Effect Of Ultrasonic Field Research Articles

Effect of ultrasonic field on the friction and oxidation characteristics of FeCrAl coatings

FeCrAl coatings were applied to the surface of F/M steel using ultrasonic vibration-assisted laser cladding (UVALC) technique. The introduction of an ultrasonic field refined the microstructure of the FeCrAl coating, enhancing its microhardness and the integrity of the oxide film at elevated temperatures. The increased hardness led to a shift in the wear mechanism from oxidation wear to abrasive wear. In high-temperature conditions, a finer microstructure of the coating resulted in a denser oxide layer, improving the tribological properties and oxidation resistance of the coating. Furthermore, high-temperature oxidation analysis revealed that the predominant oxides formed were Fe2O3 and Cr2O3.

Effect of ultrasonic field on the mechanism of electrodeposited Cu nucleation and growth

Electrodeposition technology is widely used in the surface treatment of copper foil. The unique “mechanical disturbance effect” and “cavitation effect” of ultrasonic field can effectively control the electrodeposition process of Cu and improve the quality of electrodeposited layer. In this paper, Linear Sweep Voltammetry (LSV), Cyclic Voltammetry (CV), Chronoamperometry (CA) and Chronocoulometry (CC) were used to study the electrochemical behavior of electrodeposited Cu in ultra-high acidity sulfate systems under different ultrasonic field powers. The nucleation and growth mechanism of Cu were discussed, and the surface morphology of electrodeposited layer was analyzed. The results show that the electrodeposition of Cu under the static condition (0 W) follows the diffusion controlled progressive nucleation and 3D growth mechanism, and the deposits are in the cylindrical shape with spherically agglomerated. The ultrasonic field significantly improves the mass transfer rate in the electrodeposition process, and the fine dispersion effect is obvious. The uniform and dense micro-nano layers are formed, following the 3D growth mechanism. With the increasing of ultrasonic field power, the nucleation mechanism gradually changes from the diffusion controlled progressive nucleation to the electrochemistry controlled instantaneous nucleation. In addition, there appear peeling, grooving and local microcracks on the electrodeposited layer under higher ultrasonic power condition, and it is easier to form a smooth and uniform electrodeposited layer with the ultrasonic power of 60 W compared to that with the ultrasonic power of 100 W.

Experimental investigation on flow boiling bubble motion under ultrasonic field in vertical minichannel by using bubble tracking algorithm

Bubble dynamics is important in flow boiling of minichannel, and ultrasonic field effects bubble behaviors. However, flow boiling bubble movements in minichannels under ultrasonic field have received little research attention and are still poorly understood. In this paper, the effects of ultrasonic field on bubble dynamics are experimentally studied by capturing the bubble motion behaviors of the flow boiling bubbles. The ultrasonic frequencies are set to 23, 28, 32, and 40 kHz. Bubble tracking algorithm, which studies the growth, trajectories, velocities, and traveled distances for bubbles, is created to qualitatively describe bubble motion behavior of flow boiling in minichannel. It is found that after the application of ultrasound, the detachment frequency, velocity, and travel distance of the bubbles significantly increases, and the growth behavior and trajectory are extremely complex, the two-phase gas-liquid flow is extremely unstable. The bubbles gain kinetic energy as the ultrasound frequency increases. Finally, numerical simulations are used to quantitatively investigate the mechanism of bubble motion in microchannels under ultrasonic fields.

Effect of ultrasonic field on the performance of an iron‐vanadium flow battery with non‐aqueous deep eutectic solvent electrolyte

Effect of ultrasonic field on the performance of an iron‐vanadium flow battery with non‐aqueous deep eutectic solvent electrolyte

The numerical research on the effect of ultrasonic field on metallic powders produced by the ultrasonic-assisted electrical discharge process

The numerical research on the effect of ultrasonic field on metallic powders produced by the ultrasonic-assisted electrical discharge process

Effect of ultrasonic field on microstructure evolution in friction stir welding of dissimilar Al/Mg alloys

Understanding of the microstructure evolution and the influence of ultrasonic vibration on friction stir welding (FSW) of dissimilar Al/Mg alloys is of great significance in optimizing the process parameters and improving the joint quality. In this study, the microstructure evolutions in the weld nugget zone (WNZ) of dissimilar Al/Mg joints during FSW and ultrasonic vibration enhanced FSW (UVeFSW) were characterized and compared. It was found that ultrasonic vibration (UV) has great effect on the grains structure of the WNZ in the Mg alloy side. Specially, the exerted UV changed the main dynamic recrystallization (DRX) mechanism of grains in the Mg alloy side from continuous DRX (CDRX) to discontinuous DRX (DDRX) under lower or higher welding speeds but constant tool rotation speed. Along the thickness direction, the average grain sizes near the bonding interface in the WNZ increased first and then decreased, and the maximum grain size was located at the mid-depth of the weld. Low strain shear texture appeared more in the WNZ of the Al alloy side during FSW, while in UVeFSW more locations in the WNZ were with high strain shear textures. The application of UV field improved the DRX degree in the whole weld through promoting the entanglement, aggregation and rearrangement of dislocations.

Effect of ultrasonic field on the microstructure and mechanical properties of sand-casting AlSi7Mg0.3 alloy

Abstract The injection of ultrasonic wave into a melt during casting can refine grain size, improve grain distribution, and thereby enhance casting performance. The available studies on ultrasonic-assisted casting are mostly about inserting a transducer directly into the melt. Such a method is not suitable for sand casting. Therefore, the study of ultrasonic sand casting by indirectly injecting ultrasonic waves into an aluminum alloy melt through a sand mold was proposed and carried out in this study. The effects of ultrasonic waves of different powers at different solidification stages on the microstructure and mechanical properties of the melt were studied. Compared to conventional sand casting, the samples prepared by ultrasonic sand casting have finer grains and better grain distribution, as well as higher mechanical properties. Moreover, the sample’s performance improves to different levels when the same ultrasonic wave is injected at different periods, when compared to the injection of ultrasonic waves with different powers in the same period.

Effects of ultrasonic field on structure evolution of Ni film electrodeposited by bubble template method for hydrogen evolution electrocatalysis

Effects of ultrasonic field on structure evolution of Ni film electrodeposited by bubble template method for hydrogen evolution electrocatalysis

Effect of ultrasonic field on grain refinement and stress relaxation of Be films by thermal evaporation

The beryllium (Be) films were prepared by vacuum evaporation with ultrasound on the glass slide substrates. The Be coating mainly consists of α-Be phase independent of ultrasonic vibration, while the texture and crystallinity are affected by ultrasonic vibration. With the increasing of ultrasonic power, the surface displays polygonal grains, but the grain size decreases from 130 nm to 60 nm. The cross section views show a transition from regular columnar structure to broken columnar structure owing to the ultrasonic mechanical agitation. When ultrasonic vibration is applied, the microstructure transforms from isolated islands to bicontinuous islands in the initial stage of film growth. In addition, the residual stress of Be films changes from a tensile stress to compressive stress under the effect of ultrasonic vibration, which is closely related to the transformation of microstructure.

Ultrasound assisted large scale fabrication of superhydrophilic anodized SnOx films with highly uniformed nanoporous arrays

In this paper, the effect of ultrasonic field on the morphology, optical and wetting properties of anodized SnOx film was revealed. X-ray diffraction, field emission scanning electron microscopy, ultraviolet–visible–near-infrared spectroscopy, electrochemical impedance spectroscopy and contact angle analyzer measurements were employed to characterize the as-prepared obtained films. Based on the analysis of these obtained results, it can be confirmed that the application of ultrasonic field has a significant influence on the reactive activity of Sn crystal plane, interface charge transfer, total current (including ionic current and electronic current), microstructure uniformity, and optical absorption property of anodized SnOx films. This study opens a new window to prepare highly uniformed SnOx films with excellent semiconductor performance and superhydrophilic properties by introducing the ultrasonic field to anodic oxidation process.

A study of the generalization of the three-dimensional model of nonlinear hydroacoustics of Khokhlov–Zabolotskaya–Kuznetsov in a cubic-nonlinear medium in the presence of dissipation

This article is devoted to the study of the generalization of the Khokhlov–Zabolotskaya–Kuznetsov model (3KZK) of nonlinear hydroacoustics in a cubic-nonlinear medium in the presence of dissipation. This model is described by third order quasilinear partial differential equation (3KZK). We obtained that the (3KZK) equation admits an eight parametric Lie group of the transformations. The submodels of the (3KZK) model are described by the invariant solutions of the (3KZK) equation. We have studied all essentially distinct, not linked by means of the point transformations, invariant solutions of rank 1 of this equation. The invariant solutions of rank 1 are found either explicitly, or their search is reduced to the solution of the nonlinear integro-differential equations. For example, we obtained the invariant solutions that we called by “First ultrasonic needle” and “Second ultrasonic needle”. The submodels described by this solutions have the following property: at each fixed moment of the time in the field of the existence of the solutions, near some point, the pressure increases and becomes infinite in this point. These submodels can be used, in particular, in medicine as a test in preparing for the operations with a help of an ultrasound. Also we obtained the invariant solutions that we called by “First ultrasonic knife” and “Second ultrasonic knife”. The submodels described by these solutions have the following property: at each fixed moment of the time in the field of the existence of the solution, near some plane the pressure increases and becomes infinite on this plane. The same as Ultrasonic needles, these submodels can be used, in particular, in medicine as a test in preparing for the operations with a help of an ultrasound. The presence of the arbitrary constants in the integro-differential equations, that determine invariant solutions of rank 1 provides a new opportunities for analytical and numerical study of the boundary value problems for the received submodels, and, thus, for the original (3KZK) model. With a help of these invariant solutions we researched a propagation of the intensive acoustic waves (one-dimensional, axisymmetric and planar) for which the acoustic pressure, speed and acceleration of its change are specified at the initial moment of the time at a fixed point. Under the certain additional conditions, we established the existence and the uniqueness of the solutions of boundary value problems, describing these wave processes. The graphs of the pressure distribution obtained as a result of numerical solution of these boundary problems are given. A mechanical relevance of the obtained solutions is as follows: 1) these solutions describe in a cubic-nonlinear medium with dissipation the nonlinear and diffraction effects in ultrasonic fields of a special kind, 2) these solutions can be used as a test solutions in the numerical calculations, performed in studies of ultrasonic fields generated by powerful emitters in a cubic-nonlinear medium with dissipation. Application of the obtained formulas generating the new solutions for the found solutions gives the families of the solutions containing the arbitrary constants.

Effects of ultrasonic field on the Pb‐Sn alloys during heating process

AbstractIn this work, the effects of ultrasonic field on the Pb‐Sn alloys during heating process have been discussed using electrical resistivity and thermal curves. The semi‐solid and liquid alloy have different resistivity responses to ultrasonic irradiation, due to ultrasound irradiation only available to liquid phase. Sensitive structural change by ultrasound can be only found in the liquid state, according to the resistivity drop and thermal curves. It might be due to the low volume fraction of liquid phase at initial stage and the fast solid‐to‐liquid transitions at the final stage. Ultrasound can also trigger the nucleation and growth of liquid phase, through driving the melting of solid phase at solid/liquid interface and transferring into the liquid phase. The concerned mechanisms have been discussed in detail.

Effect of ultrasonic field on microstructure and mechanical properties of as-cast 7085 aluminum alloy

The effect of an ultrasonic field on the microstructure and mechanical properties of 7085 aluminum alloy during solidification was investigated by optical microscopy, Vickers hardness test, tensile test, scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry, and electron probe micro-analysis (EPMA). The results showed that the grains of aluminum alloy were significantly refined and secondary phases were dispersed and distributed uniformly at the grain boundaries, due to ultrasonic treatment (UST). By EPMA, it was observed that the distribution of the main elements Al, Zn, Mg and Cu was more homogeneous in alloys with UST, than in alloys without UST. The mechanical properties of the aluminum alloy also significantly improved. As demonstrated by the SEM fractography of the fractured faces of several castings, fracture of the unrefined specimens occurred in a brittle manner, whereas the cracks of the refined specimens showed quasi-cleavage fracture.

Effect of ultrasonic field on the enzyme activities and ion balance of potential pathogen Saccharomyces cerevisiae

ObjectivesThis study aimed at investigating the enzyme activities and ion concentrations in potential pathogen S.cerevisiae upon ultrasonic treatment. MethodsThe activities of ATPase and antioxidase were identified by ATPase, SOD, and CAT assay kits following the instructions. Extracellular Ca2+ and K+ concentrations were determined in an atomic absorption spectrometer with calcium and potassium hollow-cathode lamps as radiation sources. ResultsSOD and CAT activities were enhanced by relatively low ultrasonic power at early time points and reduced to lower levels. Total ATPase, Na+/K+-ATPase, and Ca2+/Mg2+-ATPase activities were reduced by ultrasonic field, with higher reducing rate at stronger ultrasonic power and early time points. In addition, ultrasonic field disturbed the Ca2+ and K+ balances in S.cerevisiae cells. ConclusionsUltrasonic field resulted in the reduce even the lost of S.cerevisiae cell viability.

Invariant submodels and exact solutions of Khokhlov–Zabolotskaya–Kuznetsov model of nonlinear hydroacoustics with dissipation

We study three-dimensional Khokhlov–Zabolotskaya–Kuznetsov (KZK) model of the nonlinear hydroacoustics with dissipation. This model is described by third order quasilinear partial differential equation of the (KZK). We obtained that the (KZK) equation admits an infinite Lie group of the transformations, depending on the three arbitrary functions. This is due to the fact that in the (KZK) model the main direction of the wave’s propagation is singled out. The submodels of the (KZK) model.are described by the invariant solutions of the (KZK) equation. We studied essentially distinct, not linked by means of the point transformations, invariant solutions of rank 0 and 1 of this equation. Also we considered the invariant solutions of rank 2 and 3. The invariant solutions of rank 0 and 1 are found either explicitly, or their search is reduced to the solution of the nonlinear integro-differential equations. For example, we obtained the invariant solutions that we called by “Ultrasonic knife” and “Ultrasonic destroyer”. The submodel “Ultrasonic knife” have the following property: at each fixed moment of the time in the field of the existence of the solution near a some plane the pressure increases indefinitely and becomes infinite on this plane. The submodel “Ultrasonic destroyer” contains a countable number of “Ultrasonic knives”. The presence of the arbitrary constants in the integro-differential equations, that determine invariant solutions of rank 1 provides a new opportunities for analytical and numerical study of the boundary value problems for the received submodels, and, thus, for the original (KZK) model. With a help of these invariant solutions we researched a propagation of the intensive acoustic waves (one-dimensional, axisymmetric and planar) for which the acoustic pressure, speed and acceleration of its change, or the acoustic pressure , speed and acceleration of its change in the radial direction, or the acoustic pressure, speed and acceleration of its change in the direction of one of the axes are specified at the initial moment of the time at a fixed point. Under the certain additional conditions, we established the existence and the uniqueness of the solutions of boundary value problems, describing these wave processes. Mechanical relevance of the obtained solutions is as follows: (1) these solutions describe nonlinear and diffraction effects in ultrasonic fields of a special kind, (2) these solutions can be used as a test solutions in the numerical calculations performed in studies of ultrasonic fields generated by powerful emitters. Application of the obtained formula generating the new solutions for the found solutions gives families of the solutions containing three arbitrary functions.

Invariant solutions of the Westervelt model of nonlinear hydroacoustics without dissipation

We study three-dimensional Westervelt model of a nonlinear hydroacoustics without dissipation. We received all of its invariant submodels. We studied all invariant submodels described by the invariant solutions of rank 0 and 1. All invariant solutions of rank 0 and 1 are found either explicitly, or their search is reduced to the solution of the nonlinear integral equations. With a help of these invariant solutions we researched: (1) a propagation of the intensive acoustic waves (self-similar, axisymmetric, planar and one-dimensional) for which the acoustic pressure and a speed of its change, or the acoustic pressure and its derivative in the direction of one of the axes are specified at the initial moment of the time at a fixed point , (2) a spherically symmetric ultrasonic field for which the acoustic pressure and a speed of its change, or the acoustic pressure and its radial derivative are specified at the initial moment of the time at a fixed point. Solving of the boundary value problems describing these processes is reduced to the solving of nonlinear integral equations. We are established the existence and uniqueness of solutions of these boundary value problems under some additional conditions. Mechanical relevance of the obtained solutions is as follows: (1) these solutions describe nonlinear and diffraction effects in ultrasonic fields of a special kind, (2) these solutions can be used as a test solutions in the numerical calculations performed in studies of ultrasonic fields generated by powerful emitters. We found all the conservation laws of the first order for the Westerveld equation written in dimensionless variables.

Invariant submodels of the Westervelt model with dissipation

We study three-dimensional Westervelt model of nonlinear hydroacoustics with dissipation. We received all its invariant submodels. With the help of invariant solutions, we explored some wave processes, specifying their physical meaning. The boundary value problems describing these processes are reduced to the nonlinear integro-differential equations. We established the existence and uniqueness of the solutions of these boundary value problems under some additional conditions. Also we considered the invariant solutions of rank 2 and 3. Mechanical relevance of the obtained solutions is as follows: (1) these solutions describe nonlinear and diffraction effects in ultrasonic fields of a special kind, (2) these solutions can be used as a test solutions in the numerical calculations performed in studies of ultrasonic fields generated by powerful emitters.

Effect of ultrasonic field on isothermal kinetics of fullerene polyhydroxylation

The isothermal kinetics of fullerene polyhydroxylation under ultrasonic field was investigated. The isothermal kinetic curves of fullerene polyhydroxylation at different temperatures ranging from 293 K to 313 K were determined. By application of the isoconversion method it was established that the reaction of fullerene polyhydroxylation with sodium hydroxide and cetyl trimethyl ammonium bromide as phase transfer catalyst was kinetically an elementary reaction. The model-fitting method confirmed that the kinetics model of first-order chemical reaction best described the kinetics of fullerene polyhydroxylation under ultrasonic field and the kinetics parameters of fullerene polyhydroxylation were determined (Ea,= 29 kJ/mol and lnA=9.4 min-1). It was established that the reaction rate of fullerene polyhydroxylation under ultrasonic field is higher from 1.5 times to 2.2 times than the rate of comparative reaction under the conventional heating. The activation energy is 28% lower than the value of activation energy determined under the conventional heating, whereas the value of pre-exponential factor is 40 times higher. The decreased value of activation energy (Ea,) and pre-exponential factor (lnA) in the ultrasonic field is explained with the increase in the value of ground energy level of the resonant vibration mode (? = 500 cm-1) of C60 molecule (Ag(1) vibrational mode) and toluene molecule (out-of plane bending C-C-C vibration) and with the decreased value of anharmonicity factor.

Effect of heater size on ultrasonic enhancement of boiling in water and surfactant solutions

Experiments were performed to study enhancement of heat transfer from the wire of d = 50 µm and the tube of d = 1.5 mm in subcooled pool boiling by ultrasonic waves. The working fluids are clean water and Alkyl (8-16) Glucoside surfactant solutions of different concentrations and bulk temperature 30 °C. The wire resistance was translated to the temperature, using the calibration data, the temperature of the tube was measured by thermocouple. The differences between effect of ultrasonic field on boiling in water for heaters of d = 50 µm and d = 1.5 mm may be summarized as follows: for boiling on the wire of d = 50 µm in subcooled water, Tb = 30 °C, enhancement of heat transfer coefficient due to applied ultrasonic field is about 70% and 20% at heat flux q = 620 kW/m2 and q = 1350 kW/m2, respectively. For boiling in surfactant solutions at the same boiling conditions enhancement of heat transfer coefficient is in the range of 5–10% at heat flux q = 620 kW/m2 and 10–16% at heat flux q = 1350 kW/m2 depending on solution concentration. For boiling on the tube of d= 1.5 mm in subcooled water, Tb= 30 ℃, enhancement of heat transfer coefficient due to applied ultrasonic field is about 50% and 45% at heat flux q = 500 kW/m2 and q = 2500 kW/m2, respectively. The same values are obtained for boiling in surfactant solution of concentration C = 250 ppm. For the wire of d = 50 µm the heat transfer enhancement due to acoustic vibrations in surfactant solutions is not as strong as in water. This fact may be considered as evidence of significant role of relationship between jet flow and ultrasonic field.

Enhanced vapor bubble condensation and collapse with ultrasonic vibration

Investigation was carried out concerning the effects of ultrasonic field on the condensation and collapse of vapor bubbles in a quiescent subcooled pool. Experimental results showed that the vapor bubbles were split gradually at liquid subcooling of 15–30K, while were collapsed into many tiny bubbles when subcooling was higher than 40K. Once the ultrasonic vibration was applied, capillary waves would arise on the bubble surface, and the threshold of liquid subcooling for collapsing the bubble was diminished to 20–26K. Further, the presence of capillary wave increased the contacting area of the bubble with the cold bulk, and disturbs the thermal boundary layer in the vicinity of the vapor–liquid interface, resulting in the enhancement of condensation process. Therefore, the inertial shock of liquid on the vapor bubble was much stronger than that without ultrasonic vibration at the same liquid subcooling. This would also accelerate the instability of the bubble surface in turn. Based on the experimental data at liquid subcooling of 15–60K, empirical correlations were given to predict the condensation heat transfer of vapor bubbles with and without ultrasonic, with deviations within ±30%.