Research Projects and Interests

Research is dedicated to the development of advanced diagnostic techniques and applications to a number of fundamental and applied problems.  Research topics include traditional engineering problems in the general thermal-fluid sciences, such as combustion processes, thermal waste treatment, materials synthesis, and process monitoring.  Emerging science and engineering problems of interest include biomedical applications such as laser ablation of tissue and laser- tissue interactions, real-time analysis of aerosols and nanoparticles, and novel biomedical diagnostics.  Representative research projects, present and past, are summarized below.


   
Field Installation
Research interests include both 
fundamental science
and 
applied engineering
problems
Plasma


        
         
Solar Thermal Power
                      
Solar thermal energy holds great promise for the production of renewable and zero-emission fuels such as hydrogen from water.  Hydrogen-based fuels are desirable as a zero-emission energy source, with the added advantage of energy storage over direct solar-electric conversion. While there are many different approaches to hydrogen generation, by far the most attractive means is to split water molecules using solar energy.  Such an approach provides for a completely clean and renewable energy supply. The current approach is to develop highly reactive metal oxide materials to produce intermediary reactions that result in the splitting of water to produce hydrogen at moderate temperatures (<1000 K).  It is envisioned that the metal oxide reactors will ultimately be mounted within a solar concentrating reactor, and irradiated via heliostats.  This Task is structured toward the overall goals of solar-driven, thermochemical hydrogen production, with associated efforts toward the enabling surface science, catalysis, particle science, material synthesis, nano-structures, multiscale-multiphase physics modeling, and process simulation that will enable the realization of solar hydrogen-based fuels to power the transportation economy.  
                                                                       
Florida Energy Systems Consortium (FESC)
                          
          

           
Differential Laser-induced Perturbation Spectroscopy:
A Novel Approach for Chemical and Biochemical Sensing
                       
The development of truly new methodologies that provide improved sensitivity and/or specificity for rapid and accurate biosensing is highly desirable for in situ and in vivo cancer screening, detection of biological pathogens and/or explosives for biodefense, as well as food (e.g. pathogen detection) and building safety.  However, despite the need and motivation, to date the clinical applicability of in vivo cancer sensing schemes has been limited by the large patient-to-patient variations in fluorescence properties, while biosensing for homeland defense has been curtailed by the large variation in background signal levels combined with a lack of target specificity.  The proposed research seeks to develop a novel biosensing scheme that holds promise to significantly enhance both sensitivity and specificity as compared to the current state-of-the-art optical-based sensing methodologies.  This scheme is based on our recent research showing that the biological matrix may be altered by low intensity (i.e., below the ablation threshold) ultraviolet radiation (primarily 193 to 213 nm) such that the intrinsic fluorescence or Raman scattering response is perturbed.  Our research uses a novel sequential combination of optical probing (Raman or fluorescence), UV photochemical perturbation, and repeat optical probing to realize a powerful new spectral dimension based on difference spectroscopy that will be strongly coupled to the local biomolecular matrix. Since the targeted material is optically probed both before and after perturbation with the deep UV light source, the resulting differential response will avoid the major limitation of the current biosensing schemes, namely, the significant variations in the absolute optical response, as generally observed in patient-to-patient populations and real-world environments.   
                                                                               
Department of Homeland Security (APL 956101)
University of Florida Research & Graduate Programs (RGP)
    
     
        

                  
         
Novel Fluidized-bed Reactor for the Looping Process:
Coal to Hydrogen Production R&D

                
The objective of the project is to research and develop a novel chemical looping reactor concept for the ability to efficiently and effectively process coal gasification synthesis gas to generate discrete high-purity streams of hydrogen and sequestration-quality carbon dioxide. The research investigation will evaluate magnetically fluidized-bed reactor configurations/concepts and the magnetic, chemical, thermal, and fluid transport properties of various metal oxide particles for viability for scale-up and integration into a coal gasification facility for producing commercial quantities of hydrogen. 
                                                                     
Department of Energy (DE-FE0001321)
                          
       

                  
Solving the Plasma-Analyte Interaction Problem
               
Plasmas are a central component of many of today’s leading analytical methods for chemical analysis, microanalysis and materials characterization, including laser-ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS), inductively-coupled plasma atomic emission spectroscopy (ICP-AES), and laser-induced breakdown spectroscopy (LIBS). In all of these, the complex plasma-analyte interactions are directly related to the ultimate analyte response and to the quality of the results provided by the techniques. This research seeks to transform these analytical methods by solving the problems associated with the plasma-analyte interface, thereby providing an essential step forward in quantitative plasma-based and plasma-assisted analysis that is necessary to support, for example, larger research efforts in microanalysis, the nanosciences, novel materials development, and the biosciences. Rapid, local, accurate, direct quantitative solid sample analysis will be the outcome of the collaborative studies envisaged in this proposal.  The overall plan of research involves an integrated approach to understand and control plasma-analyte and mutual analyte-analyte interactions through a combination of theoretical modeling and innovative experimental methods. Each aspect of the program is designed to promote true synergy between the US and German research groups.
                                                                    
National Science Foundation (CHE-0822469)
Plasma-Analyte Interaction Working Group (PAIWG), a collaborative effort
of the University of Florida, Federal Institute of Materials Research and Testing (BAM)
in Berlin, and the Institute for Analytical Sciences (ISAS) in Dortmund, jointly funded
by the NSF and DFG.

                         
       

                  
      
Plasma-Particle Interactions
 
Research to understand the physical processes associated with the interactions of laser-induced plasmas with aerosol particles, including particle vaporization/dissociation, atomic diffusion of aerosol constituent atoms, and ensuing plasma optical emission. The emphasis is on the basic plasma-particle interactions, a complex problem given the highly transient nature of the laser-induced plasma, plasma non-homogeneity, and the uncertainty as to the exact mechanisms of aerosol particle dissociation. An overall project goal is to advance laser-induced plasma spectroscopy as a contemporary analytical tool, particularly for quantitative aerosol analysis.

National Science Foundation (CTS-0317410)

    

                
      
Catalytic Combustion
   
Catalytic combustion can play an important role in emissions reduction strategies, including reduction of NOx.  Research  efforts support the understanding of heterogeneous reactions from hydrocarbon fuels over noble-metal catalysts.  Program involves in situ diagnostic schemes for species measurements in coordination with development of kinetic models.

In collaboration with Siemens Power Generation

    


     
Methanol Reformation for Hydrogen Production
   
Research is focused on measurement of the evolution of reformate gases during the catalytic reformation of methanol.  Experiments are performed in a laboratory-scale reformer that utilizes in situ Raman spectroscopy.  The optical access reactor provides a clear picture of the progression of the reforming/reaction progress. 

In collaboration with NASA

           
 
     
Portable LIBS System for Field Measurements
   
Research  efforts support the development of a new instrument based on the technique of laser-induced breakdown spectroscopy (LIBS).  A prototype LIBS-based instrument is being developed to provide field-deployable, rapid analysis of a range of compounds relevant to national security, including biological compounds and explosives.  Research issues to be addressed at the University of Florida include optimization of the LIBS technique for compounds of interest, real-time analysis using chemometrics, and spectral normalization.

In collaboration with Ocean Optics, Inc., U.S. Army Research Laboratory,
and UF Department of Chemistry
(DoD DERF)

           
 
    
Laser Interactions with Corneal Tissue

Research is focused on the interactions of 193-nm ArF excimer laser beams with corneal tissue during ablation processes. Topics include quantifaction of the absorption properties (e.g. exact chromphores and cross-sections), development of dynamic ablation models, assessment of corneal transport properties, and development of real-time diagnostics.  Fundamental understanding of the corneal ablation process can lead to better therapeutic and refractive procedures.

ALCON Research, Ltd.

     
  
     
Advanced Measurement Techniques for Emerging Technologies
             
The primary objective of this program was to develop an integrated curriculum and research program to address the needs for advanced measurement techniques applicable to current and emerging technologies within the overall sphere of thermal sciences and engineering.  Relevant technology applications include several emerging areas in engineering education such as microelectronics, micro-electro-mechanical systems (MEMS), biotechnologies and bioengineering.  Our curriculum functioned to educate and train engineers in these much-needed fields by focusing on innovative, technology crosscutting measurement techniques and emphasizing relevant applications.           
                                                      
National Science Foundation (EEC-0080453)
                                     

            
   
     
Real-time Aerosol Analysis
 
Research has led to the development of a novel technique for the quantitative analysis of individual submicron-sized aerosol particles.  The technique uses laser-induced breakdown spectroscopy (LIBS) to dissociate single aerosol particles in a laser-induced plasma.  Analysis of the resulting plasma emission is used to quantify the mass and composition of aerosols.  The technique has been applied in real-time for the analysis of ambient air particles.  Single particles have been measured with sizes as small as 100 nm with corresponding mass of about 1 femtogram.  This research is promising for the real-time monitoring of fine particulate matter in ambient air.  Fine particulate matter (PM) is an air pollutant that has been increasingly associated with risks to human health.

In collaboration with Sandia National Laboratories, Livermore, California

            
   
     
Emissions Monitoring and Control
Using Fuel Additives Technologies

The research goal is to characterize particulate matter (PM) emissions from naval engines, and explore control stratagies, including metallic-based fuel additives.  In situ diagnostic techniques (RDG light scattering, LIF and laser-induced incandescence) are used to enhance understanding of the sources and mechanisms of PM formation, and the roles and mechanisms of fuel additive compounds in soot suppression.  The integrated research program is designed to realize effective and optimal control of emissions from aircraft and shipboard engines.

Office of Naval Research
(N00014-0210838)

     
    
   
    
Remote Hydrogen Leak Detection
   
Research efforts are focused on the remote detection of hydrogen leaks under ambient air conditions.  The technological approach uses the integration of Raman spectroscopy and Rayleigh light scattering using temporal and spectral data analysis in combination with pulsed laser excitation to discriminate from background contaminants and to optimize leak detection at the leak source.  A long-term project goal is the development robust detection schemes with high species sensitivity.

In collaboration with NASA

   

   
    
Analysis of in vivo Generated Implant Wear Debris
 
Advanced measurement techniques have been applied to the analysis of wear debris particles generated within patients with artificial knee implants.  Polyethylene particles were analyzed using laser light scattering and micro-Raman spectroscopy.  Metallic particles were analyzed using laser-induced breakdown spectroscopy. Research to date has produced data regarding the concentration of wear debris particles, the chemical composition of polyethylene particles, and the size and alloy composition of metallic particles.  This research is important for understanding and ultimately reducing premature implant failures, notably implant failures associated with tissue inflammatory response and osteolysis.

In collaboration with the College of Medicine, University of Florida
and Anderson Orthopaedic Research Institute, Arlington, Virginia

        
     
 
LIBS-based Analysis of Toxic Metals
   
Research activities are focused on understanding fundamental processes associated with atomic emission from metal atoms in laser-induced plasmas.  Specific studies have focused on emission from mercury, elucidating the complex interactions between mercury and oxygen species during the plasma decay process.  Additional research has focused on optimization for simultaneous detection of multiple metals, and signal enhancements using a novel conditional data analysis routine.

In collaboration with Sandia National Laboratories, Livermore, California



   
 
Real-time Process Monitoring
    
Research activities are focused on the design and implementation of rapid, real-time process monitoring techniques using laser-induced breakdown spectroscopy (LIBS).  Applications include the identification and sorting of wood products treated with chromated copper arsenate (CCA) from construction and demolition debris waste streams.  Such real-time sorting capabilities provide additional options for waste management strategies.

In collaboration with Environmental Engineering Department, University of Florida
University of Miami, Miami Florida
Sarasota County, Sarasota Florida
and Florida Department of Environmental Protection

    
     
 
Biomedical Diagnostics
   
Research is focused on the development of non-invasive laser-based diagnostic techniques for applications to both humans and animals.  Recent activities have focused on the assessment of corneal haze in animal models. The presence of corneal haze is associated with structural changes or remodeling of the corneal stroma, and in general produces a detrimental impact on visual acuity.  This research supports the long term goal of advancing the knowledge base regarding the role of corneal haze in the human vision system.

In collaboration with the College of Medicine, University of Florida



         
 
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