Date

6-2012

Degree Name

BS in Materials Engineering

Department

Materials Engineering Department

Advisor(s)

Kathy Chen

Abstract

This project, with an interdisciplinary group of two computer engineers and one materials engineer, was seeking to implement an automated temperature monitoring system which is affordable and easy to use, as well as adaptable to any arrangement and scale of a winemaker’s fermentation setup. My goal, as the materials engineer, was to design, fabricate, and test the enclosure, for the wireless nodes that are placed in the wine fermentation tanks, and the materials used for the node enclosure. For the enclosure of the system, materials selection was completed using CES software using limitations of only polymer materials which absorb less than 0.01% of water in a 24 hour period, are resistant to weak acids, cost-effective, and have a high stiffness. The material which passed all of the stages and was chosen for the design of the node enclosure was high density polyethylene (HDPE). However, to make sure that HDPE and the adhesive used to connect to individual HDPE components (PDMS) can withstand the fermenting wine environment, a two-week long preliminary test was completed. It was found that PDMS had the greatest difference in water adsorption between day 0 to day 1 and 20. HDPE had the greatest difference in water adsorption between day 20 to day 0 and 1. PS did not change. All of these changes in water adsorption were around the required limit set in the materials selection process of 0.01%. Then to make sure the PDMS adhesive could withstand the cleaning chemicals (sodium hydroxide, NaOH, and citric acid) used at the winery, a week-long degradation test was completed and found the PDMS sample’s surface changed when exposed to a sodium hydroxide solution. The PDMS samples which were exposed to the diluted citric acid solution, around 3%, had the greatest strength, average of 2.73 MPa compared to the control average of 1.2 MPa due to stress relaxation by the formation of silanols, but could also be due to the run order and human error. However, all of these changes are minor enough to where it would not affect the reliability of the node enclosure. The design was then made and a cost analysis and life cycle analysis was completed.

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