Effects Of Ultrasonic Oscillations Research Articles

Effects of ultrasonic oscillations on permeability of rocks during the paraffinic oil flow

The paper shows that depending on the degree of blockage of the pore space due to paraffin precipitation the ultrasonic treatment has different effects. If a part of permeable channels is irreversibly deteriorated, then the activation of elastic oscillations contributes to postponing the moment of blocking the remaining part and helps to maintain the oil flow through a sample at a constant level. Without additional means an ultrasonic treatment does not have a significant effect in the case of strong blockage of permeable channels. If elastic oscillations are imposed on the rock and liquid at the initial moment of flow, then the porous space of the rock will be preserved from the precipitation of paraffins.

Effects of Ultrasonic Oscillations on Colloidal Properties of Sulfonated Drilling Fluids

Summary The property development of drilling fluids strongly relies on the emergence of novelty additives and the formulation design of drilling fluids. Few studies focus on the influences of preparation technology on various properties of drilling fluids. At present, high-speed mechanical agitation is still the only method of formulating drilling fluids in the industrial community. In the paper, two kinds of sulfonated drilling fluids that were used frequently in China were prepared by the combination of high-power ultrasound and high-speed mechanical agitation. After the mechanical agitation, we exerted ultrasonic oscillations on the sulfonated drilling fluids and intensified the input of ultrasonic energy by increasing ultrasonic time or power. In addition, the superposition of mechanical agitation during ultrasonic oscillations could further help the sulfonated drilling fluids to absorb more ultrasonic energy when the time and power of ultrasonic oscillations remained unchanged. The effects of ultrasonic oscillations on the colloidal properties of sulfonated drilling fluids were investigated. The results show that the introduction of ultrasonic energy into sulfonated drilling fluids is able to cause the formation of thinner and denser mudcakes on borehole walls and further reduce the low temperature and low pressure (LTLP) and high temperature and high pressure (HTHP) filtrate volume. The HTHP accumulative filtrate volume within 30 minutes can be decreased by a maximum of 24.7%. Simultaneously, various Bingham-type rheological values, particularly yield point, get decreased. The ultrasonic improvement of filtration and rheological properties benefits from the formation of the stable colloidal structure of drilling fluids under acoustic cavitation. According to the total organic carbon (TOC) measurements, it is found that ultrasonic oscillations promote the adsorption of sulfonated additives on bentonite clays. The analysis of particle size and zeta potential also confirms that ultrasonic oscillations not only decrease the average clay particle size but also enhance the zeta potential absolute value. In our experimental range, all the colloidal properties acquire the continuing improvement with the increase in ultrasonic energy input, which cannot be achieved only through the high-speed mechanical agitation. Compared with our previous research works, the subject investigated in the paper is the given drilling fluid system, but not the bentonite suspension containing one single additive. It indicates that we take a step forward in the field application of ultrasound-assisted mud preparation technique.

Mechanism of the ultrasound influence on combustion and structure formation at SHS in titanium-base systems

Using the developed experimental setup, the effect of ultrasonic oscillations (USO) on the temperature and combustion velocity during self-propagating high-temperature synthesis (SHS) in the Ti–C, Ti–C–Ni–Mo and Ti–B systems is studied. Basing on the analysis of data known in literature and our own measurements, theoretical explanation to the observed results is proposed. The effect of the intensity of ultrasonic oscillations on the composition and structure of the final synthesis products is established. It was found that along with changes in the parameters of the combustion wave, the completeness of the interaction increases, and changes in the microstructure and phase composition of the reaction products occur. The concept of separation of the effect of USO on SHS into thermal, or macroscopic, and non-thermal, or microscopic is proposed. The former is associated with forced convection of gas around an oscillating specimen and leads to a decrease in temperature and combustion velocity. The latter is connected with a change in the melt spreading conditions, the progress of heterogeneous reactions and mass transfer in the liquid phase in the high-temperature zone of the SHS wave, which lead to a change in the phase composition and structure of the final product.

Study of Influence of Parameters of Leaching Fluorine from Spent Pot Lining

In aluminium preparation by means of electrolysis of alumina-cryolite melts one of the largest-scale type of industrial waste is spent pot lining (SPL). Chemical composition of SPL carbon part consists of various elements with fluorine as the main one. One of the solutions of the problem of reducing environmental load by means of storage of waste of this type is extraction of valuable components (such as fluorine), that can be used further for preparation of fluorine entities (cryolite, calcium fluoride), that are brought back to electrolytic process. We have held experiments on extracting fluorine from SPL by caustic liquor leaching under effect of ultrasonic oscillations on a pulp, increasing the degree of fluorine solubilization. By means of mathematical planning method of a factor experiment cross impact of three leaching parameters was stated, maximum concentration of fluorine ions in the solution (20.21 gr/dm3) was achieved in following conditions: NaOH concentration - 2%, solid-liquid ration - 6:1, process length - 90 min. The degree of fluorine extraction from SPL is 69.87%.

Edge finishing and deburring of back surfaces of microholes using micro-cutting tools

► The edge finishing and deburring of the back surfaces of micro-through holes from the front surfaces are carried out. ► Micro-cutting tools are fabricated by EDM and used for processing holes. ► Helical tool feeding is employed and workpieces are ultrasonically oscillated. ► A hole drilled using a 0.15-mm-diameter drill in a 0.2-mm-thick plate is successfully deburred and edge-finished. The edge finishing and deburring of the back surfaces of micro-through holes, such as those with a diameter smaller than 1 mm, from the front surfaces by cutting are difficult and in some cases impossible with currently available tools. We have therefore fabricated micro-cutting tools by electrical discharge machining and used them for processing the back surfaces of microholes using helical tool feeding with the assistance of ultrasonic oscillation. As a result, a hole drilled using a 0.15-mm-diameter drill in a 0.2-mm-thick plate was successfully deburred and edge-finished. This is the hole with the smallest diameter whose back surface was processed from the front surface by cutting, to the best of our knowledge. The effects of ultrasonic oscillation, namely, cutting force is reduced and the generation of secondary burrs is restrained, were also observed in this study. Moreover, cutting force was further reduced with an improved geometry of the tool's cutting part.

Effect of ultrasonic oscillations on the fluidity of heavy oil products at low temperatures

We develop a laboratory setup to estimate the force of rotation of a metal branch pipe in a viscoelastic medium. We show that 2-min action of shearing ultrasonic oscillations (frequency, 32.5 kHz; specific power, no more than 0.008 W/cm2) reduces by 17% the static limit of fluidity brought to an initial temperature of I-100 fuel oil cooled to −15°C in the wall layer of a rotating branch pipe. We obtain a linear regression dependence between the ratio of the threshold force of the onset of branch pipe motion to the consumption current of the ultrasonic transducer and the fuel temperature.

Ultrasonic Oscillations Effect on Extrusion Processing, Structure, and Properties of Blends of Propylene Based Plastomer and Ethylene/1-Octene Copolymer

The effects of ultrasonic oscillations on extrusion processing, phase morphology, and compatibility as well as mechanical properties for blends of propylene based plastomer (DP) and ethylene/1-octene copolymer (EOC) were examined. The results show that introduction of ultrasonic oscillations into polymer melts in extrusion can in situ improve their processability, including the reduction of die pressure and shear viscosity under a constant shear rate (flow rate) and the increase of throughput under the same shear stress (die pressure). Scanning electron microscopy observation reveals that with ultrasonic oscillations, morphology of reduced disperse phase (EOC) size and good interfacial adhesion between EOC and DP matrix are formed in DP/EOC blends. The interfacial tension between DP and EOC melts obtained from the Palierne emulsion model decreases with applying ultrasonic oscillations. FTIR and GPC analysis indicate that in situ copolymer formation between DP and EOC happens with ultrasonic oscillations and copolymer consequently acts as compatibilizer for the blends. Accordingly, it leads to an elevation of stress at break and elongation at break of the blends.

Effects of ultrasonic oscillations on rheological behavior and mechanical properties of novel propylene‐based plastomers

AbstractThe effects of ultrasonic oscillations on the die pressure, productivity of extrusion, melt apparent viscosity, melt surface appearance, and die swell of novel propylene‐based plastomers were studied in a specially designed ultrasonic oscillations extrusion system developed in our laboratory. The effects of ultrasonic oscillations on molecular weights, tensile strength, and dynamic mechanical properties of extrudates were also studied. The experimental results showed that the presence of ultrasonic oscillations during extrusion could significantly increase the productivity of plastomers at the same die pressure, and reduce die swell and melt fracture such as sharkskin at a given screw rotation speed. The die pressure and apparent viscosity of plastomers remarkably decreased with increasing ultrasonic intensity. Introduction of ultrasonic oscillations into plastomer melts can improve their processibility. The possible mechanism for ultrasonic improvement of rheological behavior was also proposed in this article. Under certain conditions, ultrasound‐assisted extrusion could slightly decrease the glass transition temperature (Tg) and storage modulus of plastomers due to the minor reduction in molecular weights, but showed no significant impact on yield strength and strength at break. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Effect of ultrasonic oscillations on weld line strength of PS, PMMA, and their blends

AbstractThe effect of ultrasonic oscillations on the weld line strength of amorphous polystyrene (PS), polymethyl methacrylate (PMMA), and PS/PMMA (20/80, 50/50, 80/20) blends at various temperatures was investigated. By facilitating the molecular diffusion across the weld line, the introduction of ultrasonic oscillations could evidently improve the weld line strength of PS, PMMA, and their blends. The different effects on the weld line strength of PS/PMMA (20/80, 50/50, 80/20) blends were investigated. The ultrasonic oscillations could greatly increase the weld line strength of PS/PMMA (80/20) by ∼ 70%, but was less efficient to PS/PMMA (50/50, 20/80) blends, due to the great difference of weld line morphologies of these blends. The dispersed phase of PS/PMMA (80/20) in the weld line was spherical while two different morphologies in the weld line of PS/PMMA (50/50) were observed. And the stripe‐like morphology of PS perpendicular to the flow direction in the weld line of PS/PMMA (20/80) is responsible for the little effect of ultrasonic oscillations. The fractured surfaces of PS, PMMA, and PS/PMMA (80/20) with weld line became much rougher due to the introduction of ultrasonic oscillations. The morphology study of PS/PMMA (80/20) showed that the spherical dispersed phase of PS/PMMA at the skin turned smaller under ultrasonic oscillations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2990–2997, 2006

The mechanism of ultrasonic improvement of weld line strength of injection molded polystyrene and polystyrene/polyethylene blend parts

AbstractThe effect of ultrasonic oscillations and ultrasonic oscillation‐induced modes on weld line strength of polystyrene(PS) and polystyrene/polyethylene(PS/HDPE) blend was investigated. And the mechanism of ultrasonic improvement of weld line strength of PS and PS/HDPE blend was also studied. The presence of ultrasonic oscillations can enhance the weld line strength of PS and PS/HDPE blend. Compared with mode I(ultrasonic oscillations were induced into mold at the whole process of injection molding), the induced ultrasonic oscillations as mode II(ultrasonic oscillations were induced into mold after injection mold filling) is more effective to increase weld line strength of PS and PS/HDPE blend. The mechanism for ultrasonic improvement of weld line strength of PS and PS/HDPE blend is that the ultrasonic oscillations can improve the molecular diffusion across weld line of the melt at the core, and make against the fusion of melt at the skin. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1520–1530, 2006

Effects of ultrasonic oscillation on processing behaviors of PS, EPDM, and PS/EPDM blend

AbstractIn this study, the extrusion processing behaviors of polystyrene (PS), ethylene–propylene–diene terpolymer (EPDM), and their blend (PS/EPDM, 80/20) were studied by using a special ultrasonic oscillation extrusion system developed in our laboratory. The die pressure and volume flow rate were measured at different ultrasonic intensities and screw rotation speeds. The dependences on ultrasonic intensity of die pressure, volume flow rate, and apparent viscosity of polymers, as well as die swell at the same screw rotation speed were investigated. The effects of screw rotation speed on the processing behaviors of polymers and their blend at the same ultrasonic intensity were also studied. The experimental results showed that in the presence of ultrasonic irradiation, the processibilities of polymers and their blend were improved. Their possible mechanism is discussed in this article. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1856–1863, 2006

Studies on Rheological Behavior and Structure Development of High‐Density Polyethylene in the Presence of Ultrasonic Oscillations During Extrusion

The effects of ultrasonic oscillations on properties and structure of extruded high‐density polyethylene (HDPE) were studied. The experimental results show that ultrasonic oscillations can improve the surface appearance of the HDPE extrudates; increase the productivity of the HDPE extrudates; and decrease the die pressure, melt viscosity, and flow activation energy of the HDPE. The processing properties of the HDPE improve greatly in the presence of ultrasonic oscillations. Linear viscoelastic properties tests show that dynamic shear viscosity and zero shear viscosity decrease in the presence of ultrasonic oscillations. Ultrasonic oscillations can improve crystal perfection and thermal stability of HDPE. At appropriate ultrasound intensity, ultrasonic oscillations could also increase the mechanical strength of extruded HDPE. The gel permeation chromatography (GPC) results show that at high ultrasound intensity and low rotation speed of extrusion, ultrasonic oscillations causes chain scission of HDPE, which result in a decrease of molecular weight and an increase of melt flow index.

Effects of ultrasonic oscillations on linear viscoelastic behaviors of metallocene‐catalyzed linear low density polyethylene and its blends with low density polyethylene

AbstractThe effects of ultrasonic oscillations on linear viscoelastic behaviors of metallocene‐catalyzed linear low density polyethylene (mLLDPE) and its blends with low density polyethylene (LDPE) were investigated in this article. The experimental results showed that ultrasonic oscillations can increase the cross modulus, characteristic time, plateau modulus, complex viscosity, zero shear viscosity, and flow activation energy of mLLDPE. Molecular weight of mLLDPE increases but molecular polydispersity index decreases in the presence of ultrasonic oscillations. It has been found for mLLDPE/LDPE blends that the addition of LDPE as well as ultrasonic oscillations can decrease the cross modulus but increase the characteristic time of the blends. The complex viscosity, zero shear viscosity, and flow activation energy of the blends increase by the addition of LDPE, but decrease in the presence of ultrasonic oscillations. Shear thinning effect of the blends is improved because of the addition of LDPE. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3030–3043, 2005

Effect of ultrasonic oscillations on the rheological behavior and morphology of Illite‐filled high‐density polyethylene composites

AbstractThe effects of ultrasonic oscillations on the rheological and viscoelastic properties and morphology of high‐density polyethylene (HDPE)/Illite (70/30) composites were studied. The experimental results showed that the die pressure and apparent viscosity of the HDPE/Illite (70/30) composites were reduced greatly, and so the mass‐flow rate significantly increased in the presence of ultrasonic oscillations during the extrusion. Scanning electron microscopy and linear viscoelasticity tests showed that ultrasonic oscillations improved the dispersion of the Illite particles into the HDPE matrix. The aggregation of the Illite particles disappeared on the fractured surfaces of HDPE/Illite (70/30) composites extruded in the presence of ultrasonic oscillations, and this indicated that ultrasonic oscillations promoted the homogeneous dispersion of Illite particles into the HDPE matrix. Ultrasonic oscillations caused the permanent reduction of the dynamic viscosity and zero‐shear viscosity of HDPE/Illite (70/30) composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 379–384, 2005

Effects of ultrasonic oscillations on processing behavior and mechanical properties of metallocene‐catalyzed linear low‐density polyethylene/low‐density polyethylene blends

AbstractThe influences of ultrasonic oscillations on rheological behavior and mechanical properties of metallocene‐catalyzed linear low‐density polyethylene (mLLDPE)/low‐density polyethylene (LDPE) blends were investigated. The experimental results showed that the presence of ultrasonic oscillations can increase the extrusion productivity of mLLDPE/LDPE blends and decrease their die pressure and melt viscosity during extrusion. Incorporation of LDPE increases the critical shear rate for sharkskin formation of extrudate, crystallinity, and mechanical properties of mLLDPE. The processing behavior and mechanical properties of mLLDPE/LDPE blends were further improved in the presence of ultrasonic oscillations during extrusion. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2522–2527, 2004

Influence of ultrasound on nanostructural iron formed by electrochemical reduction

A method for control of particle dimensions of nanostructural amorphous iron powder obtained by electrochemical reduction under the effect of ultrasonic oscillations in reaction medium is described in this paper. Depending on the character of ultrasonic oscillations nanostructural powders were obtained differing both in average dimension and distribution of particle dimensions. In the case of simultaneous sonocation using ultrasonic vibrations with frequencies differing from each other by a factor of ten (20 and 200 kHz), the effect is complex, but includes narrowing of the average particle dimension.

Ultrasonic oscillations effect on rheological and processing properties of metallocene‐catalyzed linear low density polyethylene

AbstractThe effects of ultrasonic oscillations and die materials on die pressure, productivity of extrusion, melt viscosity of metallocene‐catalyzed linear low density polyethylene (mLLDPE), as well as their mechanism were studied in a special ultrasonic oscillations extrusion system developed in our lab. Die materials used in our experiment included steel, brass, and polytetrafluoroethylene (PTFE). The experimental results showed that ultrasonic oscillations as well as die materials have great influence on the rheological and processing behavior of mLLDPE. Ultrasonic oscillations can greatly increase the productivity of mLLDPE melt extruded through different dies, and can decrease the die pressure and the melt viscosity of mLLDPE. Compared with steel or brass die, mLLDPE melt extruded through PTFE die is more sensitive to ultrasonic oscillations. A possible mechanism for the improved processability of mLLDPE is proposed in this article. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1873–1878, 2003

Ultrasonic improvement of rheological and processing behaviour of LLDPE during extrusion

AbstractThe effects of ultrasonic oscillations on die pressure, productivity of extrusion, melt viscosity and melt fracture of linear low density polyethylene (LLDPE) as well as their mechanism of action were studied in a special ultrasonic oscillation extrusion system developed in our Laboratory. The experimental results showed that, in the presence of ultrasonic oscillations, the melt fracture or surface distortion of LLDPE extrudate is inhibited or disappears. The surface appearance of the LLDPE extrudate was greatly improved. The productivity of LLDPE extrudate was increased in the presence of ultrasonic oscillations. The die pressure, melt viscosity and flow activation energy of LLDPE decreased with the rise in ultrasonic intensity. The shear sensitivity of LLDPE melt viscosity decreased due to the increase of its power law index in the presence of ultrasonic oscillations. Inducing ultrasonic oscillations into LLDPE melt greatly improved its processability. A possible mechanism for the improved processibility is proposed.© 2003 Society of Chemical Industry

Ultrasonic improvement of the compatibility and rheological behavior of high‐density polyethylene/polystyrene blends

AbstractThe effects of ultrasonic oscillations on the rheological behavior, mechanical properties, and morphology of high‐density polyethylene (HDPE)/polystyrene (PS) blends were studied. The experimental results show that the die pressure and apparent viscosity of HDPE/PS blends are remarkably reduced in the presence of ultrasonic oscillations and that mechanical properties of the blends are improved. The particle size of the dispersed phase in HDPE/PS blends becomes smaller, its distribution becomes narrower, and the interfacial interaction of the blends becomes stronger if the blends are extruded in the presence of ultrasonic oscillations. Ultraviolet spectra and Soxhlet extraction results show the formation of a polyethylene‐PS copolymer during extrusion in the presence of ultrasonic oscillations, which improves the compatibility of HDPE/PS blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 23–32, 2002

Ultrasonic improvement of rheological behavior of polystyrene

The effects of ultrasonic oscillation on die pressure, productivity of extrusion, melt viscosity, and melt oscillating flow of polystyrene (PS) as well as their mechanism were studied in a special ultrasonic oscillations extrusion system developed in our lab. The experimental results show that in the presence of ultrasonic oscillations, the PS melt oscillating flow or surface distortion of PS extrudate is inhibited or disappears. The surface appearance of PS extrudate gets greatly improved. The die pressure, melt viscosity, flow activation energy, and consistency efficiency of PS decreased and the productivity of PS extrudate increased in the presence of ultrasonic oscillation. The shear sensitivity of PS melt viscosity is decreased because of the increase of its power law index in the presence of ultrasonic oscillation. Introduction of ultrasonic oscillation into PS melt can greatly improve the processibility of PS. Their possible mechanism is also proposed in this article. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2451–2460, 2002