Week of March 26th, 2017
Preliminary testing. Tubing was attached and a vacuum-rated pressure gauge was temporarily used instead of the sensor. A leak was noticed after vacuum was drawn and the gauge displayed the pressure rising slowly. The solenoid valve directions were all reversed and the system pressurized instead of put under vacuum conditions. Soapy water was put at system junctions in order to see where air is leaking out (in which places bubble formed). The lid was found to be leaking, likely as a result of the rubber ring interface.
Week of March 19th, 2017
Solenoid valves are working! Code was developed and a circuit was constructed. Additionally, the device itself was put together (with the exception of tubing and the pressure sensor, which has not yet been delivered).
Week of March 12th, 2017
An IRB form was completed and submitted with respect to the user of the sterilization system. The remaining parts were ordered.
Week of February 26th, 2017
The peracetic acid was delivered. Because of the high concentration, a refrigerator is required for storage. It was safely stored in the Chemistry building. Appropriate protocol was written and submitted to the department chair of the chemistry department in an effort to expedite the pre-testing process.
Week of February 19th, 2017
A threaded glass vial was found and ordered, and a relevant machine shop order form was completed to attach it temporarily to a u-bend to introduce the liquid PAA. The abstract for the North East Biomedical Engineering Conference (NEBEC) at NJIT was written and submitted.
Week of February 12th, 2017
Various parts were ordered and tubing was discussed (which is best for intense vacuum pressures, how to cut it, how to fix it in place, etc.).
The viable cell count technique was researched and discussed as a possible method of device verification. Multiple statistical analyses were additionally researched to ensure the pressure sensor is working properly in the future. A Bland-Altman Plot was determined to be the best fit for this.
Week of January 29th, 2017
The group withdrew the money from the GoFundMe page after discussing the process with tax attorneys and the Dean of Engineering. A range of acceptable liquid PAA to be inputted into the system was calculated. A previous senior project team was contacted for help with the solenoid valving and Arduino Uno coding.
Week of January 22nd, 2017
The group performed more research regarding the required concentration and volume of PAA and VPA to perform proper sterilization. Graduate-level chemical engineering thermodynamics was looked into in order to explore vapor-liquid equilibrium (VLE). This was applied to an existing study to relate known effective levels of liquid peracetic acid sterilization to that in its vaporized state.
Week of January 15th, 2017
The group visited Home Depot to look for parts and inquire about available parts (e.g. manual valve, copper piping, male-male pipe adapters, etc.). These parts were all found, but were not ordered. Parts will be ordered as soon as the financial situation is finalized. The group also spent time performing calculations to determine how much liquid peracetic acid is required to sterilize equipment in the gallon container.
Winter Break, 2016-2017
The group made much progress regarding the overall design of the device. Additionally, a GoFundMe page was created in order to help fund the project. Calculations were made in an effort to determine how much PAA is needed to be introduced into the system for effective sterilization. Because limited research has been performed regarding this subject, there are very few peer-reviewed articles to reference and build from.