The effects of ultrasonic treatment (UST) on the solidification microstructure of a 35CrMo steel cast ingot were investigated. To avoid the erosion of a high-temperature melt, a T-shaped ultrasonic waveguide unit was used to introduce ultrasonic vibrations into a 35CrMo steel die casting melt. The experimental results show that the microstructure of the ingot was refined by ultrasonic treatment...

medical plants are adapted to different kinds of dormancy to survive in the worst situations. regarding to ecological viewpoint, this kind of adaptation is very important in respect to restriction of genetic draft and decrease of genetic resource of medicinal plants. this leads to plant survival even after prolonged drought. since some of them are endangered species and in the other hand increa...

the activated sludge process is the most widely used biological wastewater treatment for both domestic and industrial plants in the world. one of the drawbacks of conventional activated sludge (cas) processes is high sludge production. excess sludge treatment and disposal currently represents a rising challenge for wastewater treatment plants (wwtps) due to economic, environmental and regulatio...

Abstract Simultaneous reduction in activity of fat destabilizing enzymes (lipase and lipoxygenase), contaminants heavy metals (As, Cd, Pb, Hg), antinutrient phytic acid hazardous coliforms rice bran was investigated. Application washing, soaking the washed sample at different pH values (2, 6 9) alone or combination with ultrasonication were examined. While washing beneficial, its low efficiency...

introduction: periodontitis is an inflammatory periodontal disease that leads to tooth loss. recently laser has been introduced as an alternative treatment for periodontitis. the aim of the present study was to compare the effect of erbium-doped yttrium aluminum garnet (er:yag) laser with ultrasonic scaler in patients with moderate chronic periodontitis. methods: in this randomized single-blind...

In this study, spherical Nb2O5 nanoparticles were synthesized by a novel chemical method as a simple, robust, surfactant-free, non-toxic and widely applicable approach. In order to investigate the effect of initial concentration on particle sizes, nanoparticles with different initial concentration were synthesized. Ultrasonic assisted method was applied and the effects of ultrasonic treat...

This paper proposes a simultaneous tuning method for PID controllers and dead-zone compensators based on particle swarm optimization. By the proposed algorithm, PID gains and dead-zone parameters are tuned online to minimize the error between the control output and the reference input. However, since ultrasonic motors intrinsically have a varying dead-zone in the control input associated with a...

The ultrasonic Doppler method was employed to time the rapid movements (opening and closure) of the mitral and aortic valves. To exclude signals due to slowly moving structures (heart walls), the Doppler tracing was processed by a filter that eliminated low frequencies. Clear tracings containing two deflections, one due to the opening and the other to the closure of each valve, were obtained. T...

in this study, zno nanoparticles were loaded on activated carbon prepared from almond shell (zno-np-ac). then, this novel material applied as an efficient adsorbent for the ultrasonic assisted simultaneous removal of basic blue 41(bb41) and basic red 46 (br46) in binary solution.  the efficiency of proposed activated carbon was enhanced by acid treatment and subsequent modification by physical ...