Multi-Layer and Conformally Integrated Structurally Embedded Vascular Antenna (SEVA) Arrays

This work presents the design and fabrication of two multi-element structurally embedded vascular antennas (SEVAs). These are achieved through advances in additively manufactured sacrificial materials and demonstrate the ability to embed vascular microchannels in both planar and complex-curved epoxy-filled quartz fiber structural composite panels. Frequency-reconfigurable antennas are formed by these structures through the pressure-driven transport of liquid metal through the embedded microchannels. The planar multi-layer topology examines the ability to fabricate two co-located radiating structures separated by a single ply of quartz fabric within the composite layup. The multi-element linear array topology composed of microchannels embedded on to a single-layer are used to demonstrate the ability to conformally-integrate these channels into a complex curved surface that mimics an array of antennas on the leading edge of an Unmanned Aerial Vehicle (UAV). A parallel-strip antipodal dipole feed structure provides excitation and serves as the interface for fluid displacement within the microchannels to facilitate reconfiguration. The nominal design of the SEVAs achieve over a decade of frequency reconfiguration with respect to the fundamental dipole mode of the antenna. Experimental and predicted results demonstrate the operation for canonical states of the antennas. Additional results for the array topology demonstrate beam steering and contiguous operation of interconnected elements in the multi-element structure.

Optimization of molding the polymeric composite material with improved characteristics

Technological modes of forming a polymer composite material based on fluoropolymer and quartz fabric are investigated. Planning of experiment is carried out. Mathematical processing of the results is performed. Experiments were performed on industrial equipment. The material characteristics have been improved.

Development of kinetics sub-model of cyanate ester-based prepregs for autoclave molding process simulation

Autoclave molding of prepregs is an established fabrication method to produce composite components to be used in the aerospace industry and elsewhere. The process involves the excess resin to flow out and curing of the resin. The process model simulation, which is very effective to optimize the process parameters and laminate properties, requires various sub-models to account for resin flow and resin curing. This work focuses on the curing behavior and development of kinetic sub-model of a quartz fabric prepreg impregnated with cyanate ester-based resin. Differential scanning calorimetry (DSC) in both dynamic and isothermal modes has been used for the study. The dynamic study reveals that two distinct reaction mechanisms were involved during curing. The dynamic study data is used to obtain the activation energy using model-free iso-conversional method. The kinetic expression obtained using the isothermal DSC scan data is able to predict the complexity of the overall reaction which can be described by nth-order reaction kinetics for the initial phase of reaction followed by the autocatalytic reaction kinetics.

Microstructures and luminescent properties of CO2 laser annealed Y2O3:Eu3+ thin films grown on quartz fabric by electron beam evaporation

Trivalent europium ion doped yttrium oxide (Y2O3:Eu3+) luminescent thin films were grown on quartz fabric substrates using electron beam evaporation (EBE) technology, and then annealed by a pulsed CO2 laser with different resolutions from 30 to 45 dpi. Chemical composition, surface morphology, crystal structure, luminescent properties and CIE chromaticity coordinates of the Y2O3:Eu3+ deposited quartz fabric, as a function of laser resolution, were investigated by X-ray photoelectron spectrometer (XPS), Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and PG2000L fiber optic spectrometer, respectively. The results indicate that CO2 laser annealing is an efficient method to improve luminescent properties of Y2O3:Eu3+ thin films. Both the undamaged surface morphology and high crystallinity are positive factors for enhancing luminescent intensity of the deposited fabrics and the optimal luminescent properties of the film can be achieved when annealed at 35 dpi.

Synthesis, characterization and immobilization of N-doped TiO2 catalysts by a reformed polymeric precursor method

Catalysts coated quartz fabric with favorable photocatalytic activity were prepared to avoid the difficulties in its recycle and reuse.