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The mechanical properties of the interphase play a key role in determining the overall performance of carbon fiber reinforced polymer (CFRP) composite materials. For this reason, it is important to develop a method to easily and precisely investigate the mechanical performance of the interphase of CFRP materials. In this work, the surface topography of the CFRP material was examined using scanning probe microscopy (SPM), which revealed the polished flat sample can meet the requirements of the nanoindentation testing. The local mechanical performance of the interphase of the CFRP was determined using nanoindentation based on the continuous stiffness measurement (CSM) method. The results show that the size of the interphase between the carbon fiber and the matrix is about 1.5 μm, and the corresponding modulus and hardness values were estimated to be 5–11 and 0.4–3.3 GPa, respectively, considering the fiber-bias effects. Mapping of the local mechanical properties of a selected area revealed that nanoindentation reproduced excellently the surface topography and characterized precisely the properties of the interphase between the carbon fibers and the matrix. [ABSTRACT FROM AUTHOR]

In the present paper, a facile hydrothermal synthesis was successfully used to obtain a novel SubPhthalocyanine/Nickel molybdate (SubPc-Br/NiMoO4) composite electrode material for a higher-performance super-capacitor. SEM and XRD investigations revealed that SubPc-Br particles were uniformly dispersed on the surface of NiMoO4 microspheres and kept the crystal formation of NiMoO4 during the combination of SubPc-Br and NiMoO4, giving the possibility to obtain high power density. The excellent pseudo-capacitance properties of SubPc-Br/NiMoO4 were also confirmed by a series of electrochemical experiments and showed that SubPc-Br significantly enhanced the redox strength and charge transfer characteristics of the NiMoO4. The as-prepared electrode had a high specific capacitance of 1292 F g−1 at a scan rate of 1 mV s−1. Additionally, in comparison with a separate NiMoO4, the cycle stability of the SubPc-Br/NiMoO4 super-capacitor is improved by 12.9% after 1000 cycles. The enhanced performances could be mainly attributed to the unique nanostructure and a larger contact area of SubPc-Br/NiMoO4. The materials obtained using this technique and the unique properties of cycle stability are attractive. This technique has an increased potential to enlarge the applicability of the electrochemical industry. [ABSTRACT FROM AUTHOR]

The high-quality joint between SiO 2f /SiO 2 and Nb was achieved by regulating the surface structure of SiO 2f /SiO 2 . The fused silica as fillers in SiO 2f /SiO 2 surface layer was consumed by etching treatment, and quartz fibers braided in two dimensions were left. By etching treatment, the wettability of SiO 2f /SiO 2 was improved and the contact angle dropped from 138° to 37°. Furthermore, the surface structure of SiO 2f /SiO 2 was deviated from a flat to a 3D-weave, which induced the brazing alloy infiltrating into SiO 2f /SiO 2 and formed a “3D-pinning structure” in joint. It could reduce residual stress and enlarge joining area, which strengthened the joint. [ABSTRACT FROM AUTHOR]

In solar thermal power plant, the thermal energy storage (TES) system is a key component which includes thermal energy storage unit, thermal energy storage material and heat transfer fluid (HTF). We numerically simulate the dynamical thermal performances of shell–tube TES units with diverse geometric configurations, phase change materials (PCMs) including pure NaNO 3 and a composite of NaNO 3 /expanded graphite (EG), and HTFs such as synthetic oil and molten salts. In the charging/discharging process, the conjugated heat transfer behavior between the thermal storage unit and thermal carriage channel is specially concerned. Effects of the extended fin, PCMs and HTFs on improving heat performance are examined and quantified with total heat flux and effective Nusselt numbers. Together with the presented diagrams of PCM phase evolution, the roles of heat conduction and natural convection in influencing the thermal behavior of the TES units are clearly revealed. The nonuniform phase distribution of PCM due to natural convection results in a considerable time spent in the end of the charging/discharging processes. The results show that both the full melting time and solidification time can be shortened at least 14%, benefited from using the extended fins and the composite. This study is expected to provide an apprehensive interpretation of thermal transport mechanism and rational advices in optimizing the TES system operation. [ABSTRACT FROM AUTHOR]

A series of ZSM-5/SBA-15 composite supported Co catalysts were prepared and evaluated for the Fischer–Tropsch synthesis (FTS) aimed to maximise the selectivity of C 5 –C 22 hydrocarbons in the product. The composite support was prepared by physically mixing ZSM-5 and SBA-15 of varying proportions and the finished catalysts had a constant Co loading of 15wt.%. The catalysts were tested for their performance in a high pressure fixed-bed reactor operating at T = 240 °C, P = 2.0 MPa, H 2 /CO = 2 and GHSV = 1000 h − 1 . The composite supported catalysts were shown to have much improved catalytic performance over the respective single material supported catalysts. The catalyst with 20wt.% ZSM-5 in the composite support gave the maximum CO conversion (90.6%), maximum selectivity of C 5 –C 22 hydrocarbons (70.0%) and minimum selectivity of light hydrocarbons (13.3% for CH 4 and 7.0% for C 2 –C 4 alkanes). The catalysts were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy with an energy dispersive X-ray spectrometer, temperature programmed desorption and temperature programmed reduction. It was revealed that the superior catalytic performance can be attributed to the large pore size and high dispersion of Co 3 O 4 , which afforded an optimum reducibility and acid site density. [ABSTRACT FROM AUTHOR]

This article presents a fast solution to the volume-surface integral equation for electromagnetic scattering from three-dimensional (3D) targets comprising both conductors and dielectric materials by using the multilevel fast dipole method (MLFDM). This scheme is based on the concept of equivalent dipole-moment method (EDM) that views the Rao-Wilton-Glisson and the Schaubert-Wilton-Glisson basis functions as dipole models with equivalent dipole moments. In the MLFDM, a simple Taylor's series expansion of the terms Rα (α = 1, −1, −2, −3) and R̂ R̂ in the formulation of the EDM transforms the interaction between two equivalent dipoles into an aggregation-translation-disaggregation form naturally. Furthermore, benefiting from the multilevel grouping scheme, the matrix-vector product can be accelerated and the memory cost is reduced remarkably. Simulation results are presented to demonstrate the efficiency and accuracy of this method. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012. [ABSTRACT FROM AUTHOR]

Abstract: A facile and objective method is introduced to automatically quantify the filler dispersion in polymer composites through image analysis. This method consists of automatic identification of the fillers in the image and a rigorous measurement of the filler dispersion within the space of functions. Compared with previous methods, this method has the advantages of 1) automatically recognizing the fillers, 2) minimizing the subjectivity induced by the inhomogeneity and noise of the background in the images, 3) a mathematically more rigorous definition of the deviation of the filler dispersion from uniformity, 4) a single performance metric reflecting both the distribution and the size of fillers. Both synthetic and real images from model compounds are used to demonstrate the sensitivity of the proposed method to the dispersion and aggregation of fillers. The computed dispersion index shows good agreement with visual observation of synthetic images and mechanical properties of the model compounds. [Copyright &y& Elsevier]

Abstract: An anomalous decrease in the thermal stability of silicone was observed when carbon nanotubes (CNTs) were added as fillers. The decreased thermal stability is found to result from the residues of cobalt nanoparticles in CNTs, whereas CNTs synthesized with other metal catalysts do not show such a phenomenon. The analysis of thermal degradation products indicates that CNT fillers do not change the mechanism of the thermal degradation of silicone but cobalt nanoparticles within CNTs may accelerate the degradation through free radical generation. Radical scavengers such as hindered amines and impurity-free CNTs, or removal of cobalt nanoparticles by acid treatment, can mitigate the accelerated thermal degradation. [Copyright &y& Elsevier]

• Ag quantum dots are assembled on the surface of mesoporous NiMoO 4 microspheres. • Ohmic contact interface boosts the conductivity of the composite material. • Synergistic effects dramatically enhance the specific capacitance of the electrode. • The asymmetric supercapacitor shows high energy density and cycling stability. Nickel molybdate (NiMoO 4) as a ternary metal oxide has great potential as advanced electrode material for energy storage. However, the practical application of NiMoO 4 electrode is hindered by its poor electrical conductivity. In this work, the surface of mesoporous NiMoO 4 microspheres is decorated with silver quantum dots (Ag QDs/NiMoO 4) by means of "dipping and drying". It is interesting to find that an ohmic contact interface (electron anti-barrier layer) generates between the Ag QDs and NiMoO 4 microsphere. Benefitting from the high specific surface area, abundant surface active sites, enhanced interfacial conductivity and porous structure of the Ag QDs/NiMoO 4 microspheres, the composite electrode presents high specific capacitance of 3342.7 F g−1 at 1 mV s−1 and 2074 F g−1 at 1 A g−1 (nearly twice the value of the pristine mesoporous NiMoO 4 microsphere electrode), good rate capability and improved cycling stability. Furthermore, an asymmetric supercapacitor assembled with the Ag QDs/NiMoO 4 microspheres as cathode, spore-derived activated carbon microspheres as anode and 3 M KOH as aqueous electrolyte, reveals a relatively high energy density (48.5 Wh kg−1 at a power density of 212.5 kWh kg−1) and good cycling performance comparing with most of the reported NiMoO 4 -based asymmetric supercapacitors. [ABSTRACT FROM AUTHOR]

[Display omitted] Exploring capable and universal electrode materials could promote the development of alkalis (Li, Na, K) ion batteries. 2D MXene material is an ideal host for the alkalis (Li, Na, K) ion storage, but its electrochemical performance is limited by serious re-stacking and aggregation problems. Herein, we cleverly combined electrostatic self-assembly with gas-phase vulcanization method to successfully combine Ti 3 C 2 T x -MXene with ultra-long recyclability and high conductivity with MnS, which presents high specific capacity but poor conductivity. The as-prepared 3D hierarchical Ti 3 C 2 T x /MnS composites have an unique sandwich-like constituent units. The tiny MnS nanoparticles are restricted between the Ti 3 C 2 T x layers and play a key role in expanding the Ti 3 C 2 T x interlayer spacing. As a result, the 3D Ti 3 C 2 T x /MnS composites as the anode of LIBs exhibits a superior capacities of 826 and 634 mAh/g after 1000 and 3000 cycles at 0.5 and 1.0 A/g, respectively. More importantly, we reveal the reaction mechanism that the specific capacity first increases and then gradually stabilizes with the increase of charge and discharge cycle times when the as-prepared 3D Ti 3 C 2 T x /MnS was used as the anode of LIBs. In addition, we have also used this material in SIBs and PIBs and achieved remarkable electrochemical capability, with a specific capacity of 107 mAh/g after 2500 cycles at 0.5 A/g or 127 mAh/g after the 2000th cycle at 0.2 A/g, respectively. [ABSTRACT FROM AUTHOR]

Boron nitride nanosheets (BNNSs) are a structural analogue of graphene that are thought to exhibit good tribological performances, due to their typical laminated structure. However, the tribological properties of pure solid BNNSs have not been thoroughly researched, which may be resulted from the lack of knowledge regarding the synthesis of this special two-dimensional (2D) material. In this work, BNNSs were deposited on silicon wafers via nitridation of magnesium diboride (MgB 2 ) in a chemical vapor deposition system. The ammonia (NH 3 ) was used as the nitrogen source. The tribological behaviors of the synthesized BNNSs, including friction and wear resistance, were evaluated with a CSM tribometer. The results indicated that the BNNSs can decrease the friction of bare silicon wafer. The average value of the friction coefficients had no obvious change with the changes in load and frequency. The wear rate increased when the load and frequency increased. The results suggested that the BNNSs had good potential applications in industrial lubrication, after they were modified by small molecules or polymers. [ABSTRACT FROM AUTHOR]

[Display omitted] • CTS/DTE showed the excellent harvesting efficiency of 98.34%. • Charge neutralization, sweeping and bridging are the main harvesting mechanisms. • The second-order polynomial model reasonably simulated the harvesting process. • The post-harvesting water could be recycled for microalgae recultivation. As an environmentally friendly bioflocculant, chitosan has a great application potential in the field of microalgae harvesting due to its biocompatibility. In this work, three different inorganic clay minerals (kaolin, montmorillonite, and diatomite) were selected to prepare chitosan-clay composite materials (CTS/KAL, CTS/MML and CTS/DTE) as flocculants to harvest microalgae cells. The harvesting capacities of CTS/KAL, CTS/MML and CTS/DTE were accordingly 97.37%, 97.81% and 98.34% for microalgae cells under the dosage of 60 mg/L, microalgae concentration of 0.923 g/L, settling time of 30 min and pH of 10. CTS/DTE showed excellent harvesting performance for microalgae cells, mainly due to the enhancement of charge neutralization, sweeping and bridging effects. Based on the phenomenological theory, the second-order polynomial model was used to analyze the influences of different external factors on the microalgae harvesting efficiency. A reasonable performance relationship between CTS-clays for harvesting of microalgae cells and external factors was established. The analysis of carbohydrates, proteins, and fatty acids of microalgae biomass collected by CTS/KAL, CTS/MML, CTS/DTE and centrifugation showed that the harvesting of CTS-clay did not influence the properties of biomass. The experimental results of water resource recycling and re-cultivation after microalgae harvesting by CTS/KAL, CTS/MML and CTS/DTE exhibited that the growth rates of 50% circulating medium + 50% fresh BG11 culture medium were accordingly 2.512, 2.466 and 2.572 times higher than those of 100% circulating medium. It is concluded that chitosan-clay composite materials are efficient and environmentally friendly flocculants with a great applicable potential in microalgae harvesting. [ABSTRACT FROM AUTHOR]

A new electrode material consisting of MOFs (Zr-TAA, TAA: trans-aconitic acid) and MWCNTs was simply synthesized by one-pot reflux method and applied to high-performance supercapacitor. With advantages of improved conductivity and uniform pore-size distribution, the composite material shows enhanced electrochemical performance with a specific capacitance of 562.06 F g−1 and retains almost 100% of its initial capacitance after 1000 cycles when measured in 6 M KOH electrolyte. Furthermore, an asymmetric supercapacitor assembled by Zr-TAA/MWCNTs-6 as positive electrode and carbon cloth as negative electrode exhibits a superior energy density of 17.53 Wh kg−1 at a power density of 902.5 W kg−1, which demonstrates its great practical value in electrochemical energy storage applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Ternary heterojunction CN/TiO 2 -Ti 3 C 2 constructed by CN and partially oxidized Ti 3 C 2 MXene exhibits excellent performance for visible-light photocatalystic NOx removal. [Display omitted] • Ti 3 C 2 MXene can be turned to TiO 2 -Ti 3 C 2 nanosheet by partially oxidation. • Ternary heterojunction catalyst was formed by g-C 3 N 4 and partially oxidized Ti 3 C 2. • NO conversion on the catalyst is inferred to S-scheme heterojunction mechanism. • NO removal efficiency of the photocatalyst reaches up to 66.3% under visible light. Highly efficient composite photocatalysts were prepared through annealing partially oxidized Ti 3 C 2 MXene with melamine under N 2 flow. The two-dimensional Ti 3 C 2 MXene was aforehand partially oxidized to form TiO 2 -Ti 3 C 2 nanosheet by precisely controlling the oxidation conditions. Ternary g-C 3 N 4 /TiO 2 /Ti 3 C 2 MXene photocatalyst was constructed by coating melamine derived g-C 3 N 4 on TiO 2 -Ti 3 C 2 nanosheet. The photogenerated electron-hole separation was significantly enhanced by the S-scheme heterojunction. Ti 3 C 2 tightly bonded with TiO 2 benefits transfer and aggregation of photo-induced holes. The composite material has an interconnected nanosheet structure, which increases the absorption of light and the reaction interface between gaseous reactant and photocatalysts. When evaluated as NOx purification photocatalysts, the fabricated composites get the high NO removal efficiency and low NO 2 generation. Under visible light, NO removal efficiency of the composite photocatalyst can reach up to 66.3%, which is significantly better than the g-C 3 N 4 or TiO 2 -Ti 3 C 2. This work demonstrates that moderately oxidized Ti 3 C 2 MXene is a good candidate for the construction of high-performance air purification photocatalysts. [ABSTRACT FROM AUTHOR]