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To evaluate the long-term performance of bioretention cell (BRC), a study was undertaken to assess the flow distribution and conductivity. Despite initial conductivity of the original medium being the common predictor of hydraulic performance, most of the BRCs are affected by conductivity variations during actual operation. This happen due to the fact that microbial behavior plays an important role in the conductivity variations. This linkage may occur when bacteria as inert colloids transports between particles and biodegrades dissolved pollutants, either promoting or retarding flow distribution and conductivity in BRC. Flow distribution was determined by numerical simulation and tracer test, and the correlation between conductivity and flow distribution was revealed by conductivity experiment coupled with flow distribution analysis. Results revealed a non-uniform flow distribution in BRC, and seepage flow in submerged zone was virtually impossible push flow. Conductivity had an inversely proportional relationship with hydraulic efficiency where hydraulic efficiency reached the highest value (0.297) under a low hydraulic conductivity (0.000107 m/s, approximately K/Kini = 0.79). Primary cause of hydraulic capacity reduction was the initial permeability decrease due to medium structure changes. Results revealed a sharp upward trend followed by a slight decrease, and then, stabilized to a stable infiltration stage. Permeation process of sewage influent was similar to the one of potable water where the permeability reduced to 0.000102 m/s after 450 h and declined continuously. Thus, it is clear that flow distribution and conductivity in bioretention must be estimated more accurately on a microscopic scale.

A novel Al plating was developed to enhance the oxidation resistance of CoCrNiAlY–yttria-stabilized zirconia (YSZ)–LaMgAl11O19 dual-ceramic coating. The results indicated that the lanthanum magnesium hexaaluminate (LMA) layer without the Al plating sustained severe volume shrinkage, consequently initiating the formation and propagation of longitudinal micro-cracks. These micro-cracks behaved as channels that accelerated the inner diffusion of oxygen. The rapid growth of the thermally grown oxide (TGO) layer induced high interface stress, resulting in the severe fracturing of the interface between the CoCrNiAlY and YSZ layers. However, the Al plating not only effectively suppressed the volume shrinkage of the LMA layer and the initiation of large-size longitudinal micro-cracks but also induced the formation of an in-suit Al2O3 barrier layer. The strong synergistic effect of the dense ceramic layer and Al2O3 layer effectively inhibited the inner diffusion of oxygen, consequently reducing the interface stress and rapid TGO layer growth. Accordingly, a considerably effective anti-oxidation performance was achieved by the dual-ceramic coating with the Al plating.

The failure mechanism of a cylindrical shell cut into fragments by circumferential detonation collision was experimentally and numerically investigated. A self-designed detonation wave regulator was used to control the detonation and cut the shell. It was found that the self-designed regulator controlled the fragment shape. The macrostructure and micro-characteristics of fragments revealed that shear fracture was a prior mechanism, the shell fractured not only at the position of detonation collision, but the crack also penetrated the shell at the first contact position of the Chapmen-Jouguet (C-J) wave. The effects of groove number and outer layer thickness on the fracture behavior were tested by simulations. When the thickness of the outer layer was 5–18 mm, it has little effect on fragmentation of the shell, and shells all fractured at similar positions. The increase of the groove number reduced the fracture possibility of the first contact position of the C-J wave. When the groove number reached 7 with a 10 mm outer layer (1/4 model), the fracture only occurred at the position of detonation collision and the fragment width rebounded.

Precisely manipulating the built-in electric fields of heterojunctions is an effective way to promote photogenerated charge separation. In this work, BiPO4 nanorods/graphene (GA) hydrogels were prepared by hydrothermal methods. The BiPO4 nanorods were evenly embedded in the graphene hydrogel, forming a stable three-dimensional (3D) network structure. The 70% BiPO4/GA hydrogel shows the highest tetracycline hydrochloride degradation activity, which is 3.2 times that of pure BiPO4. The formation of the built-in electric field of the BiPO4/GA hydrogel is demonstrated by experimental investigation (especially in situ atomic force microscopy (AFM) surface potential investigation) and theoretical calculation. The reasons for the enhanced photocatalytic activity are the optimal built-in electric field of the interface induced by precisely manipulating the interfacial contact of the BiPO4/GA hydrogel, as well as the synergistic effect of in situ photocatalytic degradation and adsorption enrichment induced by the 3D network structure. This work provides technical approach and research ideas for the photocatalytic degradation of antibiotics through the manipulation of interlaminar built-in electric field and heterojunction.

Addressing the inherent holes transport limitation of BiVO4 photoanode is crucial to achieve efficient photoelectrochemical (PEC) water splitting. The construction of the hole-transfer bridge between co-catalysts and BiVO4 photoanode could be an effective way to overcome sluggish hole-transfer kinetics of BiVO4 photoanode. Herein, CxNy/BiVO4 photoanode was prepared by coupling carbon nitride hydrogel (CNH) containing unsaturated N on the BiVO4 photoanode during annealing. CxNy/BiVO4 photoanode exhibited excellent PEC performance and stability. Photoelectrochemical tests proved that the coupling of CxNy accelerated holes transfer and enhanced oxygen evolution kinetics. X-ray photoelectron spectroscopy (XPS) and theoretical calculations confirmed the existence of the Bi N V bond between BiVO4 photoanode and CxNy, which could serve as the hole-transfer bridge to significantly accelerate separation and transfer of carriers driven by the interfacial electric field. Moreover, it was found that the coupling of CxNy effectively inhibited the dissociation of metal ions through changing their coordination environment, resulting in the excellent stability of CxNy/BiVO4 photoanode. This result provides unique insights into vital roles of the interfacial structure, which might have a significant impact on the construction of PEC devices.

Double ceramic layer thermal barrier coatings (DCL-TBCs) of LaMgAl11O19/YSZ (LMA/YSZ) were prepared by atmospheric plasma spraying (APS). Composition, microstructure and phase stability of coatings were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and differential scanning calorimetry (DSC). The amorphous phase content of LMA coating increased with increasing the plasma gun current from 350 A to 650 A. The DCL-TBCs of LMA/YSZ whose LMA coating was prepared with a plasma gun current of 600 A (600LMA/YSZ) had the lower amorphous phase content, an excellent thermal insulation performance and the longest thermal cycling lifetime, indicating that properties of LMA coating could be largely improved by adjusting the APS conditions.

Sintering inhibition of a catalyst at high temperatures is a challenge during heterogeneous catalysis. In this paper, we report that hexagonal boron nitride (h-BN) is an optimal material for anti-sintering γ-Al2O3-supported Pt nanoparticles (NPs) originating from the high thermal conductivity of h-BN. The high thermal conductivity of h-BN ensures maximal heat dissipation from Pt NPs to γ-Al2O3, thereby causing both Ostwald ripening and particle coalescence of Pt NPs to be decelerated at elevated temperatures. Inhibition of Pt NP sintering is also shown in the reducible TiO2-supported Pt NPs with the help of h-BN. The proposed anti-sintering strategy using thermal management is universal, providing new insight into the design of anti-sintering materials and structures for a wide range of applications in heterogeneous catalysis.

The objective of the present study was to understand how the lubricant-derived ash-loaded diesel particulate filter (DPF) impacted the soot oxidation reactivity during the regeneration process. Four major commercial lubricant additives (i.e. Ca, Zn-P, Ca-Zn-P, and Mo-P) were heated up in a muffle furnace to generate ash particles, which were mixed with diesel soot in a loose-contact pattern for further analysis. Thermogravimetric analysis (TGA) was employed for both non-isothermal and isothermal conditions to examine the oxidation reaction parameters, including ignition temperature, peak temperature and burnout temperature. In the meantime, the sizes and nanostructures of the primary soot particles during the oxidation process were characterized by high-resolution transmission electron microscopy (HRTEM). Results showed that lubricant-derived ashes accelerated the oxidation of soot particles as indicated by the reduced oxidation characteristic temperatures and increased oxidation rate. Based on the analysis of HRTEM images, both surface and internal burning phenomena existed in the oxidation processes of pure soot conditions and soot-ash mixtures conditions. The structures of shell-core, onion- and capsule-like, hollow and carbonization fragments appeared sequentially through the entire oxidation processes. Comparing to the pure soot conditions, the tendency of surface burning of the soot particles was notably increased by the lubricant-derived ashes. It was thus concluded that, the lubricant-derived ash components played the role as catalyst to promote soot oxidation and favor the whole regeneration process, even though the ashes may deteriorate performance of DPF by increased backpressures.

An efficient electrocatalyst of molybdenum carbide nanodots on carbon nanosheets (nano-MoC/C-Ns) is prepared via a novel interlayer-confined strategy with the aid of MCM-22(P), a kind of multilayered two-dimensional (2D) zeolite precursor. In this strategy, the confined space of the surfactant-swollen MCM-22(P) plays a critical role in creating a unique sandwich-like structure with Mo-based organic–inorganic nanohybrids which further in situ evolve into ultrafine ∼2 nm MoC nanodots on carbon nanosheets in the following carbonization process. After etching the zeolite layers, the nano-MoC/C-Ns is successfully obtained as an efficient noble-metal-free electrocatalyst for hydrogen evolution. The intimate contact between ultrafine MoC nanodots and C nanosheets, as well as their synergetic effects, endows this catalyst with large exposed active sites and accelerated electron transport. The optimal sample achieves excellent hydrogen evolution reaction performance in acidic, neutral and alkaline media with low η10 values of 126, 185 and 92 mV (vs. the values of 28, 36 and 37 mV for a Pt/C reference in acidic, neutral and alkaline media), respectively. This synthetic strategy provides some hints for designing high-performance carbides for energy conversion and storage.

Efficient conversion of light alkanes is of essential significance for enhancing the utilization efficiency of resources and exploring the activation and evolution regulation of C-C and C-H bonds in stable molecules. The processes are often executed with catalysts under harsh conditions. The olefin yield and metal stability have been the long-standing concerns. Herein, we report a facile strategy of constructing a bifunctional Pt/HZSM-5-based catalyst by two-step atomic layer deposition (ALD) to achieve a high light olefin formation rate of 0.48 mmol gcat-1·min-1 in the catalytic cracking of n-butane at 600 °C, which is ∼2.2 times higher than that of the conventional Pt/HZSM-5 catalyst (0.22 mmol gcat-1·min-1). Moreover, the bifunctional Pt/HZSM-5-based catalyst exhibited outstanding recyclability and excellent metal stability against sintering in comparison with conventional Pt/HZSM-5. Detailed microscopic and spectroscopic characterization studies demonstrate that the metal oxide (TiO2 or Al2O3) coating not only prevents the metal from high-temperature sintering, but also regulates the proportion of coordinately unsaturated platinum surface atoms. Theoretical calculations further confirm the preference of nucleation of TiO2 or Al2O3 on coordinately unsaturated platinum sites, which in turn modulates the bifunctional dehydrogenation-cracking pathway to improve the olefin formation rate.

One challenge in the application of traditional metastable intermolecular composite (MIC) material is that MIC particles are not compatible with micro-electro-mechanical system. In the authors’ work, a solution casting method was employed to prepare aluminium/polyvinylidene fluoride (Al/PVDF) MIC films. The morphological, structural and compositional information of the samples were characterised by scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. The energy-release characteristics of Al/PVDF films were studied by thermogravimetric analysis and differential scanning calorimetry. The results show that heat output and mass loss increased as the thickness of MIC films reduced. The maximum heat release of the main exothermic peak was 1032 J/g. The kinetics process could be divided into three stages with apparent activation energy calculated by Kissinger and Starink methods of 128.86, 164.69 and 153.16 kJ/mol, respectively.

One challenge in the application of traditional metastable intermolecular composite (MIC) material is that MIC particles are not compatible with micro-electro-mechanical system (MEMS) based pyrotec...

We report a facile and versatile method to homogeneously deposit monolith membrane with uniform, high density of metallic nanoparticles via a “ship-in-a-bottle” strategy. Polyamidoamine (PAMAM) dendrimer, an excellent matrix for complexing with metal ions, is pre-infiltrated and applied as the directing agent for in-situ confined-formation of palladium nanoparticles (PdNPs) inside the mesopores. Efficiency of this method is demonstrated to prepare homogeneous PdNPs-deposited hierarchically porous graphitic carbon (HPGC) membrane with uniform metallic particle size (2.0–2.5 nm) and high palladium loading (~34.4 wt%). Taking advantages of fast molecule diffusion rate in hierarchically porous structure and high conductivity of graphitic carbon substance, the PdNPs-dispersed HPGC membranes are applied as monolith electrodes for electrochemical applications. The PdNPs-deposited HPGC membrane electrode exhibits excellent electrocatalytic activity toward the catalytic oxidation of dopamine, uric acid and ascorbic acid, as well as high sensitivity and selectivity in simultaneous determination of these compounds in real serum samples. The limit of detections for dopamine, uric acid and ascorbic acid are 1.3 × 10−8, 2.6 × 10−8 and 3.7 × 10−8 M, respectively, at least one order lower than that achieved on electrochemical sensors reported previously. This work provides a versatile method for efficient preparation and stabilization of monodisperse metallic NPs in diverse porous materials, leading to possible applications in devices, catalysis, and electrochemical sensing.

Ion bombardment of electrodes in an electric vacuum device can induce high-voltage breakdown. In order to explain this phenomenon, we, for the first time, analyzed a typical model of protons impacting the electrode with the help of a particle-in-cell (PIC)-direct simulation Monte Carlo (DSMC) code. In this model, we considered both the secondary electron yield and the gas desorption from the electrode. The temporal and spatial distribution evolution of electrons, ions, and neutrals under different electrode conditions is presented. The critical value of local gas density to induce breakdown is 1025 m−3. According to the discussion of the formation of the electrons avalanche, the electron ionizing gas is the key component for affecting the formation of a breakdown, and the production of plasma sheath near the electrode greatly contributes to the electrons avalanche.

Designing a material with the advantage of adsorption–enrichment and photocatalysis degradation has great practical significance in water treatment. BiPO4, as a promising photocatalyst for environmental purification, still suffers from small specific surface area and relative low photocatalytic activity. Herein, BiPO4–SiO2 hybrid hydrogels were successfully fabricated by facile two-step methods. BiPO4 nanorods are uniformly compounded with SiO2 spheres, and the specific surface area of BiPO4 is enhanced by 2.3 times after forming a network structure. 90% BiPO4–SiO2 hybrid hydrogel presents the highest photocatalytic degradation activities, which is 3.4 times that of pure BiPO4. The total organic carbon removal ability of BiPO4 is also enhanced by 1.1 times after constructing a hybrid hydrogel. The pollutant removal enhancement of BiPO4–SiO2 hybrid hydrogel can be attributed to the synergistic effect of adsorption–enrichment and photocatalytic degradation. Our results may provide a promising way to greatly enhance the pollutant removal performance of BiPO4, which may promote the industrial application of BiPO4.

In the present work, nanostructured 8YSZ coatings were produced by atmospheric plasma spraying using synthesized nanostructured t'-8YSZ feedstocks. The splats characteristics were systematically analysed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results indicate that there are columnar nano-grains in splats and the preferential growth orientation of columnar nano-grains is [101] direction. Finally, the growth mechanism of columnar nano-grains in splats for plasma-sprayed nanostructured YSZ coatings was proposed in detail.

Nitrogen doped carbon species (NC) was introduced into Fe based catalyst and applied into propane non-oxidative dehydrogenation. With characterizations of XRD, TEM and XPS, it was deduced that the NC modification induces the electrons transferred from NC species to Fe species, leading to electron-rich Fe species. Consequently, propane conversion and propene selectivity were increased by suppressing the by-products formation. It was also confirmed that such a modification strategy could be also extended to ones with different supports, iron precursors, and NC precursors.

Propane/propene separation is among the most energy-intensive separation processes in the petrochemical industry. Separation based on adsorption on a nanoporous material (e.g., zeolites) has spawned new ideas for this process. Therefore, we conducted grand canonical ensemble Monte Carlo simulations to investigate the adsorption and separation of propane and propene in one-dimensional (ATS, MOR, and AWO), two-dimensional (MWW, FER, and BOG) and three-dimensional (MFI, BEA, FAU) zeolites. The computation of pure components indicates that the adsorption capacity is affected by the zeolite pore diameter, dimensionality, and isosteric heat. For a given diameter, three dimensional zeolites exhibit better adsorption properties than two or one-dimensional zeolites. Zeolites with diameters ranging from 4.8 Å to 5.4 Å show high propane and propene affinity. In binary mixture simulations, the separation capacity of propane and propene increases with elevated pressure and decreased temperature. Among these zeolites, AWO exhibits the best separation performance due to its eight-ring window channel, which is consistent with experimental results. Thus, our results provide better understanding on propane and propene adsorption and separation in different zeolites, as well as insight into how production conditions could be upgraded.

Low delivery efficiency and limited tumor penetration of nanoparticle-based drug delivery systems (DDSs), the two most concerned issues in tumor therapy, have been considered as the "Achilles' heel" for tumor treatment. In this study, we have designed a highly sensitive dual-redox-responsive prodrug-based starlike polymer β-CD-b-P(CPTGSH-co-CPTROS-co-OEGMA) (CPGR) for synergistic chemotherapy. The high glutathione (GSH) concentration and high reactive oxygen species (ROS) levels are in a dynamic equilibrium in the tumor microenvironment (TME) and could trigger the disintegration of CPGR micelles, which can promote the release of anticancer drug camptothecin (CPT) completely and intelligently. In order to verify the synergistic antitumor mechanism, two corresponding single-responsive β-CD-b-P(CPTGSH-co-OEGMA) (CPG) and β-CD-b-P(CPTROS-co-OEGMA) (CPR) were altogether prepared as contrast. Both in vitro and in vivo studies confirmed the enhanced anticancer activity of CPGR micelles in comparison of single responsive micelles. This work contributes to the orchestrated design of dual-redox-responsive DDSs for synergetic antitumor chemotherapy, which provides a good approach for the development of dual-redox-responsive nanomedicine.

Pyrogenic biomass carbon has been deemed a promising alternative to Pt/C for the oxygen reduction reaction (ORR) owing to its low cost, excellent activity, and eco-friendly properties. Herein, a porous carbon tube material derived from kapok fibres was prepared by combining activation with pyrolysis. Electrochemical measurements demonstrated that the kapok fibre-derived material prepared at 900°C had excellent ORR performance with a half-wave potential –0.14 V (vs. Ag/AgCl) close to that of commercial Pt/C (–0.13 V vs. Ag/AgCl) in 0.1 mol L–1 KOH. The prepared material also displayed remarkable methanol tolerance and durability. Furthermore, the maximum power density output of the microbial fuel cell using the prepared material was (801± 40) mW m–2, comparable to that of the Pt/C cathode ((778± 31) mW m–2). The present work provides a facile way of using economical and renewable biomass to develop a porous structure and high-activity cathode ORR catalyst for fuel cell applications.

SiO2 nanotubes (NTs), with uniform diameter (∼25 nm) and tailored shell thickness (1–5 nm), and featuring chemically asymmetric surfaces (a silane-functionalized exterior surface and a negatively charged (−Si–O–) interior surface) are prepared by a facile, template-free approach. Owing to their chemically asymmetric properties, positively charged cargoes can be selectively loaded with high content into the SiO2 NTs via electrostatic interaction. Mediated by polyamidoamine dendrimers preassembled in the NTs, different noble metal nanoparticles can be selectively deposited inside the NTs with high density and uniform size. Owing to their high specific surface area and elongated pore structure with lengths up to several micrometers, the SiO2 NTs exhibit a high loading capacity (80 wt %) for positively charged therapeutic agents, which exhibit sustained cargo release properties on the order of several months if the NTs are assembled into a membrane structure.

Summary Non-oxidative propane dehydrogenation (PDH) is an attractive reaction from both an industrial and a scientific viewpoint because it allows direct large-scale production of propene and fundamental analysis of C-H activation respectively. The main challenges are related to achieving high activity, selectivity, and on-stream stability of environment-friendly and cost-efficient catalysts without non-noble metals. Here, we describe an approach for the preparation of supported ultrasmall ZnO nanoparticles (2–4 nm, ZnO NPs) for high-temperature applications. The approach consists of encapsulation of NPs into a nitrogen-doped carbon (NC) layer in situ grown from zeolitic imidazolate framework-8 on a Silicalite-1 support. The NC layer was established to control the size of ZnO NPs and to hinder their loss to a large extent at high temperatures. The designed catalysts exhibited high activity, selectivity, and on-stream stability in PDH. Propene selectivity of about 90% at 44.4% propane conversion was achieved at 600°C after nearly 6 h on stream., Highlights • Supported catalysts with stable ultrasmall ZnO nanoparticles were prepared • The N-doped carbon layer helps to protect ZnO NPs from sintering and volatilization • The catalysts exhibited excellent activity and stability in propane dehydrogenation, Chemistry; Catalysis; Nanoparticles

To optimize the reactant synthesis and improve the pressure property of Al/Bi2O3, the influencing factors in the dynamic pressure discharge of nanothermite reactions are investigated, including the oxide type, Bi2O3 particle size, and fuel-to-oxidant mole ratio. All samples are prepared by the ultrasonic mixing method. The synthesized Al/Bi2O3 composites are characterized by X-ray diffraction analysis and scanning electron microscopy. By using a closed bomb, the pressure discharge characteristics, including the peak pressure, ignition delay time, and pressurization rate, are obtained. Among the as-prepared nanothermites Al/CuO, Al/Fe2O3, and Al/Bi2O3, the latter shows the best pressure discharge performance. For the Al (100 nm)/Bi2O3 (47 nm) composite with an optimal stoichiometric ratio, the maximum peak pressure, the pressurization rate, and the shortest ignition delay time are 4559 kPa, 11.398 GPa/s, and 27.20 ms respectively. The results indicate that the nano-Bi2O3 particle size also produces a significant effect on the pressure output.

This study used polyvinylidene fluoride (PVDF) as the matrix material, (CaCu3Ti4O12, CCTO) as ceramic powders, and graphene as the carbon material to prepare a three-phase dielectric composite. The...

The defects on a ground steel ball surface are very tiny and almost invisible; the existence of the defects will extremely influence the working stability of bearing system. To detect the surface quality on a steel ball effectively, dual wavelength coaxial optical fiber sensor technology is applied in this paper, and the defects are quantified as the characteristic parameters of displacement and roughness. The Matlab software was used to simulate the light intensity modulation characteristic ratio curve of displacement and roughness detection, the initial installation interval was determined as 0.8 mm between steel ball and the fiber sensor, and the wavelengths of light source were 1310 nm and 1550 nm. Experimental results showed that the coaxial optical fiber was suitable to detect the displacement, and dual wavelength to detect the roughness. The maximum errors of sensor displacement and roughness calibration experiment were 1.67% and 2.32% respectively in the measurement of steel ball with diameter 7.938 mm. The difference between the output curves was used to identify the defective balls from the good ones, which verifies the feasibility of the methods to detect the steel ball surface defects.

Corn stalk is not suitable for direct combustion due to poor grindability, high moisture content, and insufficient heating value. The aim of this study was to optimize reaction conditions to improve the quality of corn stalk char, and to investigate the effects of carbonization on the physicochemical and combustion characteristics of corn stalks and chars. Optimal conditions for the carbonization of corn stalk were investigated with regard to temperature, holding time, and particle size. Response surface methodology (RSM) provided satisfactory models of responses, and the optimal conditions for higher heating values were obtained as follows: temperature of 551 °C, holding time of 150 min, and particle size range of 0.8–1.0 mm. In addition, after carbonization, changes in surface morphology, functional groups, and organic elements were clearly observed on the chars. The optimal point char experienced fairly complete carbonization, and holds promise for use as a solid biofuel.

We report the development of a Z-scheme g-C3N4/Ag/AgI heterojunction by photo-deposition of Ag NPs on g-C3N4 and subsequent in situ generation of AgI via partial oxidation of Ag nanoparticles. A highly selective photoelectrochemical sensor for hydrogen sulfide (H2S) detection was constructed based on a g-C3N4/Ag/AgI heterojunction and the transformation of the Z-scheme g-C3N4/Ag/AgI heterojunction to C3N4/Ag/Ag2S.

Carbon quantum dots (CDs) are rising stars for photocatalytic applications due to their low toxicity and excellent electron transfer characteristics. Doping with heteroatoms is expected to adjust the band levels and electron transfer properties of CDs, and understanding the effect of doping on CDs can aid the rational preparation of highly efficient CD-based photocatalysts. Herein, we prepared a series of metal atom (Zn, Co, Bi, Cd, or Ti) doped CDs by pyrolysis and explored the photocatalytic application of these metal doped CDs for the first time. The metal doped CDs were combined with CdS nanowires as a co-catalyst for photocatalytic hydrogen production. The Bi, Cd and Ti doped CDs/CdS composites show much better hydrogen production performance than the undoped CDs/CdS composite. Among these composites, Bi-CDs/CdS presents the optimal interfacial charge separation and the best hydrogen production performance. The hydrogen evolution rate of Bi-CDs/CdS is 4.2 times and almost one time higher than that of pure CdS and undoped CDs/CdS, respectively. Bi doping can make the CDs metallic and promote the charge transfer of CDs. Such a great enhancement originates from the outstanding electron transfer properties of Bi-doped CDs, as well as the effective charge separation between Bi-doped CDs and CdS. Bi doping was demonstrated to be an effective strategy for optimizing the photocatalytic activity of CD based composites.

It remains a great challenge to design a multifunctional and robust nanoplatform for stimuli-responsive drug delivery toward a lesion, which tactfully integrates multiple molecules with therapeutic and diagnostic characteristics. Herein, we reported a facile and ingenious cross-linked nanogel (DSA) based on the chemical cross-link of drugs as a straightforward strategy to overcome the instability of the assembly. In DSA, doxorubicin (DOX) and 5-aminolevulinic acid (ALA) were cross-linked with a disulfide linker for realizing synergistic anticancer therapy. The stability of DSA was adjusted via balancing the hydrophobic/hydrophilic property with hydrophilic NH2-PEG1k. After regulating the coordination of the DOX part and ALA moiety, the drug-loaded nanogel exhibited superior chemotherapeutic efficacies. Additionally, the DSA could selectively biosynthesize fluorescent protoporphyrin IX (PpIX) in tumor cells, which could be applied for a real-time imaging probe of accurate cancer diagnosis. Besides, the in situ synthesized PpIX in mitochondria could serve as a photosensitizer to convert oxygen into toxic reactive oxygen species under a near infrared ray at 660 nm irradiation, leading to an excellent tumor-killing efficacy. This work proposed a unique strategy for designing a series of prodrug nanogels as a universal drug delivery platform for realizing precise disease therapy and diagnostics.

The objective of the present study was to investigate and optimize the multi-injection parameters that were able to match the diesel particulate filter (DPF) after-treatment system for reduction of particulate matter (PM) generated from diesel engines. Three representative multi-injection strategies, including main plus post-injection (designated as M+Po), one pilot injection plus M+Po (Pi1+M+Po) and two pilot injections plus M+Po (Pi2+Pi1+M+Po), were selected to generate soot particles in a diesel engine. The morphology and nanostructure of soot particles, including primary particle size, fringe length, thermal stability of organic carbon (OC) and graphitization degree, were analyzed by transmission electron microscopy (TEM) and Raman spectroscopy. The OC content and oxidation reactivity were quantified by thermalgravimetric analyzer (TGA). Results revealed that pilot injection led to the formation of soot particle with smaller primary particle size, more ordered nanostructure, and higher graphitization degree, ascribing to the better air-fuel mixing, higher cylinder temperature, as well as longer residence time. On the contrary, post injection (e.g., M+Po) resulted in soot particles with more OC exhibiting larger size and more ambiguous boundary. Overall, the soot particles with more disordered nanostructure and more OC content showed better oxidation reactivity. Interestingly, the soot particle morphology and nanostructure were observed to be varying under TEM electron irradiation, which might be due to the OC heating dissolution.

Treatment of multidrug-resistant (MDR) bacterial infections increasingly relies on last-line antibiotics, such as polymyxins, with the urgent need for discovery of new antimicrobials. Nanotechnology-based antimicrobials have gained significant importance to prevent the catastrophic emergence of MDR over the past decade. In this study, phytantriol-based nanoparticles, named cubosomes, were prepared and examined in vitro by minimum inhibitory concentration (MIC) and time-kill assays against Gram-negative bacteria: Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Phytantriol-based cubosomes were highly bactericidal against polymyxin-resistant, lipopolysaccharide (LPS)-deficient A. baumannii strains. Small-angle neutron scattering (SANS) was employed to understand the structural changes in biomimetic membranes that replicate the composition of these LPS-deficient strains upon treatment with cubosomes. Additionally, to further understand the membrane-cubosome interface, neutron reflectivity (NR) was used to investigate the interaction of cubosomes with model bacterial membranes on a solid support. These results reveal that cubosomes might be a new strategy for combating LPS-deficient Gram-negative pathogens.

This paper presents an impedimetric biosensor for monitoring of crops using novel microneedle electrodes for minimally invasive, sensitive measurements, compatible with smart agriculture developments. The biosensor was fabricated through polydimethylsiloxane imprinting using a high-resolution 3D printed negative mold. This method allows for fabrication of tailored microneedles with heights up to $500\ \mu \mathrm{m}$ , required to penetrate through the epidermis of a leaf. The sensor was tested by recording the bioimpedance of Barely leaves and comparing its performance to conventional planar and needle electrodes. Furthermore, we present evidence of a diurnal pattern in plant bioimpedance that was detected by monitoring the leaf bioimpedance under controlled conditions.

To further research the relationship between structural characteristics and materials of liner on explosively formed penetrator (EFP) formation, by using the LS-DYNA finite element software, the coupling effects of the structure and material on the formation of EFP were simulated, considering six structures (truncated, conical, tulip, arc, horn, arc cone liner) and five materials (aluminum, OFHC copper, Armco iron, tantalum, tungsten alloy). Under the condition of similar liner structure and mass, liner structure has little effect on the velocity of EFP, however, density play a remarkable negative relevant role. In the respect of EFP formation, OFHC copper liner with good elongation will obviously stretch to reach a lager length-diameter ratio (L/D) at all presented structures in this article. Furthermore, liner structure should be identified to a specific material and objective requirements. Although formed EFP with low solidity, arc liner makes Armco iron, tantalum and tungsten alloy to develop L/D and flight stability. Truncated liner has great benefit to OFHC copper EFP on L/D and solidity at the expense of little flight stability. Aluminum EFP of arc cone liner has both lager L/D and suitable solidity and flight stability.

We report on a high conversion efficiency tunable laser at 426 nm by adopting an external frequency-doubling cavity pumped by a diode laser. For the frequency-doubling process at 426 nm, the major challenge of increasing the conversion efficiency is mode-match degradation originating from the severely thermal effect. Here, we find that the center of the equivalently thermal lens is not at the center of the nonlinear crystal. We minimize the variation of beam parameters of the Gaussian beam in the external cavity by optimizing the center of the thermal lens to beam waist. As a result, the mode-match degradation is reduced as the incident power is increased. Finally, a 405 mW blue light is obtained with the conversion efficiency of 81%.

Hierarchical ZSM-5 zeolites have been receiving increasing attention from both fundamental research and industrial applications. From the chemical engineering viewpoint, the introduction of building block of ZSM-5 could give consideration to both external surface acidities and diffusion properties which are important in parallel sequence reaction for the final product distribution. In this work, hierarchical ZSM-5 with different sizes of building blocks were successfully prepared by tuning the water/silica ratio during the synthesis. With varying the size of building blocks, the diffusion property and external surface acidity were finely regulated, and it significantly influences the performances of ZSM-5 during catalytic cracking reaction. The catalyst with proper size of building blocks exhibited the optimized yield of olefins and lowest carbon deposition during 72 h reaction in catalytic cracking of i-butane. The strategy proposed herein could be helpful for the engineering design of hierarchical zeoli...

Photoelectrocatalytic (PEC) oxidation is a promising method in water treatment due to the synergistic effect of photocatalytic (PC) oxidation and electro-oxidation. Up to now, developing visible-light-responsive, efficient and environmental-friendly electrode for PEC degradation application is still a challenge. In this work, novel and environmental-friendly TiO2/C3N4 core–shell nanowire arrays as an electrode were investigated for PEC degradation of bisphenol A (BPA). TiO2 nanowire arrays provide a direct electron pathway, g-C3N4 serves as a stable and environmental-friendly visible light sensitizer, and effective charge spatial separation can be achieved across the well-matched core–shell interface. Compared with TiO2 nanowire arrays, TiO2/C3N4 core–shell nanowire arrays exhibit higher PC and PEC performance. The photocurrent response of the TiO2 nanowire arrays is enhanced about two times after C3N4 shell deposition. And the PEC performance of TiO2/C3N4 core–shell nanowire arrays is significantly enhanced, which is one time higher than that of TiO2 (under 1.0 V external potential). The enhancement of PEC performance of TiO2 nanowire arrays after C3N4 modification can be attributed to the synergistic photoelectric effect, well-matched interface and efficient charge separation induced by the type-II TiO2/C3N4 band alignment. Moreover, the intermediate products of BPA degradation by PEC oxidation were analyzed by gas chromatography–mass spectrometry and five specific products were identified, and then two possible pathways for BPA degradation by PEC process were proposed.

Separation of branched chain hydrocarbons and straight chain hydrocarbons is very important in the isomerization process. Grand canonical ensemble Monte Carlo simulations were used to investigate the adsorption and separation of iso-pentane and n-pentane in four types of zeolites: MWW, BOG, MFI, and LTA. The computation of the pure components indicates that the adsorption capacity is affected by physical properties of zeolite, like pore size and structures, and isosteric heat. In BOG, MFI and LTA, the amount of adsorption of n-pentane is higher than iso-pentane, while the phenomenon is contrary in MWW. For a given zeolite, a stronger adsorption heat corresponds to a higher loading. In the binary mixture simulations, the separation capacity of n-and iso-pentane increases with the elevated pressure and the increasing iso-pentane composition. The adsorption mechanism and competition process have been examined. Preferential adsorption contributions prevail at low pressure, however, the size effect becomes important with the increasing pressure, and the relatively smaller n-pentane gradually competes successfully in binary adsorption. Among these zeolites, MFI has the best separation performance due to its high shape selectivity. This work helps to better understand the adsorption and separation performance of n- and iso-pentane in different zeolites and explain the relationship between zeolite structures and adsorption performance.

Codensification of agroforestry residue with bio-oil can improve the pellet quality with reduced energy consumption and expand the utilization of bio-oil. This study comprehensively evaluates the effect of bio-oil addition on the storage, transportation, and combustion characteristics of the pellets. The results confirm that under a low pressure of 63.69 MPa bio-oils are more efficient in improving the pellet durability than selected solid additives due to the high viscosity which generated strong adhesion force during densification and enabled stronger particle interlocking of the feedstock. In addition, the hydrophobicity of the apple tree branches pyrolysis oil (APO) added pellets were enhanced, due to the introduction of hydrophobic groups and the improvements in the surface morphology. Besides, APO improved the energy density and fuel characteristics of the pellets via the change of chemical compositions. Above all, addition of the APO additive enhanced the quality of the fuel pellets. Moreover, by a...

Knowledge about partitioning constants of hydrophobic organic compounds (HOCs) between the polymer and aqueous phases is critical for assessing chemical environmental fate and transport. The conventional experimental method is characterized by large discrepancies in the measured values due to the limited water solubility of HOCs and other associated issues. In the current work, a novel three-phase partitioning system was evaluated to determine accurate low-density polyethylene (LDPE)-water partition coefficients (KPE-w). By adding sufficient surfactant (Brij 30) to form the micellar pseudo-phase within the polymer/water system, the KPE-w values were obtained from a combination of two experimentally measured values, that is, the micelle-water partition coefficient (Kmic-w) and the LDPE-micelle partition coefficient (KPE-mic). The method presented here is capable of shortening the equilibration time to half a month, and avoiding defects of the traditional method with respect to directly measured aqueous phase concentrations. Herein, the KPE-w values were determined for HOCs with little errors. Meanwhile, based on the 120 experimental KPE-w data, several in silico models were also developed as valid extrapolation tools to estimate missing or uncertain values. Analysis of the underlying solubility interactions in the nonionic surfactant micelles were investigated, providing additional support for the reliability of the proposed method.

A parametric study was conducted for the cost reduction of polysilicon by decreasing the electrical energy loss of an existing Siemens reactor. In this work, a quartz ceramic lining was applied onto a reactor vessel, and the hot emitter mechanism was adopted to enhance the energy efficiency for the production of polycrystalline silicon. The effects of the geometrical and heat transfer parameters on the energy efficiency and productivity of the Siemens reactor were examined. Our results indicate that the ceramic lining behaved similarly to thermal insulators by restricting the heat transfer through the ceramic lining, causing the lining surface facing the heated polysilicon rod to emit thermal radiation, thus contributing to reactor’s energy efficiency. The results further demonstrated that the impact of the ceramic lining emissivity on the total radiated heat loss was very small. Furthermore, by addition of a quartz ceramic lining, there is a noteworthy reduction in the total electrical current, resulting in a smoother radial-dependent temperature and thermal stress distribution; thus, a higher deposition radius for the rods can be achieved. According to the energy efficiency analysis, the average energy consumption for the existing 24-rod Siemens reactor can be decreased from 55 kWh per kilograms polysilicon to approximately 36 kWh per kilograms polysilicon.

Oil refineries produce a variety of relatively intricate and biodegradable wastewater streams. A ternary micro-electrolysis filler (iron (Fe)-biochar (BC)-copper (Cu)) was synthesized using BC produced from waste Lycium barbarum L. branches by high-temperature anaerobic calcination, and was then used to treat oil refinery water. To evaluate the applicability of Fe-BC-Cu, the effects of various reaction parameters, including the initial pH of wastewater, Fe-BC ratio, and Fe-BC-Cu ratio, were investigated. A comparative study was conducted using three different kinds of fillers (BC, Fe-BC, and Fe-BC-Cu) to determine the reaction behavior, which was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and EDS mapping. The results of batch studies revealed that the maximum chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiency was 77.11% and 68.71%, respectively, under the optimal conditions of an initial wastewater pH of 4.0, Fe-BC ratio of 1:1, and Fe-BC-Cu ratio of 1:1:1. The reusability of the Fe-BC-Cu filler was measured to ensure that the COD removal efficiency was maintained at around 80% during 10 cycles. The results of a heavy metal analysis of the effluent indicated that the application of the Fe-BC-Cu filler in wastewater treatment presented no risk of heavy metal release. The microscopic ball-shaped structure revealed by SEM facilitated a suitable micro-electrolysis reaction rate. The removal mechanism of organic pollutants in the wastewater by the Fe-BC-Cu micro-electrolysis filler could be due to the synergistic effects of electrochemical oxidation, adsorption, and coprecipitation of iron hydroxides. The extraordinary performance of the Fe-BC-Cu micro-electrolysis filler for organic pollutant removal indicated its practical potential for industrial applications.

The primary objective of the present study is to investigate the variations of soot particles’ oxidation reactivity along the components of the exhaust after-treatment system in a diesel engine and analyze its quantitative correlation with surface functional groups (SFGs) and graphitization degree. Soot particles generated from a 16-cylinder turbocharged diesel engine were sampled thoroughly before and after the diesel oxidation catalyst (DOC), as well as after a catalyzed diesel particulate filter (CDPF). Using a set of characterization techniques of Fourier transform infrared (FTIR), Raman spectroscopy and Thermal gravimetric analyzer (TGA), the surface functional groups (SFGs), graphitization degree and oxidation reactivity of soot particle samples along the exhaust after-treatment system components were examined. Results showed that, for all conditions, soot oxidation activation energies increased almost linearly along the after-treatment system, indicating that soot particles became more and more stable, with the inherent graphitization degree achieved the highest right after the CDPF. Meanwhile, the combined characterization results also indicated that amorphous carbon and reactive light volatile fractions have been removed or oxidized via passing through the DOC and CDPF monolith. It was thus concluded that the higher oxidation activity of soot particles was characterized by lower graphitization degree and higher aliphatic C-H group concentration. The catalyst components in the after-treatment systems (DOC and CDPF) effectively increases the graphitization of the exhaust particles, leaving more stable particles that would require much higher energies from active regeneration or more powerful catalysts on the CDPF wall surface to clean them up.

A surface plasmon resonance (SPR) sensor based on side-polished two-mode fiber (TMF) coated with indium tin oxide (ITO) film is proposed. ITO enables tuning of resonance wavelength of the sensor through changing its carrier concentration. The advantages of the TMF and ITO are combined in the sensor, which can achieve high sensitivity and plasma frequencies in the near-infrared region. The impact of ITO film thickness and residual fiber thickness on the sensing performance are numerically investigated with LP01 and LP11a modes coupled to specific surface plasmon modes. The results show that the resonance wavelength locates in 1500-2200 nm and an average sensitivity of ~10149 and ~10400 nm/RIU can be achieved for LP01 and LP11a modes, respectively, when the environmental refractive index varies between 1.33 and 1.39. The penetration depths of evanescent wave for the LP01 and LP11a modes are 460 and 502 nm, respectively. Both the sensitivity and penetration depth of the sensor are larger than those of single-mode fiber and multimode fiber based SPR sensors. The proposed sensor can play an important role in various applications, including environment, medicine, and security.

Extensive true-triaxial unloading tests are conducted on rectangular Miluo granite specimens to investigate their crack propagation behavior and peak unloading strength properties. Experimental results demonstrate that their failure mode transforms from shear to slabbing with the increase in intermediate principal stresses σ2. Under a lower value of σ2 , the dominant failure mode represented by the macro shear band is composed of several meso-extensional cracks parallel to the maximum principal stress σ1, and the fracturing process indicates intensive dislocation and slide owing to the normal force acting on extensional cracks. However, the increase in σ2 exacerbates the extensional cracks and further propagates them toward the end of the specimen along the direction of σ1, if σ3 is unloaded to 0. This is primarily due to the enhanced ability to resist mutual slide and squeeze among extensional cracks in the shear band, and the promotion of crack initiation and propagation in the unloading direction (σ3 ) owing to the provided free surface. The transformation of the cracking mode is revealed via three-dimensional combined finite/discrete element modeling, scanning electron microscope observations, and acoustic emission signal feature (average frequency, rise angle, Acoustic emission (AE) counts, and accumulated AE energy) analysis. The peak unloading strength exhibits an initial increase followed by a decrease as a function of σ2. Four rock-strength criteria are employed to evaluate the true-triaxial data with emphasis on predictability in practical applications and accuracy between best-fitting functions (experimental data) and theoretical (predicted) solutions. It is demonstrated that modified the Wiebols–Cook criterion and modified Lade criterion cannot accurately estimate the unloading strength throughout the true-triaxial data. Although the Mogi 1971 criterion fits the experimental data (higher correlation coefficients) well, it cannot be correlated to strength parameters (cohesion and internal frictional angle). Hence, it fails to predict the real strength values if complex true-triaxial unloading tests are not performed. The linear Mogi criterion is recommended for predicting the true-triaxial unloading strength of granite.