Use of ultrasound for the determination of flour quality

Within the baking industry, the control of dough properties is required to achieve final product quality and consistency. Traditional methods for dough testing are slow and off-line and do not provide fundamental rheological information. There is therefore a need for the development of fast and on-line instruments capable of providing relevant data for baking. Ultrasonics provide a non-destructive, rapid and low cost technique for the measurement of physical food characteristics.In this work, the water content of dough is investigated using ultrasonic techniques. The capability of ultrasound measurements for discriminating flours for different purposes is also studied. Doughs from more than 30 flours were characterised rheologically using a Chopin Alveograph and a Brabender Extensograph. Ultrasound measurements on the doughs prepared from these flours were also performed. The measurements were correlated, showing that ultrasound was an alternative measurement method to discriminate types of flours for different purposes.     

动态条件下超声储层水敏性去除实验研究*

利用自主研制的超声发生仪,选取不同渗透率的天然岩心,模拟实际地层的温度、压力进行室内驱替实验,评价了渗流过程中超声作用对储层水敏性伤害去除的影响。研究表明,对于去除储层水敏性,超声频率存在最佳范围,频率与功率存在一定的补偿关系;超声最佳处理时间与储层物性有一定联系;渗透率恢复率与储层物性呈现较复杂的关系。研究结果有助于进一步认识超声水敏性去除的作用机理。     

Pulsed ultrasound assisted dehydration of waste oil

A method to aid the separation of the oil phase from waste oil emulsion of refineries had been developed by using a pulsed ultrasonic irradiation technology. Compared with conventional continuous ultrasonic irradiation, it is found that pulsed ultrasonic irradiation is much better to make water drop coalescence and hence dehydration of waste oil. The effects of ultrasonic irradiation parameters on waste oil dehydration are further discussed. The orthogonal experiment is also designed to investigate the degrees of influence of ultrasonic parameters and the optimal technological conditions. Under the optimal experimental conditions, the water content of waste oil is decreased from 65% to 8%, which thereby satisfies the requirements of refineries on the water content of waste oil after treatment (<10%).     

超声C扫描用喷水系统设计及其检测稳定性*

摘要：本文针对列车车体复合材料构件检测用超声C扫设备喷水系统的检测稳定性问题开展研究。基于喷水式超声耦合检测原理,设计了一种喇叭段+直管段的喷嘴,以使水流形成变径约束的层流,从而缩短喷嘴长度。结合实验分析了工艺参数对检测性能的影响。结果表明：喷嘴结构、耦合水流速、射水距离及检测方式等因素均对超声耦合稳定性及检测性能产生影响。试验结果可为喷水式耦合超声C扫技术在车体构件检测中的实际应用提供参考。     

Improved biofilm removal using cavitation from a dental ultrasonic scaler vibrating in carbonated water

The use of cavitation for improving biofilm cleaning is of great interest. There is no system at present that removes the biofilm from medical implants effectively and specifically from dental implants. Cavitation generated by a vibrating dental ultrasonic scaler tip can clean biomaterials such as dental implants. However, the cleaning process must be significantly accelerated for clinical applications. In this study we investigated whether the cavitation could be increased, by operating the scaler in carbonated water with different CO₂ concentrations. The cavitation around an ultrasonic scaler tip was recorded with high speed imaging. Image analysis was used to calculate the area of cavitation. Bacterial biofilm was grown on surfaces and its removal was imaged with a high speed camera using the ultrasonic scaler in still and carbonated water. Cavitation increases significantly with increasing carbonation. Cavitation also started earlier around the tips when they were in carbonated water compared to non-carbonated water. Significantly more biofilm was removed when the scaler was operated in carbonated water. Our results suggest that using carbonated water could significantly increase and accelerate cavitation around ultrasonic scalers in a clinical situation and thus improve biofilm removal from dental implants and other biomaterials.     

Applying ultrasonic fields to separate water contained in medium-gravity crude oil emulsions and determining crude oil adhesion coefficients

Separating produced water is a key part of production processing for most crude oils. It is required for quality reasons, and to avoid unnecessary transportation costs and prevent pipework corrosion rates caused by soluble salts present in the water. A complicating factor is that water is often present in crude oil in the form of emulsions. Experiments were performed to evaluate the performance of ultrasonic fields in demulsifying crude oil emulsions using novel pipe-form equipment. A horn-type piezoelectric ultrasonic transducer with a frequency of 20 kHz and power ranging from 80 W to 1000 W was used for experimental purposes. The influences of the intensity of ultrasonic fields, ultrasonic irradiation time, and the initial water content of crude oils were evaluated to establish the rate of water segregation from oil. The experiments applied ultrasonic-field intensities of $0.25$ W/cm³, $0.5$ W/cm³, $0.75$ W/cm³ and $1$ W/cm³ to synthetic emulsions with 10%, 15%, 20%, and 25% of the water in crude oil. Crude oil demulsification occurred for each ultrasonic field intensity tested for all the samples tested. Function β involving adhesion coefficients was expressed in terms of wave-field intensity and initial concentration of water in each of the three crude oil samples tested. The experiments demonstrated that despite the absence of any chemical demulsifier involved, water separation caused by applying ultrasonic fields was effective and occurred rapidly. As the intensity of the ultrasonic field applied increased, the amount of water segregated from crude oil also increased. Subjected to constant field intensity, higher initial water cuts (up to 15% or so) in the crude oil samples and higher ultrasonic irradiation times, resulted in greater segregation of water from crude oil in percentage terms. However, in samples with initial water cuts of 20+% long irradiation times (~5 min), resulted in a decline in water separation compared to 2-min tests. Ultrasonic field treatments offer commercially-viable and environmentally-friendly alternatives to treatments using chemical demulsifiers as they reduce desalination requirements of wastewater.     

Selective ultrasonic treatment of perforation zones in horizontal oil wells for water cut reduction

A technique for treatment of perforation zones of horizontal oil wells for water cut reduction based on selective ultrasonic treatment was suggested. The technique involves online geophysical studies of horizontal wells, determination of treatment intervals based on these studies, selective ultrasonic treatment of the chosen interval and subsequent pump-out using a specially designed jet pump. The technology does not involve reduction of the flow in the well. The developed innovative technique of water cut reduction using selective ultrasonic treatment is studied within this article. Theoretical estimations and computer modeling revealed that the position of the downhole ultrasonic tool near the sidewall of the well leads to more homogeneous distribution of the induced acoustical field and wider penetration of the acoustical waves. The developed method was tested on a horizontal well in Western Siberia, which was characterized by high water cut. Based on geophysical studies only zones with low water and high oil production were treated, this lead to a decrease of the water cut by 20% and an increase of oil production by 91% after treatment of the test well.     

Study on ultrasonic-electrochemical treatment for difficult-to-settle slime water

The treatment of slime water not only has a direct impact on the economic benefits of the coal preparation plant, but also has an important significance for the conservation and utilization of the environment and water resources in the mining area. However, under the background of increasing mechanization level of coal mining, the proportion of fine coal is increasing, and the slime water exhibits fine, high and sticky characteristics in terms of particle size, ash, and viscosity, making it difficult for the slime water to settle. In this paper, research on the treatment of difficult-to-settle slime water by ultrasound-electrochemistry is investigated. The principle of the ultrasonic-electrochemical method for treating difficult-to-settle slime water is discussed. The effects of electrodes, electrolytes, ultrasonic energy density and ultrasonic time on treatment of difficult-to-settle slime water are analyzed. Results show that ultrasound-electrochemical pretreatment for difficult-to-settle slime water is not a simple superposition of the two treatment methods, and ultrasound can promote the electrochemical reaction. The optimal ultrasonic parameters are given: ultrasonic frequency, energy density and ultrasonic time are 29 kHz, 0.5 W/m³ and 4 min respectively. Based on the basic properties of the micro-charge on the surface of coal particles, the flocculation sedimentation can be promoted effectively by the combination of sonochemical and electrochemical methods. Finally, the research status of the new treatment technology for difficult-to-settle slime water is discussed, and the development trend is pointed out.     

超声波专题实验开展及其传播特性研究

开设了超声波专题设计综合实验,测量得空气、水和白油中超声波传播速度,研究了同一介质中接收到的交变电压随传播距离的变化规律,空气、水和白油中超声波的损耗系数,水中超声波的损耗系数最大。使用Origin软件直线拟合,对实验结果进行分析和评价。     

Oil–water de-emulsification using ultrasonic technology

In this paper an oil–water de-emulsification process within large tanks using ultrasonic technology is presented. As the device would operate in hazardous areas, it should not consume an excessive amount of electrical power. Hence, the paper investigates the suitable oil–water concentrations (10–90% concentrations in step of 10%) which would lead to the fastest separation while consuming the minimum amount of power. Extensive experiments which were conducted using a powerful 20 kHz ultrasonic sensor were indicative with good repeatability that the emulsion layer with less water content (i.e. 10 to 40% water-cut) gets significantly faster separation. The experimental study was then validated through a set of finite element-based simulations for different ratios of oil water emulsions. This led to suggest a new feasible de-emulsifying device which consists of a one dimensional array of ultrasonic sensors which are vertically distributed to emit ultrasonic waves in horizontal direction and in a time multiplexed manner.     

Influence of intensity and frequency of ultrasonic waves on capillary interaction and oil recovery from different rock types

Oil saturated cylindrical sandstone cores were placed into imbibition cells where they contacted with an aqueous phase and oil recovery performances were tested with and without ultrasonic radiation keeping all other conditions and parameters constant. Experiments were conducted for different initial water saturation, oil viscosity and wettability. The specifications of acoustic sources such as ultrasonic intensity (45–84 W/sq cm) and frequency (22 and 40 kHz) were also changed. An increase in recovery was observed with ultrasonic energy in all cases. This change was more remarkable for the oil-wet medium. The additional recovery with ultrasonic energy became lower as the oil viscosity increased. We also designed a setup to measure the ultrasonic energy penetration capacity in different media, namely air, water, and slurry (sand + water mixture). A one-meter long water or slurry filled medium was prepared and the ultrasonic intensity and frequency were monitored as a function of distance from the source. The imbibition cells were placed at certain distances from the sources and the oil recovery was recorded. Then, the imbibition recovery was related to the ultrasonic intensity, frequency, and distance from the ultrasonic source.     

Water content and its effect on ultrasound propagation in concrete--the possibility of NDE

It is known that water content or moisture affects the strength of concrete. The purpose of this study is to examine the possibility of the NDE of concrete from a knowledge of the relationship between water content and ultrasonic propagation in concrete. The results of measurements made on the ultrasound velocity and the frequency component on ultrasonic propagation as a function of the water content in concrete are reported. Test pieces of concrete made from common materials were made for the fundamental studies. The test piece dimensions were 10 cm in diameter and 20 cm in length. Test pieces were immersed in water for about 50 days to saturate them. To measure the effect of different water contents, test pieces were put in a drying chamber to change the amount of water between measurements. This procedure was repeated until the concrete was completely dried and the weight no longer changed. Water contents were defined as weight percentage to full dried state. Thus water content could be changed from 8% to 0%. Using the pulse transmission method, ultrasonic propagation in the frequency range 20 to 100 kHz was measured as a function of water content. The sound velocity varied gradually from 3000 m/s to 4500 m/s according to the water content. The frequency of maximum transmission also depended on the water content in this frequency range. It is considered that the ultrasonic NDE of concrete strength is feasible.     

Sonochemical reaction with microbubbles generated by hollow ultrasonic horn

A microbubble generator with a cylindrical hollow ultrasonic horn (HUSH), gas flow path, and an orifice inside it can produce high ultrasonic pressure around the generated microbubbles. We used this microbubble generator with a HUSH as a sonochemical reactor for the degradation of indigo carmine and evaluated the sonochemical reaction by simply inserting the horn end into a liquid. The experimental results revealed that the ultrasonic irradiation around ultrasonically generated microbubbles effectively degraded indigo carmine in water. In addition, degradation experiments performed by varying the ultrasonic power and gas flow rates indicated that a continuous gas supply and ultrasonic pressure were required for generating the microbubbles, without the generation of millimeter-scale bubbles, to enhance the sonochemical reaction in water.     

Effects of low-frequency ultrasonic pre-treatment in water/oil medium simulated system on the improved processing efficiency and quality of microwave-assisted vacuum fried potato chips

The effects of low-frequency ultrasonic pre-treatment in water/oil medium simulated system on the improved processing efficiency and quality of microwave-assisted vacuum fried potato chips were investigated. The water medium system (distilled water and 5% NaCl osmotic solution) and oil medium system (90 °C) were designed with different power levels of ultrasound to simulate the ultrasonic conditions. Results showed that the changes of moisture content, water loss, solid gain and dielectric properties of potato slices were facilitated by the ultrasonic treatment. LF-NMR analysis showed the binding force between the moisture and structure in the material was significantly (p < 0.05) weakened. The changes become greater with the increase of ultrasonic power levels. Microscopic channels and disruptions were induced on the microstructure by the ultrasonic treatment. The effective moisture diffusivity of vacuum fried (VF) potato chips was increased by about 56.2%-67.0% and 53.9% with the combination of microwave energy and the ultrasonic pre-treatment in water and oil medium simulated system, respectively. The oil uptake, hardness, shrinkage, total color change and water activity of vacuum fried samples were significantly (p < 0.05) decreased by the assist of microwave energy combined ultrasonic pre-treatment.     

Evaluation of process parameters of ultrasonic treatment of bacterial suspensions in a pilot scale water disinfection system

In this study, several process parameters that may contribute to the efficiency of ultrasound disinfection are examined on a pilot scale water disinfection system that mimics realistic circumstances as encountered in an industrial environment. The main parameters of sonication are: (i) power; (ii) duration of treatment; (iii) volume of the treated sample. The specific energy (E_s) is an indicator of the intensity of the ultrasound treatment because it incorporates the transferred power, the duration of sonication and the treated volume. In this study, the importance of this parameter for the disinfection efficiency was assessed through changes in volume of treated water, water flow rate and electrical power of the ultrasonic reactor. In addition, the influences of the initial bacterial concentration on the disinfection efficiency were examined. The disinfection efficiency of the ultrasonic technique was scored on a homogenous and on a mixed bacterial culture suspended in water with two different types of ultrasonic reactors (Telsonic and Bandelin). This study demonstrates that specific energy, treatment time of water with ultrasound and number of passages through the ultrasonic reactor are crucial influential parameters of ultrasonic disinfection of contaminated water in a pilot scale water disinfection system. The promising results obtained in this study on a pilot scale water disinfection system indicate the possible application of ultrasound technology to reduce bacterial contamination in recirculating process water to an acceptable low level. However, the energy demand of the ultrasound equipment is rather high and therefore it may be advantageous to apply ultrasound in combination with another treatment.     

Enhancement of heat transfer in forced convection by using dual low-high frequency ultrasound

Combined sonication with dual-frequency ultrasound has been investigated to enhance heat transfer in forced convection. The test section used for this study consists of a channel with, on one hand, heating blocks normal to the water flow, equipped with thermocouples, and, on the other hand, two ultrasonic emitters. One is facing the heating blocks, thus the ultrasonic field is perpendicular, and the second ultrasonic field is collinear to the water flow. Two types of ultrasonic waves were used: low-frequency ultrasound (25 kHz) to generate mainly acoustic cavitation and high-frequency ultrasound (2 MHz) well-known to induce Eckart’s acoustic streaming. A thermal approach was conducted to investigate heat transfer enhancement in the presence of ultrasound. This approach was completed with PIV measurements to assess the hydrodynamic behavior modifications under ultrasound. Sonochemiluminescence experiments were performed to account for the presence and the location of acoustic cavitation within the water flow. The results have shown a synergetic effect using combined low-and-high-frequency sonication. Enhancement of heat transfer is related to greater induced turbulence within the water flow by comparison with single-frequency sonication. However, the ultrasonically-induced turbulence is not homogeneously distributed within the water flow and the synergy effect on heat transfer enhancement depends mainly on the generation of turbulence along the heating wall. For the optimal configuration of dual-frequency sonication used in this work, a local heat transfer enhancement factor up to 366% was observed and Turbulent Kinetic Energy was enhanced by up to 84% when compared to silent regime.     

Physical and chemical characteristics of ultrasonically-prepared water-in-diesel fuel: Effects of ultrasonic horn position and water content

An ultrasonic technique was applied to preparation of two-phase water-in-oil (W/O) emulsified fuel of water/diesel oil/surfactant. In this study, an ultrasonic apparatus with a 28 kHz rod horn was used. The influence of the horn tip position during ultrasonic treatment, sonication time and water content (5 or 10 vol%) on the emulsion stability, viscosity, water droplet size and water surface area of emulsion fuels prepared by ultrasonication was investigated. The emulsion stability of ultrasonically-prepared fuel significantly depended on the horn tip position during ultrasonic irradiation. It was found that the change in the stability with the horn tip position was partly related to that in the ultrasonic power estimated by calorimetry. Emulsion stability, viscosity and sum of water droplets surface area increased and water droplet size decreased with an increase in sonication time, and they approached each limiting value in the longer time. The maximum values of the viscosity and water surface area increased with water content, while the limiting values of the emulsion stability and water droplet size were almost independent of water content. During ultrasonication of water/diesel oil mixture, the hydrogen and methane were identified and the cracking of hydrocarbon components in the diesel oil occurred. The combustion characteristics of ultrasonically-prepared emulsion fuel were studied and compared with those of diesel oil. The soot and NOx emissions during combustion of the emulsified fuel with higher water contents were significantly reduced compared with those during combustion of diesel oil.     

基于超声波的食盐溶液物性的研究

利用超声波在水中的传播特性测得水密度,其相对误差为0.51%。与传统方法相比,该法具有原理简单,操作方便,精确度较高等优点。配制了45种不同浓度的食盐溶液,计算出每种溶液的密度、体积模量和超声波的传播速度,并分别给出声速与溶液浓度、密度、体积模量之间的线性定标公式。     

Effect of the fluid in the inclusions of cement paste on the ultrasonic velocity

The durability of cement composites significantly depends on the movement of the fluids into the material through the porous system. The aqueous phase contained in the pores can cause irreversible damage from the dimensional stability viewpoint. In this sense, methods for non-destructive characterization of both, the porous structure and water content should be investigated. In this work, the effect of the fluid in the inclusions of the cement paste on the ultrasonic velocity is studied. Firstly, a theoretical analysis based on the micromechanical model, considering the microstructural information of the matrix and the fluid filling the pores, is presented. Some experimental work is made later using cement paste samples, whose porous structure is maintained dry or saturate with water. In both cases, the ultrasonic velocity is measured and compared to the one predicted by the micromechanical model. Using this technique, the ultrasonic velocity can be predicted with errors below 2% in the cases of dry or water saturated cement paste.     

Ultrasound as pre-treatment for drying of pineapple

Dehydration of fruits is an alternative to reduce post-harvest loss of fruits and also a process to produce dried fruits, which can be directly consumed or become part of foodstuffs like cakes, pastries and many others. The effect of ultrasonic pre-treatment and ultrasound-assisted osmotic dehydration, before air-drying, on dehydration of pineapple (Ananas comosus) was investigated. This study allowed estimating the water diffusivity in the air-drying process for pineapples submitted to ultrasound. Results showed that the water diffusivity increased after application of ultrasound and that the overall drying time was reduced by 8% (over 1h of air-drying time). During the ultrasonic treatment in distilled water the pineapples lost sugar (23.2% in 30 min), so in this condition the ultrasonic pre-treatment can be an interesting process to produce dried fruits with low sugar content. Results showed that the water loss increased with increasing soluble solids content of the osmotic solution and that the ultrasound-assisted osmotic dehydration incorporated more sugar than conventional osmotic dehydration. The water effective diffusivity of the pineapples during the air-drying process was influenced by the pre-treatment, increasing the water effective diffusivity when ultrasound was applied.