Self-powered Wireless Sensors and Interfaces for UAVs

Research for self-powered wireless sensors and interfaces for unmanned aerial vehicles (UAVs)

Anti-inflammatory effects of zinc in PMA-treated human gingival fibroblast cells

Objectives: Abnormal cellular immune response has been considered to be responsible for oral lesions in recurrent aphthous stomatitis. Zinc has been known to be an essential nutrient metal that is necessary for a broad range of biological activities including antioxidant, immune mediator, and anti-inflammatory drugs in oral mucosal disease. The objective of this study was to investigate the effects of zinc in a phorbol-12-myristate-13-acetate (PMA)- treated inflammatory model on human gingival fibroblast cells (hGFs). Study Design: Cells were pre-treated with zinc chloride, followed by PMA in hGFs. The effects were assessed on cell viability, cyclooxygenease-1,2(COX-1/2) protein expression, PGE 2 release, ROS production and cytokine release, Results: The effects were assessed on cell viability, COX1/2 protein expression, PGE 2 release, ROS production, cytokine release. The results showed that, in the presence of PMA, zinc treatment leads to reduce the production of ROS, which results in decrease of COX-2 expression and PGE 2 release. Conclusions: Thus, we suggest that zinc treatment leads to the mitigation of oral inflammation and may prove to be an alternative treatment for recurrent aphthous stomatitis

Unravelling the Influence of Surface Modification on the Ultimate Performance of Carbon Fiber/Epoxy Composites

Article asserts that the overall performance of polymer composites depends on not only the intrinsic properties of the polymer matrix and inorganic filler but also the quality of interfacial adhesion. The authors report carbon fiber (CF)/epoxy composites with improved interfacial adhesion by covalent bonding between CFs and the epoxy matrix, which leads to the improved ultimate mechanical properties and enhanced thermal aging performance

Improving Lithium-Metal Battery Performance under the Conditions of Lean Electrolyte through MoS2 Coating

Although lithium-metal-based batteries (LMBs) offer one of the highest energy densities, the issues with Li dendrite growths and the chemical reactivity between Li and electrolytes limit their applications. To enable a stable LMB under the practical conditions of lean electrolyte, thin Li metal and high mass loading, we introduce an efficient protective coating of MoS2 onto the Li-metal anode and analyzed its electrochemical performance under practical condition. The MoS2 coating successfully stabilizes the chemical activity of Li-metal surface by preventing dendrite growth and electrolyte dry-out, which results in the enhanced Li-metal battery cycle life by three-fold under the stringent conditions. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim1

In situ fabrication of a graphene-coated three-dimensional nickel oxide anode for high-capacity lithium-ion batteries

The high theoretical specific capacity of nickel oxide (NiO) makes it attractive as a high-efficiency electrode material for electrochemical energy storage. However, its application is limited due to its inferior electrochemical performance and complicated electrode fabrication process. Here, we developed an in situ fabrication of a graphene-coated, three-dimensional (3D) NiO-Ni structure by simple chemical vapor deposition (CVD). We synthesized NiO layers on Ni foam through a thermal oxidation process; subsequently, we grew graphene layers directly on the surface of NiO after a hydrogen-assisted reduction process. The uniform graphene coating renders high electrical conductivity, structural flexibility and high elastic modulus at atomic thickness. The graphene-coated 3D NiO-Ni structure delivered a high areal density of ∼23 mg cm-2. It also exhibits a high areal capacity of 1.2 mA h cm-2 at 0.1 mA cm-2 for its Li-ion battery performance. The high capacity is attributed to the high surface area of the 3D structure and the unique properties of the graphene layers on the NiO anode. Since the entire process is carried out in one CVD system, the fabrication of such a graphene-coated 3D NiO-Ni anode is simple and scalable for practical applications. © 2018 The Royal Society of Chemistry1

Intermediate Temperature Tribological Behavior Of Carbon Nanotube Reinforced Plasma Sprayed Aluminum Oxide Coating

Tribological behavior of plasma sprayed carbon nanotube (CNT) reinforced aluminum oxide (Al2O3) composite coatings was examined at room temperature, 573 K and 873 K using tungsten carbide (WC) ball-on-disk tribometer. The weight loss due to wear of Al2O3 coating was found to be increasing with the temperature while Al2O3-CNT coating showed a decreasing trend in the weight loss with the temperature. Relative improvement in the wear resistance of Al2O3-CNT coating compared to Al2O3 coating was found to be 12% at room temperature which gradually increased to ∼ 56% at 573 K and ∼ 82% at 873 K. Protective layer as a result of tribo-chemical reaction was observed on the wear track of both of the coatings. The improvement in the wear resistance of Al2O3-CNT coating was attributed to three phenomena viz. (i) higher hardness at the elevated temperature as compared to Al2O3 coating, (ii) larger area coverage by protective film on the wear surface at the elevated temperature and (iii) CNT bridging between splats. The coefficient of friction (COF) of Al2O3 coating was nearly constant at room and elevated temperature whereas COF for Al2O3-CNT coating decreased at the elevated temperature (873 K). © 2009 Elsevier B.V. All rights reserved

Nanopatterned Graphene Field Effect Transistor Fabricated Using Block Co-polymer Lithography

This article demonstrates a successful fabrication of Nanopatterened Graphene (NPG) using a PS-b-P4VP polymer

Synthesis of uniform single layer WS2 for tunable photoluminescence

Two-dimensional transition metal dichalcogenides (2D TMDs) have gained great interest due to their unique tunable bandgap as a function of the number of layers. Especially, single-layer tungsten disulfides (WS2) is a direct band gap semiconductor with a gap of 2.1 eV featuring strong photoluminescence and large exciton binding energy. Although synthesis of MoS2 and their layer dependent properties have been studied rigorously, little attention has been paid to the formation of single-layer WS2 and its layer dependent properties. Here we report the scalable synthesis of uniform single-layer WS2 film by a two-step chemical vapor deposition (CVD) method followed by a laser thinning process. The PL intensity increases six-fold, while the PL peak shifts from 1.92 eV to 1.97 eV during the laser thinning from few-layers to single-layer. We find from the analysis of exciton complexes that both a neutral exciton and a trion increases with decreasing WS2 film thickness; however, the neutral exciton is predominant in single-layer WS2. The binding energies of trion and biexciton for single-layer WS2 are experimentally characterized at 35 meV and 60 meV, respectively. The tunable optical properties by precise control of WS2 layers could empower a great deal of flexibility in designing atomically thin optoelectronic devices. © The Author(s) 2017

Synthesis Of Aluminum Oxide Coating With Carbon Nanotube Reinforcement Produced By Chemical Vapor Deposition For Improved Fracture And Wear Resistance

Chemical vapor deposition (CVD) was used to achieve a homogeneous dispersion of carbon nanotubes (CNTs) on aluminum oxide (Al2O3) powder. This powder was plasma sprayed onto a steel substrate to produce a 96% dense Al2O3 coating with CNT reinforcement. Addition of 1.5 wt.% CNTs showed a 24% increase in the relative fracture toughness of the composite coating. The improvement in the fracture toughness is attributed to uniform dispersion of CNTs and toughening mechanism such as CNT bridging, crack deflection and strong interaction between CNT/Al2O3 interfaces. Wear and friction behavior of the CNT reinforced Al2O3 coating under dry sliding condition was investigated by ball-on-disk tribometer. With the increasing normal loads from 10 to 50 N, the wear volume loss and coefficient of friction of the coating increased, owing to transition from the mild to severe wear. Wear resistance of the Al2O3-CNT composite coating improved by ∼27% at 50 N. Coefficient of friction at 50 N was dependent on the competing phenomena of wear debris generation and graphitization due to pressure. © 2009 Elsevier Ltd. All rights reserved