Ultrasonic Density Research Articles

Modeling optimization and evaluation of tightly bound extracellular polymeric substances extraction by sonication.

Tightly bound extracellular polymeric substances (TB-EPS) are important components of sludge, playing a crucial role in the behavior of activated sludge. They are located in the innermost layer of EPS which closely combine with the cell surface and are difficult to be extracted. To fully understand the role of TB-EPS, it is extremely important to find an appropriate TB-EPS extraction protocol, which provides maximum yields of TB-EPS under the premise of minimal contribution of cell lysis. Ultrasonic method has been widely applied for TB-EPS extraction due to its unique advantages, but no one has developed a systematic and scientifically optimized method for this protocol. In this study, a novel method based on response surface methodology (RSM) was successfully developed to optimize the conditions of TB-EPS extraction. The optimal conditions were determined at an ultrasound time of 1.00min, ultrasonic density of 5.59W/mL and a mixed liquor suspended solid (MLSS) of around 1700-1800mg/L. Furthermore, combined analysis of microscopy, particle size, and excitation-emission matrix (EEM) was successfully applied to evaluate the optimal conditions. The result indicates that the optimal conditions are efficient, reliable, and reproducible which effectively solves the bottleneck problem of the conflict between cell viability and TB-EPS yield, and little effect on its chemical structure.

Effect of ultrasonic and microwave disintegration on physico-chemical and biodegradation characteristics of waste-activated sludge

ABSTRACTThe purpose of this study was to investigate the effect of ultrasonic and microwave disintegration on physico-chemical and biodegradability properties of waste-activated sludge (WAS) from a municipal wastewater treatment plant. Another aim was to carry out particle size distribution (PSD) analysis as an integral component of sludge characterization to highlight the transformation mechanisms involved in pretreatment processes and better understand the biodegradation patterns of sonicated and irradiated WAS liquids examined by means of respirometric measurements. Various combinations of sonication and microwave irradiation parameters were applied to optimize operating conditions. The optimum ultrasonic density was determined as 1.5 W/mL, and energy dosages lower than 30,000 kJ/kg TS resulted in a fairly linear increase in the soluble chemical oxygen demand (SCOD) release. An irradiation time of 10 min and a temperature of 175°C were selected as the optimum microwave pretreatment conditions for sludge liquefaction. The most apparent impact of ultrasonication on the PSD of COD was the shifting of the peak at the particulate fraction (>1600 nm) toward the lowest size range (<2 nm). Microwave heating at the selected experimental conditions and ultrasonic pretreatment at 30,000 kJ/kg TS exhibited comparable size distribution and biodegradation characteristics to those of domestic sewage.

Sonocatalytic degradation of diclofenac with FeCeOx particles in water

This paper studies the sonocatalytic degradation of diclofenac in water using FeCeOx-catalyzed ultrasound. The effects of pre-adsorption and gas addition were investigated. Nitrogen adsorption/desorption, SEM, XRD, Raman and XPS analyses of FeCeOx before and after sonication were characterized. The proposed mechanism was based on the microstructure changes of FeCeOx and reactive-species-scavenging performances. The results show that FeCeOx has excellent performance in catalyzing an ultrasonic system in water, and 80% of diclofenac was removed in 30min ([Diclofenac]=20mg/L, FeCeOx amount=0.5g/L, pH=6, ultrasonic density=3.0W/cm3, ultrasonic frequency=20kHz, temperature=298K). The Fe, Ce, and O elements remained highly dispersed in the structure of FeCeOx, and the solid solution structure of FeCeOx remained stable after the reaction. Ce (III) was gradually oxidized to Ce (IV) and Fe (III) was gradually reduced to Fe (II) after the reaction, which indicates that Fe and Ce ions with different valences coexisted in dynamic equilibrium. The amount of oxygen vacancies in FeCeOx significantly decreased after the reaction, which indicates that oxygen vacancy participated in the ultrasonic process. Singlet oxygen 1O2 was the primary reactive species in the degradation process, and the hydroxyl radicals OH and superoxide radical anion O2− also participated in the reaction. FeCeOx had excellent chemical stability with negligible leaching ions in the ultrasonic process.

Efficacy of percutaneous kyphoplasty for osteoporosis vertebral compression fractures

Objective To conclude the technology and clinical outcomes of percutaneous kyphoplasty for the treatment of osteoporotic vertebral compression fractures. Methods From June 2011 to June 2014, 29 cases of osteoporoticthoracic and lumbar vertebral compression fractures patients, who were diagnosed by ultrasonic bone mineral density measurement. X-ray, CT and MRI were treated with percutaneous kyphoplasty in Beijing 401 Hospital of China Nuclear Industry. Observed and recorded the degree of pain, patient's activity and the recovery of vertebral height in patients with 24 hours, 3 months and 6 months after operation. The index data were analyzed by SPSS17.0 statistical software, and the measurement data were analyzed by paired t test. Results Twenty-nine patients were operated successfully, 17 cases (58.62%)of back pain disappeared and 12 cases (41.38%) of back pain significantly reduced. Twenty-seven cases (93.1%) were allowed to get off bed after 24 hours of operation and 2 cases (6.9%) after 3 days. Three cases (10.34%) occurred PMMA leakage. After 24 hours, 3 months and 6 months VAS and vertebral height of the original vertebral height percentages are much better than before surgery (P 0.05). Compared after surgery 3-month and 6-month with after surgery 24 hours, the vertebral height have lost, but the lost height of the vertebral was no statistical significance (P>0.05). No infection, hematoma, spinal nerve injury and PMMA poisoning complications occurred. Conclusions Percutaneous kyphoplasty can relieve the pain and restore part of the vertebral height satisfactory with better outcomes. Key words: Percutaneous kyphoplasty; Fractures, compression; Osteoporosis; Lumbar vertebrae

Applying low frequency ultrasound on different biological nitrogen activated sludge types: An analysis of particle size reduction, soluble chemical oxygen demand (SCOD) and ammonia release

Applying low frequency ultrasound could effectively pretreat waste activated sludge (WAS) undergoing anaerobic digestion (AD), because the ultrasound can break up the flocs and cell walls. In this study, we applied ultrasound to three types of biological nitrogen activated sludge in an ice bath. Power densities ranged from 0 to 1.30 W mL−1 and reaction times ranged from 0 to 30 min. The three types of sludge included: short-cut nitrification denitrification sludge (SCND-SBR), complete nitrification denitrification sludge (CND-MUCT), and anaerobic ammonium oxidation sludge (AMX-SHARON). Experiments showed that reductions in average particle size were significantly decreased, due to breakage, at an ultrasonic duration of 10 min with different energy densities. More soluble chemical oxygen demand (SCOD) was detected when the ultrasonic density was higher and the duration was shorter, compared to when the density was lower and the duration was longer. Results suggest that ultrasonic density has a greater impact on the SCOD disintegration degree (DDCOD) as compared to operation time. Soluble proteins (SP) and NH4+N were released during the ultrasound; however, this process does not inhibit the subsequent methanogenic activity during the AD process. The ultrasonic density of 1.04 W mL−1 was the most economic and effective, with the highest efficiency in reducing particle size and releasing SCOD. Therefore, applying ultrasound can accelerate the hydrolysis rate, a rate-limiting factor during AD. This may ultimately reduce treatment construction and operational costs.

Preparation of FeCeOx by ultrasonic impregnation method for heterogeneous Fenton degradation of diclofenac

FeCeOx has been successfully synthesized by ultrasonic impregnation method and applied in diclofenac removal in heterogeneous Fenton process. The effects of ultrasonic density, impregnation time, mole ratio of Fe and Ce and calcination temperature were investigated. Nitrogen adsorption/desorption, SEM, XRD, HRTEM, Raman and XPS analyses were characterized. Stability and reusability of FeCeOx were evaluated. The results indicated that 83% degradation efficiency of diclofenac was achieved by FeCeOx under the optimum preparation conditions. Fe ions were distributed uniformly in crystal structure and the solid solution structure of FeCeOx with a lattice constriction was formed. Exposed crystalline plane (200) with a relatively high surface energy may be the main reason to provide high catalytic activity of FeCeOx. Oxygen vacancies took part in catalytic process and a portion of them were oxidized after reaction. FeCeOx showed an excellent chemical stability and reusability in heterogeneous Fenton process.

Thermo-Acoustical Molecular Interaction Studies in Ternary Liquid Mixtures by Ultrasonic Velocity Measurements at 303K

The thermo-acoustical parameters for ternary liquid mixtures namely Acetonitrile + Nitrobenzene in a non polar solvent have been estimated, from the measured values of ultrasonic velocity (U), density (ρ) and viscosity (η). Using the measured data, some of the acoustical parameters such as adiabatic compressibility(β), free length (Lf), free volume (Vf), internal pressure (πi), acoustic impedance (Z), relaxation time (τ), Gibb's free energy (ΔG), classical absorption coefficient (α/f2), cohesive energy (H) are evaluated at the temperature 303K. The behavior of these parameters with composition of the mixture has been discussed in terms of molecular interaction between the components of the liquids.

Совершенствование методики аэродинамических испытаний токоприемника путем учета плотности воздушной среды

Aerodynamic forces of current collector depend not only on the design parameters, but also on weather conditions determining the dynamic pressure. Currently, when conducting field tests, control of these conditions is not performed, this can affect the accuracy of the results. The objectivity of measurements can be provided by theoretical and experimental methods of accounting air density. A theoretical method based on the calculation of the density of air environment by using data about the temperature, atmospheric pressure and relative humidity in the area where tests of current collector was conducted. The experimental method involves the use of ultrasonic density meter of air. Density values, defined experimentally, increase the accuracy of the results due to the fact that registration takes place directly on the roof of the locomotive, where the current collection was performed. It is shown that the dependence of the vertical component of the aerodynamic forces of current collector from the air density is linear. The article also substantiates the necessity of taking into account the density of the air environment by comparison of results of tests conducted under various meteorological conditions. The method of data matching, in which there is a correction factor, is proposed and the densities are set to the value corresponding to the normal environmental conditions. Due to the lack of criteria in the normative documents for comparing two samples, set to normal conditions, it is proposed to use a statistical method - t-Student criterion. This method assumes a normal distribution of data samples, as evidenced by the results of field tests conducted earlier. Given method allows comparing the results of field tests and evaluating the quality of the current collection, not only under normal conditions, but also in the entire temperature range, relative humidity and atmospheric pressure, at which the current collector can be operated.

Degradation of polycyclic aromatic hydrocarbons (PAHs) in textile dyeing sludge with ultrasound and Fenton processes: Effect of system parameters and synergistic effect study

To establish an efficient oxidation process for the degradation of polycyclic aromatic hydrocarbons (PAHs) in textile dyeing sludge, the effects of various operating parameters were optimized during the ultrasound process, Fenton process and the combined ultrasound–Fenton process. The results showed that the ultrasonic density of 1.80w/cm3, both H2O2 and Fe2+ dosages of 140mmol/L and pH 3 were favorable conditions for the degradation of PAHs. The degradation efficiency of high molecular weight PAHs was close to or even higher than that of light molecular weight PAHs. The highest degradation efficiencies of Σ16 PAHs were obtained within 30min in the order of: Fenton (83.5%) >ultrasound–Fenton (75.5%) >ultrasound (45.5%), then the efficiencies were decreased in the other of: ultrasound–Fenton (73.0%) >Fenton (70.3%) >ultrasound (41.4%) in 60min. The extra PAHs were released from the intracellular substances and the cavities of sludge due to the disruption of sludge during the oxidation process. Also, the degradation of PAHs could be inhibited by the other organic matter in the sludge. The combined ultrasound–Fenton process showed more efficient than both ultrasound process and Fenton process not only in the surface of sludge but also in the sludge interior.

Molecular interactions in atenolol—ethanol mixtures: An ultrasonic study

In the present study ultrasonic velocity (υ), density (ρ), and viscosity (η) of the mixtures of atenolol drug with ethanol have been measured at frequency 1 MHz in the concentration range 0.1–0.0125% at 303, 308, and 313 K using multifrequency ultrasonic interferometer. The measured values have been used for calculations of the mixtures acoustical parameters. These parameters explained molecular interactions existing in the solution.

Enhancement of ultrasonic disintegration of sewage sludge by aeration

Sonication is an effective way for sludge disintegration, which can significantly improve the efficiency of anaerobic digestion to reduce and recycle use of sludge. But high energy consumption limits the wide application of sonication. In order to improve ultrasonic sludge disintegration efficiency and reduce energy consumption, aeration was introduced. Results showed that sludge disintegration efficiency was improved significantly by combining aeration with ultrasound. The aeration flow rate, gas bubble size, ultrasonic density and aeration timing had impacts on sludge disintegration efficiency. Aeration that used in later stage of ultrasonic irradiation with low aeration flow rate, small gas bubbles significantly improved ultrasonic disintegration sludge efficiency. At the optimal conditions of 0.4W/mL ultrasonic irradiation density, 30mL/min of aeration flow rate, 5min of aeration in later stage and small gas bubbles, ultrasonic sludge disintegration efficiency was increased by 45% and one third of ultrasonic energy was saved. This approach will greatly benefit the application of ultrasonic sludge disintegration and strongly promote the treatment and recycle of wastewater sludge.

Simultaneous degradation of 1,1,1-trichloroethane and solvent stabilizer 1,4-dioxane by a sono-activated persulfate process

Increasing attention has been paid to persulfate activation for the degradation of organic contaminants due to its high efficiency and low cost. However, most previous studies have overlooked the detection of generated reactive oxygen species (ROS), which plays an important role in the transformation of contaminants. In this study, the activation of persulfate by ultrasonic field (UF) for the degradation of 1,1,1-trichloroethane (TCA) and solvent stabilizer 1,4-dioxane (1,4-D), and the possible reaction mechanism were investigated. The results showed that the contaminants can be efficiently degraded under the optimal conditions of pH0=7.0, Temp. 15±2°C, persulfate 1.50mmol/L, ultrasonic frequency 400kHz, power 100W and ultrasonic density 2.67W/cm2 with initial TCA ∼20mg/L and 1,4-D ∼1.0mg/L. Coexisting 10mmol/L inorganic anions slowed down the contaminant degradation to different degrees, and the inhibiting effect followed the order of CO32−>HCO3−>Cl−>SO42−>NO3−. The electron paramagnetic resonance (EPR) technique was used to detect and identify the ROS. Results show that the applied UF could effectively activate persulfate and produce more hydroxyl radicals (OH) and sulfate radicals (SO4−), accordingly resulting in the enhanced degradation of the contaminants. Twenty-three and eight degradation intermediates were detected and identified for TCA and 1,4-D, respectively. Results indicate that the sono-activated persulfate process is a promising technique to simultaneously eliminate of TCA and 1,4-D from water or groundwater.

Ultrasonic Technique for Density Measurement of Liquids in Extreme Conditions.

An ultrasonic technique, invariant to temperature changes, for a density measurement of different liquids under in situ extreme conditions is presented. The influence of geometry and material parameters of the measurement system (transducer, waveguide, matching layer) on measurement accuracy and reliability is analyzed theoretically along with experimental results. The proposed method is based on measurement of the amplitude of the ultrasonic wave, reflected from the interface of the solid/liquid medium under investigation. In order to enhance sensitivity, the use of a quarter wavelength acoustic matching layer is proposed. Therefore, the sensitivity of the measurement system increases significantly. Density measurements quite often must be performed in extreme conditions at high temperature (up to 220 °C) and high pressure. In this case, metal waveguides between piezoelectric transducer and the measured liquid are used in order to protect the conventional transducer from the influence of high temperature and to avoid depolarization. The presented ultrasonic density measurement technique is suitable for density measurement in different materials, including liquids and polymer melts in extreme conditions. A new calibration algorithm was proposed. The metrological evaluation of the measurement method was performed. The expanded measurement uncertainty Uρ = 7.4 × 10−3 g/cm3 (1%).

Ion-solvent interactions in lanthanum(III) chloride and D-glucose-water mixed solvent systems: An ultrasonic study

Acoustic parameters such as isentropic compressibility, βs, intermolecular free length, Lf, apparent molar volume (ϕv), solvation number, Sn, viscosity B coefficients of Jones-Dole equation etc., have been evaluated from the measured values of ultrasonic velocity, density and viscosity for the solutions of lanthanum(III) chloride in d-glucose (dextrose)-water mixed solvent system of various proportions at 303.15 K temperature and atmospheric pressure. The results are discussed in the light of ion-solvent interactions and the structural effect of the solute on the solvent in the solution.

Ultrasonic studies of molecular interactions in binary mixtures of n-Butanol with water at different temperatures (308K, 318K and 328K)

The experimental ultrasonic velocity (u), density (ρ) and viscosity (ƞ) of butanol mixed with water has been measured over the full range of compositions at atmospheric pressure and at different temperatures (308, 318 and 328 K). From these experimental values the molar Isentropic compressibility (βs), Intermolecular free length (Lf), Free volume (Vf) and Acoustic impedance (Z) are calculated.

Enhanced biohydrogen production from dark fermentation of complex dairy wastewater by sonolysis

The present work describes an effectiveness of ultrasonication pretreatment for enhancement of biohydrogen production from complex dairy wastewater at optimized culture conditions obtained previously. An ultrasonic pretreatment was comprised of five ultrasonic densities (UD) (from 0 to 0.2 W/mL) at five different ultrasonication time (UT) (from 6 to 14 min). Response surface methodology (RSM) analysis showed that UD was the highly significant parameter, which predominantly influences biodegradability, hydrogen yield (HY), and specific hydrogen production rate (SHPR) enhancement during dark fermentation. Optimization of pretreatment using RSM integrated with desirability function followed by a verification test showed that maximum HY of 15.33 mmol/g COD and SHPR of 31.38 mmol/g VSS.d obtained at 0.08 W/mL and 9 min. Significant relative enhancement of HY, 27%, and SHPR, 51%, suggests that ultrasonication pretreatment of complex dairy wastewater is about 1.1–2-fold more effective for enhanced hydrogen recovery compared to unsonicated one. A successful energy balance of ultrasonication pretreatment suggests an effectiveness of the pretreatment for enhanced energy recovery.

Use of Duplex Scanning for Estimation of Liver Fibrosis

Hepatic and splenic arteries and portal and splenic veins were examined in patients with chronic hepatitis using duplex scanning. The type and power of correlations between ultrasonic characteristics and liver density were estimated. On the basis of the hemodynamic characteristics, an index for differentiating the degrees of fibrosis is suggested. Patients with chronic viral hepatitis, nonalcoholic fatty liver disease, and chronic alcoholic hepatitis were included into the trial.

Optimization of ultrasonification of slaughter blood for protein solubilization

In this study, we attempted to solubilize protein in slaughter blood (SB) using ultrasonic technology. The application of ultrasonic technology can make enzymatic degradation of SB more effective, which has no comparable alternative for treatment. The SB was homogenized by grinding it for 10 minutes at 10,000 rpm as a pretreatment for preventing its clotting, and then ultrasonic treatment was attempted to solubilize protein in SB. To maximize the efficiency of ultrasonic treatment for SB, the optimum condition of ultrasonic frequency (UF) was determined to be 20 kHz. To optimize the operation conditions of ultrasonification with 20 kHz of frequency, we used response surface methodology (RSM) based on ultrasonic density (UD) and ultrasonification time (UT). The solubilization rate (SR) of protein (%) was calculated to be 101.304 – 19.4205 X1 + 0.0398 X2 + 7.9411 X1 2 + 0.0001 X2 2 + 0.0455 X1X2. From the results of the RSM study, the optimum conditions of UD and UT were determined at 0.5 W/mL and 22 minutes, respectively, and SB treated under these conditions was estimated to have a 95% SR. Also, experimentally, a 95.53% SR was observed under same conditions, accurately reflecting the theoretical prediction of 95%.

MnO2/CeO2 for catalytic ultrasonic decolorization of methyl orange: Process parameters and mechanisms

MnO2/CeO2 catalyst was prepared and characterized by means of Brunauer–Emmet–Teller (BET) method, X-ray diffraction (XRD) and scanning electron microscope (SEM). The characterization showed that MnO2/CeO2 had big specific surface area and MnO2 was dispersed homogeneously on the surface of CeO2. Excellent degradation efficiency of methyl orange was achieved by MnO2/CeO2 catalytic ultrasonic process. Operating parameters were studied and optimized. The optimal conditions were 10min of ultrasonic irradiation, 1.0g/L of catalyst dose, 2.6 of pH value and 1.3W/ml of ultrasonic density. Under the optimal conditions, nearly 90% of methyl orange was removed. The mechanism of methyl orange degradation was further studied. The decolorization mechanism in the ultrasound-MnO2/CeO2 system was quite different with that in the ultrasound-MnO2 system. Effects of manganese and cerium in catalytic ultrasonic process were clarified. Manganese ions in solution contributed to generating hydroxyl free radical. MnO2/CeO2 catalyst strengthened the oxidation ability of ultrasound and realized complete decolorization of methyl orange.

Study on Internal Stress in Micro-Electroformed Layer

Micro electroforming technology is widely used in fabrication of multilayer or moveable metal micro devices. The fabrication of these devices is usually suffered from high internal stress in micro-electroformed layers which seriously restricts the application and development of micro electroforming technology. Therefore, to control the internal stress is very important for improving the quality and performance of micro-electroformed layer. However, published studies on internal stress in the electroforming layer were mostly based on additive-free solution. According to additive solution, the effect of ultrasonic and current density on compressive stress occurring in the electroforming layer is investigated in this paper. The results indicate that the compressive stress keeps increasing with current density within range from 0.2 to 2 A/dm2. Meanwhile, the compressive stress in ultrasonic solution decreases by 73.4 MPa averagely comparing to that in ultrasonic-free solution, and the compressive stress also keeps decreasing with the ultrasonic power which gets the lowest value at 200W. Moreover, the mechanisms of additive-induced compressive stress and ultrasonic relieving compressive stress are discussed. This research work will complement the ultrasonic-stress reduction theory and may contribute to the development of micro electroforming technology.