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Development of high concentrated slightly acidic hypochlorous acid generator for food safety
Ali Turab Jafry,이천지,김도형,한규현,성원기,이진기 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.9
Having a mild acidic pH of 5-6.5, Hypochlorous acid (HOCl) is a harmless disinfectant having excellent sterilizing capability for use in agriculture, medicine and food industry. Recently, the use of non-diaphragm electrolytic cell has shown great potential in producing Slightly acidic electrolyzed water (SAEW). However, the effect of various physical properties such as electrode gap, flow rate, current, bubble formation and temperature conditions are still under investigation. In this study, we produced 40 ppm SAEW by using a selfdeveloped non-diaphragm electrolytic cell that electrolyzed 6 % Hydrochloric acid (HCl) with H 2 and Cl 2 gas as by products. The tested range of electrolyte flow rate was 2-4 mL/min. The effect of current was studied in the range of 10-15 A. The results indicate that bubble generation by increased current decreased the average convection heat transfer coefficient between the electrode and electrolyte resulting in increased temperature. Moreover, the bubbles reduced the surface area for an efficient electrolytic reaction resulting in a decrease in available chlorine concentration. Hence, an optimized flow rate of 3 mL/min at 13 A current were found to be best process conditions for SAEW generation when the electrode size is 4 cm by 14 cm. Furthermore, the produced high concentrated HOCl showed excellent sanitization efficacy against various Escherichia coli concentrations (10 5 -10 8 cfu/mL).
Jafry, Ali Turab,Lee, Hyungdong,Tenggara, Ayodya Pradhipta,Lim, Hosub,Moon, Youngkwang,Kim, Seung-Hyun,Lee, Yongwoo,Kim, Sung-Min,Park, Sungsu,Byun, Doyoung,Lee, Jinkee Elsevier 2019 Sensors and actuators. B Chemical Vol.282 No.-
<P><B>Abstract</B></P> <P>Double-sided electrohydrodynamic jet printing of circuitry using silver nanowires (AgNWs) and dispensing of high viscosity silver nanoparticles (AgNPs) is demonstrated for the first time in the fabrication of a two-dimensional array of electrodes (3D circuitry) on a single sheet of paper. The penetration of AgNW ink through the paper’s thickness by capillary imbibition allows for multilayer electrical access to connect the individual electrodes. This makes it an automated and efficient choice as the functional area of the device is conserved and the surface of the paper is preserved. This allows for two-dimensional droplet manipulation on a paper-based digital microfluidics (PBDMF) platform. Compared to printed circuit board technology, paper-based electronics offer a range of desirable properties: they are light weight, portable, economical, flexible, biodegradable, and the materials are abundantly available. The fabricated PBDMF chip is demonstrated to be a low-cost, fully reconfigurable, and disposable point-of-care diagnostic platform for the environmental sensing of pesticide using organophosphorus hydrolase enzyme through colorimetric detection via smartphone.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Silver nanowires penetrated through paper’s thickness for making 3D interconnects. </LI> <LI> High viscosity silver nanoparticles dispensed on paper reveal no penetration. </LI> <LI> 3D circuitry in single sheet of paper printed using double-sided EHD jet printing. </LI> <LI> Two-dimensional droplet actuation achieved on a paper-based digital microfluidics. </LI> <LI> Cellphone-based colorimetric detection of methyl paraoxon from 10 to 100 μM concentration. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
A study of paper-fluidic device using wax printing and photolithography
Ali Turab Jafry,Hosub Lim,Minki Lee,Sangmyeong Kim,Jinkee Lee 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
The emergence of paper based analytical devices (μPADs) since 2007 has had a major impact on the development of low cost, environmental friendly and simple microfluidic chips, serving in the field of medical diagnosis, food preserving and environmental monitoring. Although many fabrication techniques have evolved as a result of its broad application spectrum and ease of use, the technology has still barely scratched the surface of its potential in terms of its underlying fundamental principle i.e. fluid flow analysis. In this research we have compared two fabrication techniques of photolithography and wax printing with respect to fluid flow inside the porous media. The modified channel fabrication protocol is described. Hydrophilic and hydrophobic fluids are used for a flow comparison. Previous studies so far show channel width modification for attaining different flow velocities, whereas we have modified the channel by adding cylindrical resistance and attained variable velocity profile by keeping the same length and width of channel. Results show the flow follows the Lucas-washburn equation and variation in flow profile is attained by varying resistance configuration.