Simulated electrical conductivity response of clogging mechanisms for managed aquifer recharge

Geophysics ◽  
2014 ◽  
Vol 79 (2) ◽  
pp. D81-D89 ◽  
Author(s):  
A. Rowan Cockett ◽  
Adam Pidlisecky
Keyword(s):  
Electrical Conductivity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Film Growth ◽  
Volume Fraction ◽  
Pore Space ◽  
Managed Aquifer Recharge ◽  
Aquifer Recharge ◽  
Conductive Film

Motivated by the need for improved understanding and monitoring of clogging during managed aquifer recharge, we use numerical experiments to evaluate the effect of three different clogging mechanisms on electrical conductivity (EC), porosity, specific surface area, and electrical tortuosity of a simulated sediment pack. The clogging experiments are designed to simulate effect of clogging due to: (a) addition of finer grains, (b) addition of nonconductive films, and (c) addition of conductive films. The simulations involved starting with a random grain pack of 43% porosity, and subsequently reducing the porosity as would occur during clogging. For each of the experiments, we compute the EC response, specific surface area, and electrical tortuosity across the range of porosities. The differences in EC response between (a) and (b) is minor, however, the sediment parameters measuring pore-space configuration show very different responses (i.e., specific surface area and tortuosity), indicating EC is limited in its sensitivity to specific pore configurations. The results from simulations (a) and (b) are well described by Archie’s equation. For the conductive film experiments (c), we explore the effect of film growth for four different surface conductivities ranging from [Formula: see text] to [Formula: see text]. These conductivities correspond to a range of 5–35 times more conductive than the pore fluid conductivity. The bulk EC signal for each of the films results in a distinct manifestation in terms of measured bulk EC. We fit the EC response of the conductive film experiments with a model based on volume fraction occupied by the film; although the model fit the observed results, we required a unique set of fitting parameters for each Film conductivity.

scholarly journals Carbon fibers derived from pure alkali lignin fibers through electrospinning with carbonization

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2412-2427
Author(s):  
Tunnapat Worarutariyachai ◽  
Surawut Chuangchote
Keyword(s):  
Electrical Conductivity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Smooth Surface ◽  
Synthetic Polymer ◽  
Inorganic Salts ◽  
Alkali Lignin ◽  
Surface Tension Reduction

Alkali lignin (AL) fibers with a smooth surface and fine morphological appearance were successfully produced via electrospinning using a simple heated single spinneret system, instead of typical electrospinning of lignin with added synthetic polymer blends or conventional co-axial electrospinning. To reduce the size of the fibers, glycerol was added to the spinning solution as a co-solvent for surface tension reduction and electrospinnability improvement. After electrospinning, stabilization and carbonization were subsequently performed to convert AL fibers to carbon fibers (CFs). The obtained CFs displayed rough and uneven surfaces. However, the CFs derived from glycerol-added solution showed greater electrical conductivity, specific surface area, and porosity compared with those from pure AL solution. Furthermore, the results indicated that the inorganic salts on the rough surface of CFs were successfully removed by sulfuric acid (H2SO4) washing. After H2SO4 washing, the CFs revealed a smoother surface and higher electrical conductivity, specific surface area, and porosity.

scholarly journals Structural and Morphological Quantitative 3D Characterisation of Ammonium Nitrate Prills by X-Ray Computed Tomography

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1230
Author(s):  
Fabien Léonard ◽  
Zhen Zhang ◽  
Holger Krebs ◽  
Giovanni Bruno
Keyword(s):  
Computed Tomography ◽  
Specific Surface ◽  
Ammonium Nitrate ◽  
Surface Area ◽  
Specific Surface Area ◽  
Volume Fraction ◽  
Fuel Oil ◽  
X Ray ◽  
Oil Retention ◽  
X Ray Computed

The mixture of ammonium nitrate (AN) prills and fuel oil (FO), usually referred to as ANFO, is extensively used in the mining industry as a bulk explosive. One of the major performance predictors of ANFO mixtures is the fuel oil retention, which is itself governed by the complex pore structure of the AN prills. In this study, we present how X-ray computed tomography (XCT), and the associated advanced data processing workflow, can be used to fully characterise the structure and morphology of AN prills. We show that structural parameters such as volume fraction of the different phases and morphological parameters such as specific surface area and shape factor can be reliably extracted from the XCT data, and that there is a good agreement with the measured oil retention values. Importantly, oil retention measurements (qualifying the efficiency of ANFO as explosives) correlate well with the specific surface area determined by XCT. XCT can therefore be employed non-destructively; it can accurately evaluate and characterise porosity in ammonium nitrate prills, and even predict their efficiency.

scholarly journals Pore-Scale Imaging of the Oil Cluster Dynamic during Drainage and Imbibition Using In Situ X-Ray Microtomography

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Junjian Li ◽  
Yajun Gao ◽  
Hanqiao Jiang ◽  
Yang Liu ◽  
Hu Dong
Keyword(s):  
Specific Surface ◽  
Capillary Pressure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Space ◽  
Relative Volume ◽  
Pore Scale ◽  
X Ray ◽  
Cluster Dynamic ◽  
Remaining Oil

We imaged water-wet and oil-wet sandstones under two-phase flow conditions for different flooding states by means of X-ray computed microtomography (μCT) with a spatial resolution of 2.1 μm/pixel. We systematically study pore-scale trapping of the nonwetting phase as well as size and distribution of its connected clusters and disconnected globules. We found a lower Sor, 19.8%, for the oil-wet plug than for water-wet plug (25.2%). Approximate power-law distributions of the water and oil cluster sizes were observed in the pore space. Besides, the τ value of the wetting phase gradually decreased and the nonwetting phase gradually increased during the core-flood experiment. The remaining oil has been divided into five categories; we explored the pore fluid occupancies and studied size and distribution of the five types of trapped oil clusters during different drainage stage. The result shows that only the relative volume of the clustered oil is reduced, and the other four types of remaining oil all increased. Pore structure, wettability, and its connectivity have a significant effect on the trapped oil distribution. In the water sandstone, the trapped oil tends to occupy the center of the larger pores during the water imbibition process, leading to a stable specific surface area and a gradually decreasing oil capillary pressure. Meanwhile, in oil-wet sandstone, the trapped oil blobs that tend to occupy the pores corner and attach to the walls of the pores have a large specific surface area, and the change of the oil capillary pressure was not obvious. These results have revealed the well-known complexity of multiphase flow in rocks and preliminarily show the pore-level displacement physics of the process.

scholarly journals Effect of Mesopore Development on Butane Working Capacity of Biomass-Derived Activated Carbon for Automobile Canister

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 673
Author(s):  
Byeong-Hoon Lee ◽  
Hye-Min Lee ◽  
Dong Chul Chung ◽  
Byung-Joo Kim
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Volume Fraction ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Working Capacity ◽  
Activation Time

Kenaf-derived activated carbons (AKC) were prepared by H3PO4 activation for automobile canisters. The microstructural properties of AKC were observed using Raman spectra and X-ray diffraction. The textural properties were studied using N2/77 K adsorption isotherms. Butane working capacity was determined according to the ASTM D5228. From the results, the specific surface area and total pore volume of the AKC was determined to be 1260–1810 m2/g and 0.68–2.77 cm3/g, respectively. As the activation time increased, the butane activity and retentivity of the AKC increased, and were observed to be from 32.34 to 58.81% and from 3.55 to 10.12%, respectively. The mesopore ratio of activated carbon increased with increasing activation time and was observed up to 78% at 973 K. This indicates that butane activity and retentivity could be a function not only of the specific surface area or total pore volume, but also of the mesopore volume fraction in the range of 2.8–3.8 nm and 5.5-6.5 nm of adsorbents, respectively. The AKC exhibit enhanced butane working capacity compared to commercial activated carbon with the high performance of butane working capacity due to its pore structure having a high mesopore ratio.

scholarly journals BIOMASS OF SOSNOWSKYI'S HOGWEED AS RAW MATERIAL FOR 2D THE CARBONIC NANOSTRUCTURES OBTAINING

2020 ◽  
pp. 83-92
Author(s):  
Aleksandr Petrovich Voznyakovskii ◽  
Anatoliy Petrovich Karmanov ◽  
Anna Yur'yevna Neverovskaya ◽  
Aleksey Aleksandrovich Voznyakovskii ◽  
Lyudmila Sergeyevna Kocheva ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Plant Biomass ◽  
Pore Space ◽  
Component Composition ◽  
Raw Material ◽  
Average Width ◽  
High Temperature Synthesis ◽  
Basic Portion

The possibility of the carbonization of the Sosnowskyi's hogweed (Heracléum sosnówskyi) biomass for obtaining the carbonic nanmaterials was studied. The characteristic of component composition is given and the parameters of the superficially-porous structure of plant biomass are established. The isotherms of adsorption and desorption of nitrogen on the surface are studied and it is shown that they relate to the type II according to the IUPAC classification. The distribution of times according to the sizes is investigated and it is established that the basic portion of the pore space of the vegetable raw material forms the mezopors with an average width 3.5 of nm. The specific surface area according to Brunauer-Emmet-Teller is determined, which composed 16.4 m2/g. Using a method of the carbonization of organic materials under the effect of local extremely high temperatures and oxidizers the synthesis of nanocarbonic powders, which are formed under the conditions of the self-propagating high-temperature synthesis (SHS method), was carried out. By the methods of spectral analysis (Raman spectroscopy, X-ray diffractometry) and electron microscopy it is shown that from their morphometric parameters the particles of the obtained carbonized product correspond to 2D nanocarbon in the form of grafenic nanoplates. The low-defect planar surface and the presence of the oxygen-containing terminal groups are the characteristic properties of new product. The specific surface area, which composed 179.1 m2/g, is determined. The specific surface area, which composed 179.1 m2/g, is determined. It is established that the micropores introduce the basic contribution to the specific surface area of nanomaterial on the basis of the Sosnowskyi's hogweed biomass.

scholarly journals Enhanced capacitive performance by improving the graphitized structure in carbon aerogel microspheres

RSC Advances ◽  
2020 ◽  
Vol 10 (37) ◽  
pp. 22242-22249
Author(s):  
Xichuan Liu ◽  
Lei Yuan ◽  
Minglong Zhong ◽  
Shuang Ni ◽  
Fan Yang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Aerogel ◽  
High Specific Surface Area ◽  
Activation Method ◽  
Carbon Aerogels ◽  
Capacitive Performance

Carbon aerogels (CAs) microspheres with good electrical conductivity and high specific surface area were synthesized by high temperature carbonization and CO2 activation method, which exhibit an enhanced capacitive performance in supercapacitors.

Modification of Inner Pores with Silicon Carbide Whiskers onto the Al2O3 Substrate by CVI Process

2005 ◽  
Vol 287 ◽  
pp. 212-219 ◽  
Author(s):  
W.S. Park ◽  
Doo Jin Choi ◽  
Hai Doo Kim
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Volume Fraction ◽  
Gas Permeability ◽  
Porous Alumina ◽  
Porous Ceramic ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Particulate Filter

In this study, SiC whiskers were grown in porous alumina substrate in order to enhance the filtering efficiency, performance, and durability by controlling pore morphology. This experiment was performed by chemical vapor infiltration (CVI) in order to obtain the whiskers on the inside of pores as well as on the surface of porous the Al2O3 substrate. The deposition morphology was changed remarkably with the deposition position and temperature. First, the mean diameter of whisker was decreased as the position of observation moved into the inside of substrate due to ‘the depletion effect’ and ‘the pressure effect’. Second, the deposition temperature caused the changes of the deposition type such as debris, whiskers and films and these changes of morphology affect the various properties. When SiC films were deposited, the gas permeability and the specific surface area decreased. However, the whisker showed the opposite result; a large specific surface area provides the absorption site and the whiskers in gas traveling path hinder the particles from easily flowing. Comparing with the normal pores (inter-grain open pores), the pores formed by the whiskers have relatively large volume fraction under the same pore size. Porous ceramic filters with whisker will be expected to increase the filtering efficient and gas permeability simultaneously. It is the main advantage of our whiskered filter. Therefore the porous alumina body which deposited the SiC whisker will be the promising material in order to apply to the particulate filter.

scholarly journals Modification of carbon felt anodes using double-oxidant HNO3/H2O2 for application in microbial fuel cells

RSC Advances ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 2059-2064 ◽  
Author(s):  
Yu Zhao ◽  
Yan Ma ◽  
Ting Li ◽  
Zhishuai Dong ◽  
Yuxue Wang
Keyword(s):  
Electrical Conductivity ◽  
Fuel Cells ◽  
Specific Surface ◽  
Surface Area ◽  
Anode Material ◽  
Specific Surface Area ◽  
Microbial Fuel Cells ◽  
Low Cost ◽  
High Specific Surface Area ◽  
Carbon Felt

Carbon felt is widely used as an anode material in microbial fuel cells (MFCs) because of its high specific surface area, low cost, good electrical conductivity, and biocompatibility.

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