scholarly journals GEODYNAMICS

GEODYNAMICS ◽  
2020 ◽  
Vol 2(29)2020 (2(29)) ◽  
pp. 66-78
Author(s):  
K. Bezruchko ◽  
◽  
N. Diachenko ◽  
Keyword(s):  
Fault Plane ◽  
Gas Permeability ◽  
Horizontal Shear ◽  
Diagram Method ◽  
Tectonic Stresses ◽  
Shear Field ◽  
Tectonic Disturbance ◽  
Coal Beds ◽  
Fault Scarps ◽  
The Impact

Purpose. The purpose of the paper is the reconstruction of the geodynamic development of the shear dislocation zone (shear stress fields) of the Krasnoarmiiska monocline (KM) of Donbas (Eastern Ukraine) and determining the relationships of their impact on the emergence of gas-dynamic phenomena (GDP) in coal sediments. Methodology. Methods of digital geological cartography, mining-geometric simulation, geological-structural analysis, and structural-geomorphological reconstruction are used for the analysis of structural-geological information. A complex of methods for statistical processing of data on the tectonic disturbance is used – estimation of the frequency of azimuth orientations by the roses-diagram method. Techniques of morphotectonic analysis of the coal bed (a mathematical technique for identifying the gradient structures) are applied. Results. A tectonic model of formation of pull-aparts in the mode of transtension on the territory of KM (on the example of “Dobropilska” mine) is proposed, which results in manifestations of GDP (in particular “wet blowers”) in the form of a small kettle of subsidence in zones of en echelon overlapping of shears. The latter ones are formed under the action of the shear field of tectonic stresses (the axis of space shortening is (σ1) due to the horizontal shear is oriented in azimuth 160-170° (340-350°), the axis of elongation is (σ3) – 70-80° (250-260°). At this, the combination of fringing Y and T faultings in the conditions of transtension, most likely, provides gas permeability and water permeability of the zone. Structure-kinematic relationships of formation and development of shear dislocations of KM at Donbas are researched. Originality. The structural-kinematic relationships in the formation and development of shear dislocations of the Krasnoarmiiskyi district of Donbas and their impact on the formation of GDP zones were studied firstly. They based on the developed digital model of the actual tectonic disturbance of the rock massif on the example of the mining allotments group of KM. It is established for the first time: a) subparallel disjunctives of the NE orientation (15-30°), regardless of morphology, are as the boundaries of parallelogram-like blocks, forming either scaly packets or packets of fault scarps (depending on the morphology of the faultings), limited in the strike by the fault planes of N-NE and SW fall; in the case of scaly packets in the orientation of the fall of the fault plane it is dominated by the E-SE direction, the faultings limiting the fault scarps are characterized by the opposite WN direction of the fall; b) faultings of SE orientation are morphologically represented by shear-thrusts, and with depth change not only the angle of incidence from 35° to 85°, but also the azimuth of strike (from 20-25° to 50°), forming a fanlike feathering of the main faulting in the plan; c) faultings of different morphology are represented not by a single fault plane, but by a series of disturbances on all stratigraphic horizons, which form a zone of faulting formation – a vertical "tectonic strip"; d) in the SE part of the mine "Pioner" a duplex of compression (transpression mode) was found, it is expressed by a folded system (F), up to 287 m wide and fragments of sloping, changing the strike of the Novoiverskyi thrusts; e) the zone of tension duplexes located in the chain, which have a characteristic broken-step configuration at the "Dobropilska" mine, to which “wet blowers” are connected with, develops due to local strike (transtension); f) paragenesis of deformations in the study area corresponds to the shear field of tectonic stresses with north-northwest direction of compression and east-northeast tension, in which fault-shear displacement occurs along with the disjunctive breaks. Practical significance. The established relationships of the impact of shear tectonics on the formation of GDP in coal beds are important both by clarifying the mechanism of tectonogenesis and the nature of pull-aparts formation (en echelon zones of tension), and by the possibility of using additional prognostic criteria for searching for accumulations of free methane and its sudden manifestations (GDP) in coal beds. The application of knowledge of these relationships at mining enterprises will allow reducing the costs for the struggle against dangerous GDP manifestations and predicting them reliably.

Optimal Planning of Distribution System Considering Distributed Generators

2013 ◽  
Vol 291-294 ◽  
pp. 2022-2027
Author(s):  
Hui Shi Liang ◽  
Hai Tao Liu ◽  
Jian Su
Keyword(s):  
Distribution System ◽  
Peak Load ◽  
Optimal Planning ◽  
System Construction ◽  
Peak Shaving ◽  
Diagram Method ◽  
Distributed Generators ◽  
Load Demand ◽  
Substation Planning ◽  
The Impact

This paper presents a methodology for substation optimal planning considering DG for peak shaving. Utility can take effective demand-side management (DSM) to encourage customer-owned DG to participate in peak load shaving, and it can also construct utility DG to meet the peak load demand. In this paper, the impact of DG on peak load shaving is analyzed, and DG is taken as a complement to T&D system to meet load demand, which is considered in the substation planning. Substations sizing and location and new-built utility DG capacity is optimized using Particle Swarm Optimization (PSO), in which supply area of each substation is obtained by Voronoi diagram method. Case study shows that planning result considering DG for peak shaving can defer T&D system expansion so that considerable investment can be saved. Especially for those areas with high cost of T&D system construction, constructing DG to meet peak load demand would be a more economic way.

The effect of anisotropic vesiculation on the porous-permeable evolution in magmatic foams

2021 ◽  
Author(s):  
Jenny Schauroth ◽  
Joshua Weaver ◽  
Jackie E. Kendrick ◽  
Anthony Lamur ◽  
Yan Lavallée
Keyword(s):  
Percolation Threshold ◽  
Gas Flow ◽  
Gas Permeability ◽  
Dominant Mode ◽  
Porous Network ◽  
Near Surface ◽  
Shape Distribution ◽  
Aspect Ratios ◽  
Anisotropic Expansion ◽  
The Impact

<p>Volcanoes can undergo rapid transitions between effusive and explosive eruptions that are often dependant on the melt’s ability to devolatilise and outgas. Eruptive products show widely contrasting permeability values for a given porosity owing to the fact that magma properties evolve over time and space, hence porosity and permeability vary depending on transport and deformation history, scale and orientation. The vesicularity that enables bubble coalescence and permeability development, termed the percolation threshold, is experimentally determined to be at ~30-80 %, depending on the microstructure of magma (i.e. bubble size and shape distribution, crystal content, dominant mode of rheological deformation during vesiculation and flow). During ascent of magma pressure decreases and the magma adapts to these new conditions by vesiculating and expanding against wall rocks. Friction between the vesicular magma and the conduit wall encourages shear, which modifies the architecture of the vesicular network. The geometrical constriction associated with conduits, dykes or fractures which host magma thus prevents or limits the isotropic growth of vesicles; we hypothesise that geometrical constraints instead lead to different ratios of isotropic to anisotropic expansion, which impacts vesicle coalescence and the onset and development of permeable gas flow in magma. We present experimental results detailing the impact of constricting geometry on the development of a permeable porous network, by combining various diameter basalt crucibles with different sized cylindrical cores of aphyric rhyolitic glass (0.12 wt.% H<sub>2</sub>O). We vesiculate the samples in a furnace at 1009 °C for different isothermal dwell increments, before cooling our sample assembly and determining porosity, strain and gas permeability. The vesiculated rhyolites host an impervious glass rind (due to near-surface bubble resorption via diffusion) surrounding a vesicular core; as such, we measure gas permeability of the assembly after cutting the upper and lower glassy rind, to expose the permeability of the internal porous network developed experimentally. The findings indicate that increasing anisotropy, caused by minimising the extent of isotropic vesiculation and maximising vesiculation under constricted conditions, lowers the porosity at which the percolation threshold occurs by ~30 %. We postulate that pure and simple shear, developed parallel to the constricting walls, increase bubble aspect ratios and enhance coalescence. This suggests magmatic foams form connected networks at lower porosities when they vesiculate in constricted conduits, dykes and fractures, thus impacting outgassing efficiency. This implies that the physico-chemical evolution of vesiculating magma may be more strongly linked to structural and rheological controls than previously anticipated, with important implications on ascending magma evolution and eruptive processes, such as degassing, outgassing and fragmentation.</p>

scholarly journals Apparent Permeability Model for Gas Transport in Multiscale Shale Matrix Coupling Multiple Mechanisms

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6323
Author(s):  
Xiaoping Li ◽  
Shudong Liu ◽  
Ji Li ◽  
Xiaohua Tan ◽  
Yilong Li ◽  
...  
Keyword(s):  
Pore Size ◽  
Water Distribution ◽  
Gas Transport ◽  
Water Saturation ◽  
Gas Permeability ◽  
Apparent Permeability ◽  
Permeability Model ◽  
Proposed Model ◽  
Irreducible Water Saturation ◽  
The Impact

Apparent gas permeability (AGP) is a significantly important parameter for productivity prediction and reservoir simulation. However, the influence of multiscale effect and irreducible water distribution on gas transport is neglected in most of the existing AGP models, which will overestimate gas transport capacity. Therefore, an AGP model coupling multiple mechanisms is established to investigate gas transport in multiscale shale matrix. First, AGP models of organic matrix (ORM) and inorganic matrix (IOM) have been developed respectively, and the AGP model for shale matrix is derived by coupling AGP models for two types of matrix. Multiple effects such as real gas effect, multiscale effect, porous deformation, irreducible water saturation and gas ab-/de-sorption are considered in the proposed model. Second, sensitive analysis indicates that pore size, pressure, porous deformation and irreducible water have significant impact on AGP. Finally, effective pore size distribution (PSD) and AGP under different water saturation of Balic shale sample are obtained based on proposed AGP model. Under comprehensive impact of multiple mechanisms, AGP of shale matrix exhibits shape of approximate “V” as pressure decrease. The presence of irreducible water leads to decrease of AGP. At low water saturation, irreducible water occupies small inorganic pores preferentially, and AGP decreases with small amplitude. The proposed model considers the impact of multiple mechanisms comprehensively, which is more suitable to the actual shale reservoir.

scholarly journals Gas Permeability of Cellulose Aerogels with a Designed Dual Pore Space System

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2688 ◽  
Author(s):  
Kathirvel Ganesan ◽  
Adam Barowski ◽  
Lorenz Ratke
Keyword(s):  
Porous Materials ◽  
Cell Walls ◽  
Gas Permeability ◽  
Pore Space ◽  
Nitrogen Adsorption ◽  
Space System ◽  
Fixed Amount ◽  
Hydrophilic Lipophilic Balance ◽  
Wide Range ◽  
The Impact

The gas permeability of a porous material is a key property determining the impact of the material in an application such as filter/separation techniques. In the present study, aerogels of cellulose scaffolds were designed with a dual pore space system consisting of macropores with cell walls composing of mesopores and a nanofibrillar network. The gas permeability properties of these dual porous materials were compared with classical cellulose aerogels. Emulsifying the oil droplets in the hot salt–hydrate melt with a fixed amount of cellulose was performed in the presence of surfactants. The surfactants varied in physical, chemical and structural properties and a range of hydrophilic–lipophilic balance (HLB) values, 13.5 to 18. A wide range of hierarchical dual pore space systems were produced and analysed using nitrogen adsorption–desorption analysis and scanning electron microscopy. The microstructures of the dual pore system of aerogels were quantitatively characterized using image analysis methods. The gas permeability was measured and discussed with respect to the well-known model of Carman–Kozeny for open porous materials. The gas permeability values implied that the kind of the macropore channel’s size, shape, their connectivity through the neck parts and the mesoporous structures on the cell walls are significantly controlling the flow resistance of air. Adaption of this new design route for cellulose-based aerogels can be suitable for advanced filters/membranes production and also biological or catalytic supporting materials since the emulsion template method allows the tailoring of the gas permeability while the nanopores of the cell walls can act simultaneously as absorbers.

scholarly journals On Internal Waves Propagating across a Geostrophic Front

2019 ◽  
Vol 49 (5) ◽  
pp. 1229-1248 ◽  
Author(s):  
Qiang Li ◽  
Xianzhong Mao ◽  
John Huthnance ◽  
Shuqun Cai ◽  
Samuel Kelly
Keyword(s):  
Internal Wave ◽  
Internal Waves ◽  
Wave Reflection ◽  
Wave Theory ◽  
Horizontal Shear ◽  
Mixing Rate ◽  
Reflection And Transmission ◽  
Topographic Slope ◽  
Virtual Boundary ◽  
The Impact

AbstractReflection and transmission of normally incident internal waves propagating across a geostrophic front, like the Kuroshio or Gulf Stream, are investigated using a modified linear internal wave equation. A transformation from depth to buoyancy coordinates converts the equation to a canonical partial differential equation, sharing properties with conventional internal wave theory in the absence of a front. The equation type is determined by a parameter Δ, which is a function of horizontal and vertical gradients of buoyancy, the intrinsic frequency of the wave, and the effective inertial frequency, which incorporates the horizontal shear of background geostrophic flow. In the Northern Hemisphere, positive vorticity of the front may produce Δ ≤ 0, that is, a “forbidden zone,” in which wave solutions are not permitted. Thus, Δ = 0 is a virtual boundary that causes wave reflection and refraction, although waves may tunnel through forbidden zones that are weak or narrow. The slope of the surface and bottom boundaries in buoyancy coordinates (or the slope of the virtual boundary if a forbidden zone is present) determine wave reflection and transmission. The reflection coefficient for normally incident internal waves depends on rotation, isopycnal slope, topographic slope, and incident mode number. The scattering rate to high vertical modes allows a bulk estimate of the mixing rate, although the impact of internal wave-driven mixing on the geostrophic front is neglected.

scholarly journals Design, characterization, and modeling of microcirculation systems with integrated oxygenators

2016 ◽  
Vol 5 (1) ◽  
pp. 221-228 ◽  
Author(s):  
Mathias Busek ◽  
Stefan Gruenzner ◽  
Tobias Steege ◽  
Florian Schmieder ◽  
Udo Klotzbach ◽  
...  
Keyword(s):  
Cell Culture ◽  
Gas Permeability ◽  
Basic Research ◽  
Microfluidic System ◽  
Animal Testing ◽  
Permeable Membrane ◽  
Micro Particle Image Velocimetry ◽  
Hypoxic Conditions ◽  
Culture Models ◽  
The Impact

Abstract. Here, we describe a microfluidic system for hypoxia assays on human cell culture models. These systems are developed to replace or reduce animal testing in biomedical basic research. The presented system uses a gas-permeable membrane as a gas–liquid interface and a micropump for media actuation to influence the oxygen content in two cell culture chambers. To apply well-defined hypoxic conditions to the cells, a good understanding of the mass transport phenomena is necessary. Therefore, a complete network model of the microfluidic system is presented. This model is validated by means of micro-particle image velocimetry (µPIV) and optical oxygen measurement with fluorescence lifetime detection. Finally, the impact of several process parameters, e.g., the gas permeability of the pump, is discussed using the developed model.

scholarly journals Study on the impact of confining pressure on gas permeability of tight sandstone cores

2021 ◽  
Vol 2076 (1) ◽  
pp. 012006
Author(s):  
Jianxiang Tong ◽  
Hengyang Wang ◽  
Yuyi Wang ◽  
Ya Zhang ◽  
Xiaohe Huang
Keyword(s):  
Power Function ◽  
Rate Coefficient ◽  
Gas Permeability ◽  
Confining Pressure ◽  
Experimental Sample ◽  
Tight Sandstone ◽  
Change Rate ◽  
Shengli Oilfield ◽  
Confining Pressures ◽  
The Impact

Abstract Taking the tight sandstone core of Shengli Oilfield as the experimental sample, this paper studies the permeability variation of the tight sandstone under different confining pressures. The experimental results show that when the pore pressure is constant, the measured gas permeability of core decreases with the increase of confining pressure. Power function is more reasonable to describe the influence of confining pressure on permeability of tight sandstone between power function and exponential function. Analyze the impact of confining pressure on gas permeability of tight sandstone cores by using permeability change rate coefficient D and coefficient S.

scholarly journals The Impact of the Amount and Length of Fibrillated Polypropylene Fibres on the Properties of HPC Exposed to High Temperature / Wpływ Ilosci I Długosci Fibrylowanych Włókien Polipropylenowych Na Własciwosci Hpc Poddanego Działaniu Wysokiej Temperatury

2010 ◽  
Vol 56 (1) ◽  
pp. 57-68 ◽  
Author(s):  
I. Hager ◽  
T. Tracz
Keyword(s):  
High Temperature ◽  
Surface Water ◽  
Water Absorption ◽  
Transport Properties ◽  
High Performance ◽  
Gas Permeability ◽  
Research Programme ◽  
Polypropylene Fibres ◽  
Residual Transport ◽  
The Impact

Abstract This paper presents the results of research on high performance concretes (HPC) modified by the addition of polypropylene fibres (PP fibres). The scope of the research was the measurement of the residual transport properties of heated and recooled concretes: gas permeability and surface water absorption. Seven types of concrete modified with fibrillated PP fibres were tested. Three lengths: 6, 12 and 19 mm and three amounts of fibres: 0, 0.9 and 1.8 kg/m3 were used. The research programme was designed to determine which length of fibres, used in which minimum amount, will, after the fibres melt, permit the development of a connected network and pathway for gases and liquids.

scholarly journals Laws of gas draining in the massif disturbed by mining operations

2019 ◽  
Vol 109 ◽  
pp. 00047
Author(s):  
Serhii Kurnosov ◽  
Volodymyr Zerkal
Keyword(s):  
Strain State ◽  
Abutment Pressure ◽  
Gas Permeability ◽  
Experimental Studies ◽  
Rock Massif ◽  
Gas Release ◽  
Mining Operations ◽  
Stress Strain ◽  
Stress Strain State ◽  
The Impact

A method for calculating gas permeability of the rock massif depending on its stress-strain state is presented. By using methods of the mine experimental studies, influence of mining operations in the adjacent long walls on intensity of gas release from the previously worked-out long-pillar was determined, as well as impact of the massif stress-strain state on efficiency of the drainage boreholes. Formulas were obtained for calculating coefficients of the impact of zones with static and dynamic abutment pressure on intensity of gas draining in the previously worked-out long-pillar.

scholarly journals Use of WorldView-2 Along-Track Stereo Imagery to Probe a Baltic Sea Algal Spiral

2019 ◽  
Vol 11 (7) ◽  
pp. 865
Author(s):  
George Marmorino ◽  
Wei Chen
Keyword(s):  
Baltic Sea ◽  
Dynamic Range ◽  
Spatial Scales ◽  
Image Data ◽  
Single Pair ◽  
Horizontal Shear ◽  
Stereo Imagery ◽  
General Topic ◽  
Along Track ◽  
The Impact

The general topic here is the application of very high-resolution satellite imagery to the study of ocean phenomena having horizontal spatial scales of the order of 1 kilometer, which is the realm of the ocean submesoscale. The focus of the present study is the use of WorldView-2 along-track stereo imagery to probe a submesoscale feature in the Baltic Sea that consists of an apparent inward spiraling of surface aggregations of algae. In this case, a single pair of images is analyzed using an optical-flow velocity algorithm. Because such image data generally have a much lower dynamic range than in land applications, the impact of residual instrument noise (e.g., data striping) is more severe and requires attention; we use a simple scheme to reduce the impact of such noise. The results show that the spiral feature has at its core a cyclonic vortex, about 1 km in radius and having a vertical vorticity of about three times the Coriolis frequency. Analysis also reveals that an individual algal aggregation corresponds to a velocity front having both horizontal shear and convergence, while wind-accelerated clumps of surface algae can introduce fine-scale signatures into the velocity field. Overall, the analysis supports the interpretation of algal spirals as evidence of a submesoscale eddy and of algal aggregations as indicating areas of surface convergence.

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