High Performance Materials Institute

Tallahassee, FL, United States

High Performance Materials Institute

Tallahassee, FL, United States

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Wang H.,High Performance Materials Institute | Li Y.,High Performance Materials Institute | Zeng C.,High Performance Materials Institute
Annual Technical Conference - ANTEC, Conference Proceedings | Year: 2016

This paper discussed the fabrication and characterization of a COC based pseudopiezoelectric material. A multi-layer honeycomb structure was fabricated using supercritical CO2 bonding to maintain the original structure. The disklike shape of bubble is ideal for the piezoelectric foam. The results shows that the quasi-static piezoelectric coefficient can reach up to 7000 pC/N. And thermally stimulated discharge shows that sample has a working temperature higher than 150oC. The hysteresis loop test illustrated the charge build up process inside the artificial void. The charging threshold breakdown voltage is about 5000V. Such material have applications on sensing, actuating and energy harvesting and many other fields.


Olawale D.O.,High Performance Materials Institute | Dickens T.,High Performance Materials Institute | Sullivan W.G.,High Performance Materials Institute | Okoli O.I.,High Performance Materials Institute | Wang B.,High Performance Materials Institute
Journal of Luminescence | Year: 2011

Extensive research work has been done in recent times to apply the triboluminescence (TL) phenomenon for damage detection in engineering structures. Of particular note are the various attempts to apply it in the detection of impact damages in composites and aerospace structures. This is because TL-based sensor systems have a great potential for wireless, in-situ and distributed (WID) structural health monitoring when fully developed. This review article highlights development and the current state-of-the-art in the application of TL-based sensor systems. The underlying mechanisms believed to be responsible for triboluminescence, particularly in zinc sulfide manganese, a highly triboluminescent material, are discussed. The challenges militating against the full exploitation and field application of TL sensor systems are also identified. Finally, viable solutions and approaches to address these challenges are enumerated. © 2011 Elsevier B.V. All rights reserved.


Chatterjee J.,High Performance Materials Institute | Liu T.,High Performance Materials Institute | Wang B.,High Performance Materials Institute | Zheng J.P.,Florida State University
Solid State Ionics | Year: 2010

A polymer gel electrolyte has been prepared based on polyvinyl alcohol, lithium salt and organic solvent N-methyl-2-pyrrolidone (NMP). This gel has the potential for use in secondary batteries and electrochemical capacitors. The conductivity of this gel electrolyte can be as high as 2 × 10- 3-5.8 × 10- 4 S/cm at room temperature. Functioning as separator and electrolyte, this gel system was used to evaluate the specific capacitance of an electrochemical capacitor with carbon nanotube films as the active electrodes.


Ighodaro O.L.,High Performance Materials Institute | Okoli O.I.,High Performance Materials Institute | Zhang M.,High Performance Materials Institute | Wang B.,High Performance Materials Institute
International Journal of Applied Ceramic Technology | Year: 2012

Aligned regular 2D channels were fabricated in alumina via two routes: soft metal and carbon fibers. The soft metal route was accomplished employing centrifugal forces to eject the molten metal from the green matrix. The carbon fiber route was accomplished by burning out the carbon fibers between 450°C and 630°C. In both methods, pressureless sintering followed, yielding the desired 2D channel profiles. Some porous preforms exhibited higher fracture strength than the solid specimens, and this has been attributed to the ability of the channels to reduce the population and distribution of cracks in the porous material. © 2011 The American Ceramic Society.


Li S.,High Performance Materials Institute | Park J.G.,High Performance Materials Institute | Wang S.,High Performance Materials Institute | Liang R.,High Performance Materials Institute | And 2 more authors.
Carbon | Year: 2014

This paper reports on highly sensitive aligned carbon nanotube network (CNTN)-based strain sensors produced by aerosol jet printed electrodes and polyimide substrates. Two types of sensing mechanisms were revealed. Type A sensors, whose electrodes were directly printed on the CNTNs and embedded in epoxy resin, take advantage of the intrinsic piezoresistive properties of highly oriented carbon nanotube bundles and exhibited large positive gauge factor. Type B sensors, whose electrodes were printed on the polyimide substrate, utilize the effects of applied strains on the contact resistances between layers of the CNTN structure and between CNTN and the electrodes, exhibited large negative gauge factors. Type A and B sensors achieved positive and negative gauge factors up to 20 and 40 in magnitude, respectively. The high performance and flexible nature of the sensors, combined with the capability of scalable manufacturing processes, exhibits promising application potentials. © 2014 Elsevier Ltd. All rights reserved.


Hammel E.C.,High Performance Materials Institute | Ighodaro O.L.-R.,High Performance Materials Institute | Okoli O.I.,High Performance Materials Institute
Ceramics International | Year: 2014

Ceramics with engineered porosity are promising materials for a number of functional and structural applications including thermal insulation, filters, bio-scaffolds for tissue engineering, and preforms for composite fabrication. In this application based review of advanced porous ceramics, the microstructure of porous components is discussed in terms of the necessary features required to achieve the ideal properties for the intended application. The processing methods that are capable of producing the required microstructure are addressed. Those methods which allow the pore structure to be tailored or controlled are considered the most favorable processing techniques. © 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.


Dickens T.J.,High Performance Materials Institute | Breaux J.,High Performance Materials Institute | Olawale D.O.,High Performance Materials Institute | Sullivan W.G.,High Performance Materials Institute | Okoli O.I.,High Performance Materials Institute
Journal of Luminescence | Year: 2012

This paper investigates the feasibility of using zinc sulfide manganese (ZnS:Mn) concentrated vinyl ester resin as a photon emitter for damage monitoring of polymer composites under flexural loading. Unreinforced vinyl ester resins doped with optical emitting materials (ZnS:Mn phosphors) in ratios of 550% by weight were cast, and subjected to flexural loading using standard 3-point bend tests. The intent of this work was to observe the transient response of triboluminescence (TL) throughout the failure cycle. Results indicate TL crystals emit light at various intensities corresponding to crystal concentration and imminent matrix fracture. Consequently, concentrated samples showed nearly 50% reductions of mechanical moduli. Scanning electron microscopy (SEM) revealed particulate inclusions with shearing bands and semblance of particle to resin adhesion. Despite significant parasitic effect to mechanical properties, the triboluminescent properties occur at yielding and point of matrix fracture. © 2012 Elsevier B.V.


Wu Q.,High Performance Materials Institute | Zhu W.,High Performance Materials Institute | Zhang C.,High Performance Materials Institute | Liang Z.,High Performance Materials Institute | Wang B.,High Performance Materials Institute
Carbon | Year: 2010

Single-walled carbon nanotube (SWCNT) and multi-walled carbon nanotube (MWCNT) membranes (buckypaper) and carbon nanofiber (CNF) paper were incorporated onto the surface of epoxy carbon fiber composites, as proposed fire shields. Their flammability behaviors were investigated by a cone calorimeter. SWCNT buckypaper and CNF paper did not show notable improvement on fire retardancy. However, MWCNT buckypaper acted as an effective flame-retardant shield, reducing the peak heat release rate by more than 60% and reducing smoke generation by 50% during combustion. The pore structures of buckypapers and CNF paper were characterized by scanning electron microscopy (SEM), mercury intrusion porosimetry, and N 2 adsorption isotherms. Gas permeability of buckypaper and carbon nanofiber paper was measured. The correlation between buckypaper and CNF paper properties and their fire retardancy was discussed. © 2010 Elsevier Ltd. All rights reserved.


Uddin M.J.,High Performance Materials Institute | Dickens T.,High Performance Materials Institute | Yan J.,High Performance Materials Institute | Chirayath R.,High Performance Materials Institute | And 2 more authors.
Solar Energy Materials and Solar Cells | Year: 2013

Innovative all solid state dye-sensitized photovoltaic micro-wires (DSPMs) have been developed using low-cost, thermally-stable and highly conductive titanium micro-wires and carbon nanotubes yarns (CNYs). Highly inter-aligned, ultrastrong and flexible CNYs with excellent electrical conductivity, mechanical integrity and catalytic property have been successfully used as counter electrodes (CEs). The open circuit voltage and current density of the DSPMs can remarkably be improved through optimizing the numbers of CNYs and CNYs-TiO 2 interface. Optimizing the number of CNYs in the CEs yields a photoconversion efficiency of 0.1959% with prolonged-time stability. The DSPMs were made without expensive transparent conductive oxides (TCOs), liquid electrolytes and glass or plastic cladding. The DSPMs are able to transport photocurrent over a significant distance using a simple cell configuration with a wide range of flexibility (10-180°). These cells are capable of efficiently harvesting incident photon from any direction and generate photocurrent with an efficient reproducibility throughout a large number of illumination on-off cycles. © 2012 Elsevier B.V.


Yan J.,High Performance Materials Institute | Uddin M.J.,High Performance Materials Institute | Dickens T.J.,High Performance Materials Institute | Dickens T.J.,NPGroup Inc. | Okoli O.I.,High Performance Materials Institute
Solar Energy | Year: 2013

Over the past two decades, dye-sensitized solar cell (DSSC) research continues to gain momentum since its low-cost and environmental sustainability provides a good foundation for practical applications. Recently, CNTs have been introduced into DSSCs to take advantage of their lower electrical resistance, flexibility, excellent electrocatalytic activity and mechanical integrity. This paper introduces the principle of carbon-based solar energy conversion and reviews different types of solar cells using incorporated CNTs as electrode materials. This article also reports on CNTs' outstanding electrocatalytic functions in enhancing wire-shaped solar cells' photo-energy conversion. © 2013 Elsevier Ltd.

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