Progress 07/01/11 to 02/29/12
Outputs
OUTPUTS: Colorimetric indicators for the detection of ammonia and carbon dioxide were evaluated for sensitivity, response time, reversibility, polymer miscibility, and aging stability. These indicator chemistries were immobilized into UV-curable polymeric claddings that were selected based on cross-linking density, mechanical properties, refractive index (lower than a glass core fiber refractive index of 1.45), and indicator compatibility, and coated onto glass microscope slides as a preliminary form of the fiber cladding material. The target indicator was dissolved in an appropriate solvent, then mixed with the polymer at 80%-90% solids, spin-coated onto a glass microscope slide, and cured by UV radiation or heat. The cured films were then tested in a gas-tight flow cell coupled with a light source and photodetector with optical fibers. The selected indicators were optimized via polymer matrix evaluation, the addition of free volume enhancers to increase gas diffusion, and the addition of antioxidant additives to enhance sensor stability and shelf life. The optimized sensor claddings were calibrated by exposing them to a step-up ladder of ammonia or carbon dioxide in a humidified air stream. Collaboration with Professor Larry Jacobson of the Department of Bioproducts and Biosystems Engineering at the University of Minnesota (UMN) enabled us to perform preliminary field testing of the selected sensor formulations, and establish their response characteristics. The sensors were tested with the same air flow used by UMN to monitor barn air quality before and after filtration. A semi-continuous sampling system was used to collect air samples from the intake and output of two biofilters (flat-bed and A-frame) located at UMN's West Central Research and Outreach Center in Morris, MN. These biofilters treat 100% of the ventilating air from two nursery rooms capable of housing 288 pigs. Aging studies were performed by placing the sensor film cladding samples near the duct where the barn air is pumped through. Sensor dependence on variable environmental conditions such as relative humidity and temperature was also calibrated. Based on these findings, we created a system outline, and identified the optoelectronic system components. Extensive outreach efforts to potential end users and commercial partners based on the laboratory and field testing performance resulted in great interest from SKOV A/S (Denmark), one of the world's leading specialists in ventilation systems for livestock operators around the world, and MSA, a billion-dollar U.S. company competing worldwide in the industrial safety and first responder sectors. Both companies have provided us with products specifications, including performance requirements, mechanical enclosures, and electronic interfaces, to enable us to dovetail our technology with their products. The results of our work were presented in April 2012 at the Europt(r)ode XI Conference on Chemical Sensors and Biosensors in Barcelona, Spain.  PARTICIPANTS: Manal Beshay, Chemical Sensor Scientist, served as the Principal Investigator and Project Director of this project. Ms. Beshay received an M.Sc. in Inorganic Analytical Chemistry with emphasis on supra molecular chemistry in molecular recognition and drug delivery from the University of Alexandria, Egypt in 2000. Prior to joining Intelligent Optical Systems in 2003, she has been a Quality Assurance Chemist for the Coca-Cola Company, performing quality and sensory tests on raw materials and finished products, and judging product acceptability by comparison to specifications. Ms. Beshay has extensive expertise in optical sensor development, specifically in chemical gas detection and monitoring applications. She has led the chemistry team for the development of DICAST, a distributed intelligent chemical agent sensing and transmission system that is capable of monitoring chemical warfare agent intrusions in military, government, and civilian facilities. Although Air-Sense development is based on DICAST technology, Air-Sense operates on a principle in which the indicators are designed to be simultaneously responsive and reversible, rather than act a detection system for a sudden chemical release. Ms. Beshay serves as the PI on a number of related projects for optical chemical detection in the gas and aqueous phases for monitoring and detection applications. In this project Ms. Beshay was responsible for the overall direction of the project, including sensor design, optical approach, testing, system integration and project management and reporting. Jesus Delgado Alonso, Senior Scientist, received a Ph.D. in Organic Chemistry from the Universidad Complutense de Madrid, Spain in 2000. He has over 15 years of experience in indicator dye design, synthesis, and structural and photochemical characterization, and has extensive experience in instrument development for chemical monitoring. In this project Dr. Delgado Alonso developed and optimized the indicator sensor chemistries, and managed the day-to-day sensor experiments. Sajid Wasif, Chemist, received his B.Sc in Bioengineering with emphasis in cell and tissue, nano and biomaterials, chemistry, and biology from the University of California, Los Angeles in 2010. In this project, he optimized the sensor formulations and conducted the day-to-day testing. Mr. Wasif also played a key role in the field testing of the sensors at the University of Minnesota, including sample preparations, optical and mechanical setup assembly, and data collection and correlation. Collaboration was established with Professor Larry Jacobson of the Department of Bioproducts and Biosystems Engineering at the University of Minnesota (UMN). This collaboration enabled us to perform preliminary field testing of the selected sensor formulations at UMN's West Central Research and Outreach Center to establish response characteristics. Participation in the Purdue University/USDA program "Building a Commercialization Plan" was instrumental in developing a marketing plan for Air-Sense technology, and subsequently establishing a relationship with commercial sensor companies MSA and SKOV A/S. TARGET AUDIENCES: The primary target market for Air-Sense is manufacturers of sensors for livestock ventilation systems, to provide a reliable and effective means of monitoring air quality in animal feeding and nursery environments in order to improve animal health, reduce worker exposure to high levels of gas, and reduce power consumption for unnecessary ventilation. The broader, secondary target market includes manufacturers of gas sensing and detection systems for a wide range of industries requiring real-time, continuous, multi-contaminant gas detection over large areas. Technical discussions with sensor manufacturers indicate that optical-based sensing technology can be deployed for mine safety, fire service, law enforcement, construction, oil and gas, chemical, and other industries, as well as the military. We contacted approximately 25 companies specializing in livestock ventilation, safety sensing and detection systems, and sensor manufacturing to discuss the Air-Sense technology. SKOV A/S and MSA in particular expressed a keen interest in the technology under development. SKOV A/S is a leading supplier of ventilation and automatic systems for the agriculture industry. The company develops, produces, and markets capacitive and climate sensors under the DOL Sensors brand for use in food production, animal feed, food processing, food transport and storage. SKOV has expressed an interest in establishing an immediate commercial relationship with us, wherein we will supply SKOV with Air-Sense technical performance characteristics as we advance through the development steps, and identify the system's mechanical and electronic interface parameters to ensure compatibility with their current monitoring platforms. MSA is a leading supplier of portable gas detection instruments for safety monitoring in industrial applications. MSA envisions supporting our development via periodic consulting on design and specification requirements that can meet MSA's industrial sensing criteria. Both companies have provided us with products specifications, including performance requirements, mechanical enclosures, and electronic interfaces, to enable us to dovetail Air-Sense technology with their products. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Enclosed animal feed lot facilities require effective ventilation systems that are synchronized with accurately measured temperature, humidity, and gas emissions such as ammonia, carbon dioxide, and hydrogen sulfide. The Air-Sense optical fiber-based technology is positioned to fill the gap between conventional commercial detection systems such as near-infrared tunable diode lasers, which are inexpensive but suffer from limited accuracy and high false alarm rates in agricultural environments, and state-of-the-art research devices such as open path Fourier transform infrared spectroscopy, which are very sensitive but are expensive, bulky, not rugged, and unsuitable for the low-maintenance requirements of field operation. We have demonstrated the feasibility of applying an optical sensing approach to air quality monitoring in enclosed agricultural operations. Ammonia and carbon dioxide sensors were tested in livestock field operations and displayed excellent correlation with a gas sampling system (GSS), and a high degree of sensor repeatability. We observed 5 ppm limit of detection (LOD), 17 ppm limit of quantitation (LOQ), and a 5-500 ppm measurement range for the ammonia sensor claddings, and 25 ppm LOD, 100 ppm LOQ, and a 25-60,000 ppm measurement range for carbon dioxide. The data from the field testing was processed to determine the environmental effects and potential correction functions. Initial evaluation processing of the data obtained in the field compared our sensor thin film cladding with the air monitoring system now in use by the University of Minnesota. The preliminary data synchronization steps yielded good correlation between the GSS readings and the sensor film optical changes for both the ammonia and carbon dioxide variable levels obtained from air sampled at seven locations. In addition to the good correlation of the two systems, a high degree of sensor repeatability was also observed. Samples that were aged at the barn duct were tested and compared with shelf-aged samples. Although the barn-aged samples accumulated dirt and a greasy layer on the sensor cladding, their sensing performance was noticeably unaffected. This indicates that the polymer matrix we had selected had the required protective characteristics: the optimum crosslinking density. Integrating the fibers into a cable will also increase protection against dust and large particulates for long term deployment in livestock operations. Preliminary ammonia and carbon dioxide sensor fibers 5 to 10 m long were fabricated and tested. The results indicated successful coating, light guiding, and response to the target gas at five concentrations. Air-Sense technology will synchronize livestock ventilation with elevated toxic gas emission as well as with temperature, resulting in healthier air quality for animal growth and reduced worker exposure, and reduced power consumption for unnecessary ventilation.
Publications
- Beshay, M., Delgado Alonso, J., Wasif, S., Jacobson, L., Akdeniz, N. (2012). Distributed optical fiber sensor cable for air quality. Analytical and Bioanalytical Chemistry (pending). Beshay, M., Delgado Alonso, J., Wasif, S., Jacobson, L., Akdeniz, N. Distributed optical fiber sensor cable for air quality. Electronic conference proceedings (abstract and poster), Europt(r)ode XI Conference on Chemical Sensors and Biosensors, Barcelona, Spain. April, 2012.
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