Papers by Keyword: Ultrasound (US)

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Authors: Hyung Joon Kim, Seung Moo Han
Abstract: Most ultrasound diagnosing systems for osteoporosis lack diagnostic precision due to the measurement of specific regions of interest (ROI). As well as using the existing ROI measurement method, this study introduced the concept of analyzing the distribution patterns of bone quality. Linear scanning and ultrasound transmission techniques were used to obtain the broadband ultrasound attenuation (BUA) images of the calcaneus. A 13mm-diameter ROI was selected as the position of minimum BUA value locally in the posterior calcaneus. Mean values of BUA and speed of sound (SOS) at the ROI, as well as the osteoporosis index (OI), by their linear combination, were defined. For a more accurate diagnosis of osteoporosis, OI and images of the bone quality distribution of the calcaneus were utilized together. The calcaneus is inhomogeneous and, furthermore, its images are not perpendicular to the direction of the ultrasound beam. Hence, the mean values of BUA and SOS for the entire calcaneus do not have any significant meaning. Accordingly, four image patterns of other OI in the calcaneus were defined in order to increase the correlation between diagnostic parameter and age. The results revealed a higher correlation between the bone quality index and age (r=0.75, p<0.0001), for which the pattern index was reflected on OI, than that (r=0.65, p<0.0001) of OI merely at ROI. This result confirmed the possibility of a new osteoporosis diagnostic method using the BUA distribution images of the entire calcaneus.
Authors: Yan Feng Tang, Xue Sheng Zhu, Jin Li Zhu, Jin Ming Wu, Hong Kun Zhao
Abstract: In the paper, synthesis of 1,2:5,6-di-O-isopropylidene-D-glucofranose (DAG) assisted by ultrasound were performed in the presence of ferric chloride as catalyst. The effects of some reaction parameters (e.g. power and frequency of ultrasound, reaction temperature, mass ratio of the reactant) on the yield were investigated. It was found that the reaction is greatly accelerated by the ultrasound in comparison to the control runs under mechanical stirring. The optimal ultrasound output power and frequency were found to be 200 W and 24 kHz at 40 °C with a 1:30 mass ratio of glucose to acetone. Under these optimal conditions, the yield of DAG reached 75.8%.
Authors: S. Sivasankaran, S. Sankaranarayanan, S. Ramakrishnan
Abstract: Metal oxides form part of inorganic medicines called Bhasmas, which has been used in a non-allopathic medicine system practiced in India called Ayurveda. Bhasmas may be classified under the nanomedicines of ancient India. The traditional preparation methods involve time consuming and complicated preparation procedures. This paper highlights a novel ultrasound assisted technique called sonochemical synthesis of transition metal oxides in a facile, faster, inherently safer and environmentally benign (green chemistry) way which could be considered to be used for the synthesis of metal oxides such as copper oxide which form part of the copper based Ayurvedic nanomedicine called tamra bhasma, which is copper in its oxide form and used therapeutically as a source of copper. The synthesis procedure outlined here could be considered for the preparation of other types of Bhasmas also.
Authors: Zhan Wei Xu, Gui Lin Zheng
Abstract: A novel ranging method based on self-calibration principle is proposed in the paper. This method can be used in vehicle ranging to achieve accurate distance measurement. The principle of the method, hardware architecture and experiment analysis are introduced. Self-calibration principle can eliminate the impact of the velocity of ultrasound on vehicle ranging. Plenty of experiments have been done to validate the design. Both theoretical analysis and experimental results show the effectiveness of the method. A full description of the method and implementation are presented.
Authors: Katja Pranke, Klaus Eigenfeld
Abstract: We investigated the influence of varying amplitudes at constant frequency on the grain size and mechanical properties of magnesium alloy AZ 91. Our experimental setup consists of an ultrasound generator connected to a steel gravity die by screw fitting. Magnesium alloy AZ 91 has been melted in a closed-argon-flooded steel crucible and poured into the die while ultrasound was generated. Cooling curves were recorded during the whole solidification process. The grain size and the mechanical properties were determined and analyzed. As a result, we achieved reduction in grain size as well as an increase in tensile strengths for amplitudes of up to 40% of the maximum amplitude. Yield strengths could be minimally improved in all experiments. The values of elongation and hardness (Brinell) could also be improved for nearly all investigated amplitudes. In summary it is possible to achieve both: grain refinement and increase in tensile strength, hardness and elongation.
Authors: Robert Mettin, P.E. Frommhold, X. Xi, F. Cegla, H. Okorn-Schmidt, A. Lippert, F. Holsteyns
Abstract: Applications of acoustic cavitation [ frequently suffer from certain random aspects (e.g., stochastic bubble nucleation events) as well as from its sensitivity to external parameters (like gas content in the liquid). This renders for example a prediction of bubble distributions in size and space still a difficult task. To improve this situation by a better understanding of the fundamentals, a "bottom-up" approach has recently been followed which tried to model collective bubble phenomena and bubble structures on the basis of single bubbles and their interaction [. If the behavior of individual bubbles can be well captured by the models, it is hoped to gain significant insight into a larger system of acoustically driven bubbles. Indeed, several aspects of multi-bubble systems and structures could be explained by single bubble dynamics, for instance by the inversion of the primary Bjerknes force in strong ultrasonic fields. Nevertheless, many details of bubble dynamics stay partly unclear, and considerable efforts are undertaken to improve our understanding and to optimize applications of acoustic bubbles.
Authors: Shun Zhong Jiang, Jiang Hong Fan, Wu Bing Xia
Abstract: This study introduces the basic principle of relative blood volume monitor (BVM) by comparing several ultrasonic travel time measuring methods, brings forth the high-precision ultrasonic travel time measuring method based on TDC-GP2 time measurement chip and MSP430 Single-chip Microcontroller (SCM), presents the configuration of hardware and software in the system, and illustrates the structure and time measurement principle of TDC-GP2 time measurement chip.
Authors: Yong Guang Bi, Min Xia Huang
Abstract: aniline solution for the study, the effects of ultrasonic time, reaction factors such as temperature, ultrasonic power, and the pH of its ultrasonic degradation rate. Experimental results show that: as time increases, the ultrasonic degradation rate of aniline also rise, When the ultrasound the irradiation time 80min, aniline degradation rate reached 89.3%, 90min when the degradation rate of 92.1%, the degradation rate of aniline with decreases with the rise of the temperature of the solution, more than 40°C the degradation rate decreased significantly. Aniline degradation rate increased with the initial solution pH value increases, indicating that the alkaline conditions are favorable for degradation of aniline solution. Relative to the traditional method, the method is fast, simple, degradation rate, etc..
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