Algal Control by Low-Frequency, Low-Power Ultrasonic in Eutrophic Water Bodies

2012 ◽  
Vol 433-440 ◽  
pp. 811-816
Author(s):  
Deng Ling Jiang ◽  
Guo Wei Ni ◽  
Yu Min Zhang ◽  
You Po Su
Keyword(s):  
Low Power ◽  
Ultrasonic Irradiation ◽  
Irradiation Time ◽  
Algal Growth ◽  
Low Frequency ◽  
Water Bodies ◽  
Ultrasonic Power ◽  
Water Ecosystem ◽  
Power Ultrasonic ◽  
Algal Control

Ultrasonic cavitations can control algal growth. Considering water ecosystem protection and characteristics of ultrasonic technology, low frequency and low power ultrasonic was especially suitable to control algal growth in water bodies. Effects of low-frequency and low-power ultrasonic irradiation on natural blend algal growth were investigated. The algae spices were collected from a fresh water body. It mainly consists of Cyanophyta, Bacillariophyta and Chlorophyta. The results showed that ultrasonic irradiation with frequency of 60KHz, power of 0.24W/cm2 and irradiation time of 1min, inhibited algal growth significantly. Inhibition of ultrasonic irradiation on algal growth enhanced with ultrasonic power increased. Inhibition did not increase again When ultrasonic power exceeds 0.24W/cm2. The effect of algal control was sustainable by ultrasonic irradiation with interval period of 2-4 days.

Optimization of Chlorella pyrenoidosa Removal by Low Frequency Ultrasonic Irradiation Using Response Surface Design

2011 ◽  
Vol 295-297 ◽  
pp. 1860-1865 ◽  
Author(s):  
Zhi Zhang ◽  
Chao Liu ◽  
Gong Duan Fan ◽  
Jing Luo ◽  
Yan Dong Wang
Keyword(s):  
Response Surface ◽  
Irradiation Time ◽  
Removal Rate ◽  
Low Frequency ◽  
Chlorella Pyrenoidosa ◽  
Ultrasonic Frequency ◽  
Ultrasonic Power ◽  
Control Parameters ◽  
Single Factor ◽  
Surface Design

The control parameters of the removal of Chlorella pyrenoidosa, which was irradiated by low frequency ultrasonic, is optimized by using single factor experiments and response surface methodology (RSM). First of all, the approximate ranges of the ultrasonic frequency, the ultrasonic power and the irradiation time were estimated with single factor experiments for the further experiments. And then the optimized values of the three control parameters were determined, which were analyzed by using central composite design (CCD) and RSM. The results showed that the removal rate of chlorophyll-a could reach to 64.1% after the irradiation for 6.34min by using ultrasonic of 77.7 kHz and 250W. Ultrasonic technology can remove Chlorella pyrenoidosa cells in water quickly and effectively, so as to achieve the purpose of water purification.

scholarly journals EXTRACTION OF POLYSACCHARIDES FROM LINGZHI BY ULTRASONIC-ASSISTED ENZYMATIC METHOD

2018 ◽  
Vol 56 (4A) ◽  
pp. 171
Author(s):  
Tran Quoc Hoa
Keyword(s):  
Ultrasonic Irradiation ◽  
Irradiation Time ◽  
Hot Water ◽  
Ultrasonic Power ◽  
Extraction Temperature ◽  
Assisted Extraction ◽  
Anti Cancer ◽  
Ultrasonic Assisted ◽  
Experimental Yield ◽  
Optimized Conditions

The medicinal values of polysaccharides (PS) in Lingzhi have been shown to lie in many anti-cancer effects and good benefits for human health. Lingzhi, which is rich in healthy PS, has been used more and more commonly in Vietnam in recent years. In the present work, ultrasonic-assisted enzymatic extraction (UAEE) was used for extraction of PS from Lingzhi. The experiments were conducted according to a Box-Behnken design (BBD), with four independent variables: solvent temperature, ultrasonic power, pH, and ultrasonic irradiation time. The results showed that the best adequate extraction conditions were extraction time of 144 min, extraction temperature of 55°C, ultrasonic power of 240W, pH 7.9, and ultrasonic irradiation time of 144 min. Under these conditions, the predicted optimal yield was 3.716%. Whereas by following the optimized conditions, the experimental yield of PS was 3.65% ± 0.14, which was in good agreement with that of the prediction. Compared to the hot water extraction (HWE) method, ultrasonic-assisted extraction (UAE) method and enzyme-assisted extraction (EAE) method, the yield of PS obtained by UAEE was favorable. The PS yield obtained by HWE, and EAE were 1.96% and 3.10%, respectively. These results demonstrated that UAEE was an appropriate and effective extraction of polysaccharides from Lingzhi.

Design Optimization of Low Power and Low Frequency Vibration Based MEMS Energy Harvester

2013 ◽  
Vol 475-476 ◽  
pp. 1624-1628
Author(s):  
Hasnizah Aris ◽  
David Fitrio ◽  
Jack Singh
Keyword(s):  
Low Power ◽  
Energy Harvester ◽  
Piezoelectric Materials ◽  
Geometry Optimization ◽  
Low Frequency ◽  
Substrate Thickness ◽  
Power Harvesting ◽  
Low Frequency Vibration ◽  
Length Width ◽  
Development And Utilization

The development and utilization of different structural materials, optimization of the cantilever geometry and power harvesting circuit are the most commonly methods used to increase the power density of MEMS energy harvester. This paper discusses the cantilever geometry optimization process of low power and low frequency of bimorph MEMS energy harvester. Three piezoelectric materials, ZnO, AlN and PZT are deposited on top and bottom of the cantilever Si substrate. This study focuses on the optimization of the cantilevers length, width, substrate thickness and PZe thickness in order to achieve lower than 600 Hz of resonant frequency. The harvested power for this work is in the range of 0.02 ~ 194.49 nW.

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