Impact of monovalent cations on soil structure. Part I. Results of an Iranian soil

AbstractThis study investigated the impact of monovalent cations on clay dispersion, aggregate stability, soil pore size distribution, and saturated hydraulic conductivity on agricultural soil in Iran. The soil was incubated with treatment solutions containing different concentrations (0-54.4 mmol l−1) of potassium and sodium cations. The treatment solutions included two levels of electrical conductivity (EC=3 or 6 dS m−1) and six K:Na ratios per electrical conductivity level. At both electrical conductivity levels, spontaneously dispersible clay increased with increasing K concentration, and with increasing K:Na ratio. A negative linear relationship between percentage of water-stable aggregates and spontaneously dispersible clay was observed. Clay dispersion generally reduced the mean pore size, presumably due to clogging of pores, resulting in increased water retention. At both electrical conductivity levels, hydraulic conductivity increased with increasing exchangeable potassium percentage at low exchangeable potassium percentage values, but decreased with further increases in exchangeable potassium percentage at higher exchangeable potassium percentage. This is in agreement with earlier studies, but seems in conflict with our data showing increasing spontaneously dispersible clay with increasing exchangeable potassium percentage. Our findings show that clay dispersion increased with increasing K concentration and increasing K:Na ratio, demonstrating that K can have negative impacts on soil structure.

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The impact of clay dispersion and migration on soil hydraulic conductivity and pore networks

Geoderma ◽

10.1016/j.geoderma.2021.115297 ◽

2021 ◽

Vol 404 ◽

pp. 115297

Author(s):

Awedat Musbah Awedat ◽

Yingcan Zhu ◽

John McLean Bennett ◽

Steven R. Raine

Keyword(s):

Hydraulic Conductivity ◽

Soil Hydraulic Conductivity ◽

Clay Dispersion ◽

Pore Networks ◽

Soil Hydraulic ◽

And Migration ◽

The Impact

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Impact of freeze–thaw cycles on soil structure and soil hydraulic properties

SOIL ◽

10.5194/soil-7-179-2021 ◽

2021 ◽

Vol 7 (1) ◽

pp. 179-191

Author(s):

Frederic Leuther ◽

Steffen Schlüter

Keyword(s):

Hydraulic Conductivity ◽

Soil Structure ◽

Hydraulic Properties ◽

Initial Structure ◽

Soil Hydraulic Properties ◽

Freeze Thaw ◽

Frost Action ◽

Unsaturated Hydraulic Conductivity ◽

Soil Hydraulic ◽

The Impact

Abstract. The ploughing of soils in autumn drastically loosens the soil structure and, at the same time, reduces its stability against external stresses. A fragmentation of these artificially produced soil clods during wintertime is often observed in areas with air temperatures fluctuating around the freezing point. From the pore perspective, it is still unclear (i) under which conditions frost action has a measurable effect on soil structure, (ii) what the impact on soil hydraulic properties is, and (iii) how many freeze–thaw cycles (FTCs) are necessary to induce soil structure changes. The aim of this study was to analyse the cumulative effects of multiple FTC on soil structure and soil hydraulic properties for two different textures and two different initial structures. A silt clay with a substantial amount of swelling clay minerals and a silty loam with fewer swell/shrink dynamics were either kept intact in undisturbed soil cores taken from the topsoil from a grassland or repacked with soil clods taken from a ploughed field nearby. FTCs were simulated under controlled conditions and changes in pore structure ≥ 48 µm were regularly recorded using X-ray µCT. After 19 FTCs, the impact on hydraulic properties were measured, and the resolution of structural characteristics were enhanced towards narrow macropores with subsamples scanned at 10 µm. The impact of FTC on soil structure was dependent on the initial structure, soil texture, and the number of FTCs. Frost action induced a consolidation of repacked soil clods, resulting in a systematic reduction in pore sizes and macropore connectivity. In contrast, the macropore systems of the undisturbed soils were only slightly affected. Independent of the initial structure, a fragmentation of soil clods and macro-aggregates larger than 0.8 to 1.2 mm increased the connectivity of pores smaller than 0.5 to 0.8 mm. The fragmentation increased the unsaturated hydraulic conductivity of all treatments by a factor of 3 in by a factor of 3 in a matrix potential range of −100 to −350 hPa, while water retention was only slightly affected for the silt clay soil. Already 2 to 5 FTCs enforced a well-connected pore system of narrow macropores in all treatments, but it was steadily improved by further FTCs. The implications of fewer FTCs during milder winters caused by global warming are twofold. In ploughed soils, the beneficial seedbed consolidation will be less intense. In grassland soils, which have reached a soil structure in dynamic equilibrium that has experienced many FTCs in the making, there is still a beneficial increase in water supply through increasing unsaturated hydraulic conductivity by continued FTCs that might also be less efficient in the future.

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Saturated hydraulic conductance of forest soils affected by track harvesters

Journal of Forest Science ◽

10.17221/6/2011-jfs ◽

2011 ◽

Vol 57 (No. 8) ◽

pp. 321-339 ◽

Cited By ~ 1

Author(s):

K. Rejšek ◽

P. Holčíková ◽

V. Kuráž ◽

A. Kučera ◽

P. Dundek ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Soil Structure ◽

Soil Mechanics ◽

Saturated Hydraulic Conductivity ◽

Field Surveys ◽

Study Plot ◽

Specific Objective ◽

Order Of Magnitude ◽

Guelph Permeameter ◽

The Impact

The exact data from the field of soil mechanics from specific forest stands exposed to forestry mechanization operation were obtained. Field surveys were performed on four study plots within the Křtiny Training Forest Enterprise, Masaryk Forest, followed by laboratory analyses of the collected soil samples aimed at evaluation of the impacts of Zetor 7245 Horal System, PONSSE ERGO 16 harvester and Gremo 950 forwarder on the compaction of upper soil horizons as well as on the dynamics of soil saturated hydraulic conductivity. A specific objective of the performed investigation was to assess the influence of the used hauling/skidding technology on measurable parameters of soil mechanics with the emphasis on a possibility to apply the Guelph permeameter for direct study of soil saturated hydraulic conductivity. In the measurement points affected by machinery operation, the impact of the changed soil structure on the values of saturated conductivity is very well noticeable – on study plots No. 3 and 4, the values decreased by one order of magnitude from 0.7 × 10<sup>–5</sup> m·s–1 to 0.09 × 10–5 m·s<sup>–1</sup>: specifically, (i) on study plot No. 3 and from 6.9 × 10–5 m·s–1 to 0.7 × 10–5 m·s–1, and (ii) on study plot No. 4; on study plot No. 2 even by two orders, i.e. from 1.6 × 10–5 m·s–1 up to 0.03 × 10–5 m·s–1. After the operation of a universal wheeled tractor at the Babice nad Svitavou locality, the situation partially improved by one order to 0.3 × 10–5 m·s–1, similarly like at the Rudice locality to 1.5 × 10–5 m·s–1. Significant changes were found in both surface and subsurface horizons. Field-saturated hydraulic conductivity indicates also a reduction of the pore volume after machinery traffic; however, tendencies towards restoration of the original state were detectable as soon as after six months.  

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Effect of SWCNT-Tuball Paper on the Lightning Strike Protection of CFRPs and Their Selected Mechanical Properties

Materials ◽

10.3390/ma14113140 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3140

Author(s):

Kamil Dydek ◽

Anna Boczkowska ◽

Rafał Kozera ◽

Paweł Durałek ◽

Łukasz Sarniak ◽

...

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Electrical Conductivity ◽

Copper Foil ◽

Impact Resistance ◽

Mechanical Analysis ◽

Lightning Strike ◽

Single Wall Carbon Nanotubes ◽

Carbon Fibre Reinforced Polymer ◽

The Impact

The main aim of this work was the investigation of the possibility of replacing the heavy metallic meshes applied onto the composite structure in airplanes for lightning strike protection with a thin film of Tuball single-wall carbon nanotubes in the form of ultra-light, conductive paper. The Tuball paper studied contained 75 wt% or 90 wt% of carbon nanotubes and was applied on the top of carbon fibre reinforced polymer before fabrication of flat panels. First, the electrical conductivity, impact resistance and thermo-mechanical properties of modified laminates were measured and compared with the reference values. Then, flat panels with selected Tuball paper, expanded copper foil and reference panels were fabricated for lightning strike tests. The effectiveness of lightning strike protection was evaluated by using the ultrasonic phased-array technique. It was found that the introduction of Tuball paper on the laminates surface improved both the surface and the volume electrical conductivity by 8800% and 300%, respectively. The impact resistance was tested in two directions, perpendicular and parallel to the carbon fibres, and the values increased by 9.8% and 44%, respectively. The dynamic thermo-mechanical analysis showed higher stiffness and a slight increase in glass transition temperature of the modified laminates. Ultrasonic investigation after lightning strike tests showed that the effectiveness of Tuball paper is comparable to expanded copper foil.

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Transport Properties of Natural and Artificial Smart Fabrics Impregnated by Graphite Nanomaterial Stacks

Nanomaterials ◽

10.3390/nano11041018 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1018

Author(s):

Carola Esposito Corcione ◽

Francesca Ferrari ◽

Raffaella Striani ◽

Antonio Greco

Keyword(s):

Electrical Conductivity ◽

Transport Properties ◽

Low Cost ◽

Empirical Relationship ◽

Theoretical Models ◽

Expandable Graphite ◽

Easy Method ◽

Textile Materials ◽

Fabric Materials ◽

The Impact

In this work, we studied the transport properties (thermal and electrical conductivity) of smart fabric materials treated with graphite nanomaterial stacks–acetone suspensions. An innovative and easy method to produce graphite nanomaterial stacks–acetone-based formulations, starting from a low-cost expandable graphite, is proposed. An original, economical, fast, and easy method to increase the thermal and electrical conductivity of textile materials was also employed for the first time. The proposed method allows the impregnation of smart fabric materials, avoiding pre-coating of the fibers, thus reducing costs and processing time, while obtaining a great increase in the transport properties. Two kinds of textiles, cotton and Lycra®, were selected as they represent the most used natural and artificial fabrics, respectively. The impact of the dimensions of the produced graphite nanomaterial stacks–acetone-based suspensions on both the uniformity of the treatment and the transport properties of the selected textile materials was accurately evaluated using several experimental techniques. An empirical relationship between the two transport properties was also successfully identified. Finally, several theoretical models were applied to predict the transport properties of the developed smart fabric materials, evidencing a good agreement with the experimental data.

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The Synthesis and Electrochemical Performance of Si Composite with Hollow Carbon Microtubes by the Carbonization of Milkweed from Nature as Anode Template for Lithium Ion Batteries

Energies ◽

10.3390/en13195124 ◽

2020 ◽

Vol 13 (19) ◽

pp. 5124

Author(s):

Eun Hyuk Chung ◽

Jong Pil Kim ◽

Hyun Gyu Kim ◽

Jae-Min Chung ◽

Sei-Jin Lee ◽

...

Keyword(s):

Electron Microscopy ◽

Electrical Conductivity ◽

Electrochemical Performance ◽

Pore Size ◽

Lithium Ion Batteries ◽

Polyvinylidene Fluoride ◽

Lithium Ion ◽

Size Analysis ◽

Pore Size Analysis ◽

Hollow Carbon

It has been reported that improving electrical conductivity and maintaining stable structure during discharge/charge process are challenge for Si to be used as an anode for lithium ion batteries (LIB). To address this problem, milkweed (MW) was carbonized to prepare hollow carbon microtubes (HCMT) derived from biomass as an anode template for LIB. In order to improve electrical conductivity, various materials such as chitosan (CTS), agarose, and polyvinylidene fluoride (PVDF) are used as carbon source (C1, C2, and C3) by carbonization. Carbon coated HCMT@Si composits, HCMT@Si@C1, HCMT@Si@C1@C2, and HCMT@Si@C1@C3, have been successfully synthesized. Changes in structure and crystallinity of HCMT@Si composites were characterized by using X-ray diffraction (XRD). Specific surface area for samples was calculated by using BET (Brunauer–Emmett–Teller). Also, pore size and particle size were obtained by particle and pore size analysis system. The surface morphology was evaluated using high resolution scanning electron microscopy (HR-SEM), Field Emission transmission electron microscopy (TEM). The thermal properties of HCMT@Si composites were analyzed by thermogravimetric analysis (TGA). Our research was performed to study the synthesis and electrochemical performance of Si composite with HCMT by the carbonization of natural micro hollow milkweed to form an inner space. After carbonization at 900 °C for 2 h in N2 flow, inner diameter of HCMT obtained was about 10 μm. The electrochemical tests indicate that HCMT@Si@C1@C3 exhibits discharge capacity of 932.18 mAh/g at 0.5 A/g after 100 cycles.

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Selective adsorption of monovalent cations in porous electrodes

Physical Chemistry Chemical Physics ◽

10.1039/d0cp04396f ◽

2020 ◽

Vol 22 (43) ◽

pp. 25184-25194

Author(s):

Kenji Kiyohara ◽

Yuji Yamamoto ◽

Yusuke Kawai

Keyword(s):

Pore Size ◽

Applied Voltage ◽

Selective Adsorption ◽

Porous Electrodes ◽

Monovalent Cations ◽

Hydrated Ions

Selective adsorption of hydrated ions in porous electrodes is controlled by the pore size and the applied voltage.

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Treated wastewater irrigation effects on soil hydraulic conductivity and aggregate stability of loamy soils in Israel

Journal of Hydrology and Hydromechanics ◽

10.1515/johh-2015-0010 ◽

2015 ◽

Vol 63 (1) ◽

pp. 47-54 ◽

Cited By ~ 23

Author(s):

Karsten Schacht ◽

Bernd Marschner

Keyword(s):

Hydraulic Conductivity ◽

Chemical Properties ◽

Aggregate Stability ◽

Treated Wastewater ◽

Soil Aggregate Stability ◽

Irrigation Effects ◽

Physical And Chemical ◽

The Impact

Abstract The use of treated wastewater (TWW) for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW) resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC) and soil aggregate stability (SAS). To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm) were collected for analyzing SAS and determination of selected soil chemical and physical characteristics. The mean HC values decreased at all TWW sites by 42.9% up to 50.8% compared to FW sites. The SAS was 11.3% to 32.4% lower at all TWW sites. Soil electrical conductivity (EC) and exchangeable sodium percentage (ESP) were generally higher at TWW sites. These results indicate the use of TWW for irrigation is a viable, but potentially deleterious option, as it influences soil physical and chemical properties.

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Simplified estimation of unsaturated soil hydraulic conductivity using bulk electrical conductivity and particle size distribution

Soil Research ◽

10.1071/sr12158 ◽

2013 ◽

Vol 51 (1) ◽

pp. 23 ◽

Cited By ~ 8

Author(s):

Mohammad Reza Neyshabouri ◽

Mehdi Rahmati ◽

Claude Doussan ◽

Boshra Behroozinezhad

Keyword(s):

Electrical Conductivity ◽

Particle Size ◽

Hydraulic Conductivity ◽

Particle Size Distribution ◽

Size Distribution ◽

Unsaturated Soil ◽

Soil Core ◽

Soil Hydraulic Conductivity ◽

Core Samples ◽

Soil Hydraulic

Unsaturated soil hydraulic conductivity K is a fundamental transfer property of soil but its measurement is costly, difficult, and time-consuming due to its large variations with water content (θ) or matric potential (h). Recently, C. Doussan and S. Ruy proposed a method/model using measurements of the electrical conductivity of soil core samples to predict K(h). This method requires the measurement or the setting of a range of matric potentials h in the core samples—a possible lengthy process requiring specialised devices. To avoid h estimation, we propose to simplify that method by introducing the particle-size distribution (PSD) of the soil as a proxy for soil pore diameters and matric potentials, with the Arya and Paris (AP) model. Tests of this simplified model (SM) with laboratory data on a broad range of soils and using the AP model with available, previously defined parameters showed that the accuracy was lower for the SM than for the original model (DR) in predicting K (RMSE of logK = 1.10 for SM v. 0.30 for DR; K in m s–1). However, accuracy was increased for SM when considering coarse- and medium-textured soils only (RMSE of logK = 0.61 for SM v. 0.26 for DR). Further tests with 51 soils from the UNSODA database and our own measurements, with estimated electrical properties, confirmed good agreement of the SM for coarse–medium-textured soils (<35–40% clay). For these textures, the SM also performed well compared with the van Genuchten–Mualem model. Error analysis of SM results and fitting of the AP parameter showed that most of the error for fine-textured soils came from poorer adequacy of the AP model’s previously defined parameters for defining the water retention curve, whereas this was much less so for coarse-textured soils. The SM, using readily accessible soil data, could be a relatively straightforward way to estimate, in situ or in the laboratory, K(h) for coarse–medium-textured soils. This requires, however, a prior check of the predictive efficacy of the AP model for the specific soil investigated, in particular for fine-textured/structured soils and when using previously defined AP parameters.

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