Vibration (LAT. Vibratio — Cool, trembling) — Mechanical oscillations. The vibrations also speak in a narrower sense, implying mechanical oscillations that have a tangible effect on man.
Natural source of vibration are storms, earthquakes. Artificial - various engines, vehicles, acoustic systems, vibroinstruments and t.D. Transferring through reinforcement, soil, overlap, water, the atmosphere vibration can spread to considerable distances and reach individual parts of the human body or affect the entire person, causing a local or general impact (local or total vibration).
Nothing passes without a trace
The frequency spectrum of vibration covers infrasound frequencies - up to 16 Hz., Sound - from 16 to 20,000 Hz and Ultrasound - Over 20,000 Hz. The frequency of oscillations that can cause the largest specific vibration sensation in humans, usually lies in the region of up to 8000 Hz. Vibration as an irritant is characterized by oscillatory capacity and duration of impact on the body.
The biological effect of vibration action is determined by the local energy intensity of oscillations, causing voltage variable in tissues: compression and stretching, shift from the natural axis of resting, twisting and bends of fabrics and liquids. Vibration facilitates the circulation of the fluid, can cause the decay of molecules in the cell protoplasm (the inner liquid part of the cell), intensifies enzyme reactions, increases the permeability of cell membranes, is able to cause restructuring in the chromosomal cell apparatus.
In addition, the vibration can cause the whole organism for the restructuring of many functions by engaging in the reaction of the central nervous system and endocrine systems. Moderate doses of non-intensive vibration have a stimulating effect on the CNS, intensify the redox processes and the activity of the system of the pituitary gland, the bark of adrenal glands, thyroid gland, etc., What is used in therapeutic purposes. The increase in the same dose of vibration leads to progressive functional and morphological violations in the body.
Ways to transfer vibration on the human body
For transmission methods, distinguish:
overall vibration transmitted through supporting surfaces on the body of a sitting or standing person;
Local vibration transmitted through hands or feet of man, as well as through forearm contacting with vibrating surfaces.
Source of origin
Depending on the source of the occurrence, the following types of vibration distinguish:
Local vibration transmitted by man from manual mechanized (with engines) tool;
Local vibration transmitted to man from a manual non-mechanized tool;
Total vibration 1 category — Transport vibration, affecting a person at the workplaces of vehicles moving around the terrain, roads, etc.'Example: Tractors, trucks;
Total vibration 2 categories — Transport and technological vibration, affecting a person on workplaces of machines moving on specially prepared surfaces of industrial premises and T. NS. Example: cranes, outdoor production transport;
Total vibration 3 categories — Technological vibration, affecting a person at the workplaces of stationary cars or transmitted to jobs that do not have vibration sources. Example: Machines, Foundry Machines.
Total vibration in residential premises and public buildings from external sources. Example: Vibration from the passing tram.
Total vibration in residential premises and public buildings from internal sources. Example: Elevators, Refrigerators.
The emergence of vibration
Vibration occurs in a wide variety of technical devices due to the imperfection of their design, improper operation, external conditions (for example, road leaf relief for cars), as well as specially generated vibration.
Impact on the body
Action of vibrations per person different. It depends on whether the whole organism or part is involved in it, from frequency, strength and duration, etc. The impact of vibration can limit the feeling of concussion (pallestsia) or lead to changes in the nervous, cardiovascular, musculoskeletal systems.
Due to the stressful nature of the influence of vibration, violations of the entire system of interconnection of the neurohumoral regulation of functions and metabolic processes occur: the functions of cardiovascular, digestive, gender systems, liver, kidneys, immunological protection and.D. There may be injuries of internal organs due to their offset.
Thus, with a long-term effect of vibration, a person develops vibration disease. Chronic impact of vibration causes swelling and hemorrhages in the head and spinal cord, the growing of connective tissue, swelling, hemorrhage and dystrophic changes in organs, blood composition impairment. In the arteries, there are changes like those with refrigerating endarteritis. Possible damage to the skin and its appendages (nails, hair, etc.), right up to the development of the gangremen fingers. Osteoporosis, deforming arthrosis, osteochondropathy develop in the kosost-articular apparatus.