Write (500 words):
|Question # 40153||Business & Finance||4 years ago|
Read the Notes below:
Write (500 words):
Discussion the current status of your technical and project management efforts based on the outlined schedule above.
Difficulties with deciding on what factors to pay attention to for this entire project
Not enough experience with materials and device development and no chemists or chemical engineers on duty to help guide this process
Difficulties in estimating time because we had to deviate from our original schedule
Difficulties in estimating budget because we are no longer purchasing nanowires, but synthesizing our own. Additionally we need to spend on getting a new inkjet head which puts us considerably over our original budget
Researching components and vendors
Creating the control circuit
Testing the sensors
Making a built-in method of calibration.
Power testing and selection
building the light transmitter
Building the detection circuit
Pulse Oximeter Inspection Procedure
Recipe 1: Synthesis. Ag NWs are synthesized in solution as follows. A mixture of 0.334 g PVP (poly vinylpyrrolidone) and 20 mL EG (ethylene glycol) is heated and thermally stabilized at 170 °C in a flask; 170 °C is a high enough temperature to enhance the reducing power of EG and is below the boiling temperature of EG (197.3 °C). Once the temperature has been stabilized, 0.025 g of silver chloride (AgCl) is ground finely and added to the flask for initial nucleation of the silver seeds. After three minutes, 0.110 g of silver nitrate (AgNO3), the actual silver source, is titrated for 10 min. The reason for the slow addition is that it is not desirable to create various shapes of nanostructures, such as spheres, cubes, or rods by excessively facilitating the crystal growth. After enough of the silver sources have been supplied, the flask is heated for an additional 30 min to ensure that the growth is complete. The cooled-down solution is then centrifuged three times at 6000 rpm for 30 min to remove solvent (EG), PVP, and other impurities in the supernatant. After the final centrifuge, the precipitate of AgNWs is redispersed in 30 mL of methanol.
Recipe 2: The detailed synthesis for growing longer and thinner Ag NW is as follows. First, a mixture of 0.668 g of PVP (poly vinylpyrrolidone), 0.010 g of KBr (potassium bromide), and 20 mL of EG (ethylene glycol) is heated and thermally stabilized at 170 °C in a flask. Next, 0.050 g of silver chloride (AgCl) is ground finely and added to the flask for initial nucleation of the silver seeds. After 3 min, 0.220 g of silver nitrate (AgNO3) is titrated for 10 min. Then, the flask is heated for additional 30 min to ensure that the growth is complete. The cooled-down solution is then centrifuged at 2000 rpm for 30 min to isolate the long/thin wires, which remain in the supernatant. Then, the supernatant containing the long/thin wires is centrifuged twice at 6000 rpm for 30 min to precipitate the wires. We discard the supernatant containing solvent (EG), PVP, and other impurities. After the final centrifuge, the precipitate of Ag NWs is dispersed in 5 mL of methanol. It is noticeable that the longer/thinner wire solution is less concentrated than the solution from the regular synthesis for the same volume of solvent. This is because this longer/thinner wire recipe generates numerous big silver particles, which are removed during centrifugation.
Silver nanowires w ere synthesized via a solvothermal method.
Typically, AgNO3 (0.01 mol-- 169.87 g/mol -- 1.7 g) was dissolved in ethylene glycol (100 ml) to form solution A.
Polyvinylpyrrolidone (PVP , 0.015 mol -- 2.5 g/mol -- 0.0375 g) as active agent was dissolved in ethylene glycol (100 ml) and KCl (2.22×10-5 mol -- 74.5513 g/mol -- 0.00165503886 g) was added to form solution B.
Then , the solution B was added to solution A drop wise with vigorous stirring.
After that, the mixture was moved to a 5L autoclave and heated in an oven at 160 °C for 3h.
Finally the silver nanowires were obtained by rinsing with a large amount of acetone.