Browsing by Author "Zhou, Zhou"

Now showing 1 - 5 of 5
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    Development and Characterization of Titanium Compound Nanostructures
    (2016-07-19) Zhou, Zhou; Ajayan, Pulickel M
    The development and characterization of titanium compound nanostructures have been achieved, for potential applications in energy industry. Oil and gas, one of the traditional industry fields, observes accumulating demands on active implementations of nanotechnology, for the numerous advantages that nanomaterials can introduce to both product performances and field operations. By using chemical vapor deposition and liquid exfoliation, various titanium compound nanostructures have been synthesized through this project. Attractively, these two material fabrication methods have been recognized to be industrial friendly in terms of cost efficiency and productivity. The development of nanostructures, aiming at oil and gas field applications, presents novel solutions for existing issues, such as low durability of drilling tools, high friction in mechanical operations and ineffective heat dissipation. Titanium compound nanostructures, including titanium borides, nitrides and sulfides are therefore investigated for such applications as protective coating, lubrication and thermal management.
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    Energy Storage Capacity and Superconductivity of Nanosized Titanium Diboride, and Multifunctionality of Carbon-based Nanostructures: Development of Nano-engineered Solutions
    (2019-09-30) Zhou, Zhou; Ajayan, Pulickel; Kono, Junichiro; Bayazitoglu, Yildiz
    Nanotechnology has risen into prominence since the discovery of the “buckyball” in 1985,2 due to the enhanced tunability and performance of nanomaterials.3 Keenly awaited, scalable and facile application of nanotechnology, however, remains challenging. In petroleum industry, for instance, implementation barriers in scalability, controllability, and profitability have been hindering the advancement of nanotechnology innovations. The potential of fine tuning material properties and creating novel solutions is yet to be realized. Industrial friendly, scalable synthesis of nanosized titanium diboride and multifunctional nanostructures are exploited in this thesis, to include chemical vapor deposition, liquid exfoliation and electrochemical deposition. State of the art characterization techniques reveal atomic level properties in physical structure and chemical composition. After iterative material development cycles, the performance of prototypes are evaluated experimentally and theoretically. Lithium ion storage capacity and type II superconductivity are first time reported for nanosized titanium diboride. Remarkable theoretical capacity of 385.7 mAh/g and superconductive critical temperature of 5.8 K are attributed to the dimensional confinement of the nanoscale. Titanium diboride nanoparticles exhibit remarkable charge storage capacity, demonstrating great potential for applications as lithium ion battery anode and supercapacitor material. Their high energy storage capacity together with their newly discovered superconductivity manifest the distinctive material characteristics induced by dimensional confinement. Looking beyond the enhancement of material properties offered by the nanoscale, the multifunctionality of nanostructures are explored. Impelled by the virtues of carbon nanotubes and Fe@C core-shell nanoparticles, multifunctional, nano-engineered prototypes are designed and fabricated, combining hydrophobicity, mechanical and chemical resistance, and superparamagnetic, florescent and photocatalytic properties. The multifunctionality of infiltrated carbon nanotubes and Fe@C-CNx nanostructures appeal to various applications such as protective composite and reusable photocatalyst. Bridging the gap between academic research and industrial application, nano-engineering and design thinking approaches in this thesis develop nanostructures to solve explicit problems. Size confinement induced properties and innovative designs of nano-engineered structures are vital to convey the value of nanotechnology. The developed prototypes provide innovative solutions to various existing problems, including low durability of drilling tools, high friction in mechanical operations, critical environment energy storage and hazardous water waste.
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    Energy storage devices including at least one electrode comprising a metal diboride, and related methods
    (2020-09-15) Zhou, Zhou; Kato, Keiko; Babu, Ganguli; Khabashesku, Valery N.; Ajayan, Pulickel M.; Rice University; Baker Hughes, a GE company, LLC; United States Patent and Trademark Office
    An energy storage device including a first electrode comprising lithium, a second electrode comprising a metal diboride, an electrolyte disposed between the first electrode and the second electrode and providing a conductive pathway for lithium ions to move to and from the first electrode and the second electrode, and a separator within the electrolyte and between the first electrode and the second electrode. A method of forming an energy storage device including forming a first electrode to include lithium, forming a second electrode to include a metal diboride, disposing an electrolyte between the first electrode and the second electrode, the electrolyte providing a conductive pathway for lithium ions to move to and from the first electrode and the second electrode, and disposing a separator within the electrolyte and between the first electrode and the second electrode.
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    Mechanical Activation of a Multimeric Adhesive Protein Through Domain Conformational Change
    (American Physical Society, 2013) Wijeratne, Sithara S.; Botello, Eric; Yeh, Hui-Chun; Zhou, Zhou; Bergeron, Angela L.; Frey, Eric W.; Patel, Jay M.; Nolasco, Leticia; Turner, Nancy A.; Moake, Joel L.; Dong, Jing-fei; Kiang, Ching-Hwa; Bioengineering; Physics and Astronomy
    The mechanical force-induced activation of the adhesive protein von Willebrand factor (VWF), which experiences high hydrodynamic forces, is essential in initiating platelet adhesion. The importance of the mechanical force-induced functional change is manifested in the multimeric VWF's crucial role in blood coagulation, when high fluid shear stress activates plasma VWF (PVWF) multimers to bind platelets. Here, we showed that a pathological level of high shear stress exposure of PVWF multimers results in domain conformational changes, and the subsequent shifts in the unfolding force allow us to use force as a marker to track the dynamic states of the multimeric VWF. We found that shear-activated PVWF multimers are more resistant to mechanical unfolding than nonsheared PVWF multimers, as indicated in the higher peak unfolding force. These results provide insight into the mechanism of shear-induced activation of PVWF multimers.
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    Single-molecule force measurements of the polymerizing dimeric subunit of von Willebrand factor
    (American Physical Society, 2016) Wijeratne, Sithara S.; Li, Jingqiang; Yeh, Hui-Chun; Nolasco, Leticia; Zhou, Zhou; Bergeron, Angela; Frey, Eric W.; Moake, Joel L.; Dong, Jing-fei; Kiang, Ching-Hwa; Bioengineering; Physics and Astronomy
    Von Willebrand factor (VWF) multimers are large adhesive proteins that are essential to the initiation of hemostatic plugs at sites of vascular injury. The binding of VWF multimers to platelets, as well as VWF proteolysis, is regulated by shear stresses that alter VWF multimeric conformation. We used single molecule manipulation with atomic force microscopy (AFM) to investigate the effect of high fluid shear stress on soluble dimeric and multimeric forms of VWF. VWF dimers are the smallest unit that polymerizes to construct large VWF multimers. The resistance to mechanical unfolding with or without exposure to shear stress was used to evaluate VWF conformational forms. Our data indicate that, unlike recombinant VWF multimers (RVWF), recombinant dimeric VWF (RDVWF) unfolding force is not altered by high shear stress (100dynes/cm2 for 3 min at 37∘C). We conclude that under the shear conditions used (100dynes/cm2 for 3 min at 37∘C), VWF dimers do not self-associate into a conformation analogous to that attained by sheared large VWF multimers.