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Glass fibre/epoxy composites are widely used in construction, aerospace, automotive and wind turbine industries. During the manufacturing of glass fibres, they are surface-treated with an aqueous polymeric solution in a process called as sizing. This aqueous sizing composition protects the fibers, eases its handling and facilitates the interaction of fibres and matrix at the interface which affects the mechanical properties of the composites. The present study looks at the effect of a phenomenon called as ‘sizing migration’ on the strength, stiffness and failure mechanisms under tensile, compressive and inter-laminar shear loads in unidirectional glass fiber/epoxy composites. A detailed study has been performed to elucidate how sizing morphology underlying these glass fibers impact the stress-strain behaviour of the composite. Unidirectional glass fiber/epoxy composites were manufactured using vacuum assisted resin infusion molding process which exhibited a fiber volume fraction of ∼58 ± 2%. From the analysis of the relevant mechanical parameters, an intrinsic correlation between the strength and the sizing migration phenomenon has been deduced and explained on the basis of stress-strain curves under different loading conditions. The present study can help in defining the acceptance and rejection criteria in unidirectional fabrics with sizing migration issues.

Textual entailment is a fundamental task in natural language processing. Most approaches for solving the problem use only the textual content present in training data. A few approaches have shown that information from external knowledge sources like knowledge graphs (KGs) can add value, in addition to the textual content, by providing background knowledge that may be critical for a task. However, the proposed models do not fully exploit the information in the usually large and noisy KGs, and it is not clear how it can be effectively encoded to be useful for entailment. We present an approach that complements text-based entailment models with information from KGs by (1) using Personalized PageR- ank to generate contextual subgraphs with reduced noise and (2) encoding these subgraphs using graph convolutional networks to capture KG structure. Our technique extends the capability of text models exploiting structural and semantic information found in KGs. We evaluate our approach on multiple textual entailment datasets and show that the use of external knowledge helps improve prediction accuracy. This is particularly evident in the challenging BreakingNLI dataset, where we see an absolute improvement of 5-20% over multiple text-based entailment models.

AI systems that learn through reward feedback about the actions they take are increasingly deployed in domains that have significant impact on our daily life. However, in many cases the online rewards should not be the only guiding criteria, as there are additional constraints and/or priorities imposed by regulations, values, preferences, or ethical principles. We detail a novel online agent that learns a set of behavioral constraints by observation and uses these learned constraints as a guide when making decisions in an online setting while still being reactive to reward feedback. To define this agent, we propose to adopt a novel extension to the classical contextual multi-armed bandit setting and we provide a new algorithm called Behavior Constrained Thompson Sampling (BCTS) that allows for online learning while obeying exogenous constraints. Our agent learns a constrained policy that implements the observed behavioral constraints demonstrated by a teacher agent, and then uses this constrained policy to guide the reward-based online exploration and exploitation. We characterize the upper bound on the expected regret of the contextual bandit algorithm that underlies our agent and provide a case study with real world data in two application domains. Our experiments show that the designed agent is able to act within the set of behavior constraints without significantly degrading its overall reward performance., 9 pages, 6 figures

AI systems that learn through reward feedback about the actions they take are increasingly deployed in domains that have significant impact on our daily life. In many cases the rewards should not be the only guiding criteria, as there are additional constraints and/or priorities imposed by regulations, values, preferences, or ethical principles. We detail a novel online system, based on an extension of the contextual bandits framework, that learns a set of behavioral constraints by observation and uses these constraints as a guide when making decisions in an online setting while still being reactive to reward feedback. In addition, our system can highlight features of the context which are more predicted to be more rewarding and/or are in line with the behavioral constraints. We demonstrate the system by building an interactive interface for an online movie recommendation agent and show that our system is able to act within a set of behavior constraints without significantly degrading overall performance.

While the celebrated Word2Vec technique yields semantically rich representations for individual words, there has been relatively less success in extending to generate unsupervised sentences or documents embeddings. Recent work has demonstrated that a distance measure between documents called Word Mover’s Distance (WMD) that aligns semantically similar words, yields unprecedented KNN classification accuracy. However, WMD is expensive to compute, and it is hard to extend its use beyond a KNN classifier. In this paper, we propose the Word Mover’s Embedding (WME), a novel approach to building an unsupervised document (sentence) embedding from pre-trained word embeddings. In our experiments on 9 benchmark text classification datasets and 22 textual similarity tasks, the proposed technique consistently matches or outperforms state-of-the-art techniques, with significantly higher accuracy on problems of short length.

The present research was aimed at developing surface coatings on NiTi archwires capable of protection against nickel release and to investigate the stability, mechanical performance and prevention of nickel release of titanium sputter coated NiTi arch wires. Coated and uncoated specimens immersed in artificial saliva were subjected to critical evaluation of parameters such as surface analysis, mechanical testing, element release, friction coefficient and adhesion of the coating. Titanium coatings exhibited high reliability on exposure even for a prolonged period of 30 days in artificial saliva. The coatings were found to be relatively stable on linear scratch test with reduced frictional coefficient compared to uncoated samples. Titanium sputtering adhered well with the Ni-Ti substrates at the molecular level, this was further confirmed by Inductive coupled plasma emission spectroscopy (ICPE) analysis which showed no dissolution of nickel in the artificial saliva. Titanium sputter coatings seem to be promising for nickel sensitive patients. The study confirmed the superior nature of the coating, evident as reduced surface roughness, friction coefficient, good adhesion and minimal hardness and elastic modulus variations in artificial saliva over a given time period.

A peculiar architecture of one-dimensional MnO 2 nanowires was synthesized by an optimized hydrothermal route and has been lucratively exploited to fabricate highly efficient microporous electrode overlays for lithium batteries. These fabricated electrodes comprised of interconnected nanoscale units with wire-shaped profile which exhibits high aspect ratio in the order of 10 2 . Their outstanding intercalation/de-intercalation prerogatives have also been studied to fabricate lithium coin cells which revealed a significant specific capacity and power density of 251 mAh g −1 and 200 W kg −1 , respectively. A detailed electrochemical study was performed to elucidate how surface morphology and redox reaction behaviors underlying these electrodes influence the cyclic behavior of the electrode. Rate capability tests at different C-rates were performed to evaluate the capacity and cycling performance of these coin cells.

The present study provides detailed experimental results on the synthesis and characterization of carbonized lithium titanate spinel (LTO) composites as electrode materials for lithium ion capacitor. The LTO particles were grafted with a porous carbon layer obtained from the pyrolysis of camphor. The graphitic nature of the carbon was confirmed through Raman spectroscopy. The relative contributions from the capacitive and diffusion controlled processes underlying these electrodes were mathematically modeled. Electron transport mechanism underlying these electrodes was determined by measuring the work functions (φ) of LTO and carbon grafted LTO using ultraviolet photoelectron spectroscopy. These carbon grafted LTO composites exhibited an energy density of 330 mWh·L −1 and a peak power density of 2.8 kW·L −1 , when employed as electrodes in coin cells with excellent cycling stability at the end of 4000 cycles.

The present study demonstrates a low temperature hydrothermal route for the synthesis of α-cobalt hydroxide comprising of randomly arrayed nano strands in a three dimensional plane. These micro/nano hybrid structures were used as building blocks for processing high surface area supercapacitor electrodes. Surface area of these structures was measured to be ∼100 m2 g−1. The influence of surface morphology in three different electrolytes namely lithium hydroxide, sodium hydroxide and potassium hydroxide was analyzed. The influence of surface morphology on capacitance and internal resistance was also determined and explained on the basis of redox reactions in these electrolytes. Capacitance values as high as 1024 F g−1 was attained for these structures when employed as thin film electrodes with life extending to more than 5000 cycles. Inductively coupled plasma-atomic emission spectroscopy was used to determine the electrode dissolution in the given electrolyte and the observations were co-related with the cycling stability. Low self-discharge, high rate capability along with low cost makes them promising systems for supercapacitor applications.

In the present study, lithium nickel manganese oxide powders grafted with camphoric nano-carbons have been exploited to fabricate high voltage, high capacity rechargeable electrodes for Li storage. The prepared lithium nickel manganese oxide particles were pyrolyzed using a camphoric solution to graft porous camphoric carbon layer on to the surface. A detailed study was performed to elucidate the effect of carbon content on the performance of the electrode. Relative contributions of capacitive and diffusion-controlled processes underlying these composite electrodes have been mathematically modeled. The lithium nickel manganese oxide composites showed two times higher conductivity as compared to the pristine samples. These electrodes exhibited a specific capacity value of ~154 mAhg -1 and showed good rate capability. The capacity fading was found to be ~17% at the end of 200 cycles for 100% depth of discharge. The specific capacity and capacity retention for these blends were found to be ~10% and ~40% higher respectively than pristine powders which are promising considering their low cost and facile fabrication process.

The present study reports an approach by which thin films of sucrose added olivine type LiMnPO4-Ccomposite and pristine LiMnPO4 is made by a technique of electrophoretic co-deposition in which pristine and composite samples were synthesized by a sol-gel route. These thin films with enhanced surface area is used to fabricate cathodes for rechargeable Li ion batteries. XRD confirms phase pure single crystalline orthorhombic structure. Transmission Electron Microscopy (TEM) images shows the carbon coating over LiMnPO4 and the particle size restricted in the nano regime. The presence of sp2 hybridized carbon on LiMnPO4 particles is confirmed by X-ray Photon spectroscopy (XPS). To explore the electrochemical behavior, cyclic voltammetry (CV) and cycling studies were performed. The specific capacity for LiMnPO4-C is found to be increased by 43% in comparison to the pristine LiMnPO4. It also exhibited 86% retention in capacity compared to the pristine LiMnPO4 (52%). The result indicates that a proper carbon coating can significantly improve the electronic conductivity and hence the specific capacity.

Supercapacitor electrodes assembled from meso/macroporous camphor-derived carbon sponges show highly promising performance in ac line-filtering. The coin-type supercapacitor exhibits an ultrafast frequency response with a phase angle of −78° and a RC time constant of 319 μs at 120 Hz and may be a viable alternative to the presently dominant aluminium electrolytic capacitors.

The present study demonstrates a novel approach by which ‘bulk nanostructured’ NiO micro bouquets can be processed into a high surface area electrode for supercapacitor applications. A detailed study has been performed to elucidate the impact of porosity and redox reactions on the electrochemical behavior. The spheres were synthesized using a soft template technique. An intrinsic correlation between the surface area, capacitance and the internal resistance has been deduced and explained on the basis of relative contributions from the faradic properties of NiO. These NiO spheres exhibited specific mass capacitance values as high as 1950 F g−1. Further, coin cells employing these rechargeable electrodes were also demonstrated which exhibits energy and power densities of 17 W h kg−1 and 24 kW kg−1. It has been shown that these electrodes based on such bulk nanostructures can allow significant room for high performance supercapacitor devices.

This study demonstrates a novel approach by which amorphous nickel molybdate nanoflakes were processed into high surface area electrodes for supercapacitors. Time dependent studies showed evolution of flake-like morphology from anisotropic nuclei particles exhibiting high redox activity. An intrinsic correlation between the surface area, specific capacitance and the internal resistance has been deduced and explained on the basis of relative contributions from the faradic reactions of NiMoO 4 . Relative contributions from the bulk and surface processes were mathematically modeled. The electrodes exhibited specific mass capacitance values as high as 1650 F g −1 which is the highest reported value so far. Coin cells employing these rechargeable electrodes were also demonstrated exhibiting an energy and power density of 92 W h kg −1 and 23 kW kg −1 , respectively, with excellent cyclic stability.

The present work describes the processing of alumina fiber reinforced alumina ceramic preforms consisting of chopped Al2O3 fibers (33 wt%) and Al2O3 (67 wt%) fine powders by slip casting. The preforms were pre-sintered in air at 1100 °C for 1 h. A lanthanum based glass was infiltrated into these preforms at 1250 °C for 90 min. Linear shrinkage (%) was studied before and after glass infiltration. Pre-sintered and infiltrated specimens were characterized by scanning electron microscopy, energy dispersive X-ray, X-ray diffraction, porosimetry and flexural strength. The alumina preforms showed a narrow pore size distribution with an average pore size of ∼50 nm. It was observed that introducing Al2O3 fibers into Al2O3 particulate matrix produced warp free preforms with minor shrinkage during pre-sintering and glass infiltration. It was observed that the infiltration process fills up the pores and considerably improves the strength and reliability of alumina preform.

The present study reports the synthesis of NiO hexagons with exposed {110} facets on metallic Ni backbones. Intrinsic correlations were deduced between the surface area, crystalline anisotropy and the electrochemical performance. These metal backboned hexagons were employed as supercapacitor electrodes exhibiting specific mass capacitance value as high as 2100 Fg −1 . Further, a working model button cell employing these rechargeable electrodes is also demonstrated exhibiting an energy and power density of 17 Wh kg −1 and 3.5 kW kg −1 , respectively.

The present study demonstrates a novel approach by which biowaste clam shells derived from Venerupis species can be processed into high aspect ratio one dimensional wires being an interesting candidate to biomedical applications. These nanowires were synthesized hydrothermally and exhibited an aspect ratio in the order of 10 2 with a surface area of 40 m 2 g −1 and narrowly distributed diameter size range from 40 to 130 nm. Fast Fourier transform analysis during high resolution transmission electron microscopy showed the wires exhibiting growth along (300). X-ray diffractometry and Fourier-transform Infra-red spectroscopy showed that the nanowires produced were of high purity.

A peculiar architecture of a novel class one dimensional β-Ni(OH) 2 nanorods synthesized by an optimized surfactant-free aqueous precipitation route has been lucratively exploited to fabricate highly efficient microporous electrodes for supercapacitors. These fabricated electrodes comprised of a highly porous overlay of interconnected nanoscale units with rod-shaped profile which terminates into jagged-like morphology. The surface area of these nanorods was found to be ∼91 m 2 g −1 . This architecture transcribes into a superior cycling performance (capacitance of 1150 F g −1 was achieved) with more than 99% of the initial capacitance being retained after 5000 charging/discharging cycles. Their outstanding intercalation/de-intercalation prerogatives have also been exploited to fabricate supercapacitor coin cells which reveal a significant power density of 52 kW kg −1 and energy density of 4 Wh kg −1 with extremely fast response time of 1.2 ms.

The present study highlights a low temperature process by which 1D stacked 3D microstructures of nickel sulfide comprised of nanospikes have been synthesized and assembled as cathodes for lithium chalcogenide batteries. These micro/nano-clusters were synthesized hydrothermally under different conditions. These clusters exhibited a surface area of 15 m 2 g −1 . The present study also provides the first reports on the electrochemical performance of these NiS microclusters as cathode materials in lithium fluoro-Tris-sulfonimide electrolyte for lithium ion batteries. A detailed study has been performed to elucidate how surface morphology and redox reaction behaviors underlying these electrodes impact the cyclic behavior and specific capacity. This electrode−electrolyte combination showed minimal dissolution of the electrode in the electrolyte which was confirmed by inductively coupled plasma atomic emission spectroscopy. From the electrochemical analysis performed an intrinsic correlation between the capacity, self-discharge property and the surface morphology has been deduced and explained on the basis of relative contributions from the redox reactions of nickel sulfide in lithium fluoro-Tris-sulfonimide electrolyte. A working model of lithium battery in a coin cell form is also shown exhibiting a specific capacity of 550 mAh g −1 .

Staphylococcus aureus is one of the major causes of skin and soft tissue infections. In this study we compared the antimicrobial activity of two different TiO2 nanoformulations against Staphylococcus aureus. We synthesized TiO2 nanoparticles of approximately 80 nm diameter and TiO2 nanowires of approximately 100 nm diameter. Both nanoformulations possess anti-microbial activity; were non-hemolytic and cytocompatible. However, the anti-staphylococcal activity of TiO2 nanowires was better than the nanoparticles. In broth culture, growth of S. aureus was only partially inhibited by 2% and 4 wt% TiO2 nanoparticles and completely inhibited by TiO2 nanowires till 24 h. TiO2 nanowires treated S. aureus cells exhibits diminished membrane potential than nanoparticle treated cells. The anti-microbial properties of both TiO2 nanoformulations were validated using ex vivo porcine skin model which supplements the in vitro assays. Anti-bacterial activity of the TiO2 nanowires were also validated against multi drug resistant pathogenic strains of S. aureus, showing the clinical potency of the TiO2 nanowires compared to its nanoparticles.

The present study demonstrates a facile approach by which TiO2-graphene nanocomposites can be processed into bulk powders via molten salt technique. A detailed study had been performed to elucidate the effect of graphene content (0.2–10 wt%) in these nanocomposites and its impact on the opto-electrical properties. From the analysis an intrinsic correlation between the graphene content and conductance of the composite has been explained on the basis of relative band gap and work function properties. Fluorescence spectroscopy measurements showed the excitonic intensity to be lower in these nanocomposites indicating that the recombination of photo-induced electrons and holes can be effectively inhibited. Conductivity measurements revealed mean specific conductance values about 15–55% higher than that of the TiO2 nanoparticles. Preliminary studies have shown that an efficiency of 5.4% could be attained by employing TiO2-graphene nanocomposites as photoanodes in dye sensitized solar cells.

The present study investigates in detail the synthesis and characterization of PEDOT: PSS/MnO 2 hybrid sponge electrodes for supercapacitor/battery applications. These hybrid sponges were prepared using freeze drying technique and showed hierarchical pores ranging from micron to nanometric size. Scanning electron microscopy-energy dispersive X-ray showed uniform dispersion of MnO 2 along the PEDOT: PSS matrix. Thermo gravimetric-differential thermal analysis showed higher thermal stability for these hybrid constructs compared to PEDOT: PSS sponges. From the electrochemical studies, an intrinsic correlation between overall specific capacitance, morphology and weight percentage of MnO 2 in the PEDOT: PSS matrix has been defined and explained in KOH electrolyte system. High cyclic stability was observed at the end of 2000 cycles for these hybrid sponges with less than 5 % capacitance fading. These sponges exhibit mass specific capacitance values as high as 10688 F g −1 which was found to be 35% higher compare to PEDOT: PSS sponges as obtained from Weibull statistics. The application of these electrodes was explored in a fully functional asymmetric coin cell unit where an energy and power density of 200 mWh kg −1 and 6.4 kW kg −1 , was obtained, respectively.

In this paper, we report on the electrochemical characteristics of graphene–PEDOT composite electrodes. The electrodes were made of indium tin oxide (ITO) substrates by simple processes of electrophoretic deposition of graphene followed by electropolymerization of EDOT monomer. The composite electrode was obtained by electrochemical measurements, a median specific capacitance of 1410 F/g and a median area capacitance of 199 mF cm −2 at a scan rate of 40 mVs −1. The composite showed good stability characteristics after repeated scans in cyclic voltammmetry and fared much better than a thin film of PEDOT. The thermal stability of the composite is also much superior when compared to the polymer with a weight loss temperature of 350 °C for the composite and 250 °C for the polymer, respectively. The above electrochemical and thermal behaviours of the composite are correlated to the unique morphology of electrodeposited graphene that provides a conductive and high surface area template for electropolymerization.

Camphoric carbon wrapped NiS powders have been profitably exploited to fabricate high surface area electrodes for Li storage. The NiS morphology showed a network of interconnected nanoscale units with rod like profiles which terminated into needle-like apexes spanning diameters of about 50–80 nm. These particles were pyrolyzed using a camphoric solution to form a carbon sheath wrapping. These carbon functionalized NiS powders were processed into high-surface-area cathodes for a fully functional coin cell unit. A detailed study was performed to elucidate the effect of carbon content on the performance of these coin cells. BET surface area analysis revealed that these carbon sheathed NiS could exhibit a high surface area of 32 m2 g−1 compared to pristine powders which exhibited surface area values of 20 m2 g−1. From the analysis of relevant electrochemical parameters, an intrinsic correlation between the specific capacity, internal resistance and temperature has been deduced. Relative contributions of capacitive and diffusion-controlled processes underlying these thin-film electrodes have been mathematically modeled. These thin-film electrodes exhibited specific capacity values as high as 500 mA h g−1 as determined from charge discharge curves. The present study shows that this functional material can provide the advantages of simple processing technique, low cost, and scalability.

The present study demonstrates a novel, low temperature synthetic approach by which 3-D bouquets of nickel hydroxide nitrate were processed into high surface area electrodes for supercapacitor applications. The synthesized micro-bouquets comprised randomly arrayed microporous nanoflakes (pore size: 2–6 nm) and exhibited a surface area of 150 m2 g−1. Morphological evolution studies were performed to elucidate how surface morphology of these electrode materials affect redox reactions and their ultimate performance as a supercapacitor. The electrodes were tested in three different electrolytes, namely lithium hydroxide, potassium hydroxide and sodium hydroxide. From the detailed electrochemical analysis, an intrinsic correlation between the capacitance, internal resistance and the surface morphology was deduced and explained on the basis of relative contributions from the faradaic properties in different electrolytes. Depending on the surface morphology and electrolyte incorporated, these nano/micro-hybrid electrodes exhibited specific mass capacitance value of as high as 1380 ± 38 F g−1. Inductively coupled plasma-atomic emission spectroscopy was used to determine the electrode dissolution in the given electrolyte and the findings were co-related with the cycling stability. By employing this low cost electrode design, high stability (>5000 cycles with no fading) was achieved in lithium hydroxide electrolyte. Furthermore, a working model supercapacitor in a coin cell form is also shown to exhibit peak power and energy density of 3 kW kg−1 and 800 mW h kg−1, respectively.

The present study demonstrates a novel electrodeposition approach by which Ce 3+ doped NiO nanoparticles coated on titanium foils can be processed into a high surface area electrode for rechargeable energy storage applications. A detailed study has been performed to elucidate how cerium substitution doping and redox reaction behaviors underlying these electrodes impact the cyclic and capacitive behavior of the electrode. These nanoparticles were synthesized via molten salt technique and exhibited particle size of ∼ 65 nm. From the analysis of the relevant electrochemical parameters, an intrinsic correlation between the substitutional doping amount, capacitance and the internal resistance has been deduced and explained on the basis of relative contributions from the faradic properties of the Ce 3+ doped NiO nanoparticles in different electrolytes of varied concentrations. These thin film electrodes exhibited specific mass capacitance value as high as 1500 Fg −1 and 1077 Fg −1 (1 Ag −1 ) measured from cyclic voltammetry and charge discharge curves respectively, which was found to be 5 times higher than the pristine NiO nanoparticles with a capacitance retention of >70% at the end of 2000th cycle. Further, a working model button cell employing these rechargeable electrodes is also demonstrated exhibiting an energy and power density of 92 Wh Kg −1 and 10 kW Kg −1 , respectively. It has been shown that electrodes based on such nanoparticles can allow significant room for improvement in the cyclic stability and performance of a hybrid capacitor/battery system.