Conformal Efficiency Factors of Friction Pairs in Construction Machinery

Formulae for the efficiency factor of moving friction pairs of construction equipment are investigated in terms of their mutual adaptation (conformism) during friction and wear. As a basis, the average coefficients of sliding friction and dimensions of the reference line curves, the half-sums of their products of the worn surfaces microrelief for mating parts are taken. Coefficients of sliding friction and dimensions of reference lines were determined from the partial values of microwear and micromaterial of the normalized system of relative reference lines and convergences. Calculated values of conformal efficiency factors were compared with efficiency factors obtained from the tested dependence, as well as from the wedge operator in the dry friction mode. The research was carried out on the example of model hinges of hydraulic excavator attachments

Conformal Efficiency Factors of Friction Pairs in Construction Machinery

Formulae for the efficiency factor of moving friction pairs of construction equipment are investigated in terms of their mutual adaptation (conformism) during friction and wear. As a basis, the average coefficients of sliding friction and dimensions of the reference line curves, the half-sums of their products of the worn surfaces microrelief for mating parts are taken. Coefficients of sliding friction and dimensions of reference lines were determined from the partial values of microwear and micromaterial of the normalized system of relative reference lines and convergences. Calculated values of conformal efficiency factors were compared with efficiency factors obtained from the tested dependence, as well as from the wedge operator in the dry friction mode. The research was carried out on the example of model hinges of hydraulic excavator attachments

Waste management peculiarities in far north from the perspective of environmental hazard and emergency prevention

The paper considers the peculiarities of waste management in the system of housing and communal services of the northern regions of Russia in the conditions of permafrost and harsh climatic conditions. The authors have studied the topical issues from the point of view of preventing environmental hazards and emergencies of manmade character. Thus, the aim of the present study was to develop scientifically substantiated proposals for the prevention of environmental hazards and emergencies in the regions of the Arctic zone, as well as adjacent territories of the subjects of the Russian Federation, caused by man-made impact of waste. The conducted research with conclusions and recommendations according to its results are carried out on the basis of the developed forecast and within the framework of the chosen scenarios of development of the situation with waste management on ecologically vulnerable territories. In order to achieve the goal of the research, the following scientific and applied tasks have been solved: a systematic analysis of the hazardous waste management situation in the Far North; identification of dangerous environmental factors and threats, which may contribute to emergencies with irreversible consequences for the environment, population and economic development of the Arctic; scientific justification of proposals for the prevention of technospheric impact of waste through the transition of regions to resource-saving The results of the study can be used in the development and updating of concepts, federal target, regional programs in the field of environmental security, prevention of man-made emergencies in the process of life support regions of the Far North, the northern part of Siberia, the Urals, the Far East

Greenhouse gas emission from the cold soils of Eurasia in natural settings and under human impact:Controls on spatial variability

The annual balance of biogenic greenhouse gases (GHGs; carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)) in the atmosphere is well studied. However, the contributions of specific natural land sources and sinks remain unclear, and the effect of different human land use activities is understudied. A simple way to do this is to evaluate GHG soil emissions. For CO2, it usually comprises 60–75% of gross respiration in natural terrestrial ecosystems, while local human impact can increase this share to almost 100%. Permafrost-affected soils occupying 15% of the land surface mostly in the Eurasia and North America contain approximately 25% of the total terrestrial carbon. The biogenic GHG soil emissions from permafrost are 5% of the global total, which makes these soils extremely important in the warming world. Measurements of CO2, methane, and nitrous oxide, from eighteen locations in the Arctic and Siberian permafrost, across tundra, steppe, and north taiga domains of Russia and Svalbard, were conducted from August to September during 2014–2017 in 37 biotopes representing natural conditions and different types of human impact. We demonstrate that land use caused significant alteration in soil emission and net fluxes of GHGs compared to natural rates, regardless of the type and duration of human impact and the ecosystem type. The cumulative effect of land use factors very likely supported an additional net-source of CO2 into the atmosphere because of residual microbial respiration in soil after the destruction of vegetation and primary production under anthropogenic influence. Local drainage effects were more significant for methane emission. In general, land use factors enforced soil emission and net-sources of CO2 and N2O and weakened methane sources. Despite the extended heat supply, high aridity caused significantly lower emissions of methane and nitrous oxide in ultra-continental Siberian permafrost soils. However, these climatic features support higher soil CO2 emission rates, in spite of dryness, owing to the larger phytomass storage, presence of tree canopies, thicker active layer, and greater expressed soil fissuring. Furthermore, the “Birch effect” was much less expressed in ultra-continental permafrost soils than in permafrost-free European soils. Models and field observations demonstrated that the areal human footprint on soil CO2 fluxes could be comparable to the effect of climate change within a similar timeframe. Settlements and industrial areas in the tundra function as year-round net CO2 sources, mostly owing to the lack of vegetation cover. As a result, they could compensate for the natural C-balance on significantly larger areas of surrounding tundra