last update: August 01, 2000
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STC-ERSP Program Details Principal Investigator: Christine S. Grant Project Title: An Image Sensing System for Environmentally Benign CO2 Based Surfactant Decontamination Processes (#16) Phone/Fax: 919-515-2317/919-515-3465 E-mail: grant@eos.ncsu.edu Research Plan Connectivity Outreach Components Requested Budget Allocation - Year 1 Plans for Additional Funding Research Plan Overall objectives The proposed project has as its foundation the research by Grant on the cleaning mechanisms in industrially relevant systems and reconfigurable computing hardware by Gloster (ECE at NCSU). A novel experimental approach is proposed that conducts continuous, non-invasive, visual measurements to determine, in real time, the rate and extent of contaminant removal from an enclosed flow cell. The overall research objective is to develop the ability to visualize and quantify the removal of contaminants from a solid substrate in both liquid and supercritical CO2. The project takes a systematic approach to collect, interpret and classify image data collected during decontamination operations. A novel feature of the proposed system is that the cleaning process can be optimized to minimize the amount of hazardous waste created. To maximize the impact of the proposed research, two classes of residues have been selected that are found in both food and chemical process industries: (1) viscous fluid residues and (2) heterogeneous solid residues. Both glass and metal surfaces will be investigated in this work. There are two key domains that describe decontamination for the proposed work: the cleaning domain and the image domain. The cleaning domain is defined by the parameters (e.g., flowrate, concentration) governing cleaning and the corresponding transport based mechanisms. The image domain is defined by a different set of parameters which highlight the visual characteristics of the contaminant and the corresponding image processing algorithms that link these parameters to the removal process. A critical aspect in the intelligent control of cleaning is the link between the two domains. The objectives of this research address the development of each domain, their interaction, and their contribution to decontamination. Objective 1: Utilize an experimental system for continuous, on-line monitoring of decontamination processes to evaluate key parameters in the cleaning domain. The proposed research will utilize the extensive expertise of Grant's group elucidating the fundamental mechanisms associated with cleaning both metal and glass surfaces. On a macroscopic scale, the following factors influence the degree of decontamination or cleaning achieved: (1) the physical and chemical properties of the surface or substrate (e.g., morphology, hydrophobicity), (2) the chemical composition and microscopic crystal structure of the contaminant and its film thickness, (3) the temperature, composition and concentration of decontamination reagents, (4) the contact time between solutions and contaminants, (5) the solubility of the residue in the solvents (6) the fluid microstructure and the degree of turbulence promoted during the decontamination operation and (7) interfacial phenomena. The on-line continuous rectangular experimental flow system proposed here is a logical progression from earlier research at NCSU in transport controlled environments. The new system was designed to enable visual observation during the cleaning process. This ability to record the images associated with the physical and chemical changes in the films is the first step in connecting fundamental cleaning research to an industrial system for environmentally benign cleaning. We will study the removal of a range of organic contaminants in both liquid and SCCOs from the surface of metals. Objective 2: Establish relationship between visual image data and degree of cleaning measurements. The viability of the intelligent image sensing system relies on the link between parameters in the cleaning domain and the image domain. The challenge here is for the interdisciplinary team to comprehend the critical parameters in both domains. For example, it is important to understand the timescale associated with cleaning events to develop precise measurement techniques. The establishment of a database of images that characterize the boundaries associated with contaminated and clean systems will provide the basis for initial thresholds. Relation to overall objectives of the Center The proposed research will enable a better understanding of the fundamental transport and interfacial phenomena associated with the removal of thin films and eventually particulate matter from solid surfaces. Particular attention will be paid to the diffusion and mass transfer in CO2 -surfactant systems and mechanisms associated with cleaning. Approach and Year 1-Year 5 timelines Years 1-2: Design and build modified flow visualization apparatus for both image sensing and chemical analysis of contaminant removal. Set-up will have the capability to control a number of variables including; shear, pressure, surfactant concentration and input of co-solvents in the system. Conduct experiments using a series of viscous residues similar to earlier studies in aqueous systems. Years 2-3: Continues to conduct decontamination experiments on metal substrates in the high pressure cleaning vessel. Identify critical parameters to effect optimal cleaning conditions; develop mechanistic models of removal based on fundamental interfacial and chemical principles. Years 3-4: Investigate the use of co-solvents in the cleaning system. Utilize new surfactants developed by chemists in Thrust Area D and connect chemical and visual observations with observed interfacial behaviors ( Thrust Area A). Years 2-5: Identify potential utilization of image sensing system for as a predictive indicator of cleaning conditions. Thrust area of this proposal Thrust Area C: Rate Processes Connectivity Collaborators, multi-institutional, multi-disciplinary components Dr. Ken Roberts - Chemical Engineering, NCA&T State University: We will develop supplemental cleaning experiments with Dr. Roberts to compare to other supercritical solvent systems.Dr. Clay Gloster - Electrical and Computer Engineering, NCSU: We will interact with him on the development and analysis of the image sensing system.Dr. Ruben Carbonell - Chemical Engineering, NCSU: Our researchers will interact with him to expand on the research currently underway on fabric cleaning. Related work in other thrust areas The research teams in Thrust Area D (Chemistry and Catalysis) are developing surfactants that can be used for the decontamination experiments. Researchers in Thrust Area A are also interested in the behavior of these surfactant systems in CO2 and our results will assist them in the practical application of their interfacial measurements on model systems. Sharing of resources (students, supplies, equipment, etc.) This project will utilize information developed by researchers in the electrical and computer engineering department here at NCSU. The software and associated analysis of the data relies on our interactions with Dr. Clay Gloster in the ECE department here at NCSU. We will also utilize the equipment currently being developed for a Pollution Prevention undergraduate lab in the initial stages of this research. Outreach Components Suggested K-12 Outreach Ideas The CHE Department at NCSU has a long history of both research and teaching of pollution prevention. However, the conventional chemical engineering curriculum does not give students the opportunity to think critically about the environmental aspects of subjects such as kinetics and reactor design, transport phenomena, or thermodynamics. The NCSU Chemical Engineering Pollution Prevention Option enables students to evaluate the issues that chemical engineers will face in the development of environmentally benign processes. The option requires a variety of environmental courses, a capstone senior pollution prevention course and a radioactive and hazardous waste management course to provide students with a broader perspective of the key issues in this area. In an effort to supplement the additional courses in this option, the experimental system in this proposal will be used to highlight practical environmental issues while teaching fundamental chemical engineering concepts. This experiment will relate to the issues associated with the transport during cleaning operations in the junior level unit operations laboratory. The Intelligent Image Sensing System experiment will enable students to study the use of solutions containing non-toxic surfactants in the cleaning of films from a variety of surfaces. They will: (1) investigate the relationship between Reynolds number, surfactant concentration, and contaminant viscosity in the selection of a cleaning system and (2) visually monitor the swelling, roll-up and eventual removal of contaminants from solid substrates to will expand their knowledge of both interfacial science and transport phenomena. This lab can be utilized in the demonstration of the above concepts to students interested in engineering at the middle and high school levels. Data from these experiments could also be used at the K-middle school levels to demonstrate the integration of computers with "cleaning" and the environment. We could set up the visual demonstration of the experiments without actually bringing the high pressure system to the classroom. They will most likely enjoy the visual demonstration of contaminant removal; the ability to stop the image will show them the importance of shear in cleaning - something that they most likely do on a daily basis. Requested Budget Allocation - Year 1 Personnel salaries
Plans for Additional Funding Funding agencies/programs and planned dates of submission: NSF/EPA Proposal - Submitted Summer 1999; Topic Area - Intelligent Systems development DARPA and/or NSF - Lubricant research in CO2 for MEMS applications Return to top. |
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