Partner: A. Schommartz |
Recent publications
1. | Kotopoulis S.♦, Schommartz A.♦, Postema M.♦, Sonic cracking of blue-green algae, APPLIED ACOUSTICS, ISSN: 0003-682X, DOI: 10.1016/j.apacoust.2009.02.003, Vol.70, No.10, pp.1306-1312, 2009 Abstract: Algae are aquatic organisms classified separately from plants. They are known to cause many hazards to humans and the environment. Algae strands contain nitrogen-producing cells that help them float (heterocysts). It is hypothesized that if the membranes of these cells are disrupted by means of ultrasound, the gas may be released analogous to sonic cracking, causing the strands to sink. This is a desirable ecological effect, because of the resulting suppressed release of toxins into the water. Ultrasonic algae eradication, Blue-green algae, Sonic cracking Affiliations:
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Conference papers
1. | Kotopoulis S.♦, Schommartz A.♦, Postema M.♦, Safety radius for algae eradication at 200 kHz - 2.5 MHz, IUS 2008, IEEE International Ultrasonics Symposium, 2008-11-02/11-05, Beijing (CN), DOI: 10.1109/ULTSYM.2008.0417, Vol.1, pp.1706-1709, 2008 Abstract: Algae have been proven to be a severe health hazard to humans, aquatic and semi-aquatic animals. Chemical methods available to control the algae have unwanted side-effects. For this reason, ultrasonic algae control has been under investigation. We measured the eradication effectiveness of ultrasound at three typical centre frequencies. At all three frequencies physical damage to the algae was observed. We conclude that it is possible to eradicate blue-green algae in the clinical diagnostic range. Taking into account the geometry, the low attenuation in water, and the NATO Undersea Research Centre for Human Diver and Marine Mammal Risk Mitigation Rules and Procedures, even at these low voltages, the safe swimming distance is at least several meters away from the sound source. Keywords:Ultrasound, Algae eradication Affiliations:
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2. | Postema M.♦, Schommartz A.♦, Bubbles, ultrasound, and swimmer safety, Spring Conference of the Institute of Acoustics 2008 "Widening Horizons in Acoustics", 2008-04-10/04-11, Reading (GB), Vol.30, pp.384-386, 2008 Abstract: The benefits of ultrasonics in algae control have been well known [1]. The transmit frequencies used to study this application have been as low as 20 kHz and as high as 1.7 MHz. Most commercial equipment operates in the lower ultrasonic range. There have been speculations about the physical mechanism behind the algae eradication, specifically about the role of cavitation. Furthermore, the consequences for swimmers in water subjected to ultrasonic treatment have been unknown. In this study, we investigate the role of cavitation as potential danger for swimmers. Furthermore, we give an estimate of swimmer safety radii, based on current regulations. Keywords:Ultrasound, Swimmer safety Affiliations:
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