2020 ◽  
pp. 22-31
Author(s):  
M.Ya. Maharramova ◽  
◽  
I.S. Guliyev ◽  
A.B. Huseynov ◽  
E.B. Zeynalov ◽  
...  

The paper reviews the publications on the search and exploration of carbonic nanotubes and other nanocarbonic structures in subsurface rocks. It is shown that the graphenes and carbonic nanotubes (CNT) exist in the composition of various magmatic and sedimentary rocks. They are formed in the graphite globules of volcanic rocks, as well as in the sediments, where the pressure, the particles of metallic catalysts, the tension stresses and time factors in million years compensate the absence of high temperatures. Experimental laboratory modeling of natural processes has been carried out and the reality of formation of carbonic nanostructures during the pyrolysis of volcanic gases on the lava catalysts, mechanical activation and processing of amorphous carbon or bituminous coal shown. Principal possibility of realization of technology of CNT mass production via pyrolysis of hydrocarbon crude material in the presence of different catalytically-active natural minerals has been reviewed and proven. The analysis of the aspects following the activity of mud volcanoes shows that there are all suppositions for the formation of carbonic nanostructures: the pressure bump of deep rocks out of the hot eruptive centre, methane as carbonic crude, catalytically-active breccias containing transition metals and their oxides, the process of methane burning in the medium poor of oxygen. However, it is not yet absolutely clear. As a working hypothesis we propose a model of formation of these structures due to the mud volcanism activity in the reactions of methane flow, the catalysts in which natural minerals exist. In such processes as a result of intensive methane flow, there occur negative pressure values and cavitation effects in the presence of which local temperature and pressure increase efficient for formation of adamantine and nanosize carbonic structures take place. In case if this mechanism is real, the studies point to a perspective of obtaining valuable products in conditions of natural geological processes. There are no messages or publications yet on the exploration of carbonic nanostructures in the rocks of mud volcanoes.


2021 ◽  
Vol 923 (1) ◽  
pp. 128
Author(s):  
Karina Maucó ◽  
Carlos Carrasco-González ◽  
Matthias R. Schreiber ◽  
Anibal Sierra ◽  
Johan Olofsson ◽  
...  

Abstract One of the most important questions in the field of planet formation is how millimeter- and centimeter-sized dust particles overcome radial drift and fragmentation barriers to form kilometer-sized planetesimals. ALMA observations of protoplanetary disks, in particular transition disks or disks with clear signs of substructures, can provide new constraints on theories of grain growth and planetesimal formation, and therefore represent one possibility for progress on this issue. We here present ALMA band 4 (2.1 mm) observations of the transition disk system Sz 91, and combine them with previously obtained band 6 (1.3 mm) and band 7 (0.9 mm) observations. Sz 91, with its well-defined millimeter ring, more extended gas disk, and evidence of smaller dust particles close to the star, constitutes a clear case of dust filtering and the accumulation of millimeter-sized particles in a gas pressure bump. We compute the spectral index (nearly constant at ∼3.34), optical depth (marginally optically thick), and maximum grain size (∼0.61 mm) in the dust ring from the multi-wavelength ALMA observations, and compare the results with recently published simulations of grain growth in disk substructures. Our observational results are in strong agreement with the predictions of models for grain growth in dust rings that include fragmentation and planetesimal formation through streaming instability.


2011 ◽  
Vol 368-373 ◽  
pp. 1458-1462
Author(s):  
Bao Zhu Yao

For operation roadway of anchor net support with rock urst tendency, the paper analyzed mechanism that anchor of roadway depress disaster of pressure bump by use of dynamic theory and researched influence degree of different anchor parameters on surrounding rock of roadway with rock burst hazard by use of numerical simulation software FLAC3D. The research result showed that main influencing factors of deformation of surrounding rock of roadway are length and distance of anchor bolt, sensitivity for anchor parameters of deformation of roadside is higher than roof and bottom of roadway.


Vacuum ◽  
2014 ◽  
Vol 101 ◽  
pp. 142-145
Author(s):  
Ken-ichi Kanazawa
Keyword(s):  

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