Papers by Keyword: Ultrasound

Abstract: Ultrasound is an important diagnostic tool in distinguishing interfaces between soft tissues, especially abdominal structures. Diagnostic ultrasound is used for the detection of cysts, tumors or cancers present in the abdomen. Bladder cancer is one of the common types of cancer nowadays. The volume of the bladder is less in case of presence of cyst, tumors or cancers. Considering the importance of measurement of volume of the urinary bladder, various invasive and noninvasive methods are discussed in this article. The invasive method has many disadvantages. Hence this article encompasses the various noninvasive methods and its implementation using imaging techniques are discussed. The imaging techniques include Prolate Ellipsoid Method, Double Area Method and Double Ellipsoid Method. The methodology which is being generally used to calculate the volume of the urinary bladder is Prolate Ellipsoid Method. The accuracy of the above mentioned methods is reported with relatively larger errors of about 60%. The accuracy can be increased by incorporating sophisticated, expensive 3D software packages and imaging tools.

Abstract: This paper introduces one ultrasonic distance measurement device based on single chip processor and mainly describes its hardware circuit and software design. The ultrasonic distance measurement device has many merits such as simple structure, low-cost, high-accuracy, microminiaturization, digital display and so on; this result reaches the expected target. The practice result shows that the ultrasonic telemeter has very high generalizing value.

Abstract: Dietary fiber is one of value added products from cassava pulp, byproduct of cassava starch industry. It could be produced by enzymatic digestion in which the optimal condition was studied. The three independent variables are heating temperature (°C) after adding α-amylase concentration (%v/v) and amyloglucosidase concentration (%v/v) regarding of two responses solid percentage yield and neutral detergent fiber (NDF) in the digested sample. The experimental design was based on central composite design. The highest solid percentage yield and NDF of cassava byproduct could get from enzymatic digestion condition at heating temperature at 90 °C, α-amylase concentration of 0.3 % (v/v), and amyloglucosidase concentration of 0.5 % (v/v). For ultrasound-assisted preparation was investigated at the optimum condition of enzymatic digestion. Ultrasound condition was control power of 140% and a frequency of 40 kHz for 15 min. The ultrasound was applied at pre-treatment condition (before adding α-amylase, PU) collocated with intermediate condition (before adding amyloglucosidase, IU) higher NDF yield than optimal condition at 18.78%. In addition, this ultrasound assisted technique give the highest solid percentage.

Abstract: Deep desulfurization of a hydrotreated diesel fuel was investigated with TBHP oxidation coupled with solvent extraction intensified by ultrasound. The process parameters for the oxidation desulfurization of diesel fuel, such as the type and dosage of catalyst, co-solvent, ultrasound time, molar ratio of TBHP and sulfur were investigated. The results showed that sulfur content of the hydrotreated diesel fuel was reduced from 140 ppm to 12 ppm with using 1%wt of sodium tungstate as catalyst, 20%wt of methanol as co-solvent during the reaction, reaction temperature at 90°C, ultrasound time for 15 min and TBHP/Sulfur molar ratio of 32, and ultrasound irradiation had the obvious reinforcement in oxidative desulfurization of diesel fuel.

Abstract: A new method for the evaluation of radiotherapy 3D polymer gel dosimeters has been developed using ultrasound to assess the significant structural changes that occur following irradiation of the dosimeters. Polymer gel dosimeters were being fabricated using a monomer named 2-Hydroxyl-Ethyl-Meta-Acrylate (HEMA) with the presence of gelatine as a gelling agent. The readymade gel which is the concentration for HEMA fixed at 2, 4 and 5% would then undergo an ultrasonic evaluation to test for the propagation of sound speed through it. In the observation of relationship between the ultrasound propagation speeds as the doses increase (focusing at the cross region from overlapped beams) and concentration of monomer, the propagation speed for all the three polymer gel dosimeter phantoms still varies between 1460 to 1570 m/s which is still in the range of speed of sound for human tissue [. The ultrasonic absorption attenuation coefficient dose sensitivity for polymer gel dosimeters for 2, 4 and 5% of monomer are in the range of 0.02 to 0.6 dB which is equivalent to human tissue. As a comparison, it can be seen that gel phantoms with high concentration of monomer (5%) is more sensitive to the radiation compared to the lower (2% and 4%) concentrations. Regarding the absolute results of mechanical and acoustic properties; the copolymer-in-oil phantom is equivalent with soft tissue.

Abstract: Heavy metals exist in different forms in polluted soils however only the unstable form is bioavailable and potentially threatening to the environment. This study adopted the ultrasound technique as a tool to transform the unstable heavy metal forms into soluble forms and remove them. Acoustic cavitation coupled with mechanical stirring was used to facilitate the removal of Cu and Ni from a polluted soil. Effect of sonication treating time, sonication power and slurry concentration factors on the removal efficiency (RE) were studied. Test results show that the RE increase with sonication treating time, the best RE for Cu and Ni are 40-50 minutes and 30-40 minutes respectively. Increasing the sonication power can improve the removal of Cu but particularly for Ni, the optimal sonication power is 400W. High concentration slurry is better for Cu removal but for Ni, a more dilute slurry is more effective.

Abstract: The experiments of TOC and UV₂₅₄ removal of humic acid (HA) solution by ultrasound (US) irradiation with the presence of H₂O₂ and Fe₃O₄ nanoparticles (NP) were carried out. The comparison of enhancement effect of humic acid sonolysis by H₂O₂ and NP was investigated. It was found that removal efficiency of TOC and UV₂₅₄ increased significantly in the order of US< US/NP< US/H₂O₂< NP/H₂O₂< US/NP/H₂O₂. During US/NP/H₂O₂ combining process, the contribution of H₂O₂ should be presenting most OH radicals for humic acid degradation, Fe₃O₄ nanoparticles would supply adsorption surface for humic acid to have more chance to be oxidized, and ultrasonic would work as main energy for OH radicals generation and offer sonochemical environment.

Abstract: With n-butanol/CTAB/cyclohexane as micro emulsion system, sodium tungstate and hydrochloric acid as raw material, alkali metals (Na+, K+) nitrate as dopant, pure WO3、Na+-WO3, K+-WO3 and Na+/K+-WO3 powders were prepared by ultrasonic micro-emulsion method; And performances of samples were analyzed by visible spectrophotometer. Photocatalytic activity study show that alkali metal sodium ion and potassium ion doped, photocatalytic activities of WO3 are improved markedly; When doping amount is 1.0%, catalyst amount is 2g/L, methyl orange concentration is 20mg/L, degradation time is 80 min, Na+-WO3 powder has the best photocatalytic degradation performance at 460nm, and the degradation rate is as high as 65%.

Abstract: In this paper, the heat transfer of pineapple juice was investigated on a new evaporator with ultrasound. The effects of various factors on the heat transfer coefficient were analyzed, including feed rate, evaporating temperature, temperature difference of heat transfer, and juice concentration. The proposals of design and operation for this new evaporation were also discussed.

Abstract: Iron oxide nanoparticles were synthesized by employing an ultrasonic homogenizer in conjunction to the co-precipitation of Fe (NO₃)₃·9H₂O, FeCl₂·4H₂O and NaOH. Synchrotron X-ray absorption near edge structure (XANES) spectra could be fitted with the contributions from hematite (α-Fe₂O₃) and, to a lesser extent, metallic Fe. The increase in reagent concentrations increased the Fe fraction which partly explained the change in magnetization of superparamagnetic particles. Nevertheless, the α-Fe₂O₃ composition was increased by using a longer reaction time.