Kannur floodTwitterThe Indian Meteorological Department (IMD) has issued a red alert in Kerala due to the heavy downpour that has created a flood-like situation in the several districts.The red alert has been issued for Kasargod district and orange alert has been issued for Kannur, Kozhikode, Idukki, Malappuram and Wayanad districts. IMD has also issued a yellow alert for Thiruvananthapuram, Kottayam, Ernakulam, Pathanamthitta, Kollam, Alappuzha, Thrissur and Palakkad.The heavy rains have lashed several parts of the state and many different parts of Kannur is still flooded. Three people have been reported to be dead from Kannur, Pathanamthitta and Kollam districts and several people are also missing from various districts due to the rain. Many rescue camps have been opened at the areas affected by the rain.Several fishermen have also gone missing after they set out from Vizhinjam and Shaktikulnagara in Kollam and the coastal police are trying to locate them. Helicopters have also been deployed to trace the missing fishermen. The locals have protested against the police claiming that no actions were taken by the authorities over the missing fishermen.In the wake of heavy downpour in the catchment area, the government has opened one shutter of Kallarkutty Dam in Idukki district as the water level has reached 2307.12 ft due to the south-west monsoon which continues to intensify. The IMD has predicted over 20 cm of rainfall between July 19-22 in the state. Kannur floodTwitterTwo shutters of the Malankara dam was opened on Friday and more shutters are also expected to open due to the high intensity of the rain. Other dams including Aruvikara, Pambla (lower Periyar), Boodhathankettu have also opened their shutters.
© 2018 Phys.org Illustration of electrogates. Insets show a close-up of the area surrounding the trench. Credit: IBM Research-Zurich Journal information: Applied Physics Letters Flow apparatus samples up to 1500 chemical reactions a day Each electrogate consists of a trench etched into the bottom surface of the microchannel, with one electrode patterned over the trench and a second electrode patterned a short distance in front of the trench. When a liquid sample flows along the microchannel in the absence of a voltage, it stops at the trench because the abrupt change in the contact angle creates a pinning force on the liquid. A small voltage (<10 volts) applied between the two electrodes pulls down ions from the liquid to the edge of the trench where the liquid is pinned, which makes this area more wettable. As a consequence, the contact angle of the liquid in this area decreases, causing the liquid to resume flowing across the trench and through the microchannel. The researchers demonstrated that the curvature of the trench determines the reliability and retention time of the electrogates. With a large curvature, they could achieve 100% reliability, start and stop times of less than a second, and retention times exceeding 5 minutes, which can be extended to beyond 45 minutes with additional strategies. The electrogates also work with various types of liquids, including human serum.Among its advantages, the electrogates are easy to fabricate, have long-term stability, are biocompatible, and can be implemented in multiple locations on the same chip. The researchers expect that the electrogates can be easily implemented into low-power, portable microfluidics devices in the future."We are supported by a grant from the EU, and we still have a little bit of time to 'push' electrogates further," Delamarche said. "One task (nearly complete) is to vary the options for fabricating electrogates so that technologists have more freedom to design and fabricate them. This can help spread the concept, we think. Then, we will show specific examples where combining a few electrogates can create more advanced functions for microfluidic systems." Although microfluidics devices have a wide variety of uses, from point-of-care diagnostics to environmental analysis, one major limitation is that they cannot be modified for different uses on the fly, since their flow paths are set during fabrication. In a new study, researchers have addressed this limitation by designing electrogates that can regulate the flow of liquid at different points along the microchannel—a process that can be entirely controlled with a smartphone. The researchers, Y. Arango, Y. Temiz, O. Gӧkçe, and E. Delamarche, at IBM Research-Zurich in Rüschlikon, Switzerland, have published a paper on electrogates in a recent issue of Applied Physics Letters."Point-of-care diagnostics represent a very segmented market," Delamarche told Phys.org. "For each type of test, a microfluidic device needs to be designed and fabricated to ensure optimal assay performances (volume of sample passing through the device, flow rates, time given for the reactions to take place, time given for dissolving some reagents in the chip with the sample, etc.). This is a bit frustrating, and with silicon microtechnology, it is always beneficial to cover as many applications as possible without too much redesign and changes in the manufacturing processes. "This is where electrogates help, and this is what motivated us to invent them. The idea is to make chips much more generic and transfer some of the routing and timing of the flow to a software level, i.e., a protocol uploaded on a smartphone or tablet. Changing protocols on a software level is easy, fast, flexible and convenient."Rather than using mechanical elements such as pumps and valves to control the flow, the electrogates are based on electrowetting. This process involves applying an electric voltage to control the wetting properties of the surface, which in turn controls the flow of the liquid. Explore further The researchers in their lab. Credit: IBM Research-Zurich More information: Y. Arango, Y. Temiz, O. Gӧkçe, and E. Delamarche. “Electrogates for stop-and-go control of liquid flow in microfluidics.” Applied Physics Letters. DOI: 10.1063/1.5019469 Citation: Electrogates offer stop-and-go control in microfluidics (2018, April 24) retrieved 18 August 2019 from https://phys.org/news/2018-04-electrogates-stop-and-go-microfluidics.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.