Clay effects on the contact angle and water drop penetration time of model soils

2010 ◽  
Vol 56 (3) ◽  
pp. 371-375 ◽  
Author(s):  
D. A. L. Leelamanie ◽  
Jutaro Karube ◽  
Aya Yoshida
Keyword(s):  
Contact Angle ◽  
Water Drop ◽  
Penetration Time

scholarly journals Water stable aggregates of Japanese Andisol as affected by hydrophobicity and drying temperature

2014 ◽  
Vol 62 (2) ◽  
pp. 97-100 ◽  
Author(s):  
D.A.L. Leelamanie ◽  
Jutaro Karube
Keyword(s):  
Contact Angle ◽  
Sessile Drop ◽  
Water Drop ◽  
Aggregate Stability ◽  
Water Repellency ◽  
Water Stability ◽  
Drying Temperature ◽  
Hydrophobic Materials ◽  
Soil Hydrophobicity ◽  
Penetration Time

Abstract Hydrophobicity is a property of soils that reduces their affinity for water, which may help impeding the pressure build-up within aggregates, and reducing aggregate disruption. The purpose of this study was to examine the relation of soil hydrophobicity and drying temperature to water stability of aggregates while preventing the floating of dry aggregates using unhydrophobized and hydrophobized surface Andisol. Soil was hydrophobized using stearic acid into different hydrophobicities. Hydrophobicity was determined using sessile drop contact angle and water drop penetration time (WDPT). Water stability of aggregates (%WSA) was determined using artificially prepared model aggregates. The %WSA increased as the contact angle and WDPT increased. Contact angle and WDPT, which provided maximum %WSA showing less than 1 s of floating, was around 100° and 5 s, respectively. Although the %WSA gradually increased with increasing contact angle and WDPT above this level, high levels of hydrophobicity initiated aggregate floating, which would cause undesirable effects of water repellency. Heating at 50°C for 5 h d-1 significantly affected %WSA and hydrophobicity in hydrophobized samples, but did not in unhydrophobized samples. The results indicate that the contact angle and wetting rate (WDPT) are closely related with the water stability of aggregates. The results further confirm that high levels of hydrophobicities induce aggregate floating, and the drying temperature has differential effects on hydrophobicity and aggregate stability depending on the hydrophobic materials present in the soil.

scholarly journals Effect of Nanoparticles on Wettability of Nanocoating on Carbon Steel

2016 ◽  
Vol 1 (2) ◽  
pp. 71-74
Author(s):  
Norhasnidawani Johari ◽  
Noor Azlina Hassan ◽  
Norita Hassan ◽  
Mohd Hanafi Ani
Keyword(s):  
Contact Angle ◽  
Carbon Steel ◽  
Metal Oxide ◽  
Water Drop ◽  
Metal Oxide Nanoparticles ◽  
Sol Gel ◽  
Hydrophobic Surface ◽  
Oxide Nanoparticles ◽  
Water Medium ◽  
Wetting Ability

Nanocoatings plays an important role in coating industry. The solution was being prepared through copolymerization of epoxy resin hardener and with the incorporation of metal oxide nanoparticles, Zinc Oxide (ZnO) and Silica (SiO2). ZnO and SiO2 were synthesized using sol-gel. Epoxy hardener acted as host while the metal oxide nanoparticles as guest components. The formulation of nanocoatings with excellent adhesion strength and corrosion protection of carbon steel was studied. The performance of wetting ability with different medium was analysed using contact angle. Water medium showed the addition of 3wt% of hybrid between ZnO and SiO2 was the best nanocoating to form hydrophobic surface and was also the best nanocoating surface to form hydrophilic surface with vacuum oil dropping. In oil dropping, the contact angle was smaller than 90° and the water drop tends to spreads on surface.

The effect of soil moisture extremes on the pathways and forms of phosphorus lost in runoff from two contrasting soil types

Soil Research ◽  
2017 ◽  
Vol 55 (1) ◽  
pp. 19 ◽  
Author(s):  
B. Simmonds ◽  
R. W. McDowell ◽  
L. M. Condron
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Surface Runoff ◽  
Water Drop ◽  
Organic Soil ◽  
Surface Flow ◽  
Olsen P ◽  
Excess Surface ◽  
Infiltration Excess ◽  
Penetration Time

Soil moisture and Olsen P concentrations play an important role in phosphorus (P) losses in runoff. Under moisture-rich anaerobic conditions, the reduction of Fe-oxides dissolves P from the soil into solution that may be available for loss by transport processes. Under very dry conditions, soil hydrophobicity induced by soil organic C can exacerbate infiltration-excess surface flow and soil erosion. Our hypotheses were as follows: (1) rainfall applied to a dry soil would cause greater particulate P losses in surface runoff due to hydrophobicity; (2) P losses from a wet soil would be dominated by drainage and filtered P; and (3) both runoff processes would result in environmentally unacceptable P losses at agronomically productive Olsen P concentrations depending on the sorption capacity (anion storage capacity; ASC) of the soil. Superphosphate was added to a Brown and Organic soil (Olsen P initially 7 and 13mgL–1 respectively) to create a range of Olsen P concentrations. Soils were placed in boxes, soil moisture adjusted (<10% or 90% available water holding capacity) and artificial rainfall applied at a rate equivalent to a storm event (5-year return interval; 30–35mmh–1) and surface runoff and drainage collected. Surface runoff was measured as infiltration-excess surface flow from dry Organic soil (water drop penetration time >3600s), and as saturation-excess surface flow from the wet Brown soil (water drop penetration time <5s). Total P (TP) concentrations in surface flow from both soils increased linearly with Olsen P concentration. Compared with dry Organic soil, the wet Brown soil lost a greater proportion of TP as particulate via surface runoff. However, due to the high hydraulic conductivity and low ASC, the most important pathway for the Organic soil, wet or dry, was filtered P loss in drainage. These data can be used to more effectively target strategies to mitigate P losses.

Effect of secondary succession in abandoned fields on some properties of acidic sandy soils

2020 ◽  
Author(s):  
Peter Surda ◽  
Lubomir Lichner ◽  
Viliam Nagy
Keyword(s):  
Pore Size ◽  
Secondary Succession ◽  
Water Drop ◽  
Sandy Soils ◽  
Water Repellency ◽  
Organic Carbon Content ◽  
Abandoned Fields ◽  
Water Sorptivity ◽  
The Impact ◽  
Penetration Time

&lt;p&gt;Abandonment of agricultural lands in recent decades is occurring mainly in Europe, North America and Oceania, and changing the fate of landscapes as the ecosystem recovers during fallow stage. The objective of this study was to find the impact of secondary succession in abandoned fields on some parameters of acidic sandy soils in the Borsk&amp;#225; n&amp;#237;&amp;#382;ina lowland (southwestern Slovakia). We investigated soil chemical (pH and soil organic carbon content), hydrophysical (water sorptivity, and hydraulic conductivity), and water repellency (water drop penetration time, water repellency cessation time, repellency index, and modified repellency index) parameters, as well as the ethanol sorptivity of the studied soils. Both the hydrophysical and chemical parameters decreased significantly during abandonment of the three investigated agricultural fields. On the other hand, the water repellency parameters increased significantly, but the ethanol sorptivity did not change during abandonment. As the ethanol sorptivity depends mainly on soil pore size, the last finding could mean that the pore size of acidic sandy soils did not change during succession.&lt;/p&gt;

B219 Change in Contact Angle by Plasma Irradiation and Evaporation of Water Drop

2001 ◽  
Vol 2001 (0) ◽  
pp. 417-418
Author(s):  
Sumitomo HIDAKA ◽  
Yasuyuki TAKATA ◽  
Takehiro ITO
Keyword(s):  
Contact Angle ◽  
Water Drop ◽  
Plasma Irradiation

scholarly journals Ultraviolet irradiation improves the hydrophilicity and osteo-conduction of hydroxyapatite

2020 ◽  
Author(s):  
Sho Kaneko ◽  
Yuji Yamamoto ◽  
Kaniichro Wada ◽  
Gentaro Kumagai ◽  
Yoshifumi Harada ◽  
...  
Keyword(s):  
Contact Angle ◽  
Uv Irradiation ◽  
Uv Light ◽  
Water Drop ◽  
Area Ratio ◽  
Bone Volume ◽  
High Porosity ◽  
Bone Area ◽  
Dental Surgery ◽  
Significant Difference

Abstract Background Treating a titanium or titanium alloy implant with ultraviolet (UV) light is known to improve its associated cell growth and osseointegration. However, little is known about the effect of UV irradiation on hydroxyapatite (HA), which is also used frequently in orthopaedic and dental surgery. Here we examined the effect of UV irradiation on the hydrophilicity of HA, and on its osteoconduction ability in rats. Methods HA implants of low and high porosity were treated with UV light, and photofunctionalisation was assessed by the contact angle of a water drop on the surface. HA implants were also inserted into rat femurs, and the rats were killed two or four weeks later. The bone volume and bone area ratio were calculated from microcomputed tomography and histological data. Results The contact angle of a water drop on HA implants of both porosities was significantly reduced after UV irradiation. In the rat femurs, there was no significant difference in the bone volume between the UV light-treated and control implants at two or four weeks. The bone area ratio for the UV light-treated versus control implants was significantly increased at two weeks, but there was no significant difference at four weeks. Conclusions The surface of UV-irradiated HA disks was hydrophilic, in contrast to that of non-irradiated HA disks. Photofunctionalisation accelerated the increase in the bone area ratio in the early healing stage. This technology can be applied to surgical cases requiring the early fusion of bone and HA.

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