Applying Nanosensor Technology to HVAC Systems.

2. Index: Rationale. Past Weeks. The main problems. The solutions. The method of application. Activation procedure. Other types of sensors. Conclusion. Citations.

3. Rationale Beginning on Sep. 18, 2001, terrorists began sending letters filled with anthrax spores to senators, media offices, and other people. Last year one of Dr. Nutter’s undergrad researchers, William Cantrell, investigated the spread of pathogens that were released in buildings and came up with some unnerving statistics.

4. RationaleFigure 1. According to Mr. Cantrell's research, pathogens were able to spread through two levels of a building in less than 20 minutes, even if the doors were closed. These results showed him that if people were to have a fighting chance of escaping an infected building , building designers were going to have to implement HVAC safeguards.

5. Heating, Ventilating, and Air Conditioning (HVAC) System.

6. Past weeks... Since I arrived my primary duties have been to read about nanosensors and HVAC systems and then come up with a theory of how to put these technologies together. Since my research was very open ended, I did not do any experiments. I focused more on laying the ground work for further research. Nevertheless, there were some obstacles to overcome...

7. Main Issues: The three main problems that I had to overcome in this research were: Air sampling. Nanosensor type(s). Sensor placement.

8. Solution: Injecting air into liquid. Figure 2. In order to inject air into a liquid I had to use a device called a wetted wall cyclone air collector. This device pneumatically draws in air and sprays it with a liquid (usually water). It then transfers a liquid on to whatever device one wants to pass it on to.

9. Solution: Type of nanosensor. Figure 3. The type of nanosensor that I believe would work well with a device like this would be an electrical impedance based microfluidic biosensor. Much like the one Dr. Tung has developed. There would have to be many of these sensors, each programmed to detect a certain biological agent.

10. Other type of nanosensor.Figure 4 Yale's semiconducting nanowire nanosensor. These sensors are able to “detect single virus particles or ultra-low concentrations of a targeted substance” (Technology Review). These kinds of sensors are easy to make. Researchers are in the process of finding ways to mass produce these types of senors.

11. Method of application. By putting the available technologies together in such a way that the air gets drawn in and scanned by the sensor, we will be able to create a true bioaerosol nanosensor that could be mass produced and put into service all around the world. All we would then have to do is write a program that evaluates the electrical signals of the sensor and activates the necessary procedures.

12. Activation Procedure. Bioaerosol detected. Air filtration begins (slowly). Ventilation continues for 30 min. Filters would then be exchanged and the sensors inspected/ maintained.

13. Available types of bioaerosol sensors. Other types of sensors that have been created to sense bioaerosols are: MIT's PANTHER (PAthogen Notification for THreatening Environmental Releases). Livermore's APDS (Autonomous Pathogen Detection System). These types of sensors utilize genetically engineered material in order to detect the bioaerosols.

14. Other types of bioaerosol sensors:PANTHER

15. Other types of bioaerosol sensors: APDS Utilizes antibodies attached to dye coated microbeads. When the antibodies contact the pathogens they cause the dye to change colors. This color change is then observed by the computer.

16. In conclusion... The ability to apply nanotechnology to HVAC systems is absolutely possible and could be made available in months, not years. All that is needed now is nanosensors that are specialized to detect minute particles of bioaerosols, the rest is just putting the pieces of the puzzle together.

17. Citations: “Nanosensor.” 7 May 2008. Wikipedia. 25 May 2008. <http://en.wikipedia.org/wiki/Nanosensor> . Cantrell, William. “Factors Affecting the Spread of a Bioterrorist Agent Through a Building.” Research. U of Arkansas Fayetteville. 28 April 2008. HVAC Systems and Components Handbook (2nd Edition). Automatic Temperature, Pressure, Flow Control Systems. Retrieved June 5, 2008, from Dr. Darin Nutter. (Figure 2, PANTHER & APDS)Petrovick, Martha S. (2007). Rapid Sensors for Biological-Agent Identification, 17(1), 21. Retrieved June 30, 2008, from www.ll.mit.edu/publications/journal/pdf/vol17_no1/17_1_3Petrovick.pdf. (Figure 3)Srinivasan, Balaji. Tung, Steve. (2006). Simulation of an Electrical Impedance Based Microfluidic Biosensor for Detection of E. coli cells. COMSOL Users Conference, 1-5.

18. Citations (Figure 1): http://img.dailymail.co.uk/i/pix/2007/07_02/NYshoesREX_468x624.jpg (Figure 4, Technology Review) Bullis, K. 2007. Easy-to-Make Nanosensors. Tiny electronics-based detectors could provide simple tests for cancer or bioterror agents. Technology Review. January 31, 2007, <http://www.technologyreview.com/Nanotech/18127/?a=f>. McDowall, Robert. 2006. Fundamentals of HVAC Systems. Elsevier, Oxford, UK.