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—Schematic diagram of the sensor signal conditioning circuit using LM1077 operational amplifiers (picofarad).
Source publication
The dissolved oxygen (DO) concentration is a dynamic water quality variable that is critical to fisheries. To obtain simultaneous DO data at 15-min intervals over long periods (i.e., months) at a number of points along a river, a simple, inexpensive (<US$40) differential voltage amplifier circuit was developed to provide an interface between a galv...
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Citations
... Water is continuously being contaminated by people. While contaminants are present in water, different water parameters have deviated from their standard values [1][2][3]. Three parameters are commonly used to indicate the quality of surface water. For instance, dissolved oxygen (amount of oxygen present in surface water, DO), biological oxygen demand (number of organic pollutants in water: the amount of oxygen required to degrade organic pollutants by biological means), and chemical oxygen demand (the quantity of organic and inorganic pollutants in surface water: the amount of oxygen required to break down the pollutants by use of chemicals) [4][5][6][7]. ...
Water pollution has badly affected human health, aquatic life, and the ecosystem. The purity of surface water can be measured in terms of dissolved oxygen (DO) measurements. Hence, it is desirable to have a portable and simple-to-use dissolved oxygen sensor. One possible remedy is an electrochemical sensor. Thus, we proposed an ITO-IrOx electrocatalyst for an effective and interference-free DO sensor utilizing the principle of oxygen reduction reaction (ORR). The ITO-IrOx was characterized using cyclic voltammetry (CV), scanning electron microscopy (SEM), electro-chemical impedance spectrometry (EIS), X-ray photoelectron spectroscopy (XPS), and reflectance spectroscopy-based techniques. Reflectance spectra of the ITO-IrOx electrode showed the photoresist capability. The EIS spectra revealed lower charge transfer resistance for the ITO-IrOx electrode in ORR. The IrOx film on ITO exhibited a quick (one electron, α = 1.00), and reversible electron transfer mechanism. The electrode demonstrated high stability for oxygen sensing, having a limit of detection (LOD) of 0.49 ppm and interference-free from some common ions (nitrate, sulphate, chloride etc.) found in water.
... Hands-on learning is a proven teaching mode in educational pedagogy to significantly improve the understanding of concepts taught in class and the development of bench skills. Experiments associated with oxygen in the teaching laboratory can be roughly categorized according to its (a) detection, in the air [5][6][7] and when dissolved in samples and reagents [8][9][10], (b) consumption for processes [11,12], and (c) production. The notion of generating oxygen arguably stems from the seminal work of Joseph Priestley with plant photosynthesis [13]. ...
The appreciation and understanding of gas generation through processes is vital in biochemical education. In this work, an augmented reality tool is reported to depict the redox reaction between hydrogen peroxide and sodium hypochlorite solutions, two ubiquitous oxidizing agents, to create oxygen, a combustible gas. As it operates out of smartphones or tablets, students are able to conduct the exercise collaboratively, respond in a manner similar to an actual physical experiment, and able to depict the oxygen volume changes in relation to the volume of hydrogen peroxide of different concentrations used. The tool offers to help students acquire bench skills by limiting handing risks and to mitigate possible student anxiety on handling chemical materials and implements in the laboratory. The feedback received from Year 11 and 12 high school student participants in an outreach exercise indicate the overall effectiveness of this tool. © 2018 by The International Union of Biochemistry and Molecular Biology, 2018.
