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Homoharringtonine (HHT), was first isolated from the bark of Cephalotaxus harringtonia (Knight ex J. Forbes) K. Koch and Cephalotaxus fortunei Hook trees. The bark extract is used to treat leukemia and in recent years has also been used in traditional Chinese medicine (TCM) to treat solid tumors. However, the inhibitory mechanism of HHT in the progression of hepatocellular carcinoma (HCC) is rarely studied. We aimed to evaluate the antitumor efficacy of HHT on HCC in vitro and in vivo and elucidate the underlying molecular mechanism(s). HCC cell lines, including HCCLM3, HepG2, and Huh7, were used to evaluate the antitumor efficacy of HHT in vitro. Cytotoxicity and proliferative ability were evaluated by MTT and colony formation assays. Cell cycle progression and apoptosis in HHT-treated HCC cells were evaluated by flow cytometry. To determine the migration and invasion abilities of HCC cells, wound-healing and Transwell assays were used. Finally, western blot analysis was used to reveal the proteins involved. We also established a xenograft nude mouse model for in vivo assessments of the preclinical efficacy of HHT, mainly using hematoxylin and eosin staining, immunohistochemistry, ultrasound imaging (USI), and magnetic resonance imaging (MRI). HHT suppressed the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of HCC cells, and induced cell cycle arrest at the G2 phase and apoptosis. In the HCC xenograft model, HHT showed an obvious tumor-suppressive effect. Surprisingly, Slug expression was also decreased by HHT via the PI3K/AKT/GSK3β signaling pathway at least partially suppressed the growth of HCC via the PI3K/AKT/GSK3β/Slug signaling pathway.

Hepatocellular carcinoma (HCC) is one of the most malignant tumors in the world, and patients with HCC face a poor prognosis. The conventional therapeutic strategies for HCC have undergone a challenge-riddled evolution owing to side effects and unsatisfactory efficacy. Here, aiming to provide a new method of HCC elimination, we formulated a novel multifunctional nanocapsule (PFP@PLGA/Cu12Sb4S13, PPCu) with applications in contrast-enhanced ultrasound imaging (CEUS) and photothermal therapy (PTT). These PPCu were successfully constructed with an average diameter of 346 nm (polydispersity index, PDI = 0.276). The reinforced contrast ratio of these PPCu was determined by CEUS, revealing their promising applications in image-guided monitoring of HCC treatment. Furthermore, the excellent photoabsorption and biocompatibility indicated by organ H&E staining indicated that PPCu meet quality expectations for use as photothermal transduction agent (PTA). PPCu treatment at 50 °C and higher temperatures efficiently repressed the proliferation, induced the apoptosis and decreased the motility of HCC cells. These effects might have been results of RAS/MAPK/MT-CO1 signaling pathway inhibition. In summary, PPCu were constructed to integrate CEUS and PTT successfully into therapy, which can lead to HCC elimination through RAS/MAPK/MT-CO1 signaling pathway repression.

Carbon fiber/epoxy (CF/EP) composites are highly utilized materials for many applications in aeronautical and aerospace structures because of their superior specific mechanical properties. However, delamination between adjacent plies remains a major problem owing to the inherent brittleness of epoxy matrix. In the present work, PA66 nanofiber/PCL blend films were used as interleaves to increase the interlaminar fracture energy of CF/EP composites. PA66 nanofibers maintained their one-dimensional structure during epoxy curing, while PCL first melted and then mostly phase-separated from epoxy. It was found that modes I and II fracture energies of the laminates interleaved with PA66 nanofiber/PCL blend films were increased significantly by 110% and 101%, respectively, demonstrating a synergistic effect. At the same time, the flexural strength and flexural modulus of the CF/EP laminates were unchanged. DMA tests confirmed better interfacial adhesion between PA66 nanofibres and epoxy when PCL was added. Blend interleaves with nanofibres embedded in a polymer matrix with a low melting point provide a new route to synergetic enhancement of the delamination fracture energies of CF/EP laminates.

Based on our recent work on the three-dimensional graphene fillers (3DGF) reinforced epoxy (EP) composite, here commercially available graphite platelets (GP) were incorporated together with 3DGF to modify EP in order to further improve the thermal conduction and wear resistance of the EP composites. Remarkably, only 0.14 vol% 3DGF was needed to enhance the thermal conduction of EP by 170%, in contrast with the fact that 37 times content of graphite fillers were required to achieve almost the same enhancement. Moreover, in the presence of both 5.38 vol% GP and 0.14 vol% 3DGF, the thermal conductivity of EP was further enhanced by 258%. Meanwhile, the tribological test results revealed the advantage of 3DGF over GP. The ternary EP composite modified with both 0.28 vol% of 3DGF and 5.38 vol% GP had much lower specific wear rate and coefficient of friction than those binary composites with either 3DGF or GP.

Antibiotics and antibiotic resistance genes (ARGs) are highly concerning emerging polltants. Wastewater treatment plants (WWTPs) are considered to be one of the most important anthropogenic sources of antibiotics and ARGs in the environment. Six WWTPs of a city were selected to investigate the antibiotics and ARGs in the influents and effluents, respectively. In total, 73 kinds antibiotics belonging to 7 classes were detected in WWTPs. The total concentration of those antibiotics ranged between 490.2-2288.6 ng·L

Percolative poly(vinylidene fluoride) (PVDF) composites with high dielectric constant and low dielectric loss was successfully achieved by incorporating reduced graphene oxide (rGO) decorated with magnetic iron oxide (Fe3O4) (rGO@Fe3O4) nano-fillers. The morphology, structure, thermal, electrical and magnetic properties of the composites were investigated systematically by using SEM, XRD, FTIR, TGA, DSC, impedance analyzer and magnetometer, respectively. The presence of a tiny amount of poly(sodium 4-styrene sulfonate) (PSSNa) facilitated the homogeneous distribution of rGO@Fe3O4 nanoparticles and prevented the formation of an electrical conductive network within the PVDF matrix, resulting in an excellent dielectric performance of the rGO@Fe3O4/PVDF nano-composites. With 1.0 wt% rGO@Fe3O4 incorporated in PVDF, the nanocomposite exhibited a high dielectric constant of 1297 and a low dielectric loss of 0.26 at 100 Hz. Percolation model revealed that such improvements could be attributed to the synergistic effect of the inorganic Fe3O4 and rGO, whereby the electric charges were accumulated by forming many mini-capacitors in the bulk PVDF matrix. The structure-property behavior of the final nanocomposites was discussed.

Hierarchical carbon structures with in-situ growth of small carbon particles on thick CNT (TCNT) were synthesized by a simple flame synthesis method. TEM tomography analysis indicated that flame synthesized CNT (FCNT) with different length and diameter (or carbon sphere particles) were deposited onto both the inner and/or outer tubular wall surface of the TCNT. The nano-confinement effect of the TCNT tubular space on the flame growth of carbon particles was investigated, which led to the formation of shorter and curved FCNT. Electron microscopy studies revealed that the tip growth mechanism dominated the ethanol flame-induced CNT synthesis process and the rate determining step for the flame growth of CNT was the nickel-catalyzed carbon deposit reaction rather than the mass transfer of the carbon source in the confined nano-channels of the TCNT. The influence of the type of metal catalyst on the products was also studied. Substantial improvements of electrochemical properties of TCNT after the decoration with FCNT confirmed the effectiveness and advantages of this method. The FCNT/TCNT anodes delivered a higher reversible lithium ion storage specific capacity than that of the pristine TCNT.

A simple method to fabricate three-dimensional graphene fillers (3DGFs) modified epoxy resin (EP) composite was developed in this study. This method offers a flexible fabrication process and the polymer composites obtained preserve to some extent the advantages of the traditional 3D graphene foam structure. The thermal conductivity of 3DGF/EP composites was increased successfully to 0.52 W/mK with only 0.14 vol% (0.27 wt%) graphene loading which is 1.74 times higher than that of the neat epoxy. This remarkable improvement normalized by graphene loading (i.e., the thermal conductivity enhancement efficiency) is amongst the highest reported values of carbon-based nanofiller-epoxy composites. The unique hollow 3D structure, defect-free feature and large length-thickness ratio of 3DGF compared to conventional graphene sheets are responsible for the high thermal conductivity of the epoxy composite. Further, finite element analyses also confirmed the positive effect of the filler length-thickness ratio on the thermal conductivity of 3DGF/EP composites which agreed well with experimental results. Moreover, the tribological performance of the composites was also improved by incorporation of 3DGFs.

Epoxy resins are inherently brittle caused by their highly cross-linked network structure. Herein, we report an effective method of toughening without loss of mechanical properties. Carboxylated carbon nanotubes (CNT-COOHs) were added to an epoxy (EP)/polysulfone (PSF) blend to control the phase separation behavior, fracture toughness and mechanical properties of the resultant ternary composites. Although CNT-COOHs did not change the phase separation mechanism of the EP/PSF blend they had an important influence on the final phase morphology. Rheological analysis showed that the complex viscosity and the cure-reaction rate of EP/PSF were increased by adding CNT-COOHs, leading to a significant suppression of the phase separation process which stopped at an earlier stage. Also, the fracture, mechanical and thermal properties of the EP/PSF/CNT-COOH composites were found to be increased due to the presence of CNT-COOHs.

Damping properties are critical for many applications of carbon fiber reinforced epoxy composites (CF/EP). In this paper, polysulfone (PSF)/cellulose nanocrystal (CNC) nanofibrous membranes were fabricated by electrospinning as hybrid interleaves in CF/EP composites. The damping properties of the interleaved CF/EP composites were measured by the cantilever percussion free-decay method and dynamic mechanical analysis (DMA). The strength and modulus values of the interleaved composites were obtained by tensile and flexural tests. The obtained results showed that after interleaving by the 10%PSF/0.5%CNC membranes, the damping properties of CF/EP composites were enhanced with little loss of mechanical properties. The damping mechanisms were examined and analyzed with the aid of scanning electron microscopy (SEM). It was concluded that the enhanced damping properties were due to the different energy dissipation mechanisms associated with the PSF nanoparticles generated by reaction induced phase separation and the incorporated CNCs in the EP matrix.

In this study, hierarchical short carbon fibers (SCFs) synthesized with carbon nanotubes (CNTs) were used as CNT-SCF interleaves to increase the mode I delamination fracture energy G IC of carbon fiber/epoxy (CF/EP) composite laminates. Even at a relatively low CNT-SCF areal density, 1.0 mg/cm 2 , G IC (1.17 kJ/m 2 ) was increased by 125% compared to the control laminates (0.52 kJ/m 2 ), which is a very high value compared to those results obtained by other interleaving methods in CF/EP laminates. The toughening effects of SCFs in bulk epoxy and interleaved CF/EP laminates were also studied to better understand the failure mechanisms of the hierarchical CNT-SCF structure. SEM observations revealed synergistic toughening mechanisms in these CNT-SCF interleaved CF/EP laminates.

Functionalized graphene sheets were fabricated by a simple thermal reduction method in air at 700 °C and used to prepare graphene/epoxy (G/E) composites. The incorporation of 1.0 wt% of graphene into epoxy was found to significantly improve the matrix fracture energy by ∼150% and reduce the thermal expansion coefficient by ∼30%. When these partially cured G/E composites were used as interleaves in carbon fiber/epoxy (CF/E) composites and co-cured, a remarkable 140% increase in mode I interlaminar fracture energy was achieved. Detailed toughening mechanisms of the graphene sheets in both G/E and CF/E composites were studied. Moreover, the damage sensing capacity of the graphene interleaved CF/E composites with a simple electrical response method was demonstrated, where the electrical resistance change increased almost linearly with crack increment.

Carbon nanotubes (CNTs) were coated onto glass fibres (GFs) using a one-step flame synthesis method. The GF/epoxy resin matrix interfacial bonding strength was investigated by fibre bundle pull-out tests. Results showed that, compared to the as-received GF/epoxy, significant interfacial bonding strength enhancement of ~33% was obtained for CNT-coated GFs/epoxy. Moreover, the wettability of CNT-coated GF by epoxy was increased significantly evidenced by the reduction of CNT-coated GF/epoxy contact angles. The flame synthesis method possesses the potential of efficient high-performance composites fabrication.

A hexagonal graphene-like boron-carbon-nitrogen (h-BCN) monolayer, a new two-dimensional (2D) material, has been synthesized recently. Herein we investigate for the first time the thermal conductivity of this novel 2D material. Using molecular dynamics simulations based on the optimized Tersoff potential, we found that the h-BCN monolayers are isotropic in the basal plane with close thermal conductivity magnitudes. Though h-BCN has the same hexagonal lattice as graphene and hexagonal boron nitride (h-BN), it exhibits a much lower thermal conductivity than the latter two materials. In addition, the thermal conductivity of h-BCN monolayers is found to be size-dependent but less temperature-dependent. Modulation of the thermal conductivity of h-BCN monolayers can also be realized by strain engineering. Compressive strain leads to a monotonic decrease in the thermal conductivity while the tensile strain induces an up-then-down trend in the thermal conductivity. Surprisingly, the small tensile strain can facilitate the heat transport of the h-BCN monolayers.

Zinc oxide (ZnO) has attracted much attention for various applications because of its unique electrical, optical, magnetic and piezoelectric properties. ZnO nanowires (NWs) are often grown onto the carbon fiber (CF) surface to improve the electrical conductivity and flexibility of ZnO, and it is important to understand and further enhance the interaction between ZnO NWs and CFs. Herein, ZnO NWs were grown onto carbon fabrics through a facile hydrothermal method, and the pull-off force to detach an individual ZnO nanowire from CF was measured using a nano-manipulator inside a scanning electron microscope chamber. Also, a novel dopamine-based functionalization method was developed to improve the interfacial adhesion between ZnO NWs and CFs. It was found that introducing polydopamine (PDA) on CF could increase significantly the adhesion strength between CF and ZnO NW and their interfacial shear strength with epoxy as measured by the single fiber microbond test. The hierarchical ZnO NWs on CF fabrics were then utilized to fabricate the laminates. The highest mode I and mode II interlaminar toughness were obtained in those laminates comprising CF/PDA/ZnO NWs owing to the high chemical bonding between ZnO NWs and PDA modified CF surface and strong mechanical interlocking between ZnO NWs and epoxy.

Three-dimensional (3D) graphene-based porous materials with a combination of low density, superelasticity, excellent mechanical resilience and tunable functionalities can be used in diverse applications. Here we report an approach of fabricating the stable and flexible 3D graphene aerogel materials with tunable functionality via a general silane-assisted processing that maintains an effective control of the chemistry, architecture and functionality of these porous structures. Simultaneous reduction and functionalization were achieved under both a low temperature and a low graphene oxide concentration in aqueous solution via using a facile one-step co-assembly method. The introduction of silane bonding tailors both the porous microstructure and the surface property of the lightweight aerogel effectively, subsequently providing improved mechanical properties and versatile functionalities including super compressive elasticity, outstanding cyclic resilient property, good electrical conductivity, stable viscoelastic properties, high level energy absorption capacity, excellent hydrophobicity, remarkable thermal stability and extremely high sensitivity of elasticity-dependent electrical conductivity. This opens up scalable and low-cost ways to the integration of microscopic two-dimensional graphene sheets into macroscopic 3D graphene aerogel materials, thus providing the possibility of fabricating novel lightweight porous aerogel materials with controllable functionalities and reversible compressibility for applications in numerous fields.

The mechanical properties (i.e., stress–strain relationship and peak stress) of nanosilica filled epoxies were studied using an Instron machine and a split Hopkinson pressure bar apparatus over a range of strain rates from 8 × 10−4 s−1 up to ∼5 × 103 s−1 under uniaxial compression. It was found that the nanosilica particles only reinforce epoxies slightly under both quasi-static and dynamic loading conditions. With a unit cell model, it was observed that owing to the existence of nanosilica, the surrounding strain field was changed and the strain-softening characteristics of the epoxy introduced a negative effect of the nanosilica particles as a reinforcement agent. That is, the particle strengthening effect depended on the mechanical characteristics of epoxy matrix. This was further confirmed by numerically simulating the mechanical behaviors of the composites for which (a) the matrix might assume different strain-softening or strain-hardening characteristics and (b) there were higher loadings of rigid silica particles.

A facile and effective approach by incorporating silica nanoparticles (SNPs) to fabricate high performance epoxy-based electronic packaging materials which are both thermally conductive and electrically insulating was presented. Because of the strong interaction between SNPs and silver nanowires (AgNWs), uniformly dispersed SNPs-modified epoxy was employed to promote the dispersion of AgNWs in epoxy matrix. Further, the enhanced modulus of epoxy matrix by the incorporation of SNPs effectively alleviates the modulus mismatch between stiff AgNWs and epoxy matrix. Compared with epoxy/AgNWs composites without SNPs, the resulting hybrid materials, that is, epoxy/SNP/AgNWs, showed distinct improvements in thermal conductivity without degrading their mechanical properties. Also, the SNPs were absorbed onto the surface of AgNWs forming an electrical insulation layer to disrupt the electron flows between adjacent AgNWs, hence retaining the electrical insulation of epoxy matrix. Finally, this new fabrication method is easily scalable owing to its simple procedure and use of commercial well-dispersed SNPs-modified epoxies.

The effects of nano-silica on the adhesive properties of epoxy were systematically studied by single lap-shear tests under quasi-static and cyclic loadings. The adhesives were produced from different amount of nano-silica particles incorporated into diglycidyl ether of bisphenol A (DGEBA) epoxy. Stainless steel plates were chosen as adherends. Quasi-static tests were conducted on single lap-shear joints at ambient, with and without exposure to 100% RH at 60 °C for different times. Cyclic fatigue tests were also performed on these bonded joints under tension–tension loading. The fracture surface morphology was examined using scanning electron microscopy (SEM) to identify the failure mechanisms. Compared to neat epoxy, it was found that the adhesive strength is increased by 20% under quasi-static loadings. Even after hygrothermal treatment, the benefit of having nano-silica in neat epoxy on the adhesive joint strength was retained. In cyclic fatigue, without hygrothermal aging, nano-slica/epoxy adhesives have longer lifetimes than neat epoxy; but after hygrothermal treatment, they have similar lifetimes for given stress amplitudes. Keywords: Epoxy resin, Nano-silica, Adhesive property, Lap-shear, Fatigue, Hygrothermal

This paper is focused on the determination of dynamic elastic modulus of polymer materials under high strain rate loading using the split Hopkinson pressure bar (SHPB) technique. Experiments conducted on the epoxy specimen by the traditional SHPB and the proposed vertical SHPB equipment demonstrates that the vertical SHPB can give more accurate measurements. The related factors, namely, the effect of stress inequilibrium in specimen, indentation in bars due to specimen and the tilt between specimen and bars, are extensively studied. It is concluded through theoretical analysis and numerical calculations that the influence of stress inequilibrium becomes negligible after two characteristic times. The numerical study on the indentation effect shows that the bar to specimen specific elastic modulus ratio and specific diameter ratio are critical to the level of influence on indentation. However, polymers with low elastic modulus values can still be accurately measured regardless of the indentation displayed. The numerical investigation on tilt effect indicates that the imperfect contact condition severely affects the accuracy of measured elastic modulus. This issue can be rectified by the newly proposed vertical SHPB. It can improve the contact conditions between bars and specimen significantly and offer acceptable accurate measurements for the dynamic elastic modulus of polymeric materials.

Polydispersed graphene was synthesized by grafting a thin layer of water-soluble amine functionalized polyethylene glycol monomethyl ether (PEG-NH2). PEG-NH2 functionalized graphene (PEG@rGO) was then introduced into epoxy resin via a facile solution mixing method. Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) verified that PEG was successfully grafted to the surface of graphene. The obtained PEG@rGO showed excellent dispersibility in solvents when compared to pristine graphene. As a “core-shell” filler, PEG@rGO filled epoxy nanocomposites displayed improved dielectric constant and reduced dielectric loss, exhibiting potential applications in energy storage capacitors. The mechanical strength and final decomposition temperature were also simultaneously increased.

A novel one-step flame synthesis method was used to coat carbon nanotubes (CNTs) onto plain weave S-glass fibre (GF) fabrics. Nickel chloride, as a catalyst, was applied on the GF fabrics, and CNTs were formed in an ethanol flame. Results showed that different carbon materials were synthesised, and they were sensitive to the flame synthesis parameters. Short CNTs (shorter than 0.5 μm) were dominant with a low catalyst concentration of 0.2 mol/L, and long CNTs (lengths of ~1.2–2.0 μm) started to appear when the catalyst was increased to 0.4 and 0.6 mol/L. With even higher catalyst concentration at 0.8 and 1.0 mol/L, most of the CNTs were embedded in a thick layer of carbon soot. In addition, the thermal and electrical conductivities of GF/epoxy and multi-scale CNT-GF/epoxy composites were measured. Compared to GF/epoxy composite, a more than 40% increase of thermal conductivity and 10 orders of magnitude decrease of electrical resistance were achieved in these multi-scale CNT-GF/epoxy composites.

An analytical model was developed to study the interlaminar fracture behaviour of polymer composite reinforced by carbon fibres grafted with carbon nanotubes. Delamination properties, such as load with displacement or crack (R-curve) and toughness with crack (GR-curve), can be obtained from this model. The bridging laws presented, based on the CNT pullout mechanism (CNT pullout from polymer matrix) and the CNT sword-in-sheath mechanism (CNT breakage), were incorporated into the proposed analytical model to investigate the influence of the structure of CNT growth onto CFs (CNT@CFs) on delamination properties. The numerical results showed that different toughening mechanisms led to different features of GR-curves, R-curves, and load with displacement curves. Parametric study demonstrated that strengthening the CNT@CF interface resulted in significant improvement in toughness. Further, it was found that elastic deformation of CNTs played an important role in the toughness improvement in the CNT sword-in-sheath mechanism, but no such role was evident in the CNT pullout mechanism.

A hard template method to prepare N-doped graphene foams (NGF) with superfast template removal was developed through a pyrolyzing commercial polyurethane (PU) sponge coated with graphene oxide (GO) sheets in an ethanol flame. The removal of the template was fast and facile, and could be completed in less than 60 s in an open environment. The synthesized graphene foams consisted of a unique structure of 3D interconnected hollow struts with highly wrinkled surfaces, and the morphology of the hollow struts could be tuned by controlling the GO dispersion concentration. The foams showed high hydrophobicity and were used as absorbents for a variety of organic solvents and oils. The unique NGF structure afforded a high absorption rate and capacity, and a remarkable 98.7% pore volume of the foam could be utilized for absorption of hexane, exhibiting one of the highest capacity values among existing absorptive counterparts. The N-doping brought higher capacitive performance than conventional graphene foams prepared by chemical vapor deposition on nickel foam templates. The NGFs also displayed high elasticity and could recover completely after 50% compressive strain. Owing to easy availability and reduction environment of the flame, complete thermal decomposition of the PU sponge and highly porous open-cell structure, and flame resistance of the graphene foam, the present flame method was demonstrated to be a simple, effective, and ultrafast approach to fabricate ultra-low-density NGFs with good electromechanical response, excellent organic liquid absorption, and high-energy dissipation capabilities.

Epoxy composites filled with 2D chemically reduced graphene oxide (CRGO) sheets and preformed 3D powdered rubber (PR) nanoparticles were fabricated to investigate the effect of hybrid nanofillers on the electrical, thermal and mechanical properties as well as fracture toughness. As expected, the presence of CRGO sheets endows epoxy with electrical conductivity and enhances its thermal properties, stiffness and toughness; while the addition of PR results in significant reductions in thermal stability and stiffness, but produces dramatic improvements in fracture toughness. Compared with the binary composites, the ternary composites containing hybrid 2D CRGO and 3D PR fillers provide a good balance among electrical conductivity, thermal stability, glass transition temperature, stiffness, strength and fracture toughness, which cannot be achieved by independent single-phase fillers. Based on the morphologies of the fracture surfaces and damage zones around the crack tip, various toughening mechanisms such as crack-bridging by GO sheets, sheet/sheet delamination and sheet/matrix debonding, rubber cavitation and matrix shear banding, were identified and correlated with the fracture toughness of the hybrid composites studied. Results obtained disclosed suppression of deformation and/or cavitation of the PR nanoparticles after the incorporation of CRGO, which explained the moderate improvement in fracture toughness of the hybrid composites.

As a result of manufacturing processes, thermal residual stresses often occur in fibre-reinforced polymer composites and affect the fibre/matrix interface properties, e.g. interfacial shear strength (IFSS), which is commonly evaluated by the microbond test. In thermoplastic matrices, thermal residual stresses can be relieved by annealing. In this study, to examine the effect of thermal residual stress on IFSS, microbond tests on both air-quenched (control) and annealed polyphenylene sulphide/carbon fibre samples are conducted. Comparing the pull-out results of the control to the annealed samples subjected to six different annealing temperatures between 80 and 230 °C, it is found that the thermal residual stresses in the fibre axial and radial directions are reduced progressively below and can be neglected above 120 °C. Thermal residual stresses in the fibre direction can be calculated to explain the microbond test results and construct a master curve for the IFSS. Post-debond frictional shear stresses can also be analysed in terms of the calculated fibre radial thermal residual stresses and debonded fibre morphologies.

Considering the refuse and leachate as one whole system, a conventional landfill (CL) was set as a control, transformation of dioctyl phthalate (DOP) in recirculated landfill (RL) and bioreactor landfill (BL) was studied. Results showed that DOP was detected in both leachate and refuse from CL, RL and BL. The initial DOP amount was 0.8 μg g-1 in the landfill refuse. At the day of 310, refuse sedimentation rates were 7.0%, 11.9% and 24.3% in CL, RL and BL, respectively. DOP removal rates were 17.4%, 30.8% and 31.7% in the refuse from CL, RL and BL, respectively. The residual amounts of DOP with significant differences well fitted exponential decay models in CL, RL and BL. DOP biodegradation was accelerated with the operation of leachate recirculation compared to the conventional operation, and it was further promoted with the introduction of methanogenic reactor.

The alignment of carbon nanotubes (CNTs) with residual catalyst Ni particles in epoxy resin (EP) was achieved under a low magnetic field of 0.4 T. EP composites containing different loading of CNTs were prepared at 60 °C based on the rheology results of CNT/EP suspensions. The effects of CNT loading and magnetic field on the fracture toughness (KIC), glass transition temperature (Tg) and electrical properties of the composites were studied. The obtained results showed significant enhancements in KIC, independent of the orientation of the CNTs, compared to neat epoxy. The maximum increase (∼51%) was achieved by composites with 3 wt.% aligned CNTs transverse to crack growth. Additionally, composites with magnetically aligned CNTs displayed anisotropy in KIC. Compared to CNT/EP composites with no applied magnetic field, the KIC increase was less effective at high CNT loading. Finally, toughening mechanisms, Tg and electrical conductivity results were discussed.

The objective of this study is to quantify the clinical accuracy of the Cyberknife Xsight Lung Tracking System (XLTS) in our center and calculate the PTV margin of XLTS treated lung tumors. Data from the treatment log files of 22 lung cancer patients treated with the CyberKnife XLTS were analyzed and the PTV margin was calculated. Segmentation, deformation, correlation, prediction and targeting errors were calculated from the log files of XLTS treatments. Two different methods were used to calculate anisotropic treatment margin. The relationships between tumor motion ranges and the correlation and prediction errors were also analyzed. Based on our estimation of a 4 mm global margin, 95% coverage in the S-I direction and 100% coverage in the L-R and A-P directions were obtained. Strong correlations between tumor motion range and the standard deviation (SD) of correlation and prediction errors were also found. Tumor position motion caused by respiration can be compensated using the Xsight Lung Tracking System. We found total tracking errors to be less than 4 mm in all three directions. This result could provide a reference for the selection of PTV margin for treatment with the CyberKnife XLTS.

A simple flame synthesis method was utilized for grafting functional carbon nanotubes (CNTs) onto carbon fiber fabrics. Functional organic groups found on CNTs were formed after the flame growth process. Results from electrochemical tests also showed that the accessible surface area was improved by more than 50 times after the carbon fiber fabrics were grafted with CNTs for 3 min. Hence, mode I and mode II interlaminar fracture toughness of these composite laminates, wherein carbon fiber fabrics were grafted with CNTs, increased by ∼67% and ∼60%, respectively.

Cellulose nanocrystals (CNC) were derived from microcrystalline cellulose (MCC) by sulfuric acid hydrolysis. The mechanical and fracture properties as well as fracture morphologies of CNC/epoxy (CNC/EP) composites with different CNC loadings were studied. A thermoplastic polysulfone (PSF) was added to toughen the epoxy. During the curing of PSF/EP composites, two different phase separation processes would occur due to the variation of the amount of PSF in the PSF/EP blend. The effects of CNC and PSF on the elastic modulus, strength and fracture toughness properties of the ternary PSF/CNC/EP composites were also examined. Electrospinning technique was successfully used to fabricate PSF/CNC nanofibrous membranes as an interleaf inserted into the mid-plane of the CF/EP composite laminates to increase the interlaminar fracture toughness. The results showed that after interleaving with the PSF/CNC nanofibrous membranes, mode I and mode II interlaminar fracture toughness values were enhanced compared to the non-interleaved CF/EP with neat epoxy or CNC-modified epoxy matrix as well as interleaved CF/EP laminates with PSF nanofibrous membranes. The toughening mechanisms of hybrid PSF/CNC nanofibrous membranes were examined based on the fracture surface morphologies of the composites.

Due to the higher thermal and moisture expansions of epoxy coatings than the rigid substrate, these coatings suffer from high thermal and hygroscopic stresses, leading to coating/substrate interfacial crack growth. Herein, a parametric study was conducted systematically on epoxy coatings incorporated with fillers, in order to understand their effects on coating/substrate interface delamination caused by thermal and hygroscopic stresses. A finite element model (FEM) was developed to determine an indicator J-integral value (Ji), in comparison with a critical JC value to interpret the obtained interface delamination experimental results. FE simulations showed that interfacial pre-cracks located at coating edges were more serious than those at the centre. Once delamination was triggered by thermal shock or moisture absorption, it propagated rapidly along the coating/substrate interface. However, by adding suitable micro-/nano-fillers to the coating the thermal and hygroscopic stresses give lower Ji values, so that delamination crack growth can be effectively controlled. The simulation results demonstrate that the incorporation of fillers with lower Young’s modulus, lower thermal expansion and moisture absorption coefficients, smaller size for soft fillers, larger size for rigid fillers, and suitable aspect ratios for rod-shape fillers to the coatings, are more effective against interface delamination. Hence, useful guidelines for improving the design of epoxy composite coatings against delamination growth can be obtained for different engineering applications.

Urban transportation is the main way of carbon emission, development of low-carbon transportation has become the focus of attention of the countries all over the world. This paper analyses the influencing factors of carbon emission of Tianjin transportation based on grey correlation method, putting forward that the cost of urban resident transportation, traffic volume of urban passenger, number of private car and energy consumption of urban transportation are the most important key factors. Therefore, in order to construct low-carbon transportation system, Tianjin should design the layoff of urban space reasonably to control the demand of transportation effectively to reduce the urban transportation cost first, develop urban public transportation to optimize the urban traffic structure in response to the growing urban traffic volume of passenger second , establish a series of laws and regulations to improve the urban traffic management level to strengthen the supervision of private cars third, develop and apply new technology and new energy to adjust the energy structure of urban transportation to reduce urban transportation energy consumption at last.

A single carbon fibre pullout from a polymer matrix under the influence of residual thermal stresses was numerically investigated in this paper. The finite element method was first applied to obtain the residual thermal stress components along the interface between the fibre and the matrix due to curing. Four typical carbon fibres, T300, AS4, T800HB-40B and IM7 with anisotropic properties embedded in epoxy matrix HY6010 were considered. A comparison study indicates that simplified isotropic fibre model would overestimate the compressive residual axial and interfacial radial stress by up to 30%. Therefore, the anisotropic material properties of the fibres should be considered in the theoretical study of carbon fibre pullout. The cohesive zone model was then used to study the single carbon fibre pullout test. The numerical results indicate that the residual thermal stresses have a significant influence on fibre pullout at the stage of frictional sliding after interfacial debonding, which leads higher specific pullout energy. The effects of interfacial bonding condition and the fibre geometry were investigated by a parametric study. An interesting finding is that the interfacial shear strength, which is defined as the ratio of the debonding force to the embedded area, is not a constant. It decreases with the increase in the fibre embedded length. In addition, the fibre pullout energy per unit interfacial area (specific pullout energy) increases with the embedded length due to the effect of residual thermal stresses and interfacial friction. But the specific pullout energy does not depend on the fibre radius, which means that reducing fibre radius alone would not enhance the fibre bridging effect.

A method of integrating hybrid thin films of graphene nanosheets (GNSs) and silver nanoparticles (AgNps) by in situ chemical reduction to prepare transparent conductive films (TCFs) is studied. The surface functional groups of graphite oxide (GO) serve as nucleation sites of silver ions for adsorption of AgNps. To fabricate conductive films with high transmittance, polyurethane (PU) nanofibers are introduced to help construct two-dimensional conductive networks consisting of AgNps and GNSs (AgNps–GNSs). This method requires only a low percentage of conducting AgNps–GNSs covering the transparent substrate, thereby improving the transmittance. The flexible GNSs serve as nanoscale bridges between conductive AgNps and PU nanofibers, resulting in a highly flexible TCF. The optical transmittance can be further increased after melting the PU nanofibers at 100 °C. A fused film obtained after electrospinning (ES) a PU solution for 120 s and immersion in 0.05 wt.% AgNp–GNS (5:1) solution has a surface resistance of 150 Ω/sq and 85% light transmittance. Mechanical testing shows that AgNps–GNSs on flexible substrates yield excellent robustness. Thus, TCFs with a 3:1 ratio of AgNps:GNSs have high conductivity, good mechanical durability, and barely one order of magnitude increase of surface resistance when bent to an angle of 90°.

An experimental study on the fatigue performance of nanoparticle modified epoxy was conducted. Seven material systems were examined which were: neat epoxy (E), 6 and 12 weight percent (wt.%) silica nanoparticle modified epoxy (S6, S12), 6 and 12 wt.% rubber nanoparticle modified epoxy (R6, R12), 3 wt.% each of silica and rubber nanoparticle modified epoxy (S3R3) and 6 wt.% each of silica and rubber nanoparticle modified epoxy (S6R6). Effects of those nanoparticles on the fatigue threshold (Δ G th and Δ K th ) and fatigue crack propagation rates ( da/dN ) were studied. It was found that, compared to neat epoxy (E), nanosilica (S6, S12) increased Δ G th (and Δ K th ) but nanorubber (R6 and R12) did not. However, a synergistic effect was observed on the fatigue threshold when both silica and rubber nanoparticles were added into epoxy. All these nanoparticles, individually or conjointly, decreased da/dN with silica the most effective. Morphology of the fracture surface was examined to understand the role of nanoparticles on toughening mechanisms under cyclic loading, which depended on the applied Δ G levels.

Mono-dispersed Nickel oxide nanoparticles were directly formed on the carbon fibers through a facile in situ flame synthesis method. High magnification SEM and TEM study revealed that the nickel oxide nanoparticles have a polyhedral structure and are uniformly distributed on the surface of carbon fibers. The concentration effect of the precursor used on the growth of polyhedral nickel oxide nanoparticles on carbon fibers has been studied.

In the traditional screw compressor rotors profile generation method, the process of cockamamie parameters adjustment and confirmatory will take a long time, so that the modified results can’t be estimated in advance. Based on freeform curve, two rotor profiles generation methods are presented in this paper. One method is positive, and the female and male rotor profiles are acquired by every profile segment defined with freeform curve; another one is reverse, and the rotor profiles are derived through the meshing line. The rotor profiles are fitted by freeform curve and the shape of rotor profile can be adjusted by moving the control points. Finally, the two methods are used to developed a system for designing quickly the rotor profiles.

Ultrafiltration processes are increasingly popular in drinking water treatment, as it can provide better quality water by removing microorganism and turbidity with lower filtration pore size, even without disinfection. Nonetheless, in our experiment the bacteria was occasionally detected in ultrafiltration effluent, and the related literature once had also been reported. This study was focused on the cause of secondary pollution in the drinking water ultrafiltration system, mainly from the production tank, biological stability, bacteria in air, as well as the membrane structure. And some solutions, including production water tank chlorination periodically, changing the operating mode of the ultrafiltration system, improving the design of the production tank, were studied to control secondary pollution in the treatment system.

A simple one-step method of the synthesis of carbon nanotubes (CNTs) grafted onto carbon fibers (CFs) was developed using catalysts formed in an ethanol flame, where the reducing atmosphere prevents the CFs from combustion and reduces the catalyst precursor to catalyst particles on the fibers. The growth process was studied and both the type and concentration of catalyst ions were found to affect CNT growth on CFs. The peeling force to separate the interfacial bonding between a CNT and a CF substrate was also measured by an instrumented tip of an atomic force microscope.

Double-cantilever-beam tests were applied to investigate the mode I interlaminar fracture toughness of carbon fibre/epoxy laminates, in which the epoxy matrices were incorporated with rubber and silica nano-particles, either singly or jointly. It is shown that the toughness is improved owing to the presence of these nano-particles although nano-rubber is more effective than nano-silica. Further, by keeping the total particle weight percentage constant in epoxies (e.g., at 8 and 12 wt.%) filled with equal amount of nano-silica and nano-rubber, the interlaminar toughness values of the hybrid laminates are always higher than those with nano-silica filled epoxies but lower than those with nano-rubber filled matrices. Scanning electron microscopy examination of the delaminated surfaces of composite laminates filled with nano-particles revealed that cavitation of nano-rubber particles/void growth and debonding of nano-silica from epoxy matrix are responsible for the improved interlaminar toughness observed. It is also shown that the bulk toughness of nano-particle filled epoxies cannot be fully transferred to the interlaminar toughness of composite laminates, being limited by the constraint effect imposed by the carbon fibres. Finally, the role of fibre-bridging on the delaminated crack and hence delamination toughness is discussed.

A systematic study on the effects of silica and rubber nano-particles on the fracture toughness behavior of epoxy was conducted. Mode I fracture toughness ( G IC ) of binary silica/epoxy, binary rubber/epoxy and ternary silica/rubber/epoxy nanocomposites with different particle weight fractions was obtained by compact tension tests. It is found that G IC of epoxy can be significantly increased by incorporating either rubber or silica nano-particles. However, hybrid nanocomposites do not display any “synergistic” effect on toughness. Microstructures before and after fracture testing were examined to understand the role of nano-particles on the toughening mechanisms.