Normalization of Thermal Mode of Extended Blind Workings Operating at High Temperatures Based on Mobile Mine Air Conditioners

Thermal working conditions in the deep mines of Donbass are the main deterrent to the development of coal mining in the region. Mining is carried out at the lower technical boundaries at a depth of almost 1,400 m with a temperature of rocks of 47.5-50.0 °C. The air temperature in the working faces significantly exceeds the permissible safety standards. The most severe climatic conditions are formed in the faces of blind development workings, where the air temperature is 38-42 °С. It is due to the adopted coal seam mining systems, the large remoteness of the working faces from the main air supply openings, the difficulty in providing blind workings with a calculated amount of air due to the lack of local ventilation fans of the required range. To ensure thermodynamic safety mine n.a. A.F.Zasyadko we accepted the development of a draft of a central cooling system with ground-based absorption refrigerating machines with a total capacity of 9 MW with the implementation of the three types of generation principle (generation of refrigeration, electrical and thermal energy). However, the long terms of design and construction and installation work necessitated the use of mobile air conditioners in blind development faces. The use of such air conditioners does not require significant capital expenditures, and the terms of their commissioning do not exceed several weeks. The use of a mobile air conditioner of the KPSh type with a cooling capacity of 130 kW made it possible to completely normalize the thermal working conditions at the bottom of the blind workings 2200 m long, carried out at a depth of 1220-1377 m at a temperature of host rocks 43.4-47.5 °С. It became possible due to the closest placement of the air conditioner to the face in combination with the use of a high-pressure local ventilation fan and ducts, which ensured the air flow produced by the calculated amount of air. The use of the air conditioner did not allow to fully normalize the thermal conditions along the entire length of the blind face but reduced the urgency of the problem of normalizing the thermal regime and ensured the commissioning of the clearing face

Germinal center reutilization by newly activated B cells

Germinal centers (GCs) are specialized structures in which B lymphocytes undergo clonal expansion, class switch recombination, somatic hypermutation, and affinity maturation. Although these structures were previously thought to contain a limited number of isolated B cell clones, recent in vivo imaging studies revealed that they are in fact dynamic and appear to be open to their environment. We demonstrate that B cells can colonize heterologous GCs. Invasion of primary GCs after subsequent immunization is most efficient when T cell help is shared by the two immune responses; however, it also occurs when the immune responses are entirely unrelated. We conclude that GCs are dynamic anatomical structures that can be reutilized by newly activated B cells during immune responses

Quantitatively Reduced Participation of Anti-Nuclear Antigen B Cells That Down-Regulate B Cell Receptor during Primary Development in the Germinal Center/Memory B Cell Response to Foreign Antigen

Abstract The peripheral B cell compartment contains high levels of “polyreactivity” including autospecificities. We have described a pathway that certain autoreactive B cells may take in gaining stable access to the foreign Ag-responsive peripheral compartment. This pathway was revealed in mice expressing a targeted Ig H chain transgene encoding BCRs with “multireactivity” for the hapten arsonate and DNA-based autoantigens. B cells expressing such BCRs develop to mature follicular phenotype and locale, and are not short-lived. These B cells express very low levels of BCR, indicating that they are not “ignorant” of self Ag, but do not display features of anergy in in vitro assays. Nonetheless, a variety of states of lymphocyte anergy has been described, and some may only be manifested in vivo. As such, we analyzed the ability of these B cells to participate in a T cell-dependent immune response to arsonate in vivo. These B cells mount an early primary response similar to control B cells, including homing to follicles, migration to the T-B interface, and induction of costimulatory molecules, proliferation, differentiation to AFCs, class switching, and entry into GCs and somatic hypermutation. Nonetheless, these B cells display reduced participation in the latter stages of the GC response and in the anamnestic AFC response. In total, these data suggest that while the autoreactivity of this type of B cell does not result in anergy, the ability of such B cells to participate in a cross-reactive immune response to foreign Ag is compromised.</jats:p

SUBSTANTIATION OF STRENGTH AND STABILITY PARAMETERS OF MINING IN THE SYSTEM "ROCK MASS – ANCHOR –MODIFIED CONCRETE"

The absence of a rock mass anchoring in the Donetsk basin using modified concrete reduces the safety of mining operations and does not ensure its long-term strength and stability in the workings of deep coal mines. The object of the research is mining in the system "rock mass – modified concrete anchor". The subject of the research is the substantiation of the strength and stability parameters of mining. The purpose of the research is to reveal the regularities of the stress–strain state of the "rock mass - modified concrete anchor" system to substantiate the parameters of fixing the rock mass, ensuring the safety of mining operations, increasing stability and reducing the cost of mining deep coal mines. The research methods: mathematical modeling of the stress-strain state of the "rock mass – anchor – modified concrete" system. The design scheme of a rock mass presented in the form of a thick shell with anisotropic layers of rocks under the influence of rock pressure and two boundary conditions is considered. A mathematical model of the stress-strain state (VAT) of the "rock mass-anchor-modified concrete" system is given. The obtained results of stress studies and a nomogram for the dimensionless quantities determination allowed the authors to substantiate the parameters of the system that ensure its strength and stability in the mine workings of deep coal mines.</jats:p