Papers by Keyword: Ultrasonic Wave

Abstract: Steroid microbial conversion system is a complex but controllable system with multiple factors involved. In the process of steroid microbial conversion, strain screening and selection is essential to improving productivity and reducing costs. However, good-quality strains need optimal environmental conditions to best play their roles. Therefore, environmental conditions can significantly affect the conversion rate in addition to the quality of the strains utilized. Microbial environment includes physiological and biochemical environment, physical and materialized environment and hydro-mechanical environment. For example, the composition, pH value and dissolved oxygen of culture medium affect the physiological and biochemical environment; gas-liquid interface and liquid-solid interface of culture media affect the physical and materialized environment; scattered and mixed conditions of culture system affect the hydro-mechanical environment. Representative physical factors and their applications in steroid microbial conversion system are briefly reviewed herein.

Abstract: The desulfurization process of high-sulfur coal in Weibei was studied by flotation pretreatment and microwave combined with ultrasonic wave and oxidants. Through the single factor experiment which took Chenghe coal as the sample, the optimum conditions of this process had been concluded as follows: microwave power was 250 W, microwave time was 15 min, ultrasonic temperature was 60 °C, ultrasonic time was 30 min, coal slurry concentration was 0.083 g/ml, coal particle size was less than 0.074 mm, the dosage of agents was 8 mL/g, the radio of acetic acid and hydrogen peroxide was 1:3. After fractional release pretreatment, the sulfur reduction of Chenghe coal could reached to 53.10%. As to Hancheng coal, the value was 46.41%. By analyzing XRD and XPS spectra, it showed that most inorganic sulfur were removed by flotation pretreatment, and under the function of microwave combined with ultrasonic wave and oxidants, a part of organic sulfur was removed, such as mercaptan, sulfoxide and thiophene. However, as for sulfone, the removal effect was not obvious. The results proved that the experimental method could remove most of inorganic sulfur and part of the organic sulfur and significantly reduce the coal ash.

Abstract: The performance of an ultrasonic distillation (USD) system is evaluated in Aspen Plus simulation environment. To facilitate the flowsheet development, a mathematical model of a single stage USD developed using Aspen Custom Modeler software is exported to Aspen Plus process simulator. As a case study, the separation of ethanol-ethyl acetate mixture that is known to form azeotrope 55 mole % of ethyl acetate at minimum boiling point of 71.8 ^oC is considered. Simulation results revealed the achievable purity of ethyl acetate of 99 mole % from azeotropic mixture, thus reinforcing the anticipated potentials of sonication phenomena in intensifying distillation process to overcome azeotropes.

Abstract: The system designs wireless remote control airplane model, operatie the keys of the remote controller, after the model aircraft receiving the instruction, and handle through the ARM, control the aircraft forward or backward. While the aircraft are working turn left and turn right and straight line, the system makes a judgment on the ultrasonic feedback information, and then control the aircraft’s direction of movement, and display the corresponding information on LCD. after several debugging and operating, System can work stable and reliable. This model can be widely used in the industry and agriculture and daily life, The model can be used in remote wireless detect, and market prospects.

Abstract: The separation of azeotropic mixtures is conventionally one of the most challenging tasks in industrial processes as their separation by a simple distillation is basically impossible. Vapor-liquid equilibrium (VLE) equations with ultrasonic technique was based on a number of assumptions need to be built model on MATLAB software and compared the results with experimental work to validity the model. As a case study, the influence of ultrasonic intensity and frequency on the VLE of ethanolethyl acetate mixture was investigated, and a combination of five ultrasonic intensities (from 100 and 500 W/cm²) and three frequencies (from 25 to 70 kHz) were used. It is noted that with increase the ultrasound intensity and decrease the frequency can be improved the azeotropic point and relative volatility of the mixture. The results revealed that ultrasonic waves had the potential to enhance separation of azeotropic mixtures in a distillation column.

Abstract: Abietic acid was isolated by means of isomerization and amination reaction-crystallization coupled with ultrasonic wave. Isomerization rosin and ethanolamine were used as raw materials, 95% ethanol as recrystallization solvent, the effects of reaction temperature, reaction time, agitating velocity, ultrasound intensity and recrystallization times on the purity and yield of abietic acid were investigated. The suitable isolation conditions were obtained as follow: reaction temperature 30 °C, reaction time 40 min, agitating velocity 400 rpm, ultrasound intensity 300 W and freeze crystallization of amine salt three times. The purity and yield of abietic acid were 98.52% and 54.93% when the suitable conditions were used. And it was then characterization by its melting point, specific rotation, UV, FTIR and NMR, all evidence indicated that the purification product was abietic acid.

Abstract: To promote the application of the ultrasonic technology in pollution control, the introduction and the analysis of development of this technology, the basic theory of ultrasonic degradation and the influencing factors of ultrasonic degradation were studied in this paper. The analysis of molecular weight and distribution of wastewater and the elaboration of the influences of the ultrasonic frequency, power and the duration on the degradation were conducted by GPC. And an objective and reasonable explanation was advanced: in a certain range, proper increase of the ultrasonic frequency, power or duration would enhance its degradation; but excessive increase of the frequency, power or the increase of temperature due to long duration would decrease the degradation.

Abstract: It's a type of wheeled robot based on the AT89S52 MCU, through the body and infrared emission source docking judgment target position, the differential signal to control the motor speed to improve the direction; used ultrasonic obstacle avoidance module continuously detect the front object distance; used the error compensation principle of probability and statistics on the mechanical arm debugging and correcting, so that the system may realize to the target automatically crawl.

Abstract: In order to study propagation process of partial discharge ultrasonic signal in power transformer, the finite element method is used for simulation modeling and calculation. Ultrasonic waves can be activated by partial discharges (PD) in power transformers. The ultrasonic method is used for evaluating the insulation condition of power transformers by analyzing the partial discharge signals information which is detected by AE sensors. Compared with other diagnostic methods the AE method causes relatively low disturbance, and measuring apparatus is simple and easy to use. This technique is noninvasive and immune to electromagnetic noise. Simulate partial discharge sources of different positions respectively. Achieved results indicate that the space and time distributions of the acoustic pressure depend on the induction position. Furthermore, a greater pressure gradient is observed in domains with higher speed of sound while the signal amplitude decays when it moves away from the PD source.

Abstract: The effects of ultrasonic wave on tapping surface of ‘PR107’ rubber tree were studied. Daily production and cumulative production of latex were measured to estimate the effects of ultrasonic wave on latex production. The solid substance content, dry rubber content and mechanical stability of latex were determined to study the effects of ultrasonic wave on latex quality. Results showed that ultrasonic wave could increase both daily and cumulative production of latex and maintain latex basic quality. The daily production of latex was increased and appeared two peaks both in the ultrasound-treated rubber tree and the one with no treatment. The first peak appeared on the fifth day, and the latex production by ultrasound was 212.34 ml and the control was 141.75 ml. The second peak appeared with the production 266.59 ml on the seventeenth day by ultrasound, while the control appeared on the thirteenth day with production of 193.50 ml. The latex cumulative production of ultrasound-treated trees was 209.56 ml higher than that of control in one month. There was little change in solid substance content and dry rubber content between different ultrasonic time. The best mechanical stability of latex was obtained by ultrasound-treating the rubber tree for 4-6 min. it was proved that the ultrasound was helpful in improving the latex production and quality. The application of ultrasonic wave on rubber tree is novel, and its mechanism is worth further research.