scholarly journals Influence of plasma modification on free surface energy of synthetic fibrous materials

2020 ◽  
Vol 1588 ◽  
pp. 012052
Author(s):  
Y A Timoshina ◽  
E F Voznesensky ◽  
A E Karnoukhov ◽  
I V Krasina ◽  
G R Rakhmatullina ◽  
...  
Keyword(s):  
Free Surface ◽  
Surface Energy ◽  
Free Surface Energy ◽  
Plasma Modification ◽  
Fibrous Materials

Erosion Due to Incipient Cavitation

1948 ◽  
Vol 158 (1) ◽  
pp. 297-316
Author(s):  
W. T. Bottomley
Keyword(s):  
Free Surface ◽  
Hydrostatic Pressure ◽  
Surface Energy ◽  
Thermal Equilibrium ◽  
Cavitation Erosion ◽  
Cavitation Number ◽  
Free Surface Energy ◽  
Air Bubbles ◽  
Velocity Of Sound ◽  
Supersaturated State

Van Iterson's experiments show that cavitation erosion is produced by the collapse of minute air bubbles in water in a state of air supersaturation. This is contrary to the usual conception that cavitation erosion is due to the collapse of vapour bubbles. The author gives results of experiments which indicate that the bubbles which form and collapse at the stage of incipient cavitation in aerated water are air bubbles in a supersaturated state. The experiments also show that vapour bubbles which collapse in de-aerated water are in thermal equilibrium. It is shown that the collapse of bubbles in thermal equilibrium cannot cause erosion because the vapour pressure inside and the hydrostatic pressure surrounding the bubbles are balanced during collapse. The energy producing cavitation erosion is the free surface energy liberated by the collapse of the air bubbles. The final collapse velocity is the velocity of sound in water and the magnitude of the blow produced is of the order of 120 tons per sq. in. or more. The effect of these views on the interpretation of the model tests in cavitation tunnels and on the cavitation number is discussed.

Study on the free surface energy per unit area of aluminium nanodrops using the schommers potential

2009 ◽  
Vol 50 (6) ◽  
pp. 1171-1176
Author(s):  
N. Yu. Sdobnyakov ◽  
A. N. Bazulev ◽  
V. M. Samsonov ◽  
D. A. Kul’pin ◽  
D. N. Sokolov
Keyword(s):  
Free Surface ◽  
Surface Energy ◽  
Unit Area ◽  
Free Surface Energy

An empirical model for free surface energy of strained solids at different temperature regimes

2006 ◽  
Vol 252 (15) ◽  
pp. 5384-5386 ◽  
Author(s):  
S. Garruchet ◽  
O. Politano ◽  
J.M. Salazar ◽  
A. Hasnaoui ◽  
T. Montesin
Keyword(s):  
Free Surface ◽  
Surface Energy ◽  
Empirical Model ◽  
Free Surface Energy ◽  
Temperature Regimes

Determination of free surface-energy parameters using a spatial method

2013 ◽  
Vol 6 (2) ◽  
pp. 157-159 ◽  
Author(s):  
I. A. Starostina ◽  
O. V. Stoyanov ◽  
N. V. Sokorova
Keyword(s):  
Free Surface ◽  
Surface Energy ◽  
Free Surface Energy ◽  
Energy Parameters ◽  
Spatial Method

scholarly journals Regularities of formation of adhesive contact “sol-silicate paint - substrate”

Vestnik MGSU ◽  
2019 ◽  
pp. 94-101
Author(s):  
Valentina I. Loganina ◽  
Erkebulan B. Mazhitov
Keyword(s):  
Free Energy ◽  
Free Surface ◽  
Surface Energy ◽  
Liquid Glass ◽  
Adhesive Contact ◽  
Interfacial Interaction ◽  
Free Surface Energy ◽  
Properties Of Coatings ◽  
Dispersion Component ◽  
Silicate Paints

Introduction. The use as a binder in the manufacture of silicate paints polysilicate solutions obtained by mixing liquid glass and silica sol is considered. To regulate the rheological properties of the paint, improve the filling and prevent the pigment part from sagging, it has been proposed to introduce glycerin into the binder composition. The results of studying the interfacial interaction between the paint and the substrate are given. Materials and methods. In developing the formulation of silicate paints based on polysilicate solutions, MK-2 microcalcite, marshalite, diatomite and talc of MT-GSM grade were used as a filler, and titanium dioxide as a pigment. Polysilicate solutions were obtained by reacting stabilized solutions of colloidal silica (sols) with aqueous solutions of alkali silicates (liquid glasses). Nanosil 20 and Nanosil 30 silicic acid sol were used, produced by the Promsteklocentr PC. Used potassium liquid glass with module M = 3.29. A thermodynamic method was used to assess the interfacial interaction. Results. Shown that the introduction of glycerol into the formulation of a sol of silicate paint promotes a decrease in the interfacial surface tension and a better wetting of the surface of the mortar substrate. An increase in wetting coefficient is observed. Coatings based on sol silicate paints with the addition of glycerin are characterized by increased crack resistance. An increase in tensile strength, maximum tensile properties, and decrease in the elastic modulus of paint membranes based on the composition with glycerol has been established. The values of the free surface energy of the coating based on the sol of silicate paint and the ratio of the polar to the dispersion component of the free energy of the surface are given. Coatings based on sol of silicate paint with the addition of glycerin are characterized by a large value of the free energy of the surface. In the process of moistening a decrease in the free surface energy is observed due to a decrease in the dispersion component. Conclusions. Studies have shown that the introduction of an additive of glycerin in the formulation of a silicate paint sol contributes to an increase in the performance properties of coatings based on it.

scholarly journals Surface Modification of Additively Manufactured Nitinol by Wet Chemical Etching

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7683
Author(s):  
Denis Nazarov ◽  
Aida Rudakova ◽  
Evgenii Borisov ◽  
Anatoliy Popovich
Keyword(s):  
Mechanical Properties ◽  
Free Surface ◽  
Surface Energy ◽  
Surface Composition ◽  
Three Dimensional ◽  
Physicochemical Characteristics ◽  
Contact Angles ◽  
Free Surface Energy ◽  
Flat Plates ◽  
Water Contact

Three-dimensional printed nitinol (NiTi) alloys have broad prospects for application in medicine due to their unique mechanical properties (shape memory effect and superplasticity) and the possibilities of additive technologies. However, in addition to mechanical properties, specific physicochemical characteristics of the surface are necessary for successful medical applications. In this work, a comparative study of additively manufactured (AM) NiTi samples etched in H2SO4/H2O2, HCl/H2SO4, and NH4OH/H2O2 mixtures was performed. The morphology, topography, wettability, free surface energy, and chemical composition of the surface were studied in detail. It was found that etching in H2SO4/H2O2 practically does not change the surface morphology, while HCl/H2SO4 treatment leads to the formation of a developed morphology and topography. In addition, exposure of nitinol to H2SO4/H2O2 and HCl/H2SO4 contaminated its surface with sulfur and made the surface wettability unstable in air. Etching in NH4OH/H2O2 results in surface cracking and formation of flat plates (10–20 microns) due to the dissolution of titanium, but clearly increases the hydrophilicity of the surface (values of water contact angles are 32–58°). The etch duration (30 min or 120 min) significantly affects the morphology, topography, wettability and free surface energy for the HCl/H2SO4 and NH4OH/H2O2 etched samples, but has almost no effect on surface composition.

Effectiveness Evaluation Criteria of Using Fine Powders of Secondary Concrete as a Component of Composite Binder

2021 ◽  
Vol 1017 ◽  
pp. 163-171
Author(s):  
Tatiana Drozdyuk ◽  
Arkady Ayzenshtadt ◽  
Sergey Aksenov
Keyword(s):  
Free Surface ◽  
Surface Energy ◽  
Surface Activity ◽  
Free Surface Energy ◽  
Hydration Reaction ◽  
Critical Surface ◽  
Critical Surface Tension ◽  
Composite Binder ◽  
Fine Powders ◽  
Highly Dispersed

The paper considers the possibility of using energy criteria (surface activity, free surface energy) to quantify the efficiency of a highly dispersed system consisting of fine particles of secondary concrete as a component of composite binder of the hydration type of hardening. Using the G.A. Zisman method, the value of the critical surface tension was determined for secondary concrete fractions with different degrees of dispersion, which gives an idea of the free surface energy of a surface area unit. Based on the experimental data for determining the specific surface area and critical surface tension, the free surface energy and surface activity of the studied concrete powder were calculated, which can serve as criteria for quantitative energy characteristics of raw materials for the production of composite binders. Calorimetric studies related to measurements of the thermal effects of the hydration reaction of highly dispersed samples of secondary concrete have shown that this process is exothermic, the enthalpy of hydration of which is comparable to a similar parameter for cement. It was experimentally shown that fine powders of secondary concrete are effective as components of a composite binder, but they need to be pre-activated to optimal parameters, one of which is surface activity. In addition, the symbasis of changes in surface activity, the specific heat of the hydration reaction of highly dispersed concrete fractions and the compressive strength of fine-grained concrete samples made by using a composite binder containing a highly dispersed fraction of secondary concrete was established.

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