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ultruded GFRP perforated plates are widely used in composite bridge and truss. Stress concentration is an inevitable focus of the structural design and analysis. This paper investigated the stress concentration of pultruded perforated plate under both uniaxial and biaxial stress. The hole’s radius r, the width w, height h of plate and stack layer were involved. Biaxial stress parametric Finite Element (FE) model of GFRP perforated plates were created. In terms of notch stress in GFRP perforated plate, the stress concentration of 0 degreesply is significant under unidirectional tension. When height to radius ratio is greater than 0.15 (2r/h > 0.15), the stress concentration factor (SCF) is suggested to be modified based on Tan’s model. The biaxial status of tension–compression is the governing load combination of GFRP perforated plate. The analysis method of biaxial status has been proposed in the paper. By arranging the layer angle of the non-0° layer of the laminate, the relationship between SCF of perforated plate and the anisotropic factor was found.

Catalytic pyrolysis offers a sustainable route to convert plastic wastes into fuel. We investigated the catalytic performance of coal ash (fly and bottom ash) at blending ratio of 5 wt%, and 15 wt% during pyrolysis of linear low-density polyethylene (LLDPE). The influence on activation energy and oil was characterized via thermogravimetric analyzer (TGA) and gas chromatography-mass spectrometry (GC-MS). Results have shown that 15 wt% bottom ash exhibited higher catalytic activity. The activation energy estimated by Coats-Redfern method decreased from 458.7 kJ·mol-1 to 437.8 kJ·mol-1, while the alicyclic hydrocarbon yield increased from 5.97% to 32.09%. This implies that CaO, which is abundant in bottom ash, could promote the conversion of LLDPE. Furthermore, a cradle-to-factory gate life cycle assessment was performed to investigate three scenarios (non-catalytic pyrolysis, 15 wt% fly ash, and 15 wt% bottom ash) of LLDPE conversion strategies via a normalization and weighting approach. It was found that LLDPE pyrolysis with 15 wt% bottom ash also showed the lowest normalized score of 2.83, implying the lowest environmental impact. This work has demonstrated that the recycling of coal ash, particularly bottom ash, as catalysts for LLDPE pyrolysis is effective.

Heterogenization of organic-macrocyclic metal catalysts is one of the simplest and most efficient methods for effective separation of products and cyclic application of a catalyst. By using an environmentally friendly Mn-corrolazine catalyst as the building unit, which can directly oxidize organic substrates under oxygen atmosphere and mild conditions, we theoretically constructed a novel two-dimensional (2D) Mn-corrolazine nanocatalytic material with high catalytic activity. In this material, each Mn atom maintains its electronic configuration in the monomer and can directly activate O2 as the single-atom catalyst (SAC) center to form a radical-like [Mn]-O-O under mild visible-light irradiation conditions. The newly generated [Mn]–O–O can efficiently and selectively oxidize C–H bonds to form alcohol species through H-abstraction and the rebound reaction. Moreover, the catalytic reaction is easily regulated by an external electric field along its intrinsic Mn–O–O reaction axis. The current study provides a theoretical foundation for further experimental studies and practical applications of the Mn-corrolazine-based SAC.

In this study, organic–inorganic-modified ammonium polyphosphate (APP) flame retardant (FR) was prepared by a sol–gel method that used tetraethoxysilane and vinyltriethoxysilane as precursors. Then modified APP (VTSAPP) was added into polyurethane (PU) to fabricate the FR PU/VTSAPP composites. Crucially, the structure and performance of VTSAPP were systematically characterized. The results showed that a dense hybrid silica gel layer structure was formed on the surface of APP. Ideally, the limiting oxygen index (LOI) value of PU/20VTSAPP composite increased from 19.5% for pure PU to 30% and the vertical burning test (UL-94) reached up to V-0 level. Moreover, the addition of VTSAPP dramatically decreased the released smoke of PU during combustion compared to the counterpart of APP. The FR mechanism of VTSAPP was deeply explored. It is confidently shown that phosphorus and silicon compounds of VTSAPP contributed to the formation of a more continuous and compact char and improved the thermal stability of the char layer. The results of this study distinctly confirmed that VTSAPP was an effective FR agent for PU.

This study investigates the potential of solid fuel blending as an effective approach to manipulate ash melting behaviour to alleviate ash-related problems during gasification, thus improving design, operability and safety. The ash fusion characteristics of Qinghai bituminous coal together with Fushun, Xinghua and Laoheishan oil shales (and their respective blends) were quantified using a novel picture analysis and graphing method, which incorporates conventional ash fusion study, dilatometry and sintering strength test, in a CO/CO2 atmosphere. This image-based characterisation method was used to monitor and quantify the complete melting behaviour of ash samples from room temperature to 1520 °C. The impacts of blending on compositional changes during heating were determined experimentally via X-ray diffraction and validated computationally using FactSage. Results showed that the melting point of Qinghai coal ash to be the lowest at 1116 °C, but would increase up to 1208 °C, 1161 °C and 1160 °C with the addition of 30%–50% of Laoheishan, Fushun, and Xinghua oil shales, respectively. The formation of high-melting anorthite and mullite structures inhibits the formation of low-melting hercynite. However, the sintering point of Qinghai coal ash was seen to decrease from 1005 °C to 855 °C, 834 °C, and 819 °C in the same blends due to the formation of low-melting aluminosilicate. Results also showed that blending directly influences the sintering strength during the various stages of melting. The key finding from this study is that it is possible to mitigate against the severe ash slagging and fouling issue arising from high calcium and iron coals by co-gasification with a high silica-alumina oil shale. Moreover, blending coals with oil shales can also modify the ash melting behaviour of fuels to create the optimal ash chemistry that meets the design specification of the gasifier, without adversely affecting thermal performance.

Amine-modified solid sorbents have attracted extensive interests in post-combustion carbon capture for power plants. Among various amines, polyethyleneiemine (PEI) is likely to be the most effective and promising candidate. However, previous studies have mainly focused on examining various supports to increase PEI loading and then enhance CO2 adsorption capacity. In this study, one rare earth element (Ce) and 6 first-row transition metals (from V to Cu) in the oxidation states impregnated on PEI incorporated γ-Al2O3 were prepared and investigated as potential catalyst/promotor for base-catalyzed reaction. Thermodynamic analysis, including isothermal and quasi-static CO2 adsorption tests, were implemented to evaluate the performances amongst the 7 metal oxides. The results showed that MnO2, CeO2 and Fe2O3 showed a better performance in isothermal CO2 adsorption at 75°C. Upon quasi-static tests, the results also indicates that the peak adsorption temperatures (Tpeak, a) of V2O5 and Cr2O3 shifted to high temperature region, whilst opposite behavior of MnO2 was observed. In preliminary study, density functional theory (DFT) was also adopted to assist the screening of metal oxide in terms of bond length and adsorption energies.

Inspired by the layered structure and oriented materials, this study exhibits a reinforcement and antibacterial composite consisted by polytetrafluoroethylene/glass fiber (PTFE/GF) composites and QACMt. The QACMt used as an organically modified layered particle is fabricated by a method that montmorillonite (Mt) is modified with quaternary ammonium compounds (QAC). Owing to the composites have a unique layered structure, it was considered as an ideal reinforcement to strengthen polymer. Importantly, the tensile strength and toughness of PTFE/GF composites are achieved the maximal value of 25.5 MPa and 18.1 MJ/m3, respectively. Additionally, the QACMt exhibits good antibacterial activities against S. aureus and E. coli. This work guides a layered structure to achieve exceptionally high strength and toughness, antibacterial properties.

The retained austenite content in TRIP590 steel was first measured by X-ray diffraction (XRD) method. Then, the effect of different test parameters (indexing rate, step size, field number, etc.) on the measured results of retained austenite content in TRIP590 steel by electron backscattered diffraction (EBSD) method was studied. By comparing the measured results between XRD and EBSD method, the optimal test parameters for the analysis of retained austenite content using EBSD were determined. Finally, the total content of retained austenite and the retained austenite contents with different aspect ratios in TRIP590 steel were analyzed, respectively. The results showed that the test parameters have a great influence on the measured results of retained austenite content in TRIP590 steel. In order to improve the test accuracy, high indexing rates, small step sizes and more field number are necessary for the analysis of retained austenite content in TRIP590 steel by EBSD method.

Tortuous pores are ubiquitous in natural porous media; however, the linear effects of tortuosity on the liquid flow behaviors are usually considered through capillary bundle models, which lead to inaccurate permeability prediction. Additionally, in the nanopores, due to the existence of heterogeneous viscosity and boundary slip, the effects of tortuosity on nanoconfined liquid flow behaviors are more complicated. In this paper, we comprehensively use the theoretical models and a nanoscale multi-relaxation-time lattice Boltzmann method (MRT-LBM) to characterize water flow behaviors in the tortuous nanopores, where heterogeneous viscosity and boundary slip are considered. The results show that the increase of tortuosity causes more negative effects, which results in a decreasing apparent permeability. The conventional model of the influence of tortuosity on the apparent permeability is linear[Formula: see text], which greatly underestimates the effect of tortuosity on apparent permeability. Then, a new fractal apparent permeability model [Formula: see text] based on modified tortuous effects is obtained by fitting the results from the MRT-LBM simulations. Based on the new fractal apparent permeability models, the results show that with an increasing fractal tortuosity dimension, the apparent permeability decreases rapidly first and then this trend becomes moderate. Our works can provide a more accurate basic model for studying liquid flow in porous media based on the capillary bundle model or pore network model.

An X-band switched energy storage (SES) microwave pulse compression system is presented, and its theoretical analysis, numerical simulation, and experimental research are carried out. Detailed dimensions of the resonant cavity are theoretically calculated and numerically optimized by simulation. The operation mode of the resonant cavity is TE1,0,52 at the frequency of 9.3 GHz. The output power gain is theoretically calculated as 11.7. When the width of the rectangular coupling iris is 11 mm, the coupling coefficient is 1.05, which is beneficial for high energy storage efficiency. In the preliminary experiments, the output microwave with power of 350 kW and pulsewidth of 10 ns is produced by the SES pulse compression system under the input power of 54 kW, implying a pulse power gain of 6.5.

In the present manuscript the patented non-electrode plasma electrolysis technique was successfully applied in order to deposit nano-structured Al2O3 ceramic coating on the quartz fiber. It was found that the grooves on the blank fiber were covered by Al2O3, accordingly decreasing the surface defects. In this case, the coating effectively improved the breaking strength of the quartz fiber at elevated temperatures. The coated fiber still exhibited relatively higher strength of 0.38 N/tex after annealing at 600 °C for 60 min, nearly three times as that of the blank fiber. Both the formation mechanism and the protection mechanism of the Al2O3 coating were systematically investigated. We believe that the non-electrode plasma electrolysis will find a wide range of applications in the surface modification of non-conductive fibers.

Finite element model based on a unit with cracks in the rotor of the exciter is set up. Andthen critical speed is calculated that compared to actual measured value to verify the rationality of themodel. Lastly response characteristics of the three-bearings supporting structure are studied when thefirst critical speed of the exciter with cracks is closed to the working speed. And the reliability ofconclusions is further verified by case analysis.

The acoustic behaviour of an aperture backed by sound-absorbing material under grazing flow is theoretically investigated through a linearized model. Both the dissipation effect of the material and its influence on the stability of the vortex sheet over the aperture region are formally taken into account. And thus, the coupling effect between the material and the grazing flow is considered. In the situation that the size of the aperture is considerably smaller than the shear layer thickness, the model uses the particle velocity match (PVM). The predictions of the present PVM model achieve satisfactory agreement with published experimental data. On the other hand, while the relatively thin shear layer is considered, the model is based on the rigorous particle displacement match (PDM) and predicts when the acoustic energy is possibly extracted from the mean flow.

In this paper, a comparative experimental study between R134a and its low GWP alternative R1234yf/R134a (called R513A, 44/56% weight) in a domestic refrigerator was presented. Three kinds of tests were carried out under the same ambient condition. The optimal charge for R513A is 80 g, which is 5.9% lower than that of R134a (85 g). The pull down time of R513A is reduced by 21% compared to R134a. The 24-h energy consumption of R513A is 3.5% lower than that of R134a. During the freezing test, R513A saved 43.2 min compared to the baseline test, which indicates that the freezing capacity of R513A is better than R134a. In addition, R513A shows a similar behavior to the baseline test with the discharge temperature and compressor pressure ratio of R513A lower than those of R134a.

Here we use an electron beam lithography system to pattern an ${\rm{S}}{{\rm{i}}_{3}}{{\rm{N}}_{4}}{\rm{/Si}}{{\rm{O}}_{2}}$ echelle grating using silver as a reflector on the grating grooves. The grating in this letter achieves 1.39 dB on-chip loss, a spectral resolution of ∼1300, a 1.2 dB channel nonuniformity, and less than −30 dB adjacent channel crosstalk for the transverse electric field polarization. We establish that stitching errors can lead to appreciable adjacent channel crosstalk if proper precaution is not taken to minimize them.

This study investigates the potential of producing graphene oxide (GO) from biomass via green (comparatively) processing and the impact of graphitization temperature on GO quality. Our findings show that it is possible to convert biomass into highly pyrolytic biochar, followed by shear exfoliation to produce few-layer GO. However, pyrolysis temperature is key in ensuring that the biochar is suited for effective exfoliation. Low temperatures (1000 °C) would preserve undesirable heterogenous, complex cellular structure of biomass whilst excessive temperatures (≥1300 °C) result in uncontrolled melting, coalescence and loss of functional groups. Results show 1200 °C to be the optimum graphitization temperature for miscanthus, where the resultant biochar is highly aromatic with sufficient functional groups to weaken van der Waals forces, thus facilitating exfoliation to form 6-layer GO with specific surface area of 545.3 m

Water electrolysis in neutral media has attracted concerted research efforts because of its practical applications including microbial electrolysis of wastewater and large-scale hydrogen generation by direct electrolysis of seawater. Because the corrosion of electrochemical devices is effectively reduced in neutral environments, the associated cost is consequently lowered. In this context, two-dimensional transition metal compounds have enjoyed extensive applications in the field of renewable energy because of their abundant storage capacity, easily regulated electronic structure, and unique physical and chemical features. As such, this review summarizes recent advances in the use of two-dimensional transition metal compounds as hydrogen evolution, oxygen evolution, and bifunctional catalysts for neutral water splitting. Some engineering strategies to enhance electrocatalytic performances are also discussed. Finally, the current challenges and future opportunities in bifunctional electrocatalysts for full water splitting are presented.

The photocatalytic activity of titanium dioxide (TiO2) for the purification of odour pollutants, containing reduced sulfur compounds (RSCs), could be largely improved by the coupling of porous materials. Herein, UiO-66@TiO2 nanocomposites with different blending ratios were synthesized via a readily solvothermal method and characterized experimentally by XRD (X-ray diffraction), SEM (scanning electron microscope), FTIR (Fourier transform infrared spectrum), N2 isotherms, and UV-vis DRS (diffuse reflectance spectra). The photodegradation performance of dimethyl sulfide (DMS) by synthesized UiO-66@TiO2 was investigated under various photodegradation conditions, including photocatalyst dosage, DMS concentrations and relative humidity. The results showed that the U1T3 (UiO-66:TiO2=1:3) composites exhibited the highest photocatalytic activity, which was about 17.8 and 7.1 times higher than that of pristine UiO-66 and TiO2, respectively. This indicates that the intimate contact interfaces between UiO-66 and TiO2 could promote the separation and migration efficiency of photogenerated electron-hole pairs. When relative humidity increased from 0% to 60%, the photocatalytic activity was enhanced because the moisture could assist to produce more hydroxyl radicals. However, when the relative humidity was further increased to 90%, the excessive water would compete with DMS on the surface of UiO-66 and subsequently weaken the photocatalytic effects. During the cycling experiments, U1T3 showed a stable photocatalytic performance, and the plausible photocatalytic reaction mechanism and reaction pathways of DMS were proposed. With a significant enhancement of photocatalytic performance, UiO-66@TiO2 nanocomposites could promote the practical applications of MOF-based photocatalysts for the degradation of DMS.

This study examined an isothermal CO2 gasification of four chars prepared via two different methods, i.e., conventional and microwave-assisted pyrolysis, by the approach of thermogravimetric analysis. Physical, chemical, and structural behaviours of chars were examined using ultimate analysis, X-ray diffraction, and scanning electronic microscopy. Kinetic parameters were calculated by applying the shrinking unreacted core (SCM) and random pore (RPM) models. Moreover, char-CO2 gasification was further simulated by using Aspen Plus to investigate thermodynamic performances in terms of syngas composition and cold gas efficiency (CGE). The microwave-induced char has the largest C/H mass ratio and most ordered carbon structure, but the smallest gasification reactivity. Kinetic analysis indicates that the RPM is better for describing both gasification conversion and reaction rates of the studied chars, and the activation energies and pre-exponential factors varied in the range of 78.45–194.72 kJ/mol and 3.15–102,231.99 s−1, respectively. In addition, a compensation effect was noted during gasification. Finally, the microwave-derived char exhibits better thermodynamic performances than the conventional chars, with the highest CGE and CO molar concentration of 1.30% and 86.18%, respectively. Increasing the pyrolysis temperature, gasification temperature, and CO2-to-carbon molar ratio improved the CGE.

Twisted bilayer graphene (TBG) provides a unique framework to elucidate the interplay between strong correlations and topological phenomena in two-dimensional systems. The existence of multiple electronic degrees of freedom -- charge, spin, and valley -- gives rise to a plethora of possible ordered states and instabilities. Identifying which of them are realized in the regime of strong correlations is fundamental to shed light on the nature of the superconducting and correlated insulating states observed in the TBG experiments. Here, we use unbiased, sign-problem-free quantum Monte Carlo simulations to solve an effective interacting lattice model for TBG at charge neutrality. Besides the usual cluster Hubbard-like repulsion, this model also contains an assisted hopping interaction that emerges due to the non-trivial topological properties of TBG. Such a non-local interaction fundamentally alters the phase diagram at charge neutrality, gapping the Dirac cones even for infinitesimally small interaction. As the interaction strength increases, a sequence of different correlated insulating phases emerge, including a quantum valley Hall state with topological edge states, an intervalley-coherent insulator, and a valence bond solid. The charge-neutrality correlated insulating phases discovered here provide the sought-after reference states needed for a comprehensive understanding of the insulating states at integer fillings and the proximate superconducting states of TBG., 15 pages, 9 figures, 2 tables

We systematically study the low-temperature specific heats for the two-dimensional kagome antiferromagnet, Cu$_{3}$Zn(OH)$_6$FBr. The specific heat exhibits a $T^{1.7}$ dependence at low temperatures and a shoulder-like feature above it. We construct a microscopic lattice model of $Z_2$ quantum spin liquid and perform large-scale quantum Monte Carlo simulations to show that the above behaviors come from the contributions from gapped anyons and magnetic impurities. Surprisingly, we find the entropy associated with the shoulder decreases quickly with grain size $d$, although the system is paramagnetic to the lowest temperature. While this can be simply explained by a core-shell picture in that the contribution from the interior state disappears near the surface, the 5.9-nm shell width precludes any trivial explanations. Such a large length scale signifies the coherence length of the nonlocality of the quantum entangled excitations in quantum spin liquid candidate, similar to Pippard's coherence length in superconductors. Our approach therefore offers a new experimental probe of the intangible quantum state of matter with topological order., Comment: 6 pages, 3 figures

The disposal of waste tire rubber has gained more attention from the viewpoint of green, environmental protection, and sustainability. Numerous attempts have been stated on the properties of crumb rubber concrete (CRC) and observed that there is a large reduction of compressive strength and elastic modulus of CRC with the increase of the rubber substitution rate. Based on the CRC with the crumb rubber volume content of 5%, the steel fibers and nanosilica were added to CRC to make steel fiber-and-nanosilica-reinforced crumb rubber concrete (SFNS-CRC) in this paper. The effects of the steel fiber volume content and nanosilica content on the compressive properties of SFNS-CRC were studied, including compressive strength, elastic modulus, peak strain, compression toughness, and failure pattern. The test results indicated that the modulus of elasticity and compressive strength of SFNS-CRC have the increasing tendency with the addition of steel fibers and nanosilica. Moreover, the peak strains have a significant increase with the increase of the steel fiber content and nanosilica replacement ratio. The compressive stress-strain curves of SFNS-CRC gradually plump with the increase of the steel fibers and nanosilica. Finally, the prediction formulas for the compressive strength, elastic modulus, and peak strain of SFNS-CRC were set up. A simple predicted model of the stress-strain curve for SFNS-CRC was proposed, which considers the effect of steel fibers and nanosilica.

We investigate the spin to charge conversion phenomena in Y3Fe5O12/Pt/Co1–x Tb x /Pt multilayers by both the spin pumping and spin Seebeck effects. We find that the spin transport efficiency is irrelevant to magnetization states of the perpendicular magnetized Co1–x Tb x films, which can be attributed to the symmetry requirement of the inverse transverse spin Hall effect. Furthermore, the spin transmission efficiency is significantly affected by the film concentration, revealing the dominant role of extrinsic impurity scattering caused by Tb impurity. The present results provide further guidance for enhancing the spin transport efficiency and developing spintronic devices.

The hot deformation behavior of S460ML steel with different Nb contents was investigated by single-pass compression experiment on the Gleeble-1500 thermo-machine simulator at deformation temperatures ranging from 900 to 1200 °C and strain rates from 0.1 to 5.0 s−1. The critical strain of dynamic recrystallization (DRC) under different conditions was determined by using working hardening rate-strain curves. The relationship between critical strain and peak strain of DRC was discussed. By means of regression analysis method, the hot deformation activation energy of steels and the mathematical model for predicting DRC critical strain were calculated and established, respectively. The results showed that DRC occurred during hot deformation. As the deformation temperature increased and strain rate decreased, the critical strain of DRC decreased. The critical strain (ec) showed linear relationship with peak strain (ep). As Nb content increased, the needed deformation temperature for occurring DRC increased, while the needed strain rate for it decreased. The activation energy for hot deformation of S460ML steel increased with increasing Nb content.

Magnetic Fe3O4 nanoparticles were prepared and embedded into the Combi-CLEAs to produce the magnetic Combi-CLEAs in this work. The process for magnetic Combi-CLEAs preparation was optimized, and its properties were investigated. The optimum temperature, thermal stability and optimum pH of magnetic Combi-CLEAs were similar to those of Combi-CLEAs. The catalytic performance of magnetic Combi-CLEAs was tested with the biosynthesis of (S)-ethyl 4-chloro-3-hydroxybutyrate ((S)-CHBE). Magnetic Combi-CLEAs could tolerate higher substrate concentration in the biphasic system. The catalytic efficiency and long-term operational stability of magnetic Combi-CLEAs were obviously superior to those of Combi-CLEAs in both aqueous and biphasic systems. Embedding of magnetic Fe3O4 nanoparticles endowing rigidity contributed to these improvements. Furthermore, the preparation of magnetic Combi-CLEAs was easy, and its recovery during multiple batches of reactions could be fulfilled by magnetic field. Aforementioned advantages make the magnetic Combi-CLEAs hold obvious potential for industrial application.

A simple and facile method for fabricating the cotton fabric with superhydrophobicity, self-cleaning and flame retardancy was described in the present work. Three types of antimony pentoxide sol (Sb2O5), aluminum hydroxide sol (Al(OH)3) and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (fluoroalkyl silanes) were used as coating for the cotton fabric. It was found that Sb2O5 and Al(OH)3 exhibited significant synergistic effects on the flame retardancy. When the weight ratio of Sb2O5/Al(OH)3(content 30 wt%) was 1:3, the results showed that the limiting oxygen index (LOI) value was 45.1 %, smoke density (SDR) value was 35 %, and it still passed UL94 V-0 rating. The cotton fabrics coated with fluoroalkyl silanes/Sb2O5/ Al(OH)3 showed a superhydrophobicity, anti-contamination and self-cleaning properties. In addition, the results exhibited the outstanding superhydrophobicity, oil/water separation, excellent waterproofing durability and flame retardancy of cotton fabric after 1000 cycles of washing by water, the LOI value was 40.1 %, SDR value was 39 % and WCA was 152° after 1000 cycles of washing. We believe that this simple, environmentally friendly and versatile fabrication of the cotton fabric had excellent real-life applications.

Integrated thermal protection system (ITPS) is regarded as one of the most promising thermal protection concepts with both thermal insulation and load-bearing capacities. However, the traditional layout of webs could inevitably lead to thermal short effects and high risk of buckling failure of the ITPS. A topological optimization method for the unit cell of the ITPS was established to minimize the equivalent thermal conductivity and elastic strain energy with the constraint of maintaining structural efficiency. The ITPS was re-designed consulting the optimized cell configuration. In order to control the buckling-mode shape and the associated buckling load of the ITPS, the new design was further optimized, subjected to the total weight of the initial design. Detailed finite element models were established to validate the structural responses. By contrast, the optimized design presents lower bottom surface temperature and better thermal buckling characteristics, performing a better balance between thermal insulation and load-bearing constraints.

NiMoO4 nanoparticles and quantum dots were uniformly distributed on the surface of reduced nanohole graphene oxide (rNHGO). NiMoO4@rNHGO exhibited a higher specific capacitance and better cycling stability than NiMoO4@reduced graphene oxide (rGO), which were attributed to the large surface area and high electrical conductivity. NiMoO4 nanoparticles and quantum dots (QDs) had high surface to volume ratio, which would not result in change in volume during the electro–chemical operation and induced better supercapacitor performance. Moreover, synergistic effect between NiMoO4 and the rNHGO also improved undoubtedly high specific capacitance and cycle stability.

A novel room-temperature aqueous plasma electrolysis technique has been developed in order to prepared Al 2 O 3 nano-coating on each fiber within a carbon fiber bundle. The microstructure and formation mechanism of the Al 2 O 3 nano-coating were systematically investigated. The oxidation resistance and tensile strength of the Al 2 O 3 -coated carbon fiber was measured at elevated temperatures. It showed that the dense Al 2 O 3 nano-coating was relatively uniformly deposited with 80–120 nm in thickness. The Al 2 O 3 nano-coating effectively protected the carbon fiber, evidenced by the slower oxidation rate and significant increase of the burn-out temperature from 800 °C to 950 °C. Although the bare carbon fiber remained ∼25 wt.% after oxidation at 700 °C for 20 min, a full destruction was observed, evidenced by the ∼0 GPa of the tensile strength, compared to ∼1.3 GPa of the Al 2 O 3 -coated carbon fiber due to the effective protection from the Al 2 O 3 nano-coating. The formation mechanism of the Al 2 O 3 nano-coating on carbon fiber was schematically established mainly based on the physic-chemical effect in the cathodic plasma arc zone.

Few layer graphene was formed on the surface of Ni foam using the chemical vapor deposition technique, which effectively decreased flaws and inhibited stack of graphene. The CoS nanorods were synthesized on the surface of bare Ni foam after hydrothermal method, while graphen on Ni foam facilitated to form CoS nanowires with porosity surface structure and large specific surface area. The CoS nanowires on Ni foam coated with graphene showed an high specific capacitance of 1506 F g−1 at 1 A g−1 and 88.2% capacity retention at a current density of 1 A g−1 after 5000 cycles charge-discharge test. The improved electronic conductivity of current collector Ni foam by graphene and porous microstructure of CoS nanowires catalyzed by graphene enhanced significantly supercapacitors performance. This was attributed to large CoS nanowires electrode-electrolyte contact area and reduced volume change during the charge-discharge process.

Aligned NiCo 2 S 4 nanotubes on Ni foam were obtained by the complete sulfidation of NiCo-precursor which was synthetized by hydrothermal process. The NiCo 2 S 4 nanotubes on Ni foam delivered a higher specific capacitance than NiCo 2 O 4 nanowires on Ni foam. The NiCo 2 S 4 nanotubes on Ni foam exhibited the high capacitance of 1936.2 F g −1 at 1 A g −1 . The porous NiCo 2 S 4 nanotubes on Ni foam provided a huge number of exposed active sites for electrochemical reaction. Moreover, the NiCo 2 S 4 nanotubes on Ni foam with large specific surface area facilitated the diffusion and penetration of electrolyte and improved electrochemical reaction. Therefore, after 5000 continuous charge–discharge cycles, only about 7.9% degradation in specific capacitance was observed for NiCo 2 S 4 nanotubes on Ni foam.

The microstructure of the 95 wt%Zn-2.3 wt%Al-2.7 wt%Mg bulk alloy used for hot-dip galvanization has been investigated by TEM and SEM. The alloy exhibits a multi-scales and multi-phases microstructure. The dendrite and the granular/lamellar region are observed at hundreds-micron scale, and each has finer details. The dendrite is composed of the coarse hcp-Zn grains, with MgZn2 grains between the branches, and some individual bulk MgZn2. The granular/lamellar region has a complex ternary eutectic morphology, containing the hcp-Zn lamellas, the monotectoid product of Al-bubble wrapping Zn-granule, and the Zn-Mg lamellas, and the dimension of every unit is less than 1 μm. The hcp-Zn phase, in the form of coarse grains and lamellas, is supersaturated, with numerous platelet Al precipitation about tens of nanometers inside, with the orientation relationship of (0 0 1)Al//(0 0 0 1)Zn, and [1 1 0]Al near 1 1 2 ¯ 0 Zn . The Zn-Mg lamella is a MgZn2 matrix with polygon Mg2Zn11 precipitates less than 100 nm and some Mg segregations.

A large number of pitting pits were formed on the surface of Ni foam by immersion corrosion in NaCl solution. The graphene was deposited on Ni foam templates, then 3D graphene foams were obtained by removing Ni foam in the mixed solution of ferric chloride and hydrochloric acid. It was found that pitting pits on Ni foam facilitated to form fewer-layers graphene, however, pitting pits on Ni foam induced more defects on 3D graphene foam. The graphene with fewer-layers exhibited better electrical and mechanical properties for strain sensor devices. Moreover, fewer-layers graphene effectively inhibited degradation of resistance during cycling stability tests.

Co 3 O 4 @MnO 2 core–shell arrays hybrid electrode directly grown on Ni foam for supercapacitor was obtained by two-step hydrothermal processes. Co 3 O 4 @MnO 2 core–shell arrays hybrid electrode exhibited a high specific capacitance of 1920 F g −1 at current density of 1 A g −1 . This was attributed to relative high conductivity of the Co 3 O 4 nanowire arrays and the large surface area provided by the ultrathin MnO 2 nanosheets. The porous MnO 2 nanosheets stack provided numerous channels for rapid diffusion of electrolyte ions and fast electron transport, which enhanced the electrochemical reactions. The synergetic effect between Co 3 O 4 nanowire and MnO 2 nanosheets also improved the supercapacitor performance. In addition, the Co 3 O 4 @MnO 2 core–shell arrangement also exhibited excellent cyclic stability.

The pure NiMoO4 and sphere-shaped NiMoO4@rGO nanostructure were obtained by one step hydrothermal process. The sphere-shaped NiMoO4@rGO nanostructure showed higher significantly specific capacitance value than pure NiMoO4. The enhanced capacitive performance of the as-prepared sphere-shaped NiMoO4@rGO nanostructure was attributed to the mesoporous structure, large surface area of rGO nanosheets and higher electrical conductivity. These mesoporous structures could provide more electroactive sites which promoted the electrode–electrolyte contact and enhanced ion and electron transport during the chemical reaction. Moreover, high specific capacitance also could be attributed to the positive synergistic effect between rGO and NiMoO4.

Pure CoMoO4 nanoplate arrays grew on nickel foam by one-step hydrothermal process, while flower-like nanoflake CoMoO4@RGO nanocomposites grew on nickel foam. Flower-like nanoflake CoMoO4@RGO nanocomposites electrode exhibited higher capacitance than pure CoMoO4 nanoplate arrays electrode. Maximum specific capacitance of 856.2 F g−1 was obtained at current density of 1 A g−1 for CoMoO4@RGO nanocomposites electrode. In addition, after 2000 cycles of continuous galvanostatic charge–discharge cycles, only 5.5% degradation of specific capacitance was found for CoMoO4@RGO nanocomposites. CoMoO4@RGO nanocomposites exhibited lower electrochemical resistance than pure-CoMoO4. This was because that the former had larger specific surface area and average pore diameter than the latter. The flower-like nanoflake CoMoO4 facilitated electrolyte movement during charge or discharge process and provided more active sites for the electrochemical reactions. In addition, the synergetic effect between RGO and CoMoO4 also improved the supercapacitor performance.

The thermal reduced graphene oxide deposition on nickel foam was successfully synthesized by ultrasonic and subsequent thermal reduction process. Ultrathin mesoporous Ni3S2 was formed on the bare nickel foam after hydrothermal process, while Ni3S2 nanotube arrays were formed on the surface of nickel foam with the thermal reduced graphene oxide due to catalysis action of thermal reduced graphene oxide. The resulting Ni3S2 nanotube arrays exhibited higher catalytic activity than ultrathin mesoporous Ni3S2 for hydrogen evolution reaction. In addition, and excellent stability was also obtained in Ni3S2 nanotube arrays.

With extensive first-principles density-functional calculations, we construct a three-dimensional compositional phase diagram of Ba1-xCaxZryTi1-yO3 (BCZT) with the Ca and Zr content in the ranges of 0 ≤ xCa ≤ 0.2 and 0 ≤ yZr ≤ 1. Our calculations show that, when the Zr content increases, the difference in energy and difference in the structural parameters of the cubic, tetragonal, orthorhombic, and rhombohedral phases of BCZT are reduced. Eventually, all four phases merge into a multiphase with coexisting cubic structures (MPCCS) under Zr-rich conditions, indicating that BCZT undergoes phase transition from a normal ferroelectric (NFE) to a relaxor ferroelectric (RFE), consistent with experimental observations. The 3D diagram shows that the regions of merged and separated energy surfaces correspond to the regions of the RFE and NFE, respectively, which suggests that a MPCCS corresponds to a RFE. In addition, with the MPCCS model and Landau-Devonshire theory, we provide an interpretation of the high electromechanical properties of the BCZT relaxor ferroelectric and apply it to the classical local random field and micro-macro domain transition models.

With the increasing amount of electronic waste (e-waste) generated globally, it is an enormous challenge to recycle printed circuit boards (PCBs) efficiently and environmentally friendly. However, conventional recycling technologies have low efficiency and require tough treatment such as high temperature (>200 °C) and high pressure. In this paper, a small-molecule assisted approach based on dynamic reaction was proposed to dissolve thermosetting polymers containing ester groups and recycle electronic components from PCBs. This effective approach operates below 200 °C and the polymer could be dissolved in a short time. It has a remarkable ability to recycle a wide range of commercial PCBs, including boards made of typical anhydride epoxy or polyester substrate. Besides, it is environmentally friendly as even the recycling solution could be reused multiple times. In addition, the wasted solution after recycling could be used for board bonding and damage repair. This work also demonstrates the advantage of using polymers containing ester groups as the PCB substrate in consideration of eco-friendly and efficient recycling.

Two methods are provided to accurately quantify the degree of manganese dendritic segregation in 380CL steel billet by using electron probe microanalysis, namely mapping analysis and line analysis. The quantitative accuracy of each pixel in mapping analysis is mainly investigated, and a series of experiments at different dwell times are carried out to optimize the parameter and reduce the error of quantitative analysis. Statistical analysis is used to calculate the characteristic segregation ratio value in the line or mapping analysis which can provide e.g. 12 × 104 values at about 4.3 mm2. The statistical number of data points in line analysis is studied in terms of length and position of analysis lines. For the specimens of 380CL steel billet, mapping analysis area of 1 mm2 containing over 10 dendrites is recommended for quantifying the dendritic segregation of manganese. Six 2 mm lines along different directions containing about 2000 pixel points is also proposed for more accurate line analysis of Mn segregation.

A semi-empirical impedance formula of a circular orifice under grazing flow is derived, based on a linearized potential flow model. The effect of boundary layer is considered by introducing the con ...

Fluorescent materials can be powerful contrast agents in photoelectric devices and for bioimaging. As emerging fluorescent materials, carbonized polymer dots (CPDs) with high quantum yields (QYs), long-wavelength emission and multiple functions are highly desired. Despite great progress in the synthetic methods and QYs of CPDs, multiple emission of CPDs is challenging. Therefore, we developed CPDs with dual-emission fluorescence in terms of inherent blue and red emission. In addition, CPDs with sole blue emission (B-CPDs) and red emission (R-CPDs) were synthesized, respectively, by regulating the reaction conditions to control the quantitative structure and emission centers. The absolute QY of R-CPDs in water was 24.33%. These three types of CPDs with dual/sole emission could be used in optoelectronic and bioimaging applications. With different CPDs coated on a commercially available gallium nitride light-emitting diode chip as a color-conversion layer, LEDs with blue, yellow, and red emission were achieved. Benefiting from the different emission intensities and emission peaks of R/B-CPDs in different pH conditions, they were used (without further modification) to distinguish between Porphyromonas gingivalis, Streptococcus mutans, Escherichia coli and Staphylococcus aureus in dental plaque biofilms (the first time this has been demonstrated). These findings could enable a new development direction of CPDs based on the design of multi-emission centers.

This work aims to investigate and develop a method to evaluate and predict the combustion behaviour and combustion efficiency of different biomass commonly used in power plants via simple characterisation methods. 11 types of agricultural and industrial wastes were characterised using thermogravimetric analyser to obtain the derivative thermogravimetric (DTG) data and kinetic parameters. For the samples tested, the initiation temperatures were found to be in the range between 224.39 0 C and 260.33 0 C, whilst the local minimum temperatures between 2 peaks were within the range of 360.36 to 382.74 0 C. It was established that there is a clear, direct relationship between the pre-exponential factor and the temperature interval for the first step of combustion. This trend was apparent and recorded for the 2 heating rates tested. © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of ICAE2018 - The 10th International Conference on Applied Energy.

Oil shale, as an unconventional fossil fuel, exhibits unique properties compared with coal and other petroleum. Due to the nature of sedimentary rock, large amounts of inorganic mineral impurities in rock matrix reduce the grade of oil shale, whilst increase the grinding resistance. This investigation presents the effects of microwave-enhanced pretreatment on the nature of oil shale and compared with conventional preheating process. Two Chinese oil shale from Fushun and Xingsheng Deposits were grounded and sieved into a size fraction (1-1.18mm) and were cut into eighteen cube-shaped specimens respectively. The prepared samples were processed accordingly to investigate how the grindability changed, in comparison to that of raw samples, and how the fundamental chemical properties of oil shale were altered after pretreatment. Quantitive data were used to assess the effects of different pretreatment methods on oil shale milling performance in a lab-scale pulverizer along with the impacts on moisture content, chemical properties. The uniaxial compressive strength (σmax) of Fushun oil shale was reduced 63.1% and the breakage rate increased 44.9% by short exposure to microwave irradiation. In conclusion, microwave-enhanced pretreatment presents significant improvement in oil shale milling performance compared to conventional preheating process in terms of breakage rate (Si) and uniaxial compressive strength (σmax) which showed negligible alterations. © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of ICAE2018 - The 10th International Conference on Applied Energy.

A novel noninvasive technique-microscopic laser-induced fluorescence (micro-LIF)-has been applied to achieve in situ visualization of concentration polarization (CP) of nanoparticles during cross-flow ultrafiltration at high resolutions. The reversible, highly dynamic nature of CP and its sensitive response to the filtration conditions were investigated and validated by direct visualization of the CP layer and the well depicted concentration profile near the membrane surface. Using micro-LIF, the formation of a CP layer during filtration and its back-diffusion after the filtration ceased can be directly observed. The dynamic variation of the CP layer with the cross-flow velocity and transmembrane pressure (TMP) change has also been demonstrated. The results showed that CP reached the steady state approximately 1 min after the filtration condition change. A higher cross-flow velocity and/or a lower TMP decrease the CP concentration and thickness. Further quantitative analysis of the filtration test results using the film theory model helps to obtain the particle concentration at the membrane surface and the thickness of the CP layer (30-50 μm). Accordingly, the nature of CP dynamics was characterized and the deficiency of the traditional CP model was explored.

The line intercept method is well developed for estimating the dislocation density in metals, but its application is limited by the intersection counting, which is deeply depending on the TEM image quality. Manual interscetion counting is quite time and labor consuming. If most of the dislocations has good contrast and homogenous background in an image, it is possible to perform automatic counting by the computer program. In this work a series of imaging conditions were investigated on a slightly deformed IF steel thin foil. Though the invisibility criterion remains applicable for both the conventional transmission electron microscopy (CTEM) and the scanning transmission electron microscopy (STEM), the STEM images revealed more dislocations and had more homogenous background than the CTEM images. The STEM bright field (BF), annular dark field (ADF) and annular bright field (ABF) images at a low index zone axis contained the most dislocations visible and were suitable for automatic intersection counting of dislocations.