Interface Influence During the Wetting Process

2019 ◽  
pp. 31-60
Author(s):  
João M. P. Q. Delgado ◽  
António C. Azevedo ◽  
Ana S. Guimarães
Keyword(s):  
Wetting Process

Pore wetting process characterization of Equal-Sized granular coals by using LF-NMR technology

Fuel ◽  
2021 ◽  
pp. 122670
Author(s):  
Yuebing Zhang ◽  
Quangui Li ◽  
Qianting Hu ◽  
Cheng Zhai ◽  
Mingyang Song ◽  
...  
Keyword(s):  
Process Characterization ◽  
Wetting Process ◽  
Lf Nmr

scholarly journals AERATED CONCRETE MICROWAVE REFLECTION AND TRANSMISSION PROPERTIES IN A WET ENVIRONMENT

2017 ◽  
Vol 3 ◽  
pp. 145
Author(s):  
Tarmo Koppel ◽  
Inese Vilcane ◽  
Viktor Mironov ◽  
Andrei Shiskin ◽  
Sanita Rubene ◽  
...  
Keyword(s):  
Water Content ◽  
Transmission Loss ◽  
Base Station ◽  
Microwave Propagation ◽  
Reflection And Transmission ◽  
Excess Water ◽  
Base Station Antennas ◽  
Mobile Phone Base Station ◽  
Aerated Concrete ◽  
Wetting Process

Excess water content within the building material could greatly alter the interaction of the microwave with the material. In this study aerated concrete (AEROC) block walls (60x60cm) were investigated for their microwave (2.4 GHz) properties under wetting conditions. The spray wetting of the wall was conducted to simulate the environmental processes such as raining or water damage. 50ml/m² water dosage was applied on the surface of the concrete 21 times in 1 min intervals. The results show a noticeable decrease in microwave penetration power through the material after the sample gets enriched with water. As the water content on the surface of the material rises, so does the transmission loss. During the different water content of the aerated concrete, the reflection loss varied from -15.04 dB (dry wall) to -5.03 dB (wet wall’s surface). The transmission loss continues to rise during the entire length of the experiment, from -4.5 dB as a dry sample to -8.3 dB after 441 ml (1035 ml/m² during 23 min) of sprayed water. The variation of reflected microwave power was approximately ten times, which is quite a significant indicator of alteration of microwave propagation. The results demonstrate wetting process as an considerable factor in assessing microwave propagation in near the sources, such as mobile phone base station antennas, industrial microwave heaters and ovens etc.

scholarly journals Water repellency of clay, sand and organic soils in Finland

2008 ◽  
Vol 16 (3) ◽  
pp. 267 ◽  
Author(s):  
K. RASA ◽  
R. HORN ◽  
M. RÄTY
Keyword(s):  
Preferential Flow ◽  
Management Practice ◽  
Soil Surface ◽  
Water Repellency ◽  
Organic Soil ◽  
Water Infiltration ◽  
Organic Soils ◽  
Water Repellent ◽  
Moisture Regime ◽  
Wetting Process

Water repellency (WR) delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95) at the time of sampling. WR increased as follows: sand (R = 1.8-5.0) < clay (R = 2.4-10.3) < organic (R = 7.9-undefined). At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr.), where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.;

scholarly journals (In)compressibility and parameter identification in phase field models for capillary flows

2017 ◽  
Vol 44 (2) ◽  
pp. 189-214 ◽  
Author(s):  
M. Dehsara ◽  
H. Fu ◽  
S.Dj Mesarovic ◽  
D.P. Sekulic ◽  
M. Krivilyov
Keyword(s):  
Phase Field ◽  
Triple Line ◽  
Slip Boundary Condition ◽  
Diffuse Interface ◽  
Slip Boundary ◽  
Phase Field Models ◽  
Capillary Flows ◽  
Wide Range ◽  
Mobility Parameter ◽  
Wetting Process

Phase field (diffuse interface) models accommodate diffusive triple line motion with variable contact angle, thus allowing for the no-slip boundary condition without the stress singularities. We consider two commonly used classes of phase field models: the compositionally compressible (CC) model with compressibility limited to the fluid mix within the diffuse interface, and the incompressible (IC) model. First, we show that the CC model applied to fluids with dissimilar mass densities exhibits the computational instability leading to the breakup of the triple line. We provide a qualitative physical explanation of this instability and argue that the compositional compressibility within the diffuse interface is inconsistent with the global incompressible flow. Second, we derive the IC model as a systematic approximation to the CC model, based on a suitable choice of continuum velocity field. Third, we benchmark the IC model against sharp interface theory and experimental kinetics. The triple line kinetics is well represented by the triple line mobility parameter. Finally, we investigate the effects of the bulk phase field diffusional mobility parameter on the kinetics of the wetting process and find that within a wide range of magnitudes the bulk mobility does not affect the flow.

scholarly journals Influence of the chemical structure of cation surfactants on the wetting process of rock-forming minerals

2019 ◽  
Vol 55 (2) ◽  
pp. 142-148
Author(s):  
O. N. Opanasenko ◽  
N. P. Krutko ◽  
O. L. Zhigalova ◽  
O. V. Luksha
Keyword(s):  
Cationic Surfactants ◽  
Chemical Structure ◽  
Polyhydric Alcohol ◽  
Amino Groups ◽  
Interfacial Interactions ◽  
Alkyl Chains ◽  
Chemical Structures ◽  
Adsorption Interaction ◽  
Wetting Process ◽  
Steric Hindrances

Interfacial interactions of cationic surfactants of various chemical structures at the solution / finely dispersed mineral material (quartz and dolomite) interface were studied. It is established that the modification of the surfaces of quartz and dolomite with cationic surfactants leads to a change in the structure and radius of the capillaries due to the formation of adsorption-solvate shells. The hydrophobic ability of cationic surfactants is determined by the structure of the hydrophilic part of their molecules – the balance of amino groups in the alkyl chains and the absence of steric hindrances during adsorption interaction with the surface of mineral materials. The mixture of surfactants containing six amino groups and a polyhydric alcohol glycerin has an effective hydrophobic ability from both aqueous and highly mineralized solutions.

Study of the System Wood – Coating Material. I. Wood – Liquid Coating Material

Holzforschung ◽  
2000 ◽  
Vol 54 (2) ◽  
pp. 189-196 ◽  
Author(s):  
Eva Liptáková ◽  
Jozef Kúdela ◽  
Ján Sarva
Keyword(s):  
Phase Boundary ◽  
Rheological Properties ◽  
Wood Surface ◽  
Surface Forces ◽  
Coating Material ◽  
Actual State ◽  
Wood Coating ◽  
Coating Materials ◽  
Wetting Process ◽  
Adhesion Work

Summary This paper deals with the evaluation of wood—wetting process with coating materials on the basis of interactions of surface forces on phase boundary. The obtained results are compared with the actual state in the system wood—coating material. Primary ability of coating materials—spontaneous spreading over the wood surface has been proved. There is also the secondary influence of rheological properties of coating materials causing deformations of the phase boundary, non-perfect wetting of the wood surface and apparent lowering of adhesion work. The influence of rheological properties has been expressed by using the coefficient F the meaning of which follows from the comparison between results of adhesion work computed according to modified Young-Dupré equation and of adhesion work determined on the basis of the interactions of surface forces on the phase boundary between wood and liquid coating materials. A direct dependence between the values of the coefficient F and coating materials viscosity has been proved.

Sign in / Sign up

Export Citation Format

Share Document