Effect of natural pressure drop in mine main ventilation

Natural ventilation in a mine is ventilation without the use of means of artificial ventilation. The flow of mine air is induced by the difference between the mass column in an intake and that in a return. The difference in mine air density is a result of difference between the temperature of intake air and that of return air. To a certain extent, the influence of differences in mine air humidity and chemical composition can act as well. Gassy mines in the Czech Republic and Ukraine are ventilated merely artificially, i.e. by means of exhaust ventilation. However, even in the case of this type of ventilation, when the total mine air flow is produced by fans, a natural current of air exists and acts in the ventilation network of the mine.Web of Science59250850

PROVJETRAVANJE U RUDNICIMA REPUBLIKE ČEŠKE I UKRAJINE

The present-day micro-climatic conditions in black coal mines are of such nature that in no mine natural micro-climate conditioning is sufficient any more. The original temperature of rocks grows progressively in dependence on the increasing depth of the extracted seam, or more precisely, on the mining workplace, and this growth is much more significant than previously considered. The temperature of the surrounding rocks, but also high-performance continuous miners and conveyor belt drives heat up airflow, thus worsening microclimatic conditions. This article describes micro-climatic conditions the in Czech Republic and Ukraine and some methods of deep mines air conditioning.Današnji mikroklimatski uvjeti u rudnicima bituminoznog ugljena su takvi da prirodni mikroklimatski uvjeti ni u jednom rudniku više nisu zadovoljavajući. Leţišna temperatura stijena raste progresivno s povećanjem dubine eksploatacijskog sloja ili preciznije mjesta dobivanja i taj rast je značajniji od prethodno razmatranog. Temperatura okolnih, pratećih stijena, ali takoĎer i visokoučinkoviti strojevi za kontinuirano dobivanje i pogon transpotnih traka zagrijavaju zračnu struju i tako dodatno pogoršavaju mikroklimatske uvjete. Rad opisuje mikroklimatske uvjete u podzemnim ugljenokopima Republike Češke i Ukrajine i neke metode provjetravanja dubokih rudnika

Preliminary Results of Marine Electromagnetic Sounding with a Powerful, Remote Source in Kola Bay off the Barents Sea

We present an experiment conducted in Kola Bay off the Barents Sea in which new, six-component electromagnetic seafloor receivers were tested. Signals from a powerful, remote super-long wave (SLW) transmitter at several frequencies on the order of tens Hz were recorded at the six sites along a profile across Kola Bay. In spite of the fact that, for technical reasons, not all the components were successfully recorded at every site, the quality of the experimental data was quite satisfactory. The experiment resulted in the successful simulation of an electromagnetic field by the integral equation method. An initial geoelectric model reflecting the main features of the regional geology produced field values that differed greatly from the experimental ones. However, step-by-step modification of the original model considerably improved the fit of the fields. Thereby specific features of the regional geology, in particular the fault tectonics, were able to be corrected. These preliminary results open the possibility of inverse problem solving with more reliable geological conclusions

Electrochemical activation of molecular nitrogen at the Ir/YSZ interface.

Nitrogen is often used as an inert background atmosphere in solid state studies of electrode and reaction kinetics, of solid state studies of transport phenomena, and in applications e.g. solid oxide fuel cells (SOFC), sensors and membranes. Thus, chemical and electrochemical reactions of oxides related to or with dinitrogen are not supposed and in general not considered. We demonstrate by a steady state electrochemical polarisation experiments complemented with in situphotoelectron spectroscopy (XPS) that at a temperature of 450 °C dinitrogen can be electrochemically activated at the three phase boundary between N2, a metal microelectrode and one of the most widely used solid oxide electrolytes—yttria stabilized zirconia (YSZ)—at potentials more negative than E = −1.25 V. The process is neither related to a reduction of the electrolyte nor to an adsorption process or a purely chemical reaction but is electrochemical in nature. Only at potentials more negative than E = −2 V did new components of Zr 3d and Y 3d signals with a lower formal charge appear, thus indicating electrochemical reduction of the electrolyte matrix. Theoretical model calculations suggest the presence of anionic intermediates with delocalized electrons at the electrode/electrolyte reaction interface. The ex situSIMS analysis confirmed that nitrogen is incorporated and migrates into the electrolyte beneath the electrode

Toktrapport fra det norsk/russiske økotoktet i Barentshavet og nærliggende områder

The aim of the joint Norwegian/Russian ecosystem survey in the Barents Sea and adjacent waters, August-October (BESS) is to monitor the status and changes in the Barents Sea ecosystem and provide data to support stock advice and research. The survey has since 2004 been conducted annually in the autumn, as a collaboration between the Institute of Marine Research (IMR) in Norway and the Polar branch of the VNIRO (PINRO) in Russia. The general survey plan and tasks were agreed upon at the annual IMR-PINRO Meeting in March 2022. Ship routes and other technical details are agreed on by correspondence between the survey coordinators. BESS aims at covering the entire Barents Sea. Ecosystem stations are distributed in a 35×35 nautical mile regular grid, and the ship tracks follow this design. Exceptions are the area around Svalbard (Spitsbergen), some additional bottom trawl hauls for demersal fish survey indices estimation, and additional acoustic transects for the capelin stock size estimation. Survey start for the Russian vessel was significantly delayed, resulting in REEZ being covered two-three months later than NEEZ. This resulted in reduced area coverage, decrease in the numbers of trawl hauls, and lack of standard pelagic trawl sampling. In NEEZ, RV “Kronprins Haakon” was cancelled due to difficult economic situation, making it necessary to allocate one of the two remaining vessels to the area west and north of Svalbard (Spitsbergen). This resulted in low coverage in this area, and problems with synoptic coverage in north-east of Svalbard (Spitsbergen) and thus increased uncertainty in assessment of demersal fish (e.g. Greenland halibut) and capelin. The 19-th joint Barents Sea autumn Ecosystem Survey (BESS) was carried out in two periods. The Norwegian research vessels “G.O. Sars” and “Johan Hjort” covered NEEZ in the period 16-th August to 03-th October, providing data to stock assessment, 0-group fish abundance indices, and state and changes descriptions which is comparable with earlier survey years in NEEZ. The Russian research vessel “Vilnyus” covered REEZ in the periods 20-th to 30-th September and 22-th October to 3-rd December. Survey coordinators in 2022 were Dmitry Prozorkevich (PINRO) and Geir Odd Johansen (IMR). Exchange of Russian and Norwegian experts between each country’s respective vessels did not take place in 2022. We would like to express our sincere gratitude to all the crew and scientific personnel onboard RVs “Vilnyus”, “G.O. Sars” and “Johan Hjort” for their dedicated work, as well as all the people involved in planning and reporting of BESS 2022. This report is a summary of observations and status assessment based on the survey data. Even though the survey was not well completed, the data obtained are the main source of knowledge about the ecosystem of the Barents Sea.Survey report from the joint Norwegian/Russian Ecosystem Survey in the Barents Sea and the adjacent waters August- December 2022publishedVersio

Development and validation of HERWIG 7 tunes from CMS underlying-event measurements

This paper presents new sets of parameters (“tunes”) for the underlying-event model of the HERWIG7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG7, and are obtained from a fit to minimum-bias data collected by the CMS experiment at s=0.9, 7, and 13Te. The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the dat

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

Measurement of the top quark Yukawa coupling from t(t)over-bar kinematic distributions in the dilepton final state in proton-proton collisions at root s=13 TeV

Peer reviewe

Measurement of nuclear modification factors of gamma(1S)), gamma(2S), and gamma(3S) mesons in PbPb collisions at root s(NN)=5.02 TeV

The cross sections for ϒ(1S), ϒ(2S), and ϒ(3S) production in lead-lead (PbPb) and proton-proton (pp) collisions at √sNN = 5.02 TeV have been measured using the CMS detector at the LHC. The nuclear modification factors, RAA, derived from the PbPb-to-pp ratio of yields for each state, are studied as functions of meson rapidity and transverse momentum, as well as PbPb collision centrality. The yields of all three states are found to be significantly suppressed, and compatible with a sequential ordering of the suppression, RAA(ϒ(1S)) > RAA(ϒ(2S)) > RAA(ϒ(3S)). The suppression of ϒ(1S) is larger than that seen at √sNN = 2.76 TeV, although the two are compatible within uncertainties. The upper limit on the RAA of ϒ(3S) integrated over pT, rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy ion collisions to date. © 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.Peer reviewe