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Wyszukujesz frazę "ventilation hazards" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
The influence of alternative characteristics of the vicinity of the ventilation district on air quantity
Autorzy:
Pach, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/220241.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wentylacja kopalni
rejon wentylacji
zagrożenie wentylacyjne
mine ventilation network
ventilation district
alternative characteristics
ventilation hazards
Opis:
Subnetwork with two nodes shared with entire ventilation network can be separated as its part. For the network under common ventilation conditions, one of these nodes will become the subnetwork starting node, while the other will be the subnetwork end node. According to the graphs theory, such a piece of the network can be considered as a subgraph of the graph representing the entire ventilation network. A special feature of that subgraph is lack of predecessors of the subnetwork starting node and lack of successors of the subnetwork end node. Ventilation district of a mine may be often treated as a subnetwork. Vicinity is a part of the network which is not separated as subnetwork. In the case of a ventilation district its vicinity forces air flow through the district. The alternative characteristic curve of the vicinity can therefore be compared to the characteristics curve of a fictional fan that forces the airflow in the district. The alternative characteristics (later in the text: the characteristics) of the vicinity of the ventilation district in an underground mine strongly influence air quantity and therefore play a crucial role in the reduction of methane, fire and thermal hazards. The role of these characteristics and proper selection of their approximating function were presented in the article. The reduction of resistance of an intake stopping (having influence on entire resistance of a ventilation district) produces increased airflow in the district. This changes of airflow in the district caused by a variation in internal resistance (e.g. by opening an internal regulation stopping) depends on the characteristic of the vicinity of the district. Proper selection of its approximating function is also important for this matter. The methods of determination of the alternative characteristic curve of the district vicinity are presented. From these procedures it was possible to obtain the results of air quantities and differences in isentropic potentials between an inlet and an outlet to/from the ventilation district. Following this, the characteristics were determined by graphic and analytic methods. It was proved that, in contrast to flat vicinity characteristics, steep ones have a smaller influence on the airflow modification in the district (which are caused by a regulation of the district resistance). The characteristic curve of the vicinity determines the ability to regulate air quantity and velocity in the district.
Źródło:
Archives of Mining Sciences; 2020, 65, 1; 47-58
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the Permeability of the Longwall Goaf Zones on the Location of an Area With Explosive Methane Concentration Levels
Autorzy:
Tutak, Magdalena
Palka, Dorota
Powiązania:
https://bibliotekanauki.pl/articles/2064793.pdf
Data publikacji:
2020
Wydawca:
STE GROUP
Tematy:
methane hazards
longwall
mining operation
longwall ventilation system
goaf
CFD
Opis:
One of the basic ventilation hazards and, at the same time most dangerous, in hard coal mines is the methane hazard. During the exploitation process using the longwall system with the breaking down of roof rocks, methane is released into mining excavations from both mined coal and the one left in goaves. Significant amounts of methane also flow from the underworked and overworked seams, through cracks and fissures formed in the rock mass. When accumulated at an explosive concentration level in goves and at an appropriate oxygen concentration level and the occurrence of a trigger (e.g. a spark or endogenous fire), methane may either explode or ignite. These are immensely dangerous phenomena. Therefore, the possibility of their occurrence should be limited. The article presents the results of the research aimed at determining the impact of the permeability of goaf zones on the distribution of methane and oxygen concentration levels in these goaves. The study was carried out for the longwall ventilated with the Y system. The model analysis was conducted, the results of which allowed the authors to determine these distributions. On their basis, both the location and size of the areas in which hazardous methane concentrations could occur were designated. The results are of great practical importance as they indicate areas in goaves where preventive measures should be implemented.
Źródło:
Multidisciplinary Aspects of Production Engineering; 2020, 3, 1; 238--247
2545-2827
Pojawia się w:
Multidisciplinary Aspects of Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of Toxic Substances Emission for Occupational Exposure Assessment
Autorzy:
Benczek, K. M.
Gawęda, E.
Kurpiewska, J.
Powiązania:
https://bibliotekanauki.pl/articles/90217.pdf
Data publikacji:
2000
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
emission
occupational safety
chemical hazards
methods for prediction of emission
ventilation
air purity
emisja
bezpieczeństwo pracy
zagrożenia chemiczne
wentylacja
Opis:
Methods for predicting organic solvents, chromic acid, mineral oil, styrene, and sulphuric acid emissions in painting, metal degreasing, wood preservation, chromium electroplating, turning, grinding, making glass fortified polyester laminates and lead batteries charging, injection moulding of polystyrene plastics, and making polyurethane foam processes are described. Experimentally introduced equations are based on the essential parameters of these processes. Knowing the emission and the total flow rate of ventilation, it is possible to calculate toxic agent concentration, which is the basis of occupational exposure assessment.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2000, Zeszyt Specjalny; 35-43
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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