Первый слайд презентации: SIW Theme : “Hygienic estimation of infra- and ultrasound and laser radiation. Prophylaxis of the unfavorable action.”
Слайд 2: Plan:
Introduction Characteristics of infra- and ultrasound and laser radiation. Effect of the organism by infra- and ultrasound and laser radiation. Prophylaxis of adverse effects of infra- and ultrasound and laser radiation. Conclusion. References.
Слайд 3: Introduction
Installed by the researches that prolonged exposure to noise of a person affects their health. Hearing aid man is only one gate through which noise enters the body and affects the Central nervous system. Production person “gets used” to the noise and it seems that the noise bothers him less. However, this impression is deceptive-in fact, the harmful effects of noise continues regardless of whether the person pays attention to it or not, whether there is noise in audible frequency range or not.
Слайд 4: Infrasound at working places
Infrasound -sound waves with frequencies lying either lower band of audible (acoustic) frequency is approximately 16-20’000 Hz. Energy characteristics of infrasound are common (linear) sound pressure level and the equivalent (energy)general (linear) sound pressure level. General (linear) sound pressure level, dB Lin -the value, measured on a scale of a sound level meter “linear”, or calculated by energy summation of sound pressure levels on octave bands of frequencies without adjustment-lactation octave amendments. The equivalent (energy) general (linear), L eqv, dB Lin, irregular for infrasound-level continuous broadband infrasound, which has the same mean square sound pressure as this intermittent infrasound within a certain time interval.
By the nature of spectrum, infrasound consists of: - broadband infrasound, with continuous spectrum wider than one octave; - tone infrasound, audible range which are discrete components. The harmonic nature of the infrasound install in octave bands of frequencies exceeds one lane over adjacent not less than 100 dB. By the time characteristics divides into several types: -permanent infrasound, the sound pressure level of which varies during the observation period not more than 2 times (6dB) when measuring on a scale of a sound level meter1 “linear” temporary feature “slowly”; -intermittent infrasound, the sound pressure level of which varies over the observation time of not less than 2 times (6 dB) when measuring on a scale of a sound level meter “linear” temporary feature “slowly”
The source of the infrasound The characteristic frequency the range of infrasound The levels of infrasound Road transport The entire range of the infrasound range 70-90 outside dB inside dB to 120 dB Railways and trams 10-16 dB Inside and outside from 85 to 120 dB Industrial installation aerodynamic and percussion 8-12 Hz To 90-105 dB Ventilation of industrial plants and premises, the same in the metro 3-20 Hz Up to 75-95 dB Jets About 20 Hz Outside to 130 dB
Слайд 7: Peculiarities of infrasound for organism
Infrasound adversely affects human health, especially on mental health. Brain awake person varies with a frequency of 9-13 Hz. Infrasound has a negative impact on the entire human body, including the organ of hearing, reducing auditory sensitivity at all frequencies. Infrasound vibrations are perceived as physical exercise: fatigue, headache, dizziness, vestibular disorders, reduced visual acuity and hearing, impaired peripheral circulation, a feeling of fear, etc the severity of the impact depends on the frequency range, sound pressure level and duration.
Слайд 8: Ultrasound at working places
Ultrasound -sound waves with frequencies lying above the audible (acoustic) frequency is approximately from 20 kHz to milliard Hz. According to the method of propagation of ultrasound oscillations provide: Contact method -ultrasound is spread by contact with hands or other parts of the human body with the sourse of ultrasound, workpieces, means for their retention, voices liquid, scanners, medical diagnostic and other devices, physiotherapy and surgical ultrasonic apparatus Air method - ultrasound travels through the air. Energy performance of air ultrasound are sound pressure levels in decibels in one-third octave bands with geometric mean frequencies: 12.5, 16, 20, 25, 31.5, 40, 50, 63, 80, 100 kHz.
The type of sources of ultrasound vibrations, there are: Hand sources; Stationary sources. Spectral characteristics for the ultrasonic-vibration release: Low frequency ultrasound, from 16 to 63 kHz; Mid-frequency ultrasound between 125 and 250 kHz; High-frequency ultrasound is from 1.0 to 31.5 MHz. By the mode of generation of ultrasonic vibration, there are: stable ultrasound; Pulse ultrasound. According to the method of radiation of ultrasonic vibrations: Sources with a magnetostrictive generator; Sources with piezoelectric generator.
Слайд 10: Peculiarities of ultrasound for organism
After prolonged use with low-frequency units, generating noise and an ultrasound exceeding the prescribed remote control can cause functional changes in the Central and Peripheral nervous system, cardiovascular system, auditory and vestibular apparatus, etc compared with high-frequency noise ultrasound is much weaker impact on auditory function, but causes a more pronounced deviation from the norms of vestibular function, pain sensitivity and thermoregulation. That ultrasound affects different organs and systems of man, not only via the hearing aid, is confirmed by its adverse effect on the deaf.
Слайд 11: Laser radiation at working places
Laser system includes an active (laser) medium with an optical resonator, the energy source of its excitation and, as a rule, the cooling system. Due to the monochromaticity of the laser beam and its low divergence (high degree Calibre ) are formed exclusively by the high energy exposure, allowing to obtain a local thermal effect. Laser radiation can spread over long distances and to fight back from the interface of two media that allows to use this property with the goal location, navigation, communication.
The most widespread at present in the national economy received the lasers generating electromagnetic radiation with a wavelength of 0.33, 0.49, 0.63, 0.69, 1.06, 10,6µm i.e the range of wavelengths of electromagnetic radiation includes the following areas: UV - a from 0.2 to 0.4 microns; Optical -over 0.4 to 0.75 microns; Near infrared -more than 0.75 to 1.4 microns; Far infrared -is more than 1.4 microns
Слайд 13: The main physical quantities characterizing laser radiation are:
Wavelength ƛ, µm Irradiance ( power density Wi), W/cm-the ratio of the radiation flux falling on surface area, consider the area of the site; Energy exposition N, Dj /cm2-the ratio of radiation energy falling on the surface area considered in the area of the site; Duration of pulse I,s Duration of exposure t-exposure time of laser radiation on the person within the work shift; The pulse repetition frequency fi, Hz number of pulses for 1 s.
Слайд 14: Peculiarities of laser radiation for organism
The main element of the visual apparatus human retina can be affected only by radiation in visible (0.4 µm) and near of diapasons (up to 1.4 µm), due to the spectral characteristics of the human eye. The lens and eyeball, acting as an additional focusing optics, greatly increase the concentration of energy on the retina. This, in turn, by several orders of magnitude reduces the maximum permissible level (MPL) of irradiation of the pupil
Слайд 15: Prophylaxis of adverse effects of infra- and ultrasound and laser radiation
For collective protection against exposure to elevated levels of ultrasound and infrasound can be used in the following areas: the reduction of harmful radiation of ultra-infrasonic energy in the source of its occurrence; the localization of the action of ultra-infrasound, constrictive and planning solutions; conducting organizational and preventive measures. To reduce the harmful radiation of sound energy at the source is recommended to increase the working frequency of ultra-infrasound and rule out spurious radiation of sound energy.
When working with lasers it is necessary to provide such working conditions in which not exceeded the maximum permissible levels pf exposure to eyes and skin. Security measures are to protector screens, sewer laser radiation through optical fibers, the use of protective glasses. Protective eyewear should be carefully selected depending on the operating wavelength of laser light, and their transmittance spectrum must be checked. Sunglasses should effectively restrain the radiation of the laser, however, not to be too dark. To protect against scattered radiation, in addition to using points, use a special color or finish of the walls of the laboratory, as well as, fence screens.
Слайд 17: Conclusion
Precautionary and current sanitary inspection is a part of a larger effort to prevent infra-ultrasonic, laser radiation pathology. The weakening of infra-ultrasound, laser radiation in the source of education is the most radical means of dealing with low-frequency vibrations of machines and mechanisms. Persons exposed to infra-ultrasound, laser radiation, pass preliminary and periodic medical examinations
Последний слайд презентации: SIW Theme : “Hygienic estimation of infra- and ultrasound and laser radiation: References
Пивоваров Ю.П., Королик В.В., Зиневич Л.С. Гигиена и основы экологии человека.-М.: Издательский центр «Академия», 2004..-528 с. Беляков В.Д., Жук Е.Г. Военная гигиена и эпидемиология, 1988 А.М.Большаков. Руководство к лабораторным занятиям по общей гигиене. М.Медицина, 2004-400 с. Пивоваров Ю.П. Гигиена и основы экологии человека Р-Н-Д Феникс, 2005 А.М. Лакшин, В.А. Катаева. Общая гигиена с основами экологии человека: Учебник.-М.:Медицина, 2004