Ultrasonic Disruptor Research Articles

Energy of dispersing of loamy soils to elementary particles using ultrasound

Elementary soil particles are the first soil-specific level in the soil structure hierarchy, which is also the object of the soil texture analysis. To disperse soil solids to elementary soil particles (ESP), it is necessary to break the strong bonds between particles by physical action. An effective way of physical dispersion is to treat soil suspensions with ultrasound. However, depending on the type of soil, the required energy level varies, as it is determined by the stability of the soil structure. In this work the experiment with increasing energy (from 65 to 1 101 J·mL-1) of ultrasonic dispersion at constant power equal to 32.4 W is described. Soil samples from the upper horizons of three types of loamy soils (Retisol, Phaeozem, Chernozem) were used in the experiment. For this purpose, a horn-type ultrasonic disruptor Digital Sonifier S-250D (Branson Ultrasonics, USA) with a stepped solid horn tip (13 mm) was used. It was found that the value of the total energy of dispersion Et required for complete destruction of soil aggregates to ESP depends on soil type and varies within 200–800 J·mL-1 for loamy soils with an organic matter content of 1.8–4.6 g. 100 g-1 soil. For sample preparation of soils for grain-size analysis with a subsequent determination of soil texture class according to Kachinsky classification, the value Et = 250 J·mL-1 is sufficient, as it allows obtaining the maximum amount of physical clay (<10 µm) at the minimum duration of sample preparation.

Eucalyptus spp. cellulose nanocrystals obtained by acid hydrolysis and ultrasound processing for structural strengthening in paper packaging

The objective of the present study was to obtain and evaluate the conditions of acid hydrolysis for cellulose nanocrystals (CNC) production, as well as to characterize its chemical and morphological structure and finally to realize and evaluate its application potential on paper as a structural reinforcing agent. From bleached cellulose, CNC is obtained by the acid hydrolysis process at 35, 40 or 45 °C for 25, 30 and 35 min. Then, an ultrasonic disruptor was used to reduce the particle size of the samples. The average particle diameters ranged from 203.4 to 66.4 nm, with yields from 57.57% to 30.14%. To obtain the paper, the cellulose is homogenized by mechanical stirring and is incorporated with starch (5%) and CNC (6, 12 and 18%). This suspension was vacuum filtered and the papers formed are pressed in a hydraulic press (Carver®) for five minutes under 5000kgf. The addition of CNC showed to be a good option for increasing physical and mechanical properties as they improved the paper quality. Papers produced and incorporated with 12% and 18% CNC have superior characteristics in mechanical tensile testing (8.1 MPa) compared to paper without CNC added. Optical properties were not influenced after the incorporation of CNC .

Experimental Investigation of Thermal Conductivity and Viscosity of SiO₂/Multiwalled Carbon Nanotube Hybrid Nanofluids.

In this study, the thermal conductivity and viscosity of SiO₂/multiwalled carbon nanotube (MWCNTs) hybrid nanofluids are investigated. The volume fraction of the nanofluids varied in the range of 0.5% to 2%, while the SiO₂ to MWCNTs volume proportion is either 95-5 or 90-10. The nanofluids are synthesized using a wet chemical method and a two-step technique is used to disperse nanoparticles in glycerol (base fluid). The thermal conductivities and viscosities of the nanofluids are measured using a modified transient hot-wire method and falling ball viscometer, respectively. The colloidal stability of the dispersion was investigated visually. Effective application of an ultrasonic disruptor and a suitable surfactant (gum arabic) enhance the dispersion behavior. When the effects of temperature and volume fraction on the thermal conductivity and viscosity of SiO₂/multiwalled carbon nanotube (MWCNTs) hybrid nanofluids are studied, the results showed that the thermal conductivity of nanofluids increased with an increase in the volume fraction and temperature. Further, their viscosities increased with an increase in the volume fraction but decreased when the temperature increased. The thermal conductivity and viscosity of the hybrid nanofluids increased by 16.7% and 105.4%, respectively, at a volume fraction of 2% and volume proportion of 90-10. The experimental results are compared with those predicted by classical theoretical models. Two correlations for thermal conductivity and viscosity of hybrid nanofluids are proposed on the basis of the experimental results.

Synthesis and Characterization of A‐B‐A‐Type Nonionic Dimeric Dispersants for Pigment Dispersion

AbstractAn acid‐catalyzed esterification method was employed to synthesize five A‐B‐A‐type nonionic dimeric surfactants (XOP‐3, XOP‐4, XOP‐6, XOP‐9, and XOP‐10) comprising of octyl phenyl ether (OP‐10) and a homologous series of α, ω‐dicarboxylic acids (C3, C4, C6, C9, and C10) as the spacer molecules. The various surfactants produced were characterized based on Fourier transform infrared (FT‐IR) spectroscopy, mass spectra (MS), and 1H NMR spectra. The newly synthesized series of surfactants were used for the dispersion of Hostaperm Pink E (Pigment Red 122) in an ultrasonic disruptor. Based on the selected pigment, the interfacial, colloidal, and rheological properties of the pigment dispersion were examined. The dispersion performances and properties of the surfactants produced differed based on the number of carbon atoms in hydrocarbon chains of the various spacer molecules. Due to this, surfactants created with short to moderate hydrocarbon chain spacer molecules exhibited a better dispersion performance than that of surfactants created with long hydrocarbon chain spacer molecules. The calculated cross‐sectional area values of the various surfactants synthesized confirmed their differences in dispersion performance and properties.

Effect of ZrO2 nanoparticles on thermophysical and rheological properties of three synthetic oils

This article presents an experimental study on some thermophysical properties (density, viscosity and adiabatic bulk modulus) of six nanolubricants based on synthetic oils and ZrO2 nanoparticles. Two-step method with ultrasonic disruptor was used to prepare the nanodispersions. The morphology, crystalline degree and elemental composition of nanoparticles were analyzed by electron microscopy. Visual observation, temporal variation of refractive index and dynamic light scattering were used to analyze the stability of the nanolubricants and the average size of the aggregates. The presence of new interactions between nanoparticles and base oils was studied through Fourier transform infrared spectrometer. Vibrating tube densimeters, rotational viscometer and rheometer equipped with cone-plate geometry were used within the temperature range from (278.15 to 373.15) K. The ability of some theoretical simple models to predict densities and viscosities of these nanolubricants as a function of temperature and nanoparticle concentration was also checked.

Utilizing cellulase as dispersant to prepare stable nano-pigment suspension and investigating its coloring performance on cotton fabrics

In this research, a novel nano-pigment suspension was successfully prepared in an ultrasonic disruptor using crude cellulase as dispersant. The colloidal and rheological properties of this cellulase-based suspension such as zeta potentials, particle distribution and apparent viscosity were analyzed. The measurement of zeta potentials showed that the surface charges of pigment were adjustable along with the acid–base properties of external environment due to the amphoteric character of cellulase proteins. Subsequently, its stability to high-speed centrifuge, freeze–thaw treatment and ion intensity was carefully investigated. Thermo-gravimetric analysis (TGA) was conducted to demonstrate the coverage of pigment particles by cellulase proteins. Furthermore, X-ray diffraction (XRD) characterization was utilized to disclose the combined impacts of cellulase and ultrasonic power on the crystal structures of pigment. At last, the coloring performance of this charge-adjustable nano-pigment suspension on cotton substrates was evaluated by measuring their K/S values and color fastness. Scanning Electron Microscope (SEM) was carried out to give a direct observation of the nano-pigment distributed on cotton surfaces.

Conduction heat transfer characteristics and dispersion behaviour of carbon nanofluids as a function of different parameters

Thermal conductivity enhancements in aqueous media in the presence of carbon nanotubes (SWNTs) are investigated. The SWNTs nanofluids are prepared using a two-step method. The concentration of SWNTs suspensions is below 1 wt%. The thermal conductivities of the SWNTs suspensions are measured by a modified transient hot wire method (KD2 thermal property meter). Zeta potential, turbidity measurements and sedimentation photographs have been used to characterise quantitatively colloidal stability of the dispersions. Different parameters such as mass fraction, temperature, effect of various surfactants and pH, and effect of various physical treatment techniques are discussed. The results show that SWNTs suspensions have noticeably higher thermal conductivities than the base fluid without SWNTs. For SWNTs–water suspensions at 1wt%, thermal conductivity is enhanced by 30% at 25°C. The application of a suitable surfactant (such as GA and SDS), leads to better dispersion behaviour in nanofluids and increases the settling time from 24 h to several months. At pH 9.5, a good dispersion was obtained which is attributed to charge build-up on the surface of SWNTs due to adding the dispersants (for GA and SDS). This also indicates that, among various physical treatment techniques employed in this study, the ultrasonic disruptor was the most effective method to break down the agglomerated nanoparticles suspended in base fluids.

Radial Microtubule Organization by Histone H1 on Nuclei of Cultured Tobacco BY-2 Cells

In acentriolar higher plant cells, the surface of the nucleus acts as a microtubule-organizing center, substituting for the centrosome. However, the protein factors responsible for this microtubule organization are unknown. The nuclear surfaces of cultured tobacco BY-2 cells possess particles that generate microtubules. We attempted to isolate the proteins in these particles to determine their role in microtubule organization. When incubated with plant or mammalian tubulin, some, but not all, of the isolated nuclei generated abundant microtubules radially from their surfaces. The substance to induce the formation of radial microtubules was confirmed by SDS-PAGE to be a protein with apparent molecular mass of 38 kDa. Partial analysis of the amino acid sequences of the peptide fragments suggested it was a histone H1-related protein. Cloning and cDNA sequence analysis confirmed this and revealed that when the recombinant protein was incubated with tubulin, it could organize microtubules as well as the 38-kDa protein. Histone H1 and tubulin formed complexes immediately, even on ice, and then clusters of these structures were formed. These clusters generated radial microtubules. This microtubule-organizing property was confined to histone H1; all other core histones failed to act as organizers. On immunoblot analysis, rabbit antibodies raised against the 38-kDa protein cross-reacted with histone H1 proteins from tobacco BY-2 cells. These antibodies virtually abolished the ability of the nucleus to organize radial microtubules. Indirect immunofluorescence showed that the antigen was distributed at the nuclear plasm and particularly at nuclear periphery independently from DNA.

Production and dispersion stability of nanoparticles in nanofluids

This paper presents an experimental study on the homogeneous dispersion of nanoparticles in nanofluids. In this study, various physical treatment techniques based on two-step method, including stirrer, ultrasonic bath, ultrasonic disruptor, and high-pressure homogenizer were systematically tested to verify their versatility for preparing stable nanofluids. Initially carbon black and silver nanoparticles dispersed in base fluids with the presence of surfactant were found to be highly agglomerated with the hydrodynamic diameter of 330 nm to 585 nm, respectively. After both CB and Ag nanofluids were treated by various two-step methods, stirrer, ultrasonic bath, and ultrasonic disrupter was found to do a poor performance in deagglomeration process for the initial particle clusters. However, the high-pressure homogenizer produced the average diameter of the CB and Ag particles of 45 nm and 35 nm, respectively, indicating that among various physical treatment techniques employed in this study, the high-pressure homogenizer was the most effective method to break down the agglomerated nanoparticles suspended in base fluids. In order to prepare another nanofluid with much smaller primary nanoparticles, we also employed a modified magnetron sputtering system, in which the sputtered nanoparticles were designed to directly mix with the running surfactant-added silicon oil thin film formed on a rolling drum (i.e. one-step method). We observed that Ag nanoparticles produced by the modified magnetron sputtering system were homogeneously dispersed and long-term stable in the silicon oil-based fluid, and the average diameter of Ag nanoparticles was found to be ~ 3 nm, indicating that the modified magnetron sputtering system is also an effective one-step method to prepare stable nanofluids.

Preparation of Monodispersed and Nano-Sized Spherical SiO<sub>2</sub> Particles by Emulsion Method

Spherical nano-sized SiO2 particles have been synthesized from sodium silicate by emulsion method. The influence of emulsifier content and mixing time on the morphology and particle size distribution of the resulting materials was investigated. The characteristics of the obtained SiO2 particles were examined by means of XRD, SEM, TEM, and PSA. The monodispersed shperical SiO2 with the average particle size 20 nm was obtained at a emulsifer content of 3vol% and mixing time of 60 min using ultrasonic disruptor. After calcining at 1200oC for 2 hrs, the amorphous SiO2 transformed wholly to the crystalline cristobalite. As increase in emulsifier content from 1 to 3 vol% did not nearly influence on the morphology of SiO2 particle but slightly changed the particle size distribution. The average particle size of SiO2 decreased significantly from 100 nm to 20 nm with increasing the mixing time.

Continuous spore disruption using radially focused, high-frequency ultrasound.

We report on the development of a novel, continuous-flow, radially focused ultrasonic disruptor capable of lysing Bacillus spores in the absence of added chemical denaturants, enzymes, or microparticles. Greater than 99% disruption was achieved for Bacillus globigii spores and Escherichia coli and Bacillus subtilis vegetative cells with sample residence times of 62, 12, and 12 s, respectively. Microscopic and SEM images indicated that at equivalent power levels, the incidence of cell death or loss of viability typically exceeded the efficiency of (visible) cell lysis. However, semiquantitative PCR showed up to a 1,000-fold increase in intracellular DNA availability from ultrasonically disrupted spores, and liberated DNA was intact and available for subsequent detection.

Dispersion of ceramic ink using an ultrasonic disruptor

Dispersion of ceramic ink using an ultrasonic disruptor

Agglomerate strength determination

The extent of ultrasonic cavitation forces on suspended particles was characterized by comparison to hollow glass bubble strength distributions obtained via mercury porosimetry. The effective breaking strength of the different energy input levels of the ultrasonic disruptor were found to vary between 1.1 and 80.5 MPa. Model ordered monosize silica sphere agglomerates were ultrasonically treated and the changes in the particle size distribution followed in order to determine the strength of these agglomerates. Similar analyses done on synthesized titania powders have shown the importance of drying and ethanol washing of precursor precipitates to the strength of the final oxide agglomerates.

Using an ultrasonic disruptor as an aid to wet sieving

ABSTRACT Sonic agitation of sediments by an ultrasonic disruptor greatly reduces the difficulties encountered in wet sieving. The instrument readily disperses the fine grained material allowing a quick, neat separation of the sand from the silt and clay fractions.

Using an Ultrasonic Disruptor as an Aid to Wet Sieving: NOTES

Using an Ultrasonic Disruptor as an Aid to Wet Sieving: NOTES