Effects Of Ultrasonic Time Research Articles

One-pot ultrasonic cavitational emulsification of phytosterols oleogel-based flavor emulsions and oil powder stabilized by natural saponin

Phytosterols oleogel-based flavor emulsions were successfully fabricated for the first time using natural tea saponin as emulsifier and one-pot ultrasonic technique. The effects of ultrasonic time and power, surfactant concentration, and type of flavor oils (e.g., orange, lemon and peppermint) on the emulsion droplet size were investigated. Submicron emulsions with a dispersed phase made by flavor oil (20 wt%) + phytosterol (4 wt%) were stabilized with 3 wt% saponin were obtained by applying an ultrasonic time of 5 min and ultrasonic power of 280 W. The natural tea saponin emulsions exhibited a superior stability and encapsulation efficiency of phytosterol, compared to traditional emulsifiers. Flavor oil-phytosterol enriched powders were prepared by spray-drying and characterized by SEM, XRD and repose angle. The natural saponin encapsulated oil + phytosterol powders had excellent fluidity, redispersion behavior and low phytosterol crystallinity. It was demonstrated that ultrasound is an effective and suitable technique for fabricating fortified flavor emulsions and microcapsules, which may be used for developing functional lipids-based applications in the food, beverage and cosmetic industries.

Effect of ultrasonication time on microstructure, thermal conductivity, and viscosity of ionanofluids with originally ultra-long multi-walled carbon nanotubes

The stability along with thermal and rheological characteristics of ionanofluids (INFs) profoundly depend on the protocol of preparation. Therefore, in this work, the effect of ultrasonication time on microstructure, thermal conductivity, and viscosity of INFs containing 0.2 wt% of originally ultra-long multi-walled carbon nanotubes (MWCNTs) and four different ILs, namely 1-propyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium thiocyanate, or 1-ethyl-3-methylimidazolium tricyanomethanide, was studied. The INFs were obtained by a two-step method using an ultrasonic probe. The ultrasonication process was performed for 1, 3, 10, or 30 min at a constant nominal power value of 200 W. The obtained results showed that for the shortest sonication time, the highest thermal conductivity enhancement of 12% was obtained. The extended sonication time from 1 to 30 min caused the cutting of MWCNTs and breaking the nanoparticle clusters, leading to a decrease in the average length of the nanotube bundles by approx. 70%. This resulted in a decline in thermal conductivity even by 7.2% and small deviations from the Newtonian behavior of INFs.

Modeling and optimization of porous aerogel adsorbent for removal of cadmium from crab viscera homogenate using response surface method and artificial neural network

The purpose of this study was to establish an efficient modern strategy for the reduction and control of cadmium (Cd) content in the crab viscera homogenate. To this end, the coupling of an artificial neural network (ANN) technique with the genetic algorithm (GA) method and compared the performance of GA-ANN with response surface methodology (RSM) were demonstrated in the prediction and optimization of the ultrasonic-assisted adsorption of Cd using a aerogel adsorbent. On the basis of single factor test, the data sample was established by Box–Behnken Design, and the effects of ultrasonic time, temperature, the addition amount of aerogel, and pH on the removal rate of Cd were researched. The results revealed that the RSM and GA-ANN models had relative errors and coefficients of determination R2 values of 3.90%, 0.8440, and 1.79%, 0.9283, respectively, suggesting that GA-ANN is more accurate than RSM. The maximum percentage of Cd extracted (79.13%) was obtained using GA-ANN model as ultrasonic time of 87 min, temperature of 81 °C, adsorbent dosage of 0.07 g, pH of 3.20. In conclusion, the present results provide an effective method for optimizing multi-technology coupling to reduce the toxic heavy metal content in aquatic products.

Effect of Ultrasonication Time on Microstructure, Thermal Conductivity, And Viscosity of Ionanofluids with Originally Ultra-Long Multi-Walled Carbon Nanotubes

Ionanofluids (INFs) combine the advantages of ionic liquids (ILs) and nanofluids. They are characterized by higher thermal conductivity than pure ILs, as well as non-flammability and enhanced thermal stability than conventional nanofluids. Such an augmentation leads to efficient and safe heat transfer fluids. The stability along with thermal and rheological characteristics of these hybrid systems profoundly depend on the protocol of preparation. Therefore, in this work, the effect of ultrasonication time on microstructure, thermal conductivity, and viscosity of INFs containing 0.2 wt% of originally ultra-long multi-walled carbon nanotubes (MWCNTs) and four different ILs, namely 1-propyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-butyl-1-methylpyrrolidinium is(trifluoromethylsulfonyl) imide, 1-ethyl-3-methylimidazolium thiocyanate, or 1-ethyl-3-methylimidazolium tricyanomethanide, was studied. The INFs were obtained by a two-step method usingan ultrasonic probe. The ultrasonication process was performed for 1, 3, 10, or 30 min ata constant nominal power value of 200 W. The obtained results showed that for the shortest sonication time, the highest thermal conductivity enhancement of 12% was obtained. The extended sonication time from 1 to 30 min caused the cutting of MWCNTs and breaking the nanoparticle clusters, leading to a decrease in the average length of the nanotube bundles by approx. 70%. This resulted in a decline in thermal conductivity even by 7.2% and small deviations from Newtonian behavior of INFs.

Synthesis of Ternary Fe3O4/ZnO/Chitosan Magnetic Nanoparticles via an Ultrasound-Assisted Coprecipitation Process for Antibacterial Applications

In this study, Fe3O4/ZnO/chitosan magnetic nanoparticles were synthesized by an ultrasound-assisted coprecipitation method. The magnetic nanoparticles were characterized by XRD, FT-IR, FESEM, and VSM techniques. The effects of ultrasonication time and content of chitosan on crystal size and lattice parameters of the nanoparticles were also studied via XRD spectra. FESEM measurements revealed that the coating consists of Fe3O4/ZnO nanoparticles of 15-20 nm in diameter homogeneously dispersed on the surface of chitosan substance. The VSM measurements at room temperature showed that the Fe3O4/ZnO/chitosan nanoparticles had superparamagnetic properties. These results indicated that ultrasonication time and chitosan content had a significant effect on the characteristics of nanoparticles. The antibacterial activities of the Fe3O4/ZnO/chitosan were tested against both gram-positive Saccharomyces cerevisiae and Bacillus subtilis and gram-negative E. coli bacteria using a disk diffusion method.

Comprehensive utilization of foundry dust: Coal powder and clay minerals separation by ultrasonic-assisted flotation

Clay sand casting generates a large amount of foundry dust (FD), and the presence of coal powder in the FD makes it difficult to recycle and utilize. The landfill of the FD creates a serious environmental pollution and wastes a valuable resource. To improve the above situation, the FD was analyzed and characterized by X-ray fluorescence spectrometer (XRF), X-ray diffraction (XRD) and electron probe microanalyzer (EPMA). An ultrasonic-assisted flotation process was developed for the comprehensive utilization of the FD, and the effects of ultrasonic time on the flotation performance and flotation kinetics were investigated. In addition, the two-stage flotation of the FD was conducted. Obtained results showed that the FD mainly consisted of coal powder and clay minerals, and the coal powder was covered by clay minerals. The separation efficiency of the coal powder and clay minerals can be significantly enhanced by ultrasonic pretreatment, and the optimal ultrasonic time was 30 min. The flotation kinetics analysis results indicated that the first-order model with rectangular distribution was more reasonable for the data fitting of the ultrasonic-assisted flotation. Furthermore, the concentrate and tailings obtained by the two-stage flotation had achieved an acceptable result, favoring the comprehensive utilization of the FD.

Effects of ultrasonication time on stability, dynamic viscosity, and pumping power management of MWCNT-water nanofluid: an experimental study

It is known that ultrasonication has a certain effect on thermophysical properties and heat transfer of nanofluids. The present study is the continuation of the authors’ previous research on the effects of ultrasonication on the thermophysical properties of Multi-Walled Carbon Nanotubes (MWCNTs)-water nanofluid. Investigating the effects of ultrasonication time on samples’ stability, rheological properties, and pumping power of a water-based nanofluid containing MWCNTs nanoparticle is the main objective of the present study. The two-step method has been employed to prepared the samples. Moreover, a probe-type ultrasonic device has been used, and different ultrasonication times have been applied. The samples’ stability is investigated in different periods. The results revealed that prolonging the ultrasonication time to 60 min leads to improving the samples’ stability while prolonging ultrasonication time to higher than 60 min resulted in deteriorating the stability. As for dynamic viscosity, it is observed that increasing ultrasonication time to 60 min leads to decreasing the dynamic viscosity of the samples. As for pumping power, it is observed that the maximum increase in fanning friction factor ratio is less than 3%, which shows that adding MWCNTs to water does not impose a considerable penalty in the required energy for pumping power.

Ultrasound-assisted of poly (trimethylene terephthalate) dyeing with nano-disperse blue 79: isotherms, kinetics, and thermodynamics insights

In the present study, the dyeing of Poly(trimethylene terephthalate) (PTT) were performed using disperse Blue 79 dye in the presence and absence of ultrasound waves. In this work, the effect of some important parameters such as particle size, pH and effect of ultrasonic time on dye durability and adsorption behavior of disperse Blue 79 dye were evaluated. Under ultrasonic irradiation, the optimization conditions were achieved by PTT amount (0.1 g), irradiation time (15 min), contact time (120 min) at temperature (80 °C), pH = 6. The results showed that the ultrasonic time 15 min was chosen as an optimal time for nano-dye solution fabrication. Our results reveal that in pH higher than 6, the disperse dyes was degraded and the negative effect of alkaline environment on the adsorbent hydrolysis was specified. The achieved thermodynamics parameters values and the adsorption isotherms from the experiment suggests that the adsorption kinetics of the disperse Blue 79 dye on PTT is in accordance with a pseudo second-order kinetic model. The some important isotherms including Freundlich, Nernst, Temkin and Langmuir equations were used to determine the adsorption isotherm and results show that the Nernst isotherm has a good correlation coefficient. Thermodynamic evaluation showed that Gibbs free energy was found to be negative, indicating that the process is spontaneous. In addition, the positive value of enthalpy, signifying that the process is endothermic, and the negative entropy, indicating less activity in the interface. The particle size of disperse Blue 79 dye in the presence of ultrasound waves is smaller than those in the absence of ultrasound waves. Due to the polyester nature of the adsorbent, the adsorption was performed through diffusion mechanism between the fibers, and by diffusion increasing the adsorption is improved.

Utilization of biosolids for glucose oxidase production: A potential bio-fenton reagent for advanced oxidation process for removal of pharmaceutically active compounds

The current work focuses on the production of glucose oxidase (GOD) in sterilized biosolid (BS) slurries containing BS and municipal wastewater effluent. Various parameters were optimized for maximizing the GOD production and the effects of biostimulation on GOD production was investigated by adding synthetic media components. The studies on inoculum characteristics at an inoculum age of 72 h and inoculum size of 20% (w/v) produced high GOD activities of around 6012 U/L in 25% (dw/v) BS media. Further, the effect of ultrasonication time was determined to release BS-bound GOD in order to maximize enzymes recovery. Using 1000 U/L of the BS-based GOD for 0.55 M glucose oxidation produced the maximum H2O2 concentration of 216 ppm. The produced H2O2 was utilized for bio-Fenton based advanced oxidation process for the partial removal of 15 pharmaceutically active compounds.

Experimental investigation on the stability and thermophysical properties of Al2O3/DW and CuO/DW nanofluids to be utilized in an indirect water bath heater

In this paper, 0.5–5 mass/% of Al2O3 and CuO nano-additives were dispersed in the base water by the two stage method (with a magnetic stirrer and ultra-sonication bath) to prepare different nanofluids with enhanced thermophysical properties. These nanofluids are considered to be utilized, as the bath fluid in the shell side of an indirect water bath heater to improve the thermal performance and reduce the power consumption of the heater. The effects of ultra-sonication time, surfactants, and nanoparticle size on the well formation of nanofluids, and their stabilities were probed. Densities, shear stresses, and apparent viscosities of the nanofluids were also measured to investigate the non-Newtonian behavior of samples. In addition, effects of the temperature, PH, nanoparticle type and concentration, and nanoparticle sizes on the thermal conductivities of nanofluids were investigated. Finally, nanofluids were utilized in a large-scale indirect water bath heater and its power consumption reduction compared to that of using water, as the bath fluid was measured and reported. 5 mass/% of CuO/water nanofluid at 80 °C was found the best nanofluids with the thermal conductivity enhancement of 43.28% and heater power consumption reduction of 17.1%.

Thermal and Fluid Dynamics Performance of MWCNT-Water Nanofluid Based on Thermophysical Properties: An Experimental and Theoretical Study

There are many debates on the preparation methods and the role of ultrasonication on the stability, thermophysical properties, and heat transfer performance of nanofluids. The present study, which is the continuation of the authors previous study, the effects of ultrasonication on the thermal and fluid dynamic performance of MWCNT-water nanofluid, over a different range of temperatures and solid concentrations, based on the thermophysical properties of the nanofluid, has been investigated. The effects of ultrasonication time on the stability and thermophysical properties of the nanofluid were studied over 30 days of the samples preparation. The thermophysical properties of the nanofluid have been experimentally measured at the optimum ultrasonication time. Using the experimental data, and employing different figures-of-merit, the effects that the addition of MWCNTs had on the heat transfer effectiveness and pumping power have been studied. It was confirmed that the nanofluid is a good heat transfer fluid, with a negligible penalty in pumping power. The thermal and fluid dynamic performance of the nanofluid in a microchannel heat sink has also been studied, by comparing the enhancement ratio of the convective heat transfer coefficient and the increase in pumping power.

Optimization of Glycosylation Modification Process of Ultrasound-Assisted Naked Oat Protein/ β -Glucan by Response Surface Methodology

The glycosylation modification was carried out by using naked oat protein and β-glucan as raw materials,and ultrasonic modification was used to optimize the modification process conditions. Through single factor experiments,the effects of ultrasonic time,ultrasonic power,ultrasonic temperature and β-glucan:Bare oat protein ratio on grafting degree and solubility were compared and analyzed by Box-Benhnken principle. The optimal process conditions for the modification of naked oat protein glycosylation were as follows:Ultrasonic time 95 min,ultrasonic power 240 W,ultrasonic temperature 75℃,β-glucan:Bare oat protein ratio 2:1. At this time,the degree of grafting of the glycosylation modification was 35.79%±0.86%. The grafting degree of oat protein was 2.34 times higher than that of naked oat protein. The results showed that ultrasonic assisted modification of naked oat protein could promote the process of glycosylation.

Effect of Ultrasonication on the Phase Composition of Hyrdoxyapatite Synthesized using a Hydrothermal Method

The effect of ultrasonication time after hydrothermal synthesis of hydroxyapatite (HA) using the precursor system Ca(NO3)2–(NH4)2HPO4–NH4OH on the phase composition and degree of crystallinity was examined. HA samples were studied using x-ray diffraction and FT-IR spectroscopy. The studies showed that ultrasonication regardless of the duration had no effect on the phase composition and degree of crystallinity of the synthesized HA samples. HA phase Ca10(PO4)6(OH)2 with 0.97 degree of crystallinity was present in all studied samples.

One-pot green synthesis of carboxylated cellulose nanocrystals through oxidative degradation of bamboo pulp

Carboxylated cellulose nanocrystals (CCN) were prepared from bamboo pulp by ammonium persulfate (APS) with an ultrasonication-assisted technique. The effects of ultrasonication time, APS concentration, and reaction temperature on the yield of CCN were investigated. The morphology, structure, crystallinity, and thermal properties of prepared samples were analyzed by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The CCN presented rod-like shapes with diameter ranging from 10 to 30 nm and length of 50 to 200 nm. FTIR showed that CCN still kept with the basic chemical structure of cellulose, and at the 1735 cm-1 appearing the peak of C=O. The XRD pattern indicated that CCN was characteristic of the cellulose I crystal form, and the crystallinity of CCN was 63%. TGA revealed that CCN had a lower thermal stability than bamboo pulp. This research explored a low-cost and eco-friendly way to prepare CCN.

Selective removal of antimony from refractory gold ores by ultrasound

Ultrasound is used to enhance the removal of antimony from the refractory gold ores in alkaline sodium sulfide leaching process. The effects of ultrasonic time, temperature, reagent concentration and ultrasonic power on antimony removal are discussed. The removal rate of antimony reached 94.50% when ultrasonic time was 60 min, sodium hydroxide concentration was 1 mol/L, sodium sulfide concentration was 2 mol/L, ultrasonic power was 1500 W and temperature was 55 °C. Under the conditions, the removal rate of antimony without ultrasound is only 58.37%. The results show that ultrasound can significantly improve the removal efficiency of antimony and reduce the leaching temperature and time of antimony. The leaching rate of gold increased from 13.35% to 40.56% after antimony removal. Moreover, the leaching rate of gold after antimony removal reached 68.90% under ultrasound. Therefore, ultrasound not only enhances the removal efficiency of antimony, but also improves the leaching rate of gold. The improvement of the leaching rate of antimony and gold is attributed to that the mineral particles are broken up and pyrite is decomposed by ultrasound.

Structural changes and stress relaxation behavior of κ-carrageenan cold-processed gels: Effects of ultrasonication time and power.

Ultrasound has been used for cold gelation of κ-carrageenan hydrocolloid. In this work, the effect of ultrasound conditions such as power (50-150 W) and time (20-240 s) of sonication has been investigated. The application of ultrasound to hydrocolloid dispersion caused an increase in water solubility. The texture profile analysis test was used in order to evaluate the mechanical properties of gels. Textural parameters of κ-carrageenan gels, enhanced with increasing sonication time and power up to a certain level (usually 2.5 min) and longer sonication times had negative effects. In addition, intrinsic viscosities of sonicated specimens were measured to investigate the molecular characteristics of all samples. An increase in the process time and power reduced the intrinsic viscosity. The microstructural observation by scanning electron microscope determined that applying power ultrasound on κ-carrageenan dispersions influenced the formation of gel networks significantly.

Ultrasonic aqueous synthesis of corrosion resistant hydroxyapatite coating on magnesium alloys for the application of long-term implant.

For the orthopedic application, the promising biodegradable magnesium alloys gained increasing attention. In order to improve the interface bonding strength and corrosion resistance of magnesium alloys, a novel ultrasonic aqueous synthesis approach was performed to produce hydroxyapatite coating on biodegradable magnesium alloys. The effect of ultrasonic time on the composition, microstructure, interface bonding strength and corrosion resistance of HA coated magnesium alloys were investigated. A dense and crack-free HA coating was synthesized by only ultrasonic cavitation for 1 h in the aqueous solution containing Ca2+ and PO43- ions and the coating was constituted of bamboo leaf-like HA staggered irregularly, which endowed magnesium alloy with a sufficient interface bonding strength of 18.1 ± 2.2 MPa. The electrochemical performance and mineralization ability of the coated magnesium alloys were carried out in the simulated body fluids. Compared with bare magnesium samples, the coated samples presented excellent corrosion resistance and could rapidly induce apatite formation after only three days of immersion in the simulated body fluid (SBF). Moreover, in the immersion test of 90 days, HA coatings could provide a long-term protection for magnesium alloy substrate, indicating that ultrasonic aqueous synthesized HA coating could be acted as a promising modified biomaterial on magnesium alloys for the orthopedic application.

An experimental investigation on the effects of ultrasonication time on stability and thermal conductivity of MWCNT-water nanofluid: Finding the optimum ultrasonication time

The primary objective of the present study is to investigate the possible effects of ultrasonication time on stability and thermal conductivity of MWCNT-water nanofluid. The samples have been prepared in three different solid concentrations of 0.1, 0.3, and 0.5 vol.% applying different ultrasonication times, ranging from 10 to 80 min. The stability of the samples has been investigated over 30 days after preparation by conducting zeta potential analysis and visual observation. It is found that increasing the ultrasonication time until 60 min results in enhancing the stability of the samples in all the solid concentrations while prolonging the ultrasonication time leads to deteriorating the stability. The thermal conductivity of the samples has been experimentally measured over different temperatures ranging from 25 to 60 °C, and it is found that increasing the solid concentration and temperature results in enhancing the thermal conductivity. Moreover, the effects of ultrasonication time on thermal conductivity have also been studied, and it is found that increasing the ultrasonication time leads to a gentle enhancement in thermal conductivity. The maximum conductivity was achieved by applying 60 min ultrasonication. Thus, it is concluded that 60 min ultrasonication is the optimum time in which the thermal conductivity and stability reached their highest point.

Preparation of LiFePO4/C via high-temperature ball-milling route and Box-Behnken design-based optimization

LiFePO4/C cathode material was prepared via high-temperature ball-milling route with ultrasonic dispersion as mixing process using eutectic molten salt (0.76 LiOH·H2O-0.24 Li2CO3) as lithium source. Box-Behnken design was used to study the combined effects of ultrasonic time, ball-milling temperature, and ball-milling time on the discharge capacity to obtain the optimum predicted conditions. The optimum conditions were as follows: ultrasonic time was 63 min, ball-milling temperature was 638 °C, and ball-milling time was 7 h. LiFePO4/C prepared from the optimized experimental conditions exhibited a well electrochemical performance; its discharge capacity was 161.3 mAh g−1 at a 0.1 C-rate which was in consistence with the predicted discharge capacity of 160.2 mAh g−1. Moreover, its capacity retention rate achieved 93.6% at a 10 C-rate over 100 cycles.

Fabrication of Silicon Quantum Dots from Silicon Nanowires by a Combined Process of Chemical Etching and Ultrasonication

Silicon quantum dots (SiQDs) have special optical and electronic properties such as bright emission, size-dependent and wavelength-tunable luminescence, broad excitation spectra, and photostability that are rarely found in bulk substrate. Current approaches such as CVD, and laser pyrolysis to produce SiQDs involve complex equipment in combination with harsh chemicals. Here we present a simple and novel technique for conversion of silicon nanowires (SiNWs) to SiQDs. The method combines single step metal assisted chemical etching (MACE), ultrasonication and post chemical etching. Using AgNO3/HF solution, uniform SiNWs were produced by MACE for one hour to obtain a reduced reflectance of 1%. The SiNWs were harvested from the substrate by using ultrasonication and showed an average length of 1.5 um, ascertained from SEM images. Sonication for a fixed duration resulted in conversion of wires into silicon nanoparticles (SiNPs) with diameter varying from 30 to 710 nm. By controlling the time as well as the power of ultrasonication, smaller and uniform SiNPs can be produced. Subsequently, the SiNPs were subjected to a controlled chemical etching in a mixture of HF and H2SO4 to reduce the size further down to less than 10 nm. Here the etch rate and termination of etching are significant factors in determining the dimension of QDs and thereby their emission wavelength. This step enables the stability of photoluminescence of SiNPs by converting them to H-terminated SiNPs. As the etching proceeded, solution color changed from brown to yellow indicating a preliminary result for size reduction. The quantum confinement effect will be verified using photoluminescence as SiQDs emit blue-shifted photons when the size reduces to about 4 nm. The effects of ultrasonication time and power, and the controlled chemical etching on the emission properties of SiQDs will be presented.