Research on ultrasonic excitation for the removal of drilling fluid plug,paraffin deposition plug,polymer plug and inorganic scale plug for near-well ultrasonic processing technology

Near-well ultrasonic processing technology attracts more attention due to its simple operation, high adaptability, low cost and no pollution to the formation. Although this technology has been investigated in detail through laboratory experiments and field tests, systematic and intensive researches are absent for certain major aspects, such as whether ultrasonic excitation is better than chemical agent for any plugs removal; whether ultrasound-chemical combination plug removal technology has the best plugs removal effect. In this paper, the comparison of removing drilling fluid plug, paraffin deposition plug, polymer plug and inorganic scale plug using ultrasonic excitation, chemical agent and ultrasound-chemical combination plug removal technology is investigated. Results show that the initial core permeability and ultrasonic frequency play a significant role in plug removal. Ultrasonic excitation and chemical agent have different impact on different plugs. The comparison results show that the effect of removing any plugs using ultrasound-chemicals composite plug removal technology is obviously better than that using ultrasonic excitation or chemical agent alone. Such conclusion proves that ultrasonic excitation and chemical agent can cause synergetic effects.     

Nonlinear propagation in ultrasonic fields: measurements, modelling and harmonic imaging

In high amplitude ultrasonic fields, such as those used in medical ultrasound, nonlinear propagation can result in waveform distortion and the generation of harmonics of the initial frequency. In the nearfield of a transducer this process is complicated by diffraction effects associated with the source. The results of a programme to study the nonlinear propagation in the fields of circular, focused and rectangular transducers are described, and comparisons made with numerical predictions obtained using a finite difference solution to the Khokhlov-Zabolotskaya-Kuznetsov (or KZK) equation. These results are extended to consider nonlinear propagation in tissue-like media and the implications for ultrasonic measurements and ultrasonic heating are discussed. The narrower beamwidths and reduced side-lobe levels of the harmonic beams are illustrated and the use of harmonics to form diagnostic images with improved resolution is described.     

Recent Advances of Diffraction Tomography in Geophysics,Ultrasonics, and Optics

A tutorial review of diffraction tomography is given along with an overview of recent advances of this technique in borehole geophysics, ultrasonic imaging, and optical microscopy. First, the basic principles of diffraction tomography are presented. Then, we discuss a generalized inversion algorithm, valid for irregularly spaced data and a non-uniform background, and present reconstructions based on ultrasonic water tank data and underground georadar data. Next, we discuss a hybrid filtered backpropagation algorithm for ultrasonic and optical imaging. Quantitative images, based on experimental data, are presented of objects embedded in water or in biological tissue and probed by ultrasound, and of fibers embedded in an index matching liquid and probed by laser light.     

Anisotropic attenuation of transverse ultrasound in cubic crystals of Ge,Si, and diamond with various isotopic compositions

The attenuation of transverse ultrasound in germanium, silicon, and diamond crystals is considered with allowance for competing isotopic and anharmonic scattering processes. The dependence of the attenuation of transverse ultrasound on the direction of the wave vector of quasi-transverse phonons is analyzed within an anisotropic continuum model. The Landau—Rumer mechanism is considered for anharmonic scattering processes. Given the second-and third-order elastic moduli, the parameters are found determining ultrasonic absorption in the above crystals with various degrees of isotopic disorder. The attenuation coefficients of transverse ultrasound associated with isotopic and anharmonic scattering processes are shown to have qualitatively different angular dependences. Therefore, from studying the anisotropic attenuation of ultrasound in cubic crystals, one can determine the dominant mechanism of ultrasonic absorption in isotopically modified crystals.     

Ultrasonic flowmeters: half-century progress report, 1955-2005

Ultrasonic flowmeters are one of the fastest-growing technologies within the general field of instruments for process monitoring, measurement and control. Today, acoustic/ultrasonic flowmeters utilize clamp-on and wetted transducers, single and multiple paths, paths on and off the diameter, passive and active principles, contrapropagating transmission, reflection (Doppler), tag correlation, vortex shedding, liquid level sensing of open channel flow or flow in partially-full conduits, and other interactions. Ultrasonic flowmeters are applicable to liquids, gases, and multiphase mixtures, but not without limits. However, no single technology, nor one type of interaction within a technology, can be best for all fluids, occasions and situations. Users who select a particular type of ultrasonic flowmeter over one based on a competing (nonultrasonic) technology often do so for one (or more) of the following reasons: ultrasonic equipment provides a useful measurement whether the fluid is single-phase or not single-phase; equipment is easy to use; flow regime can be laminar, transitional or turbulent; transducers are totally external (no penetration of the pressure boundary); transducers, if not clamp-on, are minimally invasive; no excess pressure drop; when certain conditions are met, accuracy can be better than 0.5%; fast (ms) response; reliable despite temperature extremes; reasonable purchase price, installation, operating and maintenance costs. Sometimes mass flowrate is obtainable. Energy flowrate might be achieved for natural gas and biogas in the near future. How did ultrasonic flowmeters advance in the past fifty years to support such claims? This paper tries to answer this question by looking at ultrasonic flowmeter inventions and publications since 1955, to see how four key problems were solved.     

Novel applications of ultrasonic atomization in the manufacturing of fine chemicals,pharmaceuticals, and medical devices

Liquid atomization as a fluid disintegration method has been used in many industrial applications such as spray drying, coating, incineration, preparation of emulsions, medical devices, etc. The usage of ultrasonic energy for atomizing liquid is gaining interest as a green and energy-efficient alternative to traditional mechanical atomizers. In the past two decades, efforts have been made to explore new applications of ultrasonic misting for downstream separation of chemicals, e.g., bioethanol, from their aqueous solutions. Downstream separation of a chemical from its aqueous solutions is known to be an energy-intensive process. Conventional distillation is featured by low energy efficiency and inability to separate azeotropic mixtures, and thus novel alternatives, such as ultrasonic separation have been explored to advance the separation technology. Ultrasonic misting has been reported to generate mist and vapor mixture in a gaseous phase that is enriched in solute (e.g., ethanol), under non-thermal, non-equilibrium, and phase change free conditions. This review article takes an in-depth look into the recent advancements in ultrasound-mediated separation of organic molecules, especially bioethanol, from their aqueous solutions. An effort was made to analyze and compare the experimental setups used, mist collection methods, droplet size distribution, and separation mechanism. In addition, the applications of ultrasonic atomization in the production of pharmaceuticals and medical devices are discussed.     

The ultrasonic cleaning process: its dependence on the energy density,time of action,temperature, and modulation of the sonic field

Objective evaluation of the efficiency of ultrasonic cleaning machines has hitherto been frustrated by the lack of suitable measuring processes for the quantitative determination of the degree of cleaning, and the acoustic energy existing in the bath. A method for obtaining reproducible measurements of the degree of cleaning and the effects of various parameters on the ultrasonic cleaning process are described. In particular, the relations between the energy density, the electrical power supplied to the ultrasonically excited tanks, and the degree of cleaning are discussed. Experiments carried out using different types of oscillation modulation show that optimal cleaning efficiency is achieved with a simple half-wave modulation form.     

The influence of pressure on the acoustic cavitation in saturated CO2-expanded N,N-dimethylformamide

CO₂-expanded organic solvent is a kind of important fluid medium and has broad applications in chemical industry, environmental protection and other fields. Ultrasonic cavitation in gas expanded liquids (GXLs) is conducive to enhancing mass transfer and producing many exciting phenomena. In this paper, the ultrasonic cavitations and streaming in the saturated CO₂-expanded liquid N, N-dimethylformamide (DMF) at 4.2 MPa and 5.2 MPa are observed by a high-speed camera. The cavitation intensity and time trace of pressure pulses are recorded using a PZT hydrophone. The influences of gas–liquid equilibrium pressure and ultrasonic power on the cluster dynamics of transient and stable cavitation are examined. The excess molar enthalpies required for CO₂ dissociation from DMF are calculated by Peng-Robinson equations of state and the change of surface free energy of CO₂-expanded DMF is predicted. The results show that the excess enthalpy of the mixture is one of the key factors to control ultrasonic cavitation at high pressurized conditions, while the surface tension is the key factor for low pressure. As the increase of applied ultrasonic power, the formation and collapsing frequency of bubble clusters increases, and the amplitude and cyclic frequency of pressure pulse are enhanced. The transient cavitation intensity increases as it reaches a maximum value at a certain ultrasonic power and then decreases. The change trends of stable cavitation intensity under different pressures are basically same. It can be concluded from the evidence that ultrasonic cavitation in CO₂-expanded DMF is affected by the combined effect of compression and substitution: compression depresses the nucleation and growth of bubbles, while the high solubility of CO₂ in DMF is conducive to the generation of bubbles in cavitation.     

Comparison of ultrasonic degradation rates constants of methylene blue at 22.8 kHz, 127 kHz, and 490 kHz

Techniques such as solvent extraction, incineration, chemical dehalogenation, and biodegradation have been investigated for the degradation of hazardous organic compounds. We found ultrasound to be an attractive technology for the degradation of hazardous organic compounds in water. However, the effects of ultrasonic frequency on degradation rate constants were not investigated quantitatively. In this study, the degradation process of a model for hazardous organic compound methylene blue was investigated using ultrasonic irradiation. The study focused on the effects of ultrasonic frequency and ultrasonic power on the degradation rate constant. The apparent degradation rate constants were estimated based on time dependence of methylene blue concentration assuming pseudo-first-order kinetics for the decomposition. A linear relationship between the apparent degradation rate constant and ultrasonic power was identified. In addition, the apparent degradation rate constants at frequencies of 127 and 490 kHz were much larger than those at 22.8 kHz. A relationship between the apparent degradation rate constant and the sonochemical efficiency value (SE value) was also found. Based on these results, a simple model for estimating the apparent degradation rate constant of methylene blue based on the ultrasonic power and the SE value is proposed in this study.     

Investigation on ultrasonic volume effects: Stress superposition,acoustic softening and dynamic impact

Conventional high power ultrasonic vibration has been widely used to improve manufacturing processes like surface treatment and metal forming. Ultrasonic vibration affects material properties, leading to a flow stress reduction, which is called ultrasonic volume effect. The volume effect contains multi-mechanisms such as stress superposition due to oscillatory stress, acoustic softening by easier dislocation motion and dynamic impact leading to extra surface plastic deformation. However, most researches ignored the stress superposition for the convenience of measurement, and few studies considered ultrasonic dynamic impact since the relatively low ultrasonic energy in macro scale. The purpose of this study is to investigate the characteristics and mechanisms of different ultrasonic volume effects in micro-forming. A 60 kHz longitudinal ultrasonic-assisted compression test system was developed and a series of ultrasonic-assisted compression tests at different amplitudes on commercially pure aluminum A1100 in micro-scale were carried out combining the surface analysis by SEM, EDX and micro-hardness test. Three different ultrasonic volume effects, stress superposition, acoustic softening and dynamic impact, were confirmed in the ultrasonic-assisted compression tests. In order to quantitatively predict stress superposition, a hybrid model for stress superposition is developed considering the elastic deformation of experimental apparatus in practice, the evolution of the modeling results fitted well with the experimental results. With low ultrasonic amplitude, stress superposition and acoustic softening occurred because vibrated punch contacted with the specimen all the time during compression. However, with higher amplitude, due to the extra surface plastic deformation by larger ultrasonic energy, forming stress was further reduced by the ultrasonic dynamic impact. A possible method to distinguish the effects of dynamic impact and acoustic softening is to analyze the waveform of the oscillatory stress in the process. In the case of ultrasonic dynamic impact effect, a higher amount of oxidation was observed on the specimen surface, which could be the result of local heating by surface plastic deformation and surface friction when the vibrated punch detached from the specimen. The findings of this study provide an instructive understanding of the underlying mechanisms of volume effects in ultrasonic-assisted micro-forming.     

A comparison between the sonochemical and thermal reaction of 5H,5Cl-dibenz[a,d]cycloheptatriene with nitrobenzene

The reaction of 5H,5Cl-dibenzo[a,d]cycloheptatriene with nitrobenzene was investigated under both thermal (210 degrees C) and ultrasonic (50 degrees C, 40 kHz) activation. The reaction products of both procedures are similar, but their amounts depend on the activation source. To account for the products a common electron transfer reaction is postulated through the dibenzotropylium cation. The differences between the thermal and ultrasonic process is thought to arise from the role of nitrobenzene as oxidant. Under thermal conditions this occurs throughout the reaction mixture but under sonication it occurs only in the cavitation bubble and in its immediate vicinity.     

Effects of ultrasonic and graft treatments on grafting degree,structure, functionality,and digestibility of rapeseed protein isolate-dextran conjugates

Rapeseed protein isolate (RPI) and dextran conjugates were prepared by traditional and ultrasonic assisted wet-heating. The effects on the grafting degree (GD), structure, functionality, and digestibility of conjugates were studied. Ultrasonic frequency, temperature, and time all significantly affected the GD. Under the optimum conditions (temperature of 90 °C and time of 60 min), compared to traditional wet-heating, ultrasonic treatment at 28 kHz significantly increased the GD by 2.12 times. Compared to RPI, surface hydrophobicities of conjugates were significantly decreased by graft and ultrasonic treatments. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and amino acid composition results confirmed that traditional graft reaction involved cysteine (Cys) and lysine (Lys) whereas the ultrasonic assisted one involved only Cys. Both were from the 12S globulin subunit and cruciferin. Fourier transform infrared spectrum (FT-IR) and circular dichroism (CD) results showed that graft treatment significantly changed secondary structure and ultrasonic treatment had the greatest impact on the decrease in the β-sheet (19.1%) and the increase in the random coil (49.6%). Graft and ultrasonic treatments both made surface structure looser and more porous. The two treatments also caused molecular weight to become bigger, and ultrasonic treatment had the greatest effect on the increase (68.2%) in 110–20.5 kDa. Structural modifications of RPI by grafting to dextran caused improvements of solubility (at pH 5–6), emulsifying activity (at pH 4–10), emulsion stability (at pH 4–5 and 9–10), and thermal stability (at temperature 90–100 °C). The digestibility of conjugates was decreased by graft and ultrasonic treatments and the conjugates were mainly digested in the intestinal phase. The ultrasonic assisted wet-heating was an efficient and safe method for producing RPI-dextran conjugates and improving the utilization value of rapeseed meal.     

光弹法测量超声换能器声场

超声换能器声场的测试对于超声检测具有基础性作用,而传统的超声换能器声场测试方法具有一些局限性。本文介绍了搭建的动态激光光弹实验平台,并利用动态光弹法测量了纵波换能器和横波换能器辐射声场的特征,由瞬态声场图像获得了传声介质的声波速度及超声换能器的中心频率;由稳态声场图像获得了声场的近场长度、指向性和扩散角等参数;分析了光弹实验系统和测量方法可能引起测量误差。本文结果表明动态光弹法是一种有效的定量测量超声换能器声场的方法。     

The development of recent high-power ultrasonic transducers for Near-well ultrasonic processing technology

With the reduction of crude oil throughout the world, enhance oil recovery technology has become a major oil research topics, which can greatly increase the recovery ratio of the crude oil before the dawning of renewable energy era. Near-well ultrasonic processing technology, as one new method, has attracted more attention for Enhanced Oil Recovery due to its low cost, good applicability and no environmental pollution in recent rears. There are two important relevant aspects about Near-well ultrasonic processing technology: (a) how to enhance the oil flow through the rocks into the pumping pool and (b) how to reduce the oil viscosity so that it can be easier to pump. Therefore, how to design a high-power ultrasonic equipment with excellent performance is crucial for Near-well ultrasonic processing technology. In this paper, recent new high-power ultrasonic transducers for Near-well ultrasonic processing technology are summarized. Each field application of them are also given. The purpose of this paper is to provide reference for the further development of Near-well ultrasonic processing technology.With the reduction of crude oil throughout the world, enhance oil recovery technology has become a major oil research topics, which can greatly increase the recovery ratio of the crude oil before the dawning of renewable energy era. Near-well ultrasonic processing technology, as one new method, has attracted more attention for Enhanced Oil Recovery due to its low cost, good applicability and no environmental pollution in recent rears. There are two important relevant aspects about Near-well ultrasonic processing technology: (a) how to enhance the oil flow through the rocks into the pumping pool and (b) how to reduce the oil viscosity so that it can be easier to pump. Therefore, how to design a high-power ultrasonic equipment with excellent performance is crucial for Near-well ultrasonic processing technology. In this paper, recent new high-power ultrasonic transducers for Near-well ultrasonic processing technology are summarized. Each field application of them are also given. The purpose of this paper is to provide reference for the further development of Near-well ultrasonic processing technology     

The ultrasonic characteristics of high frequency modulated arc and its application in material processing

To solve the difficulty of introducing traditional ultrasonic transducers to welding molten pool, high frequency current is used to modulate plasma arc and ultrasonic wave is excited successfully. The characteristics of the excited ultrasonic field are studied. The results show that the amplitude-frequency response of the ultrasonic emission is flat. The modulating current is the main factor influencing the ultrasonic power and the sound pressure depends on the variation of arc plasma stream force. Experimental study of the welding structure indicates grain refinement by the ultrasonic emission of the modulated arc and the test results showed there should be an energy region for the arc ultrasonic to get best welding joints.     

Elastic wave thermal fluctuations,ultrasonic waveforms by correlation of thermal phonons

It is widely recognized that acoustic degrees of freedom coupled to a thermal bath have amplitudes which fluctuate with a mean square proportional to temperature; this is the basis for the Debye theory of the heat capacity of insulating solids. It is shown here that these elastic wave thermal phonons have correlation functions identical to the system's ultrasonic Green's function, and furthermore that thermal noise in ultrasonic detectors should have correlation functions equivalent to conventional waveforms obtained by active transmission and reception. This suggests the possibility of doing ultrasonics without a source. Theory for the identity is presented, and several room temperature laboratory confirmations are conducted in the frequency range 0.1-1.0 MHz. The thermal nature of the origin of these correlations is established by comparing their strength with theoretical expectations. Applications are discussed.     

Fiber optic liquid leak detection technique with an ultrasonic actuator and a fiber Bragg grating

We present a technique for liquid leak detection in which ultrasonic and optical waves are introduced into a fiber simultaneously. The system is based on an ultrasonic technique using an ultrasonic actuator and a fiber Bragg grating receiver. A fiber-guided ultrasonic wave is utilized to stress the fiber Bragg grating, which is remote from the ultrasonic transmitter. When the traveling ultrasonic wave encounters a liquid, part of the wave will leak out from the fiber, which results in an ultrasonic strain decrease in the fiber Bragg grating. The ultrasonic wave and its attenuation are detected by the light variation of a narrowband laser source reflected and transmitted from the fiber Bragg grating, and the amplitude variation of the ultrasound can eventually be correlated with the fiber area coupled with the liquid.     

超声轴向传播技术评价长骨的研究

用超声轴向传播技术评价长骨状况已成为近年来的一个研究热点。本文首先介绍了第一到达波(FAS)法、超声Lamb波及柱面导波法在评价长骨皮质骨状况方面的研究进展,最后分析和讨论了当前研究中存在的问题及应该研究的方向。     

Degradation,isomerization and stabilization of three dicaffeoylquinic acids under ultrasonic treatment at different pH

Dicaffeoylquinic acids (diCQAs) are found in a variety of edible and medicinal plants with various biological activities. An important issue is the low stability of diCQAs during extraction and food processing, resulting in the degradation and transformation. This work used 3,5-diCQA as a representative to study the influence of different parameters in ultrasonic treatment on the stability of diCQAs, including solvent, temperature, treatment time, ultrasonic power, duty cycle, and probe immersion depth. The generation of free radicals and its influence were investigated during the treatment. The stability of three diCQAs (3,5-diCQA, 4,5-diCQA and 3,4-diCQA) under the certain ultrasonic condition at different pH conditions was evaluated and found to decrease with the increase of pH, further weakened by ultrasonic treatment. Ultrasound was found to accelerate the degradation and isomerization of diCQAs. Different diCQAs showed different pattern of degradation and isomerization. The stability of diCQAs could be improved by adding epigallocatechin gallate and vitamin C.     

Effect of sonochemical scouring on the surface morphologies,mechanical properties,and dyeing abilities of wool fibres

Ultrasonics has the potential to reduce the cost and environmental impact of textile processing. This work investigates the effects of ultrasonic irradiation during wool scouring on fibre surface morphologies, fibre mechanical properties, and fibre dyeing abilities. A range of ultrasonic frequencies were used in the scouring bath to examine the forms of fibre cuticle damage. It is observed that wool fibres underwent ultrasonic irradiation at a low frequency have severe modifications of the fibre surface structure. Despite some visible disruptions to the fibre scale structure however, ultrasonic irradiation has shown a negligible impact on the fibre mechanical properties, especially bending abrasion resistance which depends largely on the fibre surface conditions, and is responsible for the handle and pilling propensity of the resultant fabrics. Dyeing abilities were investigated on wool samples using commercially available acid dye and reactive dye. It is found that ultrasonically scoured wool has a quicker dye uptake in the early stage of low temperature dyeing for both acid dye and reactive dye, than the conventionally scoured wool.