ABSTRACT This experimental investigation analyzes the soot formation effects of oxygen concentrat... more ABSTRACT This experimental investigation analyzes the soot formation effects of oxygen concentration in the oxidizer stream (O2 + N2) ventilating laminar jet nonpremixed methane flames. The base flame incorporates air as the oxidizer; two additional flames, with respective oxygen concentrations of 50% and 100% in the ventilating coflow, are also examined. The microstructure of soot collected from selected flame locations is determined combining thermophoretic sampling and transmission electron microscopy. A laser-light extinction technique is employed along with tomographic inversion to measure the soot volume fraction distributions within the three flames. The results indicate that soot surface growth and oxidation rates in the methane/50% oxygen flame are higher compared to the respective rates in the methane/air base flame. The rate of soot inception becomes stronger with increasing oxygen content in the oxidizer stream. Soot yields diminish with increasing oxygen concentration, as do luminous flame spatial dimensions. Soot aggregate data on the soot annulus suggest a higher degree of agglomeration under oxygen-enriched conditions. Finally, the fractal dimensions of selected soot aggregate samples are measured to be 1.64 (methane/air flame) and 1.65 (methane/50% oxygen flame), being similar to previously published values for carbonaceous soot.
A numerical investigation of the fundamental processes governing the energy, mass and momentum ex... more A numerical investigation of the fundamental processes governing the energy, mass and momentum exchanges between the solid, liquid and gas phases of a vaporizing slurry droplet is presented. The configuration studied consists of an isolated slurry droplet containing a single solid particle in its core, and which is vaporizing in a convecting environment. The model allows for independent motion of the solid particle core along the axis of symmetry of the slurry droplet, and it accounts for variable gas-phase properties as well as variable liquid-phase viscosities and latent heat. Additional features of the model include consideration of the surafce blowing effect and droplet surface regression due to vaporization, internal liquid circulation with transient droplet heating, and droplet deceleration with respect to the free flow. The numerical calculation employs an iterative solution procedure that has been successfully used previously for an isolated all-liquid droplet.
The thermal contraction/expansion of an isolated liquid volume inside a closed-end carbon nanotub... more The thermal contraction/expansion of an isolated liquid volume inside a closed-end carbon nanotube is described in terms of high-resolution transmission electron microscope (TEM) observations in real time. The liquid volume is of the order of 1 atto (10^-18) liter. ... Items in iDEA are protected by copyright, with all rights reserved, unless otherwise indicated.
Inkjet-patterned hydrophilic spots on superhydrophobic paper overlaid with pH indicators to creat... more Inkjet-patterned hydrophilic spots on superhydrophobic paper overlaid with pH indicators to create a point-of-care diagnostic device for droplet sampling at 50 Hz.
Electromagnetic waves in the frequency range of 0.1-10 THz have remained the least explored and d... more Electromagnetic waves in the frequency range of 0.1-10 THz have remained the least explored and developed in the entire spectrum, creating what is widely known as the “Terahertz Gap”. In recent years, THz waves have attracted much attention and continuous interests owning to their prospective applications in many important fields such as astronomy, chemical analysis, biological sensing, imaging and security screening. Among many in-development THz quasi-optical components, THz attenuators, polarizers and filters have been highly demanded in spectroscopy, polarization interferometry, polarimetric detection (e.g. polarization of Cosmic Microwave Background), and other systems. However, conventional methods for realizing the above components usually require complicated microfabrication processes such as photolithography or chemical etching. Therefore, new innovations in materials and processes for cost-effective, and potentially high performance THz quasi-optical components are of imme...
The Journal of Undergraduate Research at the University of Illinois at Chicago
Electrospinning is a technique to produce nanofibers more efficiently. In electrospinning, electr... more Electrospinning is a technique to produce nanofibers more efficiently. In electrospinning, electricity spins fibers by extracting the polymer from the solvent and stretching it, all in one continuous electric field. Basics of electrospinning are discussed in sequence from simple homogenous fibers through a single nozzle to heterogeneous core-shell fibers from double, concentric nozzles. Experimental set-up is described and the effect of different variables in the process of electrospinning on nanofiber quality is illustrated. Formation of carbon nanotube fibers with porous walls from polyethylene oxide/polyacrylnitrile (PEO/PAN) core-shell fibers is the definitive objective.Zipped LaTex file
An environmentally-safe, water-borne coating consisting of titania nanoparticles and fluorine-fre... more An environmentally-safe, water-borne coating consisting of titania nanoparticles and fluorine-free polyethylene copolymers, forming a transparent, substrate-independent, superhydrophobic water barrier.
This article presents a theoretical study of the deformation of a spherical liquid droplet imping... more This article presents a theoretical study of the deformation of a spherical liquid droplet impinging upon a flat surface. The study accounts for the presence of surface tension during the spreading process. The theoretical model is solved numerically utilizing deforming finite elements and grid generation to simulate accurately the large deformations, as well as the domain nonuniformities characteristic of the
A solution-processable approach in creating gold circuit electrodes with features as fine as 100 ... more A solution-processable approach in creating gold circuit electrodes with features as fine as 100 μm is demonstrated, using a piezoelectrically driven printhead to deposit metallic nanoparticle suspensions. The suspensions consist of gold particles ranging 520 nm in ...
Electromagnetic waves in the frequency range of 0.1-10 THz have remained the least explored and d... more Electromagnetic waves in the frequency range of 0.1-10 THz have remained the least explored and developed in the entire spectrum, creating what is widely known as the " Terahertz Gap ". In recent years, THz waves have attracted much attention and continuous interests owning to their prospective applications in many important fields such as astronomy, chemical analysis, biological sensing, imaging and security screening. Among many in-development THz quasi-optical components, THz attenuators, polarizers and filters have been highly demanded in spectroscopy, polarization interferometry, polarimetric detection (e.g. polarization of Cosmic Microwave Background), and other systems. However, conventional methods for realizing the above components usually require complicated microfabrication processes such as photolithography or chemical etching. Therefore, new innovations in materials and processes for cost-effective, and potentially high performance THz quasi-optical components...
ABSTRACT This experimental investigation analyzes the soot formation effects of oxygen concentrat... more ABSTRACT This experimental investigation analyzes the soot formation effects of oxygen concentration in the oxidizer stream (O2 + N2) ventilating laminar jet nonpremixed methane flames. The base flame incorporates air as the oxidizer; two additional flames, with respective oxygen concentrations of 50% and 100% in the ventilating coflow, are also examined. The microstructure of soot collected from selected flame locations is determined combining thermophoretic sampling and transmission electron microscopy. A laser-light extinction technique is employed along with tomographic inversion to measure the soot volume fraction distributions within the three flames. The results indicate that soot surface growth and oxidation rates in the methane/50% oxygen flame are higher compared to the respective rates in the methane/air base flame. The rate of soot inception becomes stronger with increasing oxygen content in the oxidizer stream. Soot yields diminish with increasing oxygen concentration, as do luminous flame spatial dimensions. Soot aggregate data on the soot annulus suggest a higher degree of agglomeration under oxygen-enriched conditions. Finally, the fractal dimensions of selected soot aggregate samples are measured to be 1.64 (methane/air flame) and 1.65 (methane/50% oxygen flame), being similar to previously published values for carbonaceous soot.
A numerical investigation of the fundamental processes governing the energy, mass and momentum ex... more A numerical investigation of the fundamental processes governing the energy, mass and momentum exchanges between the solid, liquid and gas phases of a vaporizing slurry droplet is presented. The configuration studied consists of an isolated slurry droplet containing a single solid particle in its core, and which is vaporizing in a convecting environment. The model allows for independent motion of the solid particle core along the axis of symmetry of the slurry droplet, and it accounts for variable gas-phase properties as well as variable liquid-phase viscosities and latent heat. Additional features of the model include consideration of the surafce blowing effect and droplet surface regression due to vaporization, internal liquid circulation with transient droplet heating, and droplet deceleration with respect to the free flow. The numerical calculation employs an iterative solution procedure that has been successfully used previously for an isolated all-liquid droplet.
The thermal contraction/expansion of an isolated liquid volume inside a closed-end carbon nanotub... more The thermal contraction/expansion of an isolated liquid volume inside a closed-end carbon nanotube is described in terms of high-resolution transmission electron microscope (TEM) observations in real time. The liquid volume is of the order of 1 atto (10^-18) liter. ... Items in iDEA are protected by copyright, with all rights reserved, unless otherwise indicated.
Inkjet-patterned hydrophilic spots on superhydrophobic paper overlaid with pH indicators to creat... more Inkjet-patterned hydrophilic spots on superhydrophobic paper overlaid with pH indicators to create a point-of-care diagnostic device for droplet sampling at 50 Hz.
Electromagnetic waves in the frequency range of 0.1-10 THz have remained the least explored and d... more Electromagnetic waves in the frequency range of 0.1-10 THz have remained the least explored and developed in the entire spectrum, creating what is widely known as the “Terahertz Gap”. In recent years, THz waves have attracted much attention and continuous interests owning to their prospective applications in many important fields such as astronomy, chemical analysis, biological sensing, imaging and security screening. Among many in-development THz quasi-optical components, THz attenuators, polarizers and filters have been highly demanded in spectroscopy, polarization interferometry, polarimetric detection (e.g. polarization of Cosmic Microwave Background), and other systems. However, conventional methods for realizing the above components usually require complicated microfabrication processes such as photolithography or chemical etching. Therefore, new innovations in materials and processes for cost-effective, and potentially high performance THz quasi-optical components are of imme...
The Journal of Undergraduate Research at the University of Illinois at Chicago
Electrospinning is a technique to produce nanofibers more efficiently. In electrospinning, electr... more Electrospinning is a technique to produce nanofibers more efficiently. In electrospinning, electricity spins fibers by extracting the polymer from the solvent and stretching it, all in one continuous electric field. Basics of electrospinning are discussed in sequence from simple homogenous fibers through a single nozzle to heterogeneous core-shell fibers from double, concentric nozzles. Experimental set-up is described and the effect of different variables in the process of electrospinning on nanofiber quality is illustrated. Formation of carbon nanotube fibers with porous walls from polyethylene oxide/polyacrylnitrile (PEO/PAN) core-shell fibers is the definitive objective.Zipped LaTex file
An environmentally-safe, water-borne coating consisting of titania nanoparticles and fluorine-fre... more An environmentally-safe, water-borne coating consisting of titania nanoparticles and fluorine-free polyethylene copolymers, forming a transparent, substrate-independent, superhydrophobic water barrier.
This article presents a theoretical study of the deformation of a spherical liquid droplet imping... more This article presents a theoretical study of the deformation of a spherical liquid droplet impinging upon a flat surface. The study accounts for the presence of surface tension during the spreading process. The theoretical model is solved numerically utilizing deforming finite elements and grid generation to simulate accurately the large deformations, as well as the domain nonuniformities characteristic of the
A solution-processable approach in creating gold circuit electrodes with features as fine as 100 ... more A solution-processable approach in creating gold circuit electrodes with features as fine as 100 μm is demonstrated, using a piezoelectrically driven printhead to deposit metallic nanoparticle suspensions. The suspensions consist of gold particles ranging 520 nm in ...
Electromagnetic waves in the frequency range of 0.1-10 THz have remained the least explored and d... more Electromagnetic waves in the frequency range of 0.1-10 THz have remained the least explored and developed in the entire spectrum, creating what is widely known as the " Terahertz Gap ". In recent years, THz waves have attracted much attention and continuous interests owning to their prospective applications in many important fields such as astronomy, chemical analysis, biological sensing, imaging and security screening. Among many in-development THz quasi-optical components, THz attenuators, polarizers and filters have been highly demanded in spectroscopy, polarization interferometry, polarimetric detection (e.g. polarization of Cosmic Microwave Background), and other systems. However, conventional methods for realizing the above components usually require complicated microfabrication processes such as photolithography or chemical etching. Therefore, new innovations in materials and processes for cost-effective, and potentially high performance THz quasi-optical components...
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Papers by C. Megaridis