from a tire / coating contact) by a certain sequence of practical operations.

A clear definition of degrees of the effect of the tire and the road would allow to distribute the obligations and responsibility between the relevant sectors (tire manufacturers and road organizations).

The existing system of approving the type of vehicle for noise characteristics is now based on the overall level of noise of the vehicle. For him and the manufacturer of vehicles is responsible.

However, the manufacturer should not be responsible for that part of noise emissions, which does not depend on it. In the nearby past, this logical connection had no technical substantiation.

The public irritation caused by the noise of the city transport movement is associated with the general noise. The overall noise is made up of noise emissions produced by individual noise generators. Therefore, for the success of solving the problem as a whole, test conditions and measurement methods should be developed to determine both the total noise and measurements of its components.

Definition:

Noise generator - device, apparatus, machine producing audio signals (wave oscillations, pulses).

In the case of modern, from an acoustic point of view of vehicles, contact noise Tire / coating gradually goes to the fore.

6. Determination and assessment of rolling noise in the interaction of tire and road coating

The rolling noise can be divided into two components of noise - internal and external noise.

Internal noise creates discomfort for the driver and passengers inside the vehicle. There is interaction between the vehicle and the tire, therefore it is necessary to understand both air and the structural transmission of sound waves through the body of the vehicle.

In the context of the environment, we consider the problems of external noise as part of the overall discomfort caused by the noise of transport movement.

The evaluation of external noise is currently based on measurements on the side of the road of the overall noise level in dB.

When conducting research to reduce rolling noise, measurements are used on the side of the road to determine improvements in general.

A microphone is used, installed at 7.5 m from the road axis at an altitude of 1.2 m.

The rolling noise should be determined as follows: the vehicle is rolling under the slope at a given speed with the engine turned off and the clutch.

The rolling rate is set to accurately install rolling conditions (vehicle mass, rolling angle).

The main parameters affecting the noise level by test results:

road: The road plays a role in:

1. The process of generating noise (surface particle size)

2. Its propagation (properties of acoustic absorption)

vehicle:

1. Tires (vehicle weight, air pressure in the chamber, dimensions). Tire sizes significantly affect the generation of noise (the more the tire, the "noise"

2. Number of "noise sources from a tire"

3. The effects of diffraction (dispersion of sound waves) originating due to the forms of the vehicle body

rolling conditions:

noise increases with increasing speed

noise is reduced with increasing temperature

noise changes at a given speed under the influence of torque

7. Basic research approach to reduction of rolling noise

Reducing rolling noise for tire manufacturers is a difficult task.

Therefore, to obtain a clear understanding of various physical phenomena involved in the generation and distribution of noise, a fundamental research approach is required.

Simultaneously with the long-term scientific approach, it is necessary to have rapid results from research to ensure the implementation, step by step, improving the design of tires with a commercial purpose.

To reduce rolling noise, it is necessary to establish control over sources and to realize the complex environment, including: road, vehicle, rolling conditions.

For this, it is necessary to study the acoustic mechanism of both generation and noise propagation from a moving source away from the road and then use the results obtained to determine the noise criteria.

The process has three phases:

phase 1 - Clarification:

The problem is analyzed experimentally and theoretically in order to understand generation and distribution.

phase 2 - Forecast:

After the problem is understood, you need to be able to simulate the situation in order to predict discomfort in a given situation, i.e. From the global noise level along the road to approach the definable combination of noise "Tire + road + vehicle" under certain rolling conditions.

phase 3 - Amendment:

After discomfort becomes predicted, the knowledge gained can be used to achieve the goal - to improve the tire concept to obtain an optimal version of the desired performance.

8. The spread of noise in the car.

The air noise from the primary sources penetrates the salon a / m through body looser (doorways, front gender technological holes), as well as glazing a / m. The thicker the glass and the body panel, the higher their sound insulation properties. Air noise from primary sources is the lower than the most optimal design of the sources themselves: engine, transmission, exhaust systems, tires (height and tread pattern). Structural noise penetrates in a / m through suspension elements to the body of a power unit, transmission, exhaust system, chassis. Vibration transmitted through the suspension elements makes fluctuate everything without exception of the body panel, which in turn emit structural noise. In addition, the sound emitted by the elements of the exhaust system (pipes, a resonator, silencer) leads to an additional excitation of the floor a / m, which makes a tangible contribution to the overall level of internal noise. In the overall level of noise in the cabin, a considerable share is made by reflected sound. Reflected sound - the sound when reflecting the sound flows published by primary sources, from the road surface.

9. Methods of combating noise.

We are divided into constructive and passive. Constructive method: the use of balanced power units and transmission nodes; Proper selection and calculation of the elastic elements of the suspension of the power unit, transmission, chassions, exhaust system; The correct calculation of the design of the exhaust system and determining the points of its suspension to the body; Proper modeling of the structure of the body and its rigidity; The choice of progressive designs of window seals and doorways, etc. Passive method: use of noise insulating and gasket materials. The use of protective housings.

10. Previous assessment of noise characteristics of a / m.

Creating a silent car is impossible just as it is impossible to build an eternal engine. However, it is completely legal. Settlement of the problem of creating a car with minimal acoustic radiation. Naturally, the approach of the design of the car in quality to the design with minimal acoustic radiation is possible when used, first of all means, which represents acoustics at the disposal of a researcher and designer engineer. First of all, the use of vibration insulation and vibration absorption, sound insulation and sound absorption should be considered. This is the first set of methods and means, the reasonable use of which leads to a decrease in the noise of the car. Another combination of methods and means to be used to reduce noise is based on the organization of car workflows and design development that provide minimal acoustic radiation and based on relevant minimization criteria. Vibration isolation (WE) and vibration absorption (VP). The transmission of sound energy from the place of its occurrence to the elements that emit it, is primarily through the parts of the engine or the car units, followed by the transmission of the body panels, which fluctuate under the action of this energy and create noise. The means used in the car to reduce the level of sound vibration, first, prevent the propagation of the energy of the oscillatory motion according to the design (vibration insulation), and secondly, absorb the energy of the oscillatory movement on the path of its propagation (vibration absorption). The oscillatory energy in the sound frequency range is transmitted by structural elements in the form of elastic longitudinal, bending and shear (twisting) waves. In the range of workloads, the deformation of the solid is directly proportional to the voltage (linearity of the deformation process). The properties of the waves and their characteristics in the propagation of rods, plates with different methods of fixing (boundary conditions) are described quite fully in literary sources. Let us dwell only on the determination of the mechanical resistance of the structure (impedance), since the excitation of the construction applied at the point or along the surface line in the car and its units is very widespread. In such problems, the required value is often the oscillatory power transmitted from the source of the excitation in the design, I propagated on it in the form of vibration. The value of the oscillatory capacity transmitted to the structure depends on its mechanical resistance relative to the exciting force.

When analyzing the vibration insulating properties of the car body, i.e., when studying the propagation of vibration on it, it can be considered as a set of interconnected plates and rods. The actual nature of the spread of vibrations on the body is determined by the vibration and insulating properties of these compounds. Taking into account that in the manufacture of the body, it is used mainly welding, we can assume that these compounds are rigid in the overwhelming number. The car units with the body and together are connected, as a rule, with the help of hinges. Such compounds have greater vibration insulation than tough.

Under the obstacle and its vibration-insulating properties, they mean the local jump-like mass change, which can be caused by either a simple logical change in the design or the special placement of the vibration-retention mass in the structure to which the ribs can be attributed.

The widespread use of vibration-heading masses in the design of the car is constrained by increased metal consumption. Experience in using vibration-heading masses in related fields of technology (shipbuilding, tractor construction) shows that their effectiveness is higher than the larger the mass per unit length of the connection.

Stiffness ribs also ensure the effect of energy delay, however, in a very narrow frequency range (the rigid ribs have a pronounced discreteness of action).

Vibrating absorption in vibrational systems is partially due to losses, which are primarily taken to characterize using the energy loss coefficient. Usually on the resonance of the system the value of the oscillatory displacement is inversely proportional to the loss factor. Outside the resonance, these quantities depend on one from another. The design will have large vibrating absorbing properties, if it is used for its manufacture with large internal friction or apply special coatings with a higher loss factor.

List of used literature.

1. Golubev, Novikov "Environment and Transport"

2. Bolopas, Savich "Transport and Environment"

3. Lucanin V.N, and others. "Reducing noise of cars."

4. Fomenko A.Ya. "Reducing motor noise in cities."

5. Malov R.V. et al. "Automobile transport and environmental protection".