THE ANALYSIS OF ADMISSIBLE LEVEL OF FORMALDEHYDE IN AIR

By production of glued and plate wood-base materials with use of carboamidoformaldehyde pitches (KFS) the main lack of technology of which is toxicity of these materials to the person. Toxicity is caused by allocation from these materials of gas, harmful to the person, - formaldehyde which is cancerogenic substance. Wood-shaving plates from needle (DSTP) and large-size shaving (OSB), fiber boards (DVP) including the Intermediate-density fiberboard (MDF), and also plywood of general purpose and different types of special plywood (decorative, bakelized, etc.), first of all, belong to such materials. The Russian Ministry of Health has established very strict requirements on release of formaldehyde in air both in premises, and in free air the admissible level of which makes (DU) only 0,01 mg/m3 of air when testing materials by chamber method. The plate materials released now can exceed DU of 17 times stated above. Especially it concerns DSTP. Despite attempts of institute Vniidrev through appeals to relevant authorities of the Ministry of Health to increase such admissible level in our country, generally for plate materials, were not crowned with success yet and this level in real time remains in force. It is possible to use such plates in premises only at very small saturation them room void volume (the saturation is defined as the relation of surface area of plates indoors to room void volume). So, by our researches for example it is proved that the written dvukhtumbovy table made of DSTP of class of release of formaldehyde E2 can be established in living room of 20 sq.m only one and no more. Only in this case, at small saturation room void volume plates, the release of formaldehyde in air of the room will meet requirements of domestic DU. In premises the case furniture is in reality with much bigger saturation that leads to room gas contamination formaldehyde. In too time abroad formaldehyde size DU in air much more also makes 0,124 mg/m3 of air. In this regard the purpose of our work consisted in the analysis of DU of formaldehyde in air of foreign researches.

ADAPTATION OF THE LEAF STRUCTURE OF OAK PETIOLATE (QUERCUS ROBUR) TO THE GAS CONTENT OF THE AIR

The conducted studies have revealed possible ways of adaptation of oak petiolate at the organ-organizational level of the organization and established morphological and anatomical structure of the leaf under conditions of atmospheric gas contamination were shown.

PREVALENCE OF NEOPLASMS IN EMPLOYEES OF A GRID ENERGY ENTERPRISE

The working conditions of the employees of the grid power company are associated with high levels of EMF, dust and gas contamination, which determined the growth of neoplasms, increased the risk of their occurrence, the average degree of industrial conditionality in older age and experience groups, and the need to develop medical and preventive recommendations.

Anthropogenic impact on the air environment condition of megalopolis and suburban areas of forestland

The anthropogenic impact of the megalopolis on the release of volatile matters by woody plants, air ionization in the suburban areas of the forestland for the period 1998 - 2018 was monitored. A decrease in the emission of volatile matters by woody plants, negative ions, an increase in positive ions was revealed. The composition of the air environment of a megalopolis for a long time was studied. It has been established that anthropogenic factors (dust content, gas contamination, electromagnetic radiation) increase the amount of positive ions by order of magnitude. It was revealed that the presence of electromagnetic radiation significantly affects the physical properties of air. The effect of ionization and volatile matters on the deposition rate of suspended particles was determined in laboratory conditions. Theoretical studies have been carried out, on the basis of which deterministic, differential equations of the effect of ionization on dust content, gas contamination of the air environment and the interaction of air ionization with polydisperse dust, volatile substances to produce adsorbate and its deposition rate have been obtained. The data of experimental and theoretical studies made it possible to develop measures to reduce anthropogenic environmental factors, which will improve the ecological situation and reduce the incidence of megalopolis residents.

Simulation of dynamic phenomena in the ventilation network due to sudden gas outburst

An increase in the pace of cleaning and preparatory work, a transition to deeper horizons, a high concentration of machines and mechanisms in places where minerals are excavated and transported increase the likelihood of one of the most difficult and dangerous types of underground accidents - sudden outbursts of coal, rock and gas. In the event of a sudden outburst, the air distribution existing in the ventilation network experiences a sharp dynamic effect, leading to a violation of the stability of the ventilation of the workings close to the center of the outburst and the overturning of the air flow in them. The methane released in this case forms an atmosphere dangerous for humans in the adjacent workings. The size of the gas contamination zone depends on many factors: the intensity of the outburst, the ventilation scheme of the mine, the presence of ventilation facilities, their number, and others, and can become the object of special studies, including the study of the outburst process itself and its interaction with the ventilation network. The specificity of the occurrence of an oytburst as a type of accidents does not allow obtaining statistical and experimental results directly during its course, which greatly complicates the study of this process. In this regard, the most acceptable research method that allows assessing the results of the interaction of the outburst with the ventilation network and, guided by them, to develop effective measures to eliminate its consequences and restore the normal functioning of the mine, is the simulation method using a PC. The article analyzes the stages of changes in the mining-geological and mining-technical conditions preceding the occurrence of the outburst, the stage of the outburst, the calculation formulas are given, by which it is possible to evaluate the configuration and dynamics of the development of the zone polluted with methane as a result of the outburst. The results of modeling the gas-dynamic manifestations of the outburst and its effect on the state of mine ventilation are of great importance in ventilation calculations in emergency modes in order to use the possibilities of ventilation effects on an emergency, limit emergency zones and increase the effectiveness of eliminating the consequences of an accident.

What is the physics behind the Larson mass–size relation?

ABSTRACT Different studies have reported a power-law mass–size relation M ∝ Rq for ensembles of molecular clouds. In the case of nearby clouds, the index of the power-law q is close to 2. However, for clouds spread all over the Galaxy, indexes larger than 2 are reported. We show that indexes larger than 2 could be the result of line-of-sight superposition of emission that does not belong to the cloud itself. We found that a random factor of gas contamination, between 0.001 per cent and 10 per cent of the line of sight, allows to reproduce the mass–size relation with q ∼ 2.2–2.3 observed in Galactic CO surveys. Furthermore, for dense cores within a single cloud, or molecular clouds within a single galaxy, we argue that, even in these cases, there is observational and theoretical evidence that some degree of superposition may be occurring. However, additional effects may be present in each case, and are briefly discussed. We also argue that defining the fractal dimension of clouds via the mass–size relation is not adequate, since the mass is not necessarily a proxy to the area, and the size reported in M−R relations is typically obtained from the square root of the area, rather than from an estimation of the size independent from the area. Finally, we argue that the statistical analysis of finding clouds satisfying the Larson’s relations does not mean that each individual cloud is in virial equilibrium.