Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Ultrasonic

Investigate and Comparison Effect add Amorphous and Crystalline - Nano SiO2 on Properties of Concrete

Rami Joseph Aghajan Sldozian

Engineering and Technology Journal, 2015, Volume 33, Issue 3, Pages 547-555

In this paper, the study included the comparison between amorphous silica and crystalline silica (quartz), and with nano scale size, two types of silicawere added to concrete by ratios (5%, 10%, 15%, and 20%) as a replacement by the weight of cement. Destructive and non-destructive tests wereconducted on the specimens, the results show in destructive test the compressive and tensile strength increase in 15%wt addition ratio in both types of silica, but in amorphous silica was high than in quartz.The results of non-destructive tests show in (Schmidt Hammer) the 15% ratio in both kinds of silica show high hardness than other ratios. Ultra sonic (pules velocity) test, noted the better quality was in 15% ratio in amorphous silica and also show fastest pules velocity.

Kinetics, Thermodynamic and Mechanism of Ultrasonic Degradation of Benzene in Aqueous Solution

Ismail K.Al-Khateeb; Adawiya J.Haider; Ahmed M. Mohammed

Engineering and Technology Journal, 2014, Volume 32, Issue 1, Pages 34-45

Ultrasonic technology, as an innovative technology,was used for degradation of benzene in an aqueous solution under ultrasound frequency of 20 kHz at different temperatures with initial concentration of 100 and 200 mg/L. Kinetic and thermodynamic of benzene degradation in aqueous solution were investigated.
While the mechanism of benzene sonolysis was discussed. The degradation rate of benzene increased with increasing electric power, sonication time and by decreasing liquid volume, temperature and initial concentration of benzene. The beneficial effect of which power electrical or ultrasound on removal rates is believed to be due to increased cavitational activity occurring at higher levels of
power. As power increases, the number of collapsing (effective) cavities also increases, which is leading to enhanced degradation rates. Thermodynamic parameters indicated that benzene degradation was spontaneous and exothermic in nature. The obtained data was fitted through the pseudo-first order model.

Enhancement of Porous Silicon Formation by Using Ultrasonic Vibrations

Ali H. Al-Hamdani

Engineering and Technology Journal, 2012, Volume 30, Issue 5, Pages 849-854

Anodic electrochemical etching enhanced by ultrasonically is developed to fabricate luminescent porous silicon (PS) material. The samples prepared by the new etching method exhibit superior characteristics to those prepared by conventional direct current etching. By applying ultrasonically enhanced etching, PS microcavities with much higher quality factors can be fabricated. The improved quality induced by
ultrasonic etching can be ascribed to increased rates of escape of hydrogen bubbles and other etched chemical species from the porous silicon pores surface.