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This paper conducts modeling and vibration analysis of a spinning cylindrical shell attached with a beam, namely, an assembled cylindrical shell-beam structure, which is reinforced by graphene nanoplatelets (GPLs). The available performance attributes of the beam and cylindrical shell, determined by the Halpin-Tsai model together with the rule of mixture, are deemed to change continuously along their thickness directions. In accordance to the Euler-Bernoulli beam theory and the Donnell's shell theory, the Lagrange's equation is applied to obtain the coupled governing equations of the assembly. Besides, the substructure modal synthesis method is used to acquire vibration behaviors of the nanocomposite assembled shell-beam structure. The influences of the graphene nanoplatelet (GPL) distribution pattern, GPL weight fraction, length-to-width ratio and length-to-thickness ratio of GPLs, and spinning speed on the vibration performance of the assembled shell-beam structure. The findings could provide an important light on the design of coupled nanocomposite cylindrical shell-beam assembly for outstanding mechanical performance. [ABSTRACT FROM AUTHOR]

The size-dependent bending and free vibration of bi-directional functionally graded graphene nanoplatelets reinforced composite (BDFG-GPLRC) microbeams are investigated based on the Timoshenko beam theory and isogeometric analysis (IGA). The modified couple stress theory (MCST) is employed to describe the scale effect of microbeams. GPLs are distributed as power functions along the thickness and axis directions and four types of distribution patterns are taken into account. Employing the minimum potential energy principle and Hamilton's principle, the government equations are established and solved by IGA. Correctness and accuracy of this method are verified by comparing with a published paper. By means of several numerical examples, the effects of GPL weight fraction, power-law indexes, boundary conditions and scale parameter on bending and free vibration behaviors of BDFG-GPLRC microbeams are studied in detail. [ABSTRACT FROM AUTHOR]

The paper investigates nonlinear dynamic behavior of functionally grade graphene nanoplatelets reinforced (FG-GPLRC) shell with radius as a high-order function using the classical thin shell theory (CTST) and the Von Karman-Donnell geometrical nonlinearity assumption. Different from cylindrical or conical shells, variations of radius are formulated as quadratic or/and cubic functions, generating three types of funnel shells. To verify the computation, the fundamental frequencies are compared with the previous literatures and Finite Element Analysis. The effects of various parameters including geometries, materials, temperature are considered. Obtained results of the shell promisingly make a significant contribution to various fields of engineering. [ABSTRACT FROM AUTHOR]

This paper presents the characterisation and for the first time the application of a nanocomposite based on reduced graphene oxide (rGO) modified with antimony nanoparticles (SbNPs) in the stripping analysis of Cd2+, Pb2+, Cu2+ and Hg2+ in natural water samples. The nanocomposite was easily synthesised by a chemical reduction approach using sodium borohydride as the reductant agent. The designed experiment investigated the remarkable rGO electronic properties with the synergetic combination of metallic SbNPs. The results showed that the GC/rGO-SbNPs electrode selective detected the heavy metal ions (HMIs) with suitable sensitivity. Under optimal conditions, the proposed electrode showed a good linear relationship with the concentration of Cd2+, Pb2+, Cu2+ and Hg2+ ranging from 0.1 to 4.5 µmol L−1 with detection limits for simultaneous determination of 45.3, 16.5, 34.1 and 4.8 nmol L−1, respectively. This presented work enables a full understanding of rGO-SbNPs properties in stripping analysis of HMIs, as well as a novel approach for future in situ analysis. [ABSTRACT FROM AUTHOR]

In this paper, a conductive layer is developed by printing a graphene nanoparticles-based conductive ink on the silk fabric showing surface resistance of 2.3 Sand conductivity of Sm, respectively. The printed silk fabric is utilized to fabricatemode wideband antenna for aeronautical radio-navigation applications centered at 4200 MHz. Excellentimpedance bandwidth of 26.4% is obtained by incorporating a patch-ground shorting stub. The antenna has reasonable radiation efficiency above 74% including packaging losses and conical radiation pattern at higher order mode. The simulation and measurements are performed considering practical scenario showing excellent measured results. [ABSTRACT FROM PUBLISHER]

In this work, graphene nanoplatelets (GNP) are used to reinforce epoxy adhesives, and the effects of GNP on mode I fracture toughness of adhesive under water aging condition are studied through double cantilever beam (DCB) test. Although the GNP reinforced adhesives deliver slightly higher GIC than neat epoxy before water aging, they exhibit an exceptional 21.93% higher GIC after immersing in water for 56 d, at a GNP content of 0.25 w.t.%. According to the experimental results, the effectively dispersed GNP could significantly alleviate the degradation rate in mode I fracture toughness due to the water aging. For example, compared to the non-aging condition, the mode I fracture toughness of neat epoxy decreases by 29.19% after 56 d of water aging. In a stark contrast, the degradation rate for 0.25 w.t.% GNP reinforced adhesive is only 15.76%. In addition, it is observed that GNP greatly improves the fracture surface roughness of DCB samples, which suggests that the incorporation of GNP is able to delay the negative effect of water aging on mode I fracture toughness of adhesive by lowering the diffusion of water into the adhesive, while increasing torturous of the crack propagation path. [ABSTRACT FROM AUTHOR]

This study aims to investigate the influence of rigid polyurethane foam (RPUF) as a filling material on the energy absorption performance of thin-walled tubes through experiments. Hybrid graphene oxide-silica nanoparticles (GO-SiO2) was prepared using the electrostatic adsorption method and its potential application in RPUF enhancement were investigated. The interaction between GO and nano SiO2 inhibits the agglomeration of each other and improved the mechanical properties and energy absorption capacity of RPUF. When the GO-SiO2 hybrid content was 6 wt%, the compressive strength and total energy absorption of the GO-SiO2/RPUF composite material increased by 99.59% and 89.63% compared with those of pure RPUF, respectively. In addition, the deformation characteristics of empty tube and foam-filled tube under lateral compression were compared, and the influence of the RPUF material's mechanical properties on the energy absorption characteristics of foam-filled tube was further analyzed. Test results show that the foam material can effectively improve the stability of the compression deformation of thin-walled circular tubes and improve the compression resistance of the structure. Improving the mechanical properties of RPUF materials can further increase the bearing capacity and energy absorption of foam-filled tubes. The results in this study validated the feasibility of using GO-SiO2 hybrid as a new nano-reinforcing filler for RPUF, and provide an experimental reference for the engineering application of foam-filled tubes as energy absorption components. [ABSTRACT FROM AUTHOR]

Polyvinylidene fluoride (PVDF), polyamide (Nylon) and anodic aluminum oxide (AAO) filter membranes were coated with in-situ synthesized silver nanoparticle/reduced graphene oxide (AgNP/rGO) nanocomposite by vacuum filtration, and surface-enhanced Raman scattering (SERS) performance of the prepared substrates was investigated using Rhodamine 6G (R6G) as a probe molecule. Analyte solutions were applied by drop casting and penetrated into the flexible PVDF and Nylon-based substrates within minutes, enabling very fast SERS measurements; however, this step took up to 2 hrs in the rigid AAO-based substrate. Scanning electron microscopy and Energy-dispersive X-ray spectroscopy mapping results showed that filter membrane surfaces were completely covered with AgNP/rGO nanocomposite at which AgNPs were uniformly distributed on rGO flakes; however, some large, partially reduced or unreduced GO flakes decorated with AgNP agglomerates (AgNP/GO) were also observed. Higher SERS signals were generally obtained from these AgNP/GO flakes compared to the AgNP/rGO coated regions, since they contain higher amount of oxygen-rich functional groups which enabled a higher chemical and electromagnetic enhancement in SERS signals. All the substrates could detect 10−7 M R6G even after being stored in a vacuum desiccator for 3 months, indicating that AgNP/rGO coated filter membranes are promising as stable SERS substrates thanks to their long shelf life. [ABSTRACT FROM AUTHOR]

In this study, the mechanical response and damage characteristics of single lap joints (SLJs) including graphene nanoplatelets (GNPs) were investigated under tensile and three-point bending tests. To this end, Aluminum 2024 substrates were bonded by Araldite 2014–2 adhesive reinforced by GNP with various percentages as 1%, 2%, 3%, and 4% by weight. The results demonstrated that GNP added samples exhibiting a higher ability to resist loads showed better performance for both experiments compared to pure samples. The maximum improvements in the 3 wt.% GNP added samples were obtained as 91.2% in the lap shear test and 45.1% in the three-point bending test. The addition of GNP to the adhesive acted as a barrier against growing cracks, causing the formation of special toughening mechanisms such as crack deviation, bridging, and pull out, which either stopped the cracks or deviated them from their path. These mechanisms improved the fracture characterization of samples in failures. However, more amount of GNP higher than 3 wt.% led to sharp decreases due to the non-uniform local stress concentrations as a result of agglomerations. [ABSTRACT FROM AUTHOR]

In this experimental investigation, graphene nano additive was used at different proportions from 25 to 100ppm with an interval of 25ppm. It was then dispersed into the neat diesel and 20% Calophyllum inophyllum blend and its properties were determined. Further, experimentation was conducted for selected fuels in a CI engine. The discussions revealed that BTHE increased by 0.54 and 0.03% for CI20 with GNA of 25 and 50ppm. VE was decreased by 0.19, 0.32, 0.59, and 0.70%. EGT was decreased by 7.69, 7.57, 6.71, 6.81, and 7.55% for CI20 with GNA of 25 to 100 ppm. CO emissions were decreased by 12.8, 10.37, 8.71, and 1.65%, HC emissions were lessened by 72.44, 74.48, 75.5, and 76.5%, NOx emissions were reduced by 19.34, 17.56, 19.53, and 16.88%, opacity reduced by 7.1, 5.13, 4.47, and 4.07% for CI20 with GNA of 25 to 100ppm. The maximum cylinder pressure was reduced by 0.76, 1.02, 1.55, and 0.36%, RPR was increased by 36.58%, 33.69%, 38.82%, and 35.33% for CI20 with GNA of 25 to 100ppm. 90% MFB was taken for all blends at the difference of approximately 1°CA from that of diesel. Therefore, CI20 with GNA proportions is a promising substitute for diesel fuel. [ABSTRACT FROM AUTHOR]

Green nanocomposites based on polylactic acid (PLA) and Wood Flour (WF) with different loadings of graphene nanoparticles (GNPs) were produced by compressing molding process. The mechanical strength, dimensional stability, and viscoelastic behavior of nanocomposites were characterized by static mechanical analysis (flexural and tensile), water uptake, and dynamic mechanical analysis (DMA) tests. Results indicated that the incorporation of GNPS into the fabricated samples, significantly improved the mechanical properties of the composites. However, the water absorption and thickness swelling of the composites progressively decreased with increasing GNPs content. In general, the specimens filled with GNPs showed the highest values of storage and loss modulus compared with the other ones, due to the highest interaction taking place at the matrix–filler interface. Morphological images show that the GNPs were homogeneously and well-dispersed in the composites. Based on the findings obtained from the present study, it can be said that the optimum content of GNPs for the fabricated WPC samples is 2%. [ABSTRACT FROM AUTHOR]

This is the first research on the pre-thermal buckling and vibration analysis of imperfect graphene nanoplatelets reinforced composite (GPLRC) doubly curved open cylindrical micropanel in the framework of numerical based two dimensional-generalized differential quadrature method (2D-GDQM). Additionally, the small-scale effects are analyzed based on nonlocal strain gradient theory (NSGT). The stresses and strains are obtained using the high order shear deformable theory (HOSDT). Rule of mixture is employed to obtain varying mass density, thermal expansion, and Poisson's ratio, while module of elasticity is computed by modified Halpin–Tsai model. In addition, nonlinear temperature changes along the GPLRC micro panel's thickness direction. Governing equations and boundary conditions of the GPLRC doubly curved open cylindrical micropanel are obtained by implementing Hamilton's principle. Besides, for the validation of the results, the results of current model are compared to the results acquired from analytical method. The results show that GPL weight function ( g GPL ), imperfection, the ratio of shell curvatures (R1/R2), NSG parameters, and geometric parameters have significant influence on the frequency and pre-thermal buckling characteristics of the GPLRC doubly curved open cylindrical micropanel. [ABSTRACT FROM AUTHOR]

Friction stir welding (FSW) has gained enormous attention as a well-established solid-state welding technique. Loss of strength and compromise on heat-affected zone has always been an issue in welding. The addition of Graphene Nanoplatelets and Boron Carbide in Al6061 via FSW has been studied hereby. The effect of individual and hybrid combination of both reinforcements in the Al6061 matrix was explored by using a comparative approach with non-reinforced FSW reference. A detailed microstructural investigation, utilising the optical and scanning electron microscopy was conducted. The mechanical behaviour was examined by employing micro-hardness and tensile testing. Fractography was carried out to inspect the tensile tested fractured FSW samples. Maximum strength was displayed by the boron carbide added FSW joint at the cost of ductility. The tendency of graphene nanoplatelets to cluster led to the deterioration of mechanical profile at the respective FSW joint. A dominant behaviour of boron carbide was observed in the hybrid combination of the reinforcements at the FSW joint. [ABSTRACT FROM AUTHOR]

Nanofiltration membranes with fast water permeability and good separation efficiency along with acceptable stability are an urgent need for various applications. Herein, graphene oxide (GO) is functionalised with silver nanoparticles (Ag NPs) using different ratios (0.01, 0.02, and 0.03). The Ag NPs have been prepared from orange peel extractive by a green chemical method. The GO/Ag NPs functionalised membranes (ratio 0.03) with thickness ~385 ± 10 nm exhibit an excellent selectivity for various dye molecules with good water permeance, i.e. methylene blue (99 ± 1% rejection and permeability ~287 ± 10 L.m−2.h−1.bar−1), crystal violet (rejection 99 ± 1% and permeability 862 ± 10 L.m−2.h−1.bar−1), safranin O (rejection 99 ± 1% and permeability 625 ± 10 L.m−2.h−1.bar−1) etc. Further, the GO/Ag NPs functionalised membrane (Thickness ~385 ± 10) has been used for organic solvent nanofiltration (OSN), and the membrane exhibits high separation efficiency up to ~97% for several dye molecules in methanol solvent along with good permeance (530 ± 20 L.m−2.h−1.bar1). Besides this, these membranes are stable under different conditions for up to ~70 days. We hope that the good separation efficiency and high permeance of GO/Ag NPs composite membranes can be utilised in various wastewater treatment, desalination, and organic solvent nanofiltration applications. [ABSTRACT FROM AUTHOR]

Over the past decade, mechanical characterization data for nanoparticle-reinforced polymer matrix composites have shown significant improvements in compressive strength and interlaminar shear strength, in comparison with baseline properties. While the synergistic reinforcing influence of nanoparticle reinforcement is obvious, a simple rule-of-mixtures approach fails to quantify the dramatic increase in mechanical properties. Consequently, there is an immediate need to investigate and understand the mechanisms at the nanoscale that are responsible for such unprecedented strength enhancements. A multi-scale and multi-physics simulation approach is considered computationally more viable since relying on a single time or length scale may require huge amounts of computational resources and can potentially lead to inaccurate results. A proof-of-concept case study involving crack initiation in a graphene nanoplatelet is presented, together with a methodology for computing the atomisticJ-integral based on Hardy estimates of continuum fields. The same methodology will be used to gain a better understanding of the influence of nanoscale phenomena on continuum-scale mechanical properties of a polymer nanocomposite. It is envisioned that the current research will contribute towards the understanding of advanced nanostructured composite materials within the context of integrated computational materials engineering. [ABSTRACT FROM PUBLISHER]

The formation of novel structures by the passage of an electric current through graphite is described. These structures apparently consist of hollow three-dimensional graphitic shells bounded by curved and faceted planes, typically made up of two graphene layers. The curved structures were frequently decorated with nano-scale carbon particles, or short nanotubes. In some cases, nanotubes were found to be seamlessly connected to the thin shells, indicating that the formation of the shells and the nanotubes is intimately connected. Small nanotubes or nanoparticles were also sometimes found encapsulated inside the hollow structures, while fullerene-like particles were often seen attached to the outside surfaces. With their high surface areas and structural perfection, the new carbon structures may have applications as anodes of lithium ion batteries or as components of composite materials. [ABSTRACT FROM AUTHOR]

High concentrations of antibiotics have been identified in aquatic environments that have reduced water quality. These compounds are usually highly toxic, mutagenic, carcinogenic, and low biodegradable. The aim of this study is to optimize the effectiveness of graphene quantum dot nanoparticles (GQD-NPS) in the presence of hydrogen peroxide for the removal of ciprofloxacin (CIP) from aqueous media. Specific factors were examined such as, pH (3–11), [H2O2]/[GQD-NPS] (0.66–3.00), contact time (15–90 min), and CIP initial concentration (50–150 mg/L). High values for the coefficient of determination, R2 and R2adj predicted were 0.9916 and 0.9719 showed that the removal of AB92 dye using adsorption can be described by the RSM. The optimum conditions of pH, [H2O2]/[GQD-NPS], contact time, and CIP initial concentration were found to be 7, 0.66, 15 min, and 150 mg/L, respectively. Second-order equation with a very high correlation coefficient was fitted for CIP removal prediction. The basic conclusion is that the prepared GQD-NPS/H2O2 can be used successfully for the removal of ciprofloxacin, which can also be optimized and controlled to maximize ciprofloxacin removal from aqueous solutions. [ABSTRACT FROM AUTHOR]

The novel high hydrophobic graphene/vinyl-functionalized SiO2 composites were prepared via self-assembly of graphene sheets on the surface of vinyl-functionalized silica (VF-SiO2) nanoparticles. The resulting graphene/functionalized SiO2 composites exhibited rapid absorption rate, high absorption capacity and convenient separation in oil-water separation. Furthermore, the composites could be easily recovered and reused at least 12 times without any loss of its activity and showed great potential for large-scale application in water treatment. [ABSTRACT FROM AUTHOR]

Graphene – a carbon nanomaterial has gained huge research interest due to its intriguing and extraordinary properties such as large surface area, excellent electrical conductivity, ultra-thinness, high electron mobility, and superior mechanical strength. The combination of graphene with other inorganic nanoparticles can significantly boost its physiochemical properties and hence, opens up new frontiers of its utilization. Grapheneis significantly exploited for the energy storage systems due to its great potential for electrochemical energy storage. However, the experimental electrochemical performance of graphene is still far away from the theoretical facts. This study critically evaluated the existing synthesis routes for the production of graphene, graphene-based composites and their utilization in the energy storage applications. Furthermore, the techno-economic analysis of the synthesis methods was undertaken to determine the best routes in terms of sustainability for commercial graphene production. Lastly, the fundamental understanding of graphene growth mechanisms and the overall intricacies of the synthesis processes were highlighted and the possible way forward is proposed. Therefore, in the quest for the development of effective alternative yet sustainable energy storage devices; it is hoped that this research will give useful insights to researchers and key players in the electronics industry. [ABSTRACT FROM AUTHOR]

This article investigates the tribological behavior of nanoparticles (NPs) of titanium dioxide anatase TiO2 (A), graphene, and TiO2 (A) + graphene added to the pure base oil group ΙΙ (PBO-GΙΙ). The morphology of these two nanostructures of TiO2 (A) and graphene was characterized by transmission electron microscopy (TEM). Oleic acid (OA) was blended as a surfactant into the formulation to help stabilize the NPs in the lubricant oil. A four-ball test rig was used to determine the tribological performance of six different samples, and an image acquisition system was used to examine and measure the wear scar diameter of the stationary balls. Field emission–scanning electron microscopy (FE-SEM) was used to examine the wear morphology. Energy-dispersive X-ray spectroscopy (EDX), element mapping, and Raman spectroscopy were employed to confirm the presence of (TiO2 (A) + graphene) and the formation of a tribolayer/film on the mating surfaces. Moreover, a 3D optical surface texture analyzer was utilized to investigate the scar topography and tribological performance. The experiments proved that adding (0.4 wt% TiO2 (A) + 0.2 wt% graphene) to the PBO-GΙΙ optimized its tribological behavior. These excellent results can be attributed to the dual additive effect and the formation of a tribofilm of NPs during sliding motion. Furthermore, the average reductions in the coefficient of friction (COF), wear scar diameter (WSD), and specific wear rate (SWR) were 38.83, 36.78, and 15.78%, respectively, for (0.4 wt% TiO2 (A) + 0.2 wt% graphene) nanolubricant compared to plain PBO-GΙΙ lubricant. [ABSTRACT FROM AUTHOR]

A facial route to synthesize a new composite material that consists of TiO2 nanoparticles grown over the Cu2Se-graphene (Cu2Se-G) through ultrasonic techniques was reported, which was characterized through some general analyses. The photoreduction of CO2 to CH3OH performance of the Cu2Se-graphene-TiO2 (Cu2Se-G-TiO2) nanocomposite was tested with GC (GCMS-QP2010 SE) under UV and visible light. Our excellent results indicate strong reduction rates of CO2 compared to original TiO2 and binary Cu2Se-G. We explain in our study the scavenger effect and the mechanism from CO2 to CH3OH. [ABSTRACT FROM AUTHOR]

Surface characteristics of graphene have an important impact on its performance. Substantial attention has been devoted to studying the static wetting behaviour of a graphene-coated substrate with little attention to the dynamic wetting behaviour. The impact of contact line forces (CLFs) on the droplet-spreading process has not been revealed completely yet. A series of molecular dynamics (MD) simulation is performed to investigate the spreading process of the water droplet on the graphene-coated substrate in this research. The increase of interaction potential parameter between substrate and water droplet makes the spreading radius getting bigger and the final static contact angle smaller. Apart from that, the higher hydrophilicity of underlying substrate can lead to the greater averaged forces of atoms near contact line. CLFs correlate well with the variation of kinetic energy of water molecules located in the contact line region. Surface tensions of water droplets on graphene-coated substrates are also examined. The liquid-vapour and solid-vapour surface tensions are constant. An increase in the surface tension of liquid-solid lead to the increase of balanced contact angles of water on the substrate. The results are useful for understanding the effect of CLFs on the dissipation of kinetic energy of water molecules. [ABSTRACT FROM AUTHOR]

This study deals with the retrofication of micro- and macrostructural defects in joining aluminum and copper alloy using eccentric weave friction stir welding. In addition, graphene nanoparticles were added to strengthen the weldments. Welding experiments were conducted with two types of stir tool as (normal and offset pin) in linear and eccentric weave pattern. Results from this study reveal the possibility of tool tribology on eccentric stirring with tool pin offset producing a very minimal wear of 5 µm in comparison to other patterns of weld; defects on microscopic and macroscopic view of the weldments prove the existence of fragmental cracks in eccentric welding, and mechanical properties viz. yield strength of 187 MPa, ultimate tensile strength of 217 MPa, and elongation of 10% were found for the eccentric weave welded joints. This reveals the achievement of robust welded joints in the aluminum and copper alloys by eccentric weave welding with pin offset. [ABSTRACT FROM PUBLISHER]

Here, we developed a simple and efficient route for the preparation of three-dimensional (3D) Co3O4-anchored graphene composites using the sacrificial template-assisted method and the subsequent deposition process of Co3O4 nanoparticles. As structural guiding materials, polystyrene (PS) spheres provide 3D porous architectures with a high surface area. 3D porous graphene materials serve as conductive supporters for the deposition of Co3O4 nanoparticles through precipitation growth. The 3D porous composite structures of Co3O4/graphene composites were intensively investigated using scanning electron microscope, transmission electron microscope, and X-ray diffraction. The 3D Co3O4/graphene composites show a high specific capacitance of 328 F g−1 with efficient and fast charge–discharge process in aqueous 6 M KOH electrolyte. In addition, the composites provide a good cycle lifetime, which retained 98% capacitance retention over 2000 cycles. [ABSTRACT FROM AUTHOR]

An amperometric biosensor based on tricobalt tetraoxide nanoparticles (Co3O4), graphene (GR), and chitosan (CS) nanocomposite modified glassy carbon electrode (GCE) for sensitive determination of glutamate was fabricated. Scanning electron microscopy was implemented to characterize morphology of the nanocomposite. The biosensor showed optimum response within 25 s at pH 7.5 and 37 °C, at +0.70 V. The linear working range of biosensor for glutamate was from 4.0 × 10−6to 6.0 × 10−4 M with a detection limit of 2.0 × 10−6 M and sensitivity of 0.73 μA/mM or 7.37 μA/mMcm2. The relatively low Michaelis–Menten constant (1.09 mM) suggested enhanced enzyme affinity to glutamate. The glutamate biosensor lost 45% of its initial activity after three weeks. [ABSTRACT FROM AUTHOR]

The aim of the present study is to obtain natural rubber-based composites with optimal conductivity at a lowest possible filler amount. For this reason, two different conductive nanoparticles—multiwall carbon nanotubes and graphene—have been used at different amounts. The dynamic and dielectric properties of the rubber composites have been investigated and compared. The results reveal improvement in the dielectric permittivity of the composites with the increasing amount of MWCNTs. The percolation threshold is reached and surpassed when MWCNTs concentration is over 6 phr. The dielectric permittivity of the composites comprising GNP does not change considerably as dependent on the filler amount. At the concentrations chosen those samples are considered to be dielectrics. The data from the mechanical thermal analysis show that polymer-filler interaction in the composites comprising MWCNTs is stronger than that in composites filled with GNP. That fact is an evidence of the better reinforcing effect produced by MWCNTs. [ABSTRACT FROM PUBLISHER]

Growing biomedical applications of non-fluorescent nanoparticles (NPs) for molecular imaging, disease diagnosis, drug delivery, and theranostics require new tools for real-time detection of nanomaterials, drug nano-carriers, and NP-drug conjugates (nanodrugs) in complex biological environments without additional labeling. Photothermal (PT) microscopy (PTM) has enormous potential for absorption-based identification and quantification of non-fluorescent molecules and NPs at a single molecule and 1.4 nm gold NP level. Recently, we have developed confocal PTM providing three-dimensional (3D) mapping and spectral identification of multiple chromophores and fluorophores in live cells. Here, we summarize recent advances in the application of confocal multicolor PTM for 3D visualization of single and clustered NPs, alone and in individual cells. In particular, we demonstrate identification of functionalized magnetic and gold–silver NPs, as well as graphene and carbon nanotubes in cancer cells and among blood cells. The potential to use PTM for super-resolution imaging (down to 50 nm), real-time NP tracking, guidance of PT nanotherapy, and multiplex cancer markers targeting, as well as analysis of non-linear PT phenomena and amplification of nanodrug efficacy through NP clustering and nano-bubble formation are also discussed. [ABSTRACT FROM AUTHOR]

Crystallization behavior of nanocomposite based on graphene nanoplatelets have been considered due to its critical effect on performance of the final product. In this study, nanocomposite based on Poly(lactic acid)/graphene nanoplatelets was prepared via solution method. To improve the dispersion of graphene nanoplatelets in the matrix, functionalization using acid treatment and acylation reaction were accomplished. Characterization of functionalization reaction and grafting reaction between Poly(lactic acid) (PLA) and functionalized graphene nanoplatelets was tracked by Fourier Transform Infrared Spectroscopy, Raman, elemental analysis, Fourier transform infrared attenuated total reflection, and thermogravimetry analysis. The results showed that the reaction was successfully performed. Transmission electron microscopy results demonstrated that a relatively fine dispersion of FGNp was achieved in the PLA matrix. Non-isothermal and isothermal crystallization behavior were studied using differential scanning calorimetry. Isothermal kinetic of crystallization was studied by combination of the DSC data and theory of Avrami. [ABSTRACT FROM AUTHOR]

Pd/graphene composites were successfully prepared in H2O/TX-100/[BMIM]PF6microemulsion in whichions were reduced in situ by TX-100 and graphene oxide was reduced by hydrazine hydrate. In the confinement region of the microemulsion, ultrafine Pd nanoparticles (NPs) supported on graphene composites were successfully prepared. The as-prepared composite materials of Pd NPs and graphene were characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, and x-ray diffraction. It is demonstrated that the size distribution of Pd NPs is narrow, with an average size of 4 nm. The Pd/graphene composites were tested as electrocatalysts for application in fuel cells. Cyclic voltammetry and chronoamperometry measurements show good electrocatalytic performance of the composite materials for oxidation of ethanol in alkaline medium. [ABSTRACT FROM AUTHOR]

The climate-change and environmental literature, including that on aerosols, is replete with mention of black carbon (BC) and soot. The terms are used interchangeably in much of the literature, although BC and soot commonly have operational and source-based definitions, respectively, and reliable reference samples and aerosol standards do not exist for either one. The uncertainty about their exact chemical nature and properties can be decreased by materials-based measurement techniques and terminology. Here, we discuss ambiguities in common uses of BC and soot and propose the term ns-soot, where “ns” refers to carbon nanospheres, for a characteristic constituent of BC and soot. Based on its composition, morphology, and structure, we define ns-soot as particles that consist of nanospheres, typically with diameters <100 nm, that possess distinct structures of concentrically wrapped, graphene-like layers of carbon and with grape-like (aciniform) morphologies. We additionally propose that, because of their importance for climate modeling and health issues, distinctions are made among bare, coated, and embedded ns-soot particles. Copyright 2014 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

The collective dielectric relaxation studies have been carried out on nanoparticles/isotropic fluid mixed ferroelectric liquid crystals (FLCs). It has been observed from the dielectric loss spectra that the mixing of nanoparticles (Graphene Oxide and ZnO) and isotropic fluid (Water) into FLCs possesses two dielectric relaxations in low frequency range (i.e. Goldstone and associated novel relaxation). The behavior of novel relaxation peak is found to be anomalous in terms of its strong dependence on type of nanoparticles/fluids, external electric field and temperature variation. The effective dipolar contribution of nanoparticles/fluids into FLC dipole moment could be the probable reason for such relaxation. [ABSTRACT FROM PUBLISHER]