TECHNOLOGY AREA(S): Air Platform, Chemical/Biological Defense, Human Systems

ACQUISITION PROGRAM: PMA-265 F/A-18 Hornet/Super Hornet

OBJECTIVE: Develop a non-chemical / non-electrical discharge means of breaking down (detoxifying) toxic hydrocarbons in aircraft breathing air systems containing toxic hydrocarbons from absorbing aerosols, vapors from organic compounds and organophosphates in engine lubricants.

DESCRIPTION: Incidents have occurred where Navy F/A-18 pilots have experienced symptoms such as shortness of breath, disorientation, confusion, and headaches during flights with no clear cause identified. In order to reduce or prevent these symptoms, there is a need to improve cabin air quality and remove bleed air contaminants in the F/A-18 aircraft, thus eliminating adverse effects on the health of the pilots.

The aircraft utilizes engine bleed air that is filtered through an on-board oxygen generating systems (OBOGS) to provide the oxygen supply for pilots. The OBOGS uses a molecular sieve to concentrate oxygen in pressurized air from the turbine engine compressor, on a schedule associated with aircraft altitude, in order to compensate for the decrease in oxygen partial pressure and to protect the pilot against rapid decompression. Since the bleed air intake occurs in real-time, decomposition and filtering of volatile organic compounds, organophosphates, and other bleed air contaminants would improve the air quality and allow the aircrews to perform their missions without any deleterious effects to their health.

The F/A-18 aircraft is extremely limited in terms of available space and weight, so size, weight, and power (SWaP) are important parameters. A chemical solution would add maintenance cost and the need for additional storage space for the consumable chemicals. An electrical discharge system will not be considered as this system is in a high-oxygen, low-humidity environment that may experience rapid pressure changes.

An optical sources solution to this problem is to use specific wavelengths that target these hydrocarbon bonds. The optical source size should not be greater than 15 cubic inches, should not weigh more than 16 ounces, and should not consume more than 200 Watts of power. By using an optical field that is resonant to the molecular bonds of these hydrocarbons, these bonds can be disassociated into less toxic constituents that can then be collected by onboard filters. Breaking these hydrocarbon bonds into smaller constituents such as CO2 and CO would be the ideal case because filters are readily available on the aircraft. The table below shows disassociation energies for common chemical bonds in organic substances is shown below. The goal of this approach is to break the double bonds of Carbon Carbon to where its concentration is less than 0.4 ppm.

�Dissociation Energies for Interatomic Bonds in Organic Substances�

Dissociation Energy Maximum Wavelength for:
Chemical Bond_____UV Dose[kcal/gmol]_______Dissociation [nm]

�

�C-C__________________82.6___________________346.1�
�C=C_________________145.6__________________196.1�
�C≡C_________________199.6__________________143.2�
�C-Cl__________________81.0__________________353.0�
�C-F_________________ 116.0__________________246.5�
�C-H__________________98.7__________________289.7�
�C-N__________________72.8__________________392.7�
�C=N________________ 147.0__________________194.5�
�C≡N_________________212.6__________________134.5�
�C-O__________________85.5__________________334.4�
�C=O (aldehydes)_______176.0__________________162.4�
�C=O (ketones)_________179.0__________________159.7�
�C-S__________________ 65.0__________________439.9�
�C=S_________________166.0__________________172.2�
�H-H_________________104.2__________________274.4�
�N-N__________________52.0__________________549.8�
�N=N_________________ 60.0__________________476.5�
�N≡N_________________226.0_________________126.6�
�N-H (NH)_____________ 85.0_________________336.4�
�N-H (NH3)____________102.2_________________280.3�
�N-O__________________48.0__________________595.6�
�N=O_________________162.0_________________176.5�
�O-O(O2)______________119.1_________________240.1�
�-O-O-_________________47.0__________________608.3�
�O-H (water)___________117.5__________________243.3�
�S-H___________________83.0__________________344.5�
�S-N__________________115.2__________________248.6�
�S-O__________________119.0__________________240.3�

Proposers should provide a means of generating an optical field that will perform the photo-disassociation of carbon and phosphates molecules. Additionally, proposers should demonstrate that their techniques will reduce Volatile Organic Compound (VOC) concentration within an acceptable limit for sustained flight operation as outlined in MIL-SPEC 27210, Performance Specification: Oxygen, Aviator�s Breathing, Liquid and Gas [Ref 10]. The product/system resulting from this SBIR effort would produce a high flow rate of purified air that does not degrade over time and is easy to maintain.

PHASE I: Design and demonstrate the feasibility of an optical field of sufficient intensity at the correct wavelength that will perform the photo-disassociation of volatile organic compounds and organophosphates. Determine the amount of the VOC and organophosphates that are broken down into other constituents. Demonstrate the way to deal with different velocity classes of the VOC and organophosphates. Develop Phase II plans.

PHASE II: Design, build, and demonstrate a prototype system that can be dropped into an operational environment such as F/A-18 aircraft. Provide interface, power, and form factor specifications. Create a test plan to demonstrate system performance for various test conditions such as high flow rates, high temperature, and high humidity [Ref 10].

Successful completion of Phase II will require: (1) a ground test demonstration with experimental temperature ranges of 200�C to 600�C for real-time measurement to quantify the decomposition of constituents in turbine engine exhaust products. Provide a list of specific target compounds and chemical classes; and (2) a demonstration of the 'proof-of-concept' that the system can break down VOC particulates.

PHASE III DUAL USE APPLICATIONS: Assist the Navy in transitioning the technology to the fleet. Follow-on activities including Government and civilian uses, could be: (1) reduction of contamination in liquids and gases, such as in municipal drinking water supplies; (2) ultrapure water filtering systems for industrial processing and pharmaceutical manufacturing; (3) water and reagents for use in experimentation; and (4) gases used in sterile rooms. The product/system resulting from this SBIR effort would be able to reduce or eliminate the need for chemical aerosols, chemical preservatives, and microfiltration for the treatment of liquids and/or gases. There is a growing demand for improvements in hospital settings to reduce the transmission of pathogens. This demand is driven by hospitals that must deal with increasing cases of infections, not caused by the patient's diagnosis upon admission, but rather due to airborne pathogens that exist in a hospital environment. These airborne pathogens pose additional health risks to patients and result in additional costs to the hospital. Successful system development would reduce or remove airborne contaminants/pathogens, in the presence of a person/people when the cockpit/hospital room is occupied.

REFERENCES:

1. Centers, P.W.� �Potential neurotoxin formation in thermally degraded synthetic ester turbine lubricants�. Archives of Toxicology, 1992, 66(9), 679-680. https://www.ncbi.nlm.nih.gov/pubmed/1482292

2. Liyasova, M., Li, B., et al. �Exposure to tri-o-cresyl phosphate detected in jet airplane passengers�. Toxicology and Applied Pharmacology, 2011, 256(3), 337-347. https://www.ncbi.nlm.nih.gov/pubmed/21723309

3. Megson, D., Ortiz, X., et al.� �A comparison of fresh and used aircraft oil for the identification of toxic substances linked to aerotoxic syndrome�. Chemosphere, 2016, 158, 116-123. https://www.ncbi.nlm.nih.gov/pubmed/27258902

4. Michaelis, S.� �Contaminated aircraft cabin air�. Journal of Biological Physics and Chemistry, 2011, 11, 132-145. http://www.itcoba.net/24MI11A.pdf

5. Neer, A., Andress, J.R., Haney, R.L., and Mathison, L.C.� �Preliminary investigation into thermal degradation behavior of mobil jet oil II�. 41st International Conference on Environmental Systems, Portland, Oregon, 2011, 17-21, DOI: 10.2514/6.2011-5110.

6. Overfelt, R.A., Jones, B.W., Loo, S.M., et al.� �Sensors and prognostics to mitigate bleed air contamination events�. Airliner Cabin Environmental Research, 2012 Report No. RITE-ACER-CoE-2012-05. http://bleedfree.eu/wp-content/uploads/2015/10/bleedairreport.pdf

7. Ramsden, J.J.� �Jet engine oil consumption as a surrogate for measuring chemical contamination in aircraft cabin air�. Journal of Biological Physics and Chemistry, 2013, 13, 114-118. http://www.oprus2001.co.uk/11RA13L.pdf

8. Winder, C. and Balouet, J.C.� �The toxicity of commercial jet oils�. Environmental Research, 2002, 89(2), 146-164. https://www.ncbi.nlm.nih.gov/pubmed/12123648

9. Bakthisaran, S. �The application of UV technology to pharmaceutical water treatment." European Journal of Parenteral Sciences, 1998, 3(4), pp. 97-102.

10. MIL-PRF-27210H. (2009) �Performance Specification: Oxygen, Aviator�s Breathing, Liquid and Gas�. http://everyspec.com/MIL-PRF/MIL-PRF-010000-29999/MIL-PRF-27210H_32996/

KEYWORDS: Bleed Air; OBOGS; Ultraviolet; Organic; Contaminants; Wavelength