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The aim of this paper is to investigate the adhesion of municipal solid waste incinerator bottom ash (MSWIBA) and limestone to asphalt using the principles of surface energy theory. MSWIBA asphalt mixes are known for their satisfactory water stability, with adhesion being a crucial factor, as demonstrated in previous freeze-thaw splitting tests. Contact angles of ground MSWIBA and limestone were measured using a capillary rise test, eliminating the influence of material surface structure. Subsequently, adhesion work and spalling work were calculated to correlate with water-induced damage. The results showed that the sequence of adhesion work was fine MSWIBA > limestone > coarse MSWIBA, while the sequence of spalling work was coarse MSWIBA > limestone > fine MSWIBA. The adhesion of MSWIBA asphalt mixes was evaluated using the water boiling test image method to validate the findings of surface energy theory. In both asphalt tests, the spalling rate followed this sequence: coarse MSWIBA > limestone > fine MSWIBA. The Adhesion index ER ranked as follows: ER Fine MSWIBA > ER limestone > ER coarse MSWIBA. These results suggest that the water stability of MSWIBA asphalt mixes is influenced by the surface energy of the components. Consequently, indices derived from surface energy theory can be applied in formulating and predicting the properties of MSWIBA asphalt mixes. [ABSTRACT FROM AUTHOR]

A new phosphor-in-glass film (PiGF) color converter with high heat dissipation capability was proposed for high-power laser illumination. To intensify heat conduction, a composite structure was fabricated by welding the PiGF to a copper block through a silver layer. The PiGF converter was found to have a high quantum yield and similar fluorescence lifetime as the original phosphors. The optical characteristics of this material were investigated by varying the thickness of PiGF and the lase power. Under the excitation of 8.78W laser power, the PiGF converter with 100 μm film thickness enables a luminous efficacy of 187.9 lm/W, a CCT of 6150 K, and a perfect chromaticity coordinate of (0.3174, 0.3351). In addition, a maximum luminous flux of 4449 lm was obtained when the laser power reached 27.42 W. Besides, The PiGF converter displayed low working temperature and stable optical performance under the sustained excitation test, which indicates that the PiGF converter exhibits excellent opto-thermal performances. In general, an effective solution is put forward for the heat dissipating obstacle of laser lighting. [ABSTRACT FROM AUTHOR]

The current trend in the asphalt industry is to increase the utilization of recycled asphalt pavement (RAP). In general, there are two types of RAP binder in RAP aggregates, the mobilized RAP binder and the immobilized RAP binder. The former can be blended into the virgin binder to coat aggregates during asphalt blending, while the latter can be treated as black rocks because they have already become an outer crust of RAP aggregates. Studies have focused on the mobilized RAP binder quantification and the significance of mobilized RAP binder to mixture performances. However, it remains unknown whether the immobilized RAP binder affects mixture performances. This study developed a laboratory procedure for immobilized RAP aggregates preparation and investigated the contribution of immobilized RAP binder to asphalt-aggregate interaction as well as the performance of 100% recycled asphalt mixtures. The work of adhesive energy and the K-B-G* model were adopted to characterize the asphalt-aggregate interaction for asphalt mortar. Resilient modulus and dissipated creep strain energy were used to evaluate the stiffness and cracking resistance of 100% recycled asphalt mixtures. Results showed that the immobilized RAP binder can strengthen the asphalt-aggregate interaction and improve the cracking resistance of 100% recycled asphalt mixtures by increasing total asphalt content. However, if the total asphalt content remains the same, the immobilized RAP binder increases stiffness but decreases the cracking resistance of 100% recycled asphalt mixtures. [ABSTRACT FROM AUTHOR]

Research on the aging process of styrene-butadiene-styrene block copolymers (SBS) block copolymers modifier has practical significance in guiding the recycling of SBS-modified asphalt pavement. The objective of this study is to investigate the aging process of SBS modifier under various oxygen and thermal conditions to address the variations of physical properties and chemical reaction during the service life of recycled asphalt pavement (RAP). In the proposed testing process, SBS modifier was thermal oxidative and vacuum thermal aged at different temperatures and time prior to blending with base asphalt to prepare SBS-modified asphalt. SBS modifier was first dissolved by carbon tetrachloride (CCl4) and then tested through infrared (IR), gel permeation chromatography (GPC), and thermogravimetric (TGA) tests to investigate the variations on microstructure and chemical compositions of aged SBS modifier. The effect of aged SBS modifier on performance of SBS-modified asphalt was evaluated by comparing the mechanical and chemical properties of base and SBS-modified asphalts. Based on the results of the experimental program, appearance variation, modifying effects, and chemical reaction of SBS modifier under oxygen condition were obviously different from that of vacuum condition. The chemical reaction of SBS modifier was not significant at vacuum and high temperature condition, instead, a small amount of degradation was observed. Degradation of mechanical performance of SBS-modified asphalt was mainly caused by aging of base asphalt. Therefore, the SBS modifier in the RAP was suggested to be considered in the mixture design. [ABSTRACT FROM AUTHOR]

This work investigated the effects of the aging process on the performance of asphalt binder under multiple environmental conditions based on multitechnique experimental results. The aging process of matrix asphalt binder with the increase of temperature for 96 h, 192 h, and 288 h was simulated by an aging oven. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to quantify the microcosmic characteristics of asphalt after aging. The results showed that the aging process of asphalt is an oxidation process, and the oxygen-containing functional groups (C═O and S═O) increased with aging. At the macroscopic level, the changes of adhesion properties and bond strength of asphalt were studied by testing the changes in three major indexes. The penetration and ductility of asphalt decreased, and the softening point increased with aging. The changes of rheological performance were tested by dynamic shear rheometer (DSR) and Brookfield viscometer. Mutual transformation of aromatic phenol, colloid, and asphaltene led to an increase in asphalt viscosity and decrease in workability. Antifatigue performance gradually decreased under the action of load with the extension of time. The elastic properties were finally damaged by fatigue. [ABSTRACT FROM AUTHOR]

Inspired by the concept of conserving resources, bottom ash has been increasingly utilized in road construction as a readily available waste material. This study sought to address this gap by quantifying the carbon benefits associated with bottom ash application. Through a comprehensive analysis grounded in life cycle theory, author evaluated the changes in energy consumption and carbon emissions before and after the integration of bottom ash into the road construction process. The analysis employed the raw material production stages of different pavement materials as the system boundary. By determining the optimal amount of bottom ash and calculating the associated values, the study proposed an efficient application scheme for utilizing bottom ash in urban engineering construction projects. The results showed that bottom ash had the least carbon reduction effect in permeable bricks, followed by cement concrete and cement stabilized macadam mixture. The most significant effect was observed in asphalt mixtures. However, energy consumption increased with the addition of bottom ash in asphalt mixtures, whereas it decreased in the other three products. The carbon reduction after applying bottom ash was predicted based on the annual growth rate of urban road construction. Under the premise of maintaining the non-destructive application performance of asphalt mixtures, the optimal carbon reduction benefit for a 20% addition of bottom ash was approximately 17,369.9 tons. In cement-stabilized crushed stone mixtures, the optimal carbon reduction benefit ws achieved with a bottom ash content of 30%, approximately 15,797.7 tons. The practice of utilizing bottom ash in road works was significant in terms of maximising the benefits of carbon reduction. • The carbon benefits of bottom ash dosing in engineering were studied. • Based on life cycle theory and carbon emission factor approach. • The carbon reduction of using bottom ash in actual road was calculated. • Bottom ash application had a striking carbon reduction effect compared to landfill. [ABSTRACT FROM AUTHOR]

• A VN62 fluorescent sensor with ESIPT propertywas designed, synthesized and characterized. • VN62 sensor exhibited rapid and stable detection of Al3+ with a remarkable fluorescence enhancement in aqueous solution. • The sensing mechanism of VN62 sensorto Al3+ wasreasonably speculated based on experimental results and theoretical calculations. • VN62 sensor was capable of recognizing Al3+ by test strips and imaging Al3+in plants and living cells. A new acylhydrazone fluorescent sensor (VN62) with excited intramolecular proton transfer (ESIPT) characteristics has been designed and synthesized through condensation of o -vanillin with 6‑hydroxy-2-naphthoic hydrazide for selective detection of Al3+ in aqueous medium. The structure of the VN62 sensor was characterized by various techniques such as 1H and 13C NMR and mass spectrometry, and also confirmed by single crystal X-ray diffraction. The VN62 sensor showed a remarkable fluorescence enhancement response to Al3+ over a broad pH range in a nearly 100 % aqueous solution without interference by most of tested metal ions and anions. Through fluorescence titration and a Job's plot experiment, the binding stoichiometry of VN62 with Al3+ was found to be 1:1. The limit of detection of VN62 toward Al3+ was determined as 39.6 nM and the binding constant was 2.66 × 104 M−1. Comprehensive analyses by HR-MS, 1H NMR and density functional theory calculations illustrated that the VN62 sensor coordinated with Al3+, forming a stable trigonal bipyramid structure complex, which blocked the ESIPT and photoinduced electron transfer processes and simultaneously promoted an intramolecular charge transfer process, thereby leading to strong cyan fluorescence. Moreover, VN62 -loaded test strips were successfully applied for rapid and visual detection of Al3+. Furthermore, the VN62 sensor was used to visualize Al3+in plants and live cells. The results indicated that the VN62 sensor has great potential for detecting Al3+in biological systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Increasing the specific impulse has become one of the main trends in the development of Hall thrusters and may be achieved by increasing the proportion of multiply charged ions in the plume. In this study, the multiple ionization characteristics of Hall thrusters with large height–radius ratios and their effects on the specific impulse and other performance parameters were examined via numerical simulations. The simulation results show that the proportion of multiply charged ions in a Hall thruster with a large height–radius ratio increases by 7.8 percentage points, compared with that of the traditional Hall thruster, and the multiply charged ions can obtain a higher average jet velocity under an accelerating voltage, thereby improving the specific impulse and thrust of the thruster. Further analyses show that a structure with a large height–radius ratio reduces the cooling effect of the channel wall on the electrons, and the increase in electron temperature effectively promotes the occurrence of the multiple ionization process. In addition, the smaller wall area and the larger magnetic field intensity in the near-wall region inhibit the electron near-wall conduction and prevent the potential negative effect of the increase in electron current caused by multiply charged ionization, which ensures a high level of efficiency. It was proved that multiple ionizations contribute positively to the specific impulse and efficiency of Hall thrusters with a large height–radius ratio. This serves as a reference for the high specific impulse design of Hall thrusters with large height–radius ratios and provides a new optimization perspective for improving the specific impulse of Hall thrusters. [ABSTRACT FROM AUTHOR]

[Display omitted] • ML models predicted the strength of the cementitious material using the waste composition. • CaO, water-binder ratio, SiO 2 , water glass modulus, Al 2 O 3 influenced strength via SHAP analysis. • SHAP showed intricate links between CaO, SiO 2 , Al 2 O 3 , and strength, aiding optimization. This study examines the analysis and treatment of diverse types of solid waste alkaline-activated cementitious materials utilizing machine learning techniques. To account for the variability of solid waste alkaline-activated cementitious materials, three crucial chemical components (aluminum trioxide, calcium oxide, and silicon dioxide) were chosen as representative features. A total of 274 pertinent datasets were collected and split into training and testing sets with an 80% to 20% ratio for analysis. Six machine learning models, including multilayer feedforward neural network, genetic algorithm neural network, support vector machine, random forest, radial basis function neural network, and long short-term memory network, were employed to construct predictive models. The optimal hyperparameters were identified via grid search. The performance of the models was assessed using the training and testing sets, revealing that all models exhibited strong predictive and generalization capabilities on both sets. Among the models, the support vector machine model achieved the highest performance, yielding an R2 value of 0.9054, MAE of 4.1460, and NRMSE of 0.0997. Through the utilization of SHAP (Shapley Additive Explanations) analysis, the interplay between factors and the significance of features were examined. Calcium oxide, water-to-binder ratio, silicon dioxide, modulus of water glass, and aluminum trioxide were recognized as the primary factors that influence the compressive strength. The research findings offer guidance for optimizing the performance of alkaline-activated cementitious materials made from solid waste. [ABSTRACT FROM AUTHOR]

With the continuing increase in the use of recycled asphalt pavement (RAP) and recycled asphalt shingle (RAS) for highway construction, there is a concern over how much of the aged asphalt binder inside RAP/RAS can be blended into virgin asphalt binder. In this study, the RAP/RAS binder mobilization rates of 13 different mixtures produced by three different types of asphalt plants in Tennessee were determined using fluorescence microscopy and gel permeation chromatography (GPC). A multiple regression model was developed to explore the factors critical to enhancing the mobilization rate of the RAP/RAS binder. Results showed that the RAP/RAS binder mobilization rate was significantly lower than 100% for most mixtures, indicating that only part of the RAP/RAS binder was mobilized during the production process. The mixing and delivery temperatures had significant influence on the mobilization rate of RAP/RAS binder. In addition, the aging degree of RAP/RAS binder also significantly affected the mobilization rate. [ABSTRACT FROM AUTHOR]

• The intermolecular interaction between virgin and aged asphalt. • The interaction affected the mixed binder performance. • The interaction degree was related to the chemical difference of binders. The mixing process of virgin and aged asphalts is the essential of the rejuvenation of recycled asphalt pavement. The molecular association of asphalt may be decomposed and reconstructed due to the intermolecular interactions while virgin and aged asphalts are blended together. This study investigated the mixing effect between virgin and aged asphalts use rotational viscometer (RV), gel permeation chromatography (GPC) and molecular simulation methods. The high temperature viscosity of the mixed binder was tested by RV, which indicates that the viscosity of the mixed binder was not a linear superposition of virgin and aged asphalt. The GPC was used to test molecular weight of virgin, aged and mixed binders. The comparison between tested and calculated GPC curves shows that the molecular weight of the mixed binder was not the superimposed of virgin and aged asphalts. The molecular simulation indicates that the asphaltene and resin molecules had a tendency of gathering together. The mixing of two asphalt binders with different chemical structures could narrow the distance between aggregated molecules. [ABSTRACT FROM AUTHOR]

Asphalt rejuvenation technology is an effective method to recycle reclaimed asphalt pavement (RAP) for the production of high-quality recycled asphalt mixtures. This approach contributes to mitigating environmental pollution and facilitating resource recycling. In this study, the impact of rejuvenator molecules on the rejuvenation process was explored by utilizing theoretical models and dynamics simulations. Free volume theory models were used to calculate the diffusion coefficient, while molecular dynamics (MD) simulations revealed the internal energy changes during diffusion. Molecules with high interaction with aged asphalt are easier to reach the homogeneous state in diffusion systems under higher temperatures. The quantification of blending by Fick's 2nd law suggests that the blending process consists of three stages: an intense diffusion phase, a stabilization phase, and a homogeneous state phase. The time taken to reach the homogeneous stage depends on the chemical structure of the rejuvenators and the temperature. This study elucidates the molecular-scale mechanism of RAP rejuvenation and provides a roadmap for improving environmentally friendly RAP rejuvenation technology. • Blending process consists of three phases. • Interactions and free volume control the diffusion process. • Saturated-based molecules is more susceptible to high-temperature excitation. [ABSTRACT FROM AUTHOR]

It is shown from the experimental results of existing Hall thrusters that erosion phenomena occur in the magnetic poles when the maximum magnetic field is located in the plume region. The developed Particle-in-Cell model is used in this paper for simulation research on magnetic pole erosion of Hall thrusters. The simulation results show that when the maximum magnetic field is located in the plume region, there is a large potential drop between the channel outlet and the magnetic pole. Therefore, low-energy ions close to the outlet plane are accelerated to bombard the magnetic pole surface, which is an important reason for the magnetic pole erosion. Moreover, the ion flux and energy bombarded on the magnetic pole under two conditions (magnetic pole grounding and floating) are calculated and compared. It is shown from the simulation results that grounding the magnetic pole can reduce the potential drop between the channel outlet and magnetic pole, thereby reducing the ion energy and flux bombarded on the magnetic pole and effectively alleviating the erosion of the magnetic pole. [ABSTRACT FROM AUTHOR]

Abstract It is commonly accepted that high neutral density or low bulk axial velocity will efficiently enhance ionization. At present, all the operation of neutral gas flow inside the Hall thruster is an attempt to reduce axial velocity of neutral gas and extend residence time. Based on the idea, we proposed the azimuthal diversion rail (ADR) Hall thruster for the first time in preliminary work, and provided a kind of brand new method to reduce axial velocity of neutral gas. Compared to other modes, such kind of mode features simple structure, light weight and significant effect, in which axial movement is transformed to circumferential movement through elastic collision, thus the residence time and neutral density in the channel can be increased, ionization degree and discharge performance are improved accordingly. However, we found in the ADR research process made at later stage, the location of ADR in the discharge channel exerts significant impact on discharge. Therefore, this paper studies the effect of the ADR location on the discharge performance of Hall thrusters. The location of the ADR can affect the distribution of the propellant density in the channel of the Hall thruster, thereby affecting the propellant utilization and performance. The thrust, specific impulse, efficiency and propellant utilization of the ADR are measured in three different locations in the channel, respectively. The propellant density in the ionization zone is higher when the ADR is flush with the anode top surface. Furthermore, the propellant utilization can be increased by 12% and 9% compared with that at the bottom and the middle of the anode, respectively, resulting in the thrust being increased by up to 3.2 mN (10%) and 2 mN (8.5%) and the anode efficiency being increased by up to 9% and 6%. The location of the ADR has a significant effect on the performance of the thruster. The sensible placement of the rail can effectively increase the propellant density in the ionization zone to improve the performance. The results of the study can be used to guide the design of Hall thrusters with ADR. Highlights • Effects of the azimuthal diversion rail location on performance of Hall thrusters is studied. • It is proved the rail placement can increase the propellant density in the ionization zone. • Azimuthal diversion rail location can be used to improve the hall thruster performance. [ABSTRACT FROM AUTHOR]

To improve the performance of thrusters by using two permanent ring-shaped magnets to push a magnetic field downward, we propose an annular–cylindrical combined-channel Hall thruster and numerically study its performance. The results indicate that, compared with simple annular channels, the annular–cylindrical combined channel can effectively increase the neutral gas density contained within it and increase the degree of ionization, efficiency, thrust, and specific impulse. Moreover, the sputtering zone of discharge channel is in front of the permanent magnets, i.e., wall erosion occurs upon ion bombardment during discharge. However, ions cannot bombard the permanent magnetic rings, thus guaranteeing a constant magnetic field and long discharge lifetime. [ABSTRACT FROM AUTHOR]

Abstract A 200-W Hall thruster was designed using permanent magnets placing the axial maximum magnetic field outside of the channel, and the anode/gas distributor as an integrated U-shaped structure. A split structure is adopted for the discharge channel to conveniently change the wall material. With the initial conditions that the anode mass flow is maintained at 0.8 mg/s, 1.0 mg/s and 1.2 mg/s over a voltage range of 150–400 V (at 50 V intervals), the discharge properties were determined for the two thruster models with the channel walls composed of graphite and boron nitride (BN). The results demonstrate that under identical operating parameters, the properties of the thruster with the graphite channel walls are similar to the properties of the thruster with the BN channel walls. The maximum difference of the discharge current between the two wall materials is 6.2%; the maximum difference of the thrust and the specific impulse is 3.3%, and that of the anode efficiency is 1.7% (absolute value). These differences are smaller than the corresponding parameter differences observed from changing wall materials in other common Hall thrusters. Highlights • A permanent magnet Hall thruster with graphite channel wall is studied. • Results show differences are smaller with graphite and BN wall. • This study given a new choice of Hall thruster discharge wall to prolong life. [ABSTRACT FROM AUTHOR]

The present study investigated functional group distribution of virgin and aged asphalt binder through liquid chromatography (LC) transform, a device that combines the functions of Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The corresponding molecular models of virgin and PAV aged asphalt components were constructed. The temperature-dependent density of the model was calculated to verify the accuracy of the model. The chemical structure of the components was evaluated using a series of indicators, including the aromatic index, the aging index, the C O index and the δ (CH 3 )/δ (CH 3  + CH 2 ). The structural changes of components with molecular weight of the virgin and aged asphalt were also analyzed. The molecular simulation results indicated that the molecular model developed in this study was consistent with real asphalt. [ABSTRACT FROM AUTHOR]

In this paper, a new “convex” external magnetic pole structure is proposed. With this structure, two different configurations of the cathode inside and outside the magnetic separatrix can be realized by changing the position of the magnetic separatrix instead of changing the position of the cathode in the radial direction. Furthermore, the discharge plume, coupling voltage, and performance of the thruster under different configuration conditions are studied experimentally. The experimental results indicate that, when the cathode is located inside the magnetic separatrix, the effective acceleration voltage is higher, the coupling voltage between the cathode and the thruster is lower, and the thruster performance (including thrust, specific impulse, and efficiency) is higher. When the cathode is located outside the magnetic separatrix, the effective acceleration voltage is lower, the coupling voltage between the cathode and the thruster is higher, and the thruster performance is degraded. When the cathode is located inside the magnetic separatrix, the thrust and specific impulse can be increased up to 2.3%, and the efficiency—up to 4.6%. This study provides a new method for the design of the magnetic separatrix and is of great importance for the coupling-matching design of the cathode and thruster. [ABSTRACT FROM AUTHOR]

With the use of high percentage recycled asphalt pavement (RAP), there is an increasing concern over how much of the aged binder in RAP that can be blended into virgin binder. In this study, a laboratory procedure was proposed based on fluorescence microscopy for quantifying the mobilization rate of aged binder in plant-produced RAP mixtures. This procedure was derived from the mean gray value of an asphalt-coated aggregate particle. A linear blending chart was developed and used to relate aged binder content to the mean gray value of binder blend. The mobilization rate of aged binder was calculated on the basis of surface area proportion of aggregates with different size. Three types of asphalt mixtures, including one warm mix with foaming technology, two hot mixes with or without rejuvenator, were used to validate the proposed method. Results indicated that the mobilization rate varied by aggregate type (virgin or RAP). Compared with hot mix, warm mix with foaming technology showed a slightly higher mobilization rate. [ABSTRACT FROM AUTHOR]

Discharge characteristics of a non-wall-loss Hall thruster were studied under different channel lengths using a design based on pushing a magnetic field through a double permanent magnet ring. The effect of different magnetic field intensities and channel lengths on ionization, efficiency, and plume divergence angle were studied. The experimental results show that propellant utilization is improved for optimal matching between the magnetic field and channel length. While matching the magnetic field and channel length, the ionization position of the neutral gas changes. The ion flow is effectively controlled, allowing the thrust force, specific impulse, and efficiency to be improved. Our study shows that the channel length is an important design parameter to consider for improving the performance of non-wall-loss Hall thrusters. [ABSTRACT FROM AUTHOR]

Hall thruster is an attractive type of electric propulsion that is being developed to replace the chemical propulsion deployed in many tasks on satellites. The research on Hall thrusters in China has gradually progressed from basic theory to engineering applications, especially with the experience of on-orbit flight tests in low earth and geostationary equatorial orbits. This paper discusses the progress of research on Hall thrusters in China in recent years. This includes the beam focusing, scaling, high specific impulse, long lifetime, and effective magnetic field excitation techniques, as well as the stabilization technique of low-frequency oscillation, along with other types of Hall thrusters, such as cylindrical Hall, double-stage Hall, cusped field, nested-channel Hall, and anode layer Hall thrusters. In conclusion, this paper discusses the programs intended for the future focusing on the development of thrusters, their application prospects, and their use in space applications. [ABSTRACT FROM AUTHOR]

In a 1350-W Hall-effect thruster, in which a technique for pushing down the magnetic field is implemented, a catastrophic discharge phenomenon is identified by varying the magnetic field strength while keeping all other operating parameters constant. According to experiments, before and after the discharge catastrophe, the plume changes from focusing state to a divergent state, and discharge parameters such as discharge current and thrust exhibit noticeable changes. The divergence half-angle of the plume increases from 22° to 46°. The oscillation amplitude and mean values of the discharge current significantly increase from 0.8 A to 4 A and from 4.6 A to 6.3 A, respectively, while the thrust increases from 89.3 mN to 91 mN. Analysis of the experimental results shows that as the maximum magnetic field of the thruster we developed is in the plume region, the acceleration occurs in the plume region and a large number of Xe 2+ ions appear in the plume area, the catastrophic discharge phenomenon observed. [ABSTRACT FROM AUTHOR]

A hollow indented anode is proposed for increasing the neutral gas density in a discharge channel, in order to improve the performance of the thruster. The experimental results show that a hollow indented anode structure can effectively improve the performance, compared to a hollow straight anode under similar operating conditions, in terms of thrust, propellant utilization, ionization rate, and anode efficiency. Furthermore, simulations show that the indented anode can effectively increase the neutral gas density in a discharge channel and on the centerline of the channel, compared to a hollow straight anode. In addition, it can increase the ionization rate in the channel and the pre-ionization in the anode. Therefore, the hollow indented anode could be considered as an important design idea for improving thruster performance. [ABSTRACT FROM AUTHOR]

A low-power Hall-effect thruster was designed with two permanent magnet rings. This Hall-effect thruster contains a symmetrical double-peak magnetic field with a gradient larger than that of conventional Hall-effect thrusters. The matching of the anode position with the magnetic field determines the performance of the thruster to a very large extent. This study investigates the laws and mechanisms that govern the front end of a U-shaped hollow anode at the inner magnetic separatrix, the outer magnetic separatrix, and the area between them and influence the discharge characteristics of the thruster. The study shows that with the increase of anode length, the ionization and acceleration zones are pushed down toward the channel outlet and even into the plume region. At the same operating point, both the thrust and the efficiency are the largest when the anode is placed between the inner and outer magnetic separatrices. When the anode is placed at the inner magnetic separatrix, both the thrust and the efficiency are small because of the heavy energy loss on the walls, despite the high degree of ionization. Finally, when the anode is at the outer magnetic separatrix, the performance of the Hall-effect thruster is the poorest because of the lower degree of ionization and larger divergence angle of the plume upon the shift of the ionization zone toward the plume region. [ABSTRACT FROM AUTHOR]

A 200 W No-Wall-Losses Hall Thruster (NWLHT-200 W) is designed and processed to verify the technology of pushing down magnetic field with two permanent magnetic rings. To create a magnetic field, NWLHT-200 W uses two permanent magnetic rings (inner and outer) in the absence of magnetic screen or magnetic component. The anode is at the internal magnetic separatrix position, and the thruster shell is hollow to enhance the heat dissipation of ceramics. The magnetic field strength at the channel outlet is 90% of the maximum magnetic field. In this study, the experimental results concerning the thrust, discharge current, specific impulse, and efficiency are presented and examined. Our experiments show that 'no erosive discharge' of wall is achieved within the range of 120-460 W; the maximum efficiency of the anode may reach 49%. The thruster designed can work stably for a long time, without any auxiliary heat dissipation equipment (heat pipe or radiator), which significantly prolongs the life of Hall thrusters. [ABSTRACT FROM AUTHOR]

This study adopts double permanent magnetic rings and four permanent magnetic rings to form two symmetrical magnetic peaks and two asymmetrical magnetic peaks in the channel of a Hall thruster, and uses a 2D-3V PIC-MCC model to analyze the influence of magnetic strength on the discharge characteristic and performance of Hall thrusters with an intermediate electrode and double-peaked magnetic field. As opposed to the two symmetrical magnetic peaks formed by double permanent magnetic rings, increasing the magnetic peak value deep within the channel can cause propellant ionization to occur; with the increase in the magnetic peak deep in the channel, the propellant utilization, thrust, and anode efficiency of the thruster are significantly improved. Double-peaked magnetic field can realize separate control of ionization and acceleration in a Hall thruster, and provide technical means for further improving thruster performance. Graphical abstract: [ABSTRACT FROM AUTHOR]

The characteristics of low-frequency oscillations of double-stage Hall thrusters are quite different from those of conventional single-stage Hall thrusters. In this paper, the effects of double-stage discharge on the low-frequency oscillations are experimentally investigated. The results indicate that the amplitude significantly decreases with increasing magnetic field strength and voltage during the ionization stage. Meanwhile, data analysis reveals that ionization occurs in both stages and that the transport ion current between the two stages is the key factor that affects the amplitude and main frequency of the oscillations. Two new processes, namely the ion transport and ion recombination caused by double-stage discharge, are found to be relevant to the change in the current oscillations. To summarize, the ionization stage relieves the oscillations in the acceleration stage, leading to a reduction in the amplitude of the discharge current. [ABSTRACT FROM AUTHOR]

The high amplitude pulse current during Hall thruster start-up is an important source of electromagnetic interference, which impacts the safety and reliability of the propulsion system. The characteristics of the pulse current, including the pulse current's integrated area, peak value, and transient time, are studied experimentally and theoretically under different Hall thruster discharge parameters. Results show that the pulse current's integrated area is determined by the atom density in the channel before Hall thruster start-up; the effects of coil current on the peak value and transient time of the pulse current are negligible. As the discharge voltage and mass flow rate increase, the pulse current peak value increases, the pulse current duration is inversely proportional to the discharge voltage and directly proportional to the mass flow rate. [ABSTRACT FROM AUTHOR]

The strength and shape of the magnetic field are the core factors in the design of the Hall thruster. However, Hall current can affect the distribution of static magnetic field. In this paper, the Particle-In-Cell (PIC) method is used to obtain the distribution of Hall current in the discharge channel. The Hall current is separated into a direct and an alternating part to calculate the induced magnetic field using Finite Element Method Magnetics (FEMM). The results show that the direct Hall current decreases the magnetic field strength in the acceleration region and also changes the shape of the magnetic field. The maximum reduction in radial magnetic field strength in the exit plane is 10.8 G for an anode flow rate of 15 mg/s and the maximum angle change of the magnetic field line is close to 3° in the acceleration region. The alternating Hall current induces an oscillating magnetic field in the whole discharge channel. The actual magnetic deformation is shown to contain these two parts. [ABSTRACT FROM AUTHOR]

The incorporation of high percentage (>30%) recycled asphalt pavement (RAP) into asphalt mixtures has become more popular. Various methods have been proposed to determine how much of RAP binder can be effectively blended into virgin binder. However, few methods can be used to test the blending efficiency of plant-produced asphalt mixtures. This study proposed a method of measuring the blending efficiency of plant-produced mixtures using Fourier Transform Infrared Spectroscopy (FTIR). Three types of asphalt mixtures, including one warm mix, two hot mixes with or without rejuvenator, were used to validate the proposed method. Results indicate that RAP particles varied in oxidation, but mixing RAP binder with virgin binder could reduce this heterogeneity. Among the three mixtures, warm mix showed the highest blending efficiency, while adding rejuvenator had a limited effect on the blending efficiency. The proposed method was further verified using Gel Permeation Chromatography (GPC). [ABSTRACT FROM AUTHOR]

Dispose and utilization of municipal solid waste incinerator bottom ash (MWSIBA) is one of the imperative issues in environmental protection. The applicability of substitution for natural aggregate with MWSIBA in asphalt mixture was investigated by the performance and micro structure of asphalt mixtures with diverse porosity levels of MWSIBA (varying the replacement percentage). The effects of porosity of MWSIBA on asphalt mixture performance were captured by determination of Marshall stability, tensile strength, dynamic stability and the maximum flexural-tensile strain. The horizontal vibration extraction procedure test was implemented for the heavy metal leaching concentration to evaluate the environmental safety of MWSIBA asphalt mixture. Chemical and micro-morphologic characterization for MSWIBA were conducted to explore the mechanism of moisture damage resistance of asphalt mixture. Results indicated that porosity and replacement rate of MWSIBA exerted impacts on properties of asphalt mixture. The rutting resistance of asphalt mixture decreased due to the addition of MWSIBA, resulting in a reduction in high temperature performance. MWSIBA with porosity no less than 19% was beneficial to the improvement of moisture susceptibility and low temperature performance of asphalt mixture, while high mixing amount of MWSIBA was unfavorable to the properties of asphalt mixture. The water immersion stimulated the hydration reaction in MWSIBA, leading to the formation of C-(A)-S-H gel with strong cementation property, which enhanced the adhesion between MWSIBA and asphalt binder. MWSIBA asphalt mixture presented lower heavy metal concentration and better environmental safety than MSWIBA. • The applicability of substitution for natural aggregate with MWSIBA in asphalt mixture was investigated. • Both porosity and replacement rate of MWSIBA exerted impacts on properties of asphalt mixture. • The formation of C-(A)-S-H gel contributed to superior resistance to moisture damage of MWSIBA asphalt mixture. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of amine ASA on the moisture resistance was analyzed based on the thermodynamic properties. • Amine ASA increased the polar components and decreased the polar components of asphalt. • Amine ASA enhanced the dry adhesive and reduced the free energy released with moisture. • The ER indicating the moisture resistance and compatibility of an asphalt-aggregate combination was enhanced by ASA. • The SFE-based criteria for material selection of HMA were tentatively proposed. This study investigates the moisture damage mechanism and material selection of hot-mix asphalt (HMA) with amine-based antistripping agent (ASA). The surface free energy (SFE) of virgin and ASA modified asphalts and five aggregates with different acidities were measured, yielding the compatibility of each asphalt-aggregate combination. The corresponding compacted mixtures were evaluated by tensile strength ratio (TSR) considering the freeze–thaw and MIST conditioning. The use of amine ASA changed the thermodynamic properties of asphalt by decreasing the nonpolar components and increasing the polar components, which enhanced the work of adhesion between asphalt and aggregate and reduced the free energy released at the presence of water. The wettability of asphalt over aggregate was also increased due to the ASA, suggesting a better coating quality of asphalt mixtures was achieved. All those changes led to the increased energy ratio (ER), indicating the improved moisture resistance and compatibility of materials. At the molecular level, it might be because the amino groups from ASA adsorbed the silanol groups at the aggregate surface, leading to a stronger bond between asphalt and aggregate. The asphalt mixtures with acidic aggregate exhibited more serious moisture damage, which could be attributed to the lower dry adhesion energy and the larger free energy released with moisture. To enhance the moisture resistance, the selection of compatible asphalt-aggregate combinations seemed more effective than the use of amine ASA. The ERs of all the asphalt-aggregate combinations correlated well with the TSR results, and the SFE-based criteria for material selection of HMA were tentatively proposed. [ABSTRACT FROM AUTHOR]

The incorporation of recycled (aged) binder into virgin asphalt has become more popular in asphalt paving industry nowadays. However, the exact mechanism of the diffusion process between virgin and aged binders is still largely unclear. This paper presents a study in which molecular dynamics (MD) simulation was employed to investigate the diffusion between virgin and aged binders. Two asphaltic models with three components including asphaltenes, resin, and oil were built with different components ratio. The model of aged binder was constructed by increasing the asphaltenes ratio on the basis of virgin binder. The results of simulation was verified by GPC and both show that the diffusion of large molecules in asphalt was a critical factor for the diffusion of binders in that it was more susceptible to the changes of temperature. In an inter-diffusion model of virgin and aged binders, the diffusion coefficients of binders were not only determined by the diffusion ability itself, but also influenced by the properties of the diffusion acceptor. Based on this finding, the effect of different sequence of adding rejuvenator during recycling of asphalt mixtures was investigated. The result shows that adding rejuvenator into aged binder first could accelerate the inter-diffusion rate between virgin and aged binder in maximum level, thus increased the efficiency of recycling. [ABSTRACT FROM AUTHOR]

In this work, we synthesize two new dyes with phenothiazine (PTZ) as π-bridge, benzothiadiazole (BTD) as acceptor moiety, and rhodanine-3-acetic acid (-RA) / cyanoacrylic acid (-CA) as anchoring group. In combination with a previously reported one with anchoring group of carboxylic acid (-CH), the effects of the three anchoring groups on material properties and the performance of dye-sensitized solar cells (DSSCs) are investigated. It is found that in terms of anchoring group for DSSC dye, the moiety features of electron-pulling ability, the spatial stretching, as well as its conjugation to the main molecular axis should be considered simultaneously. When attached over a para-phenyl group to a phenothiazinyl-benzothiadiazolyl dye, among the three commonly used anchoring groups of -RA, -CA and -CH, the last one is the best, with which the CBPTZ-BTD1 based DSSC exhibits the highest power conversion efficiency of 6.69%, mainly due to the highest dye loading, open-circuit voltage, and rather high fill factor. [Display omitted] • Three phenothiazinyl-benzothiadiazolyl dyes are reported for DSSC applications. • Dye anchoring groups are acid of rhodanine-3-acetic, cyanoacrylic, and carboxylic. • The carboxylic acid dye based DSSC exhibits the efficiency of 6.69%. [ABSTRACT FROM AUTHOR]

Traffic-data recovery plays an important role in traffic prediction, congestion judgment, road network planning and other fields. Complete and accurate traffic data help to find the laws contained in the data more efficiently and effectively. However, existing methods still have problems to cope with the case when large amounts of traffic data are missed. As a generalization of vector algebra, geometric algebra has more powerful representation and processing capability for high-dimensional data. In this article, we are thus inspired to propose the geometric-algebra-based generative adversarial network to repair the missing traffic data by learning the correlation of multidimensional traffic parameters. The generator of the proposed model consists of a geometric algebra convolution module, an attention module and a deconvolution module. Global and local data mean squared errors are simultaneously applied to form the loss function of the generator. The discriminator is composed of a multichannel convolutional neural network which can continuously optimize the adversarial training process. Real traffic data from two elevated highways are used for experimental verification. Experimental results demonstrate that our method can effectively repair missing traffic data in a robust way and has better performance when compared with the state-of-the-art methods. [ABSTRACT FROM AUTHOR]

The magnetic field distribution of Hall thrusters has a crucial impact on its performance. Studies have mostly focused on the magnetic field distribution within the channel and near the channel exit, but less attention has been paid to the magnetic field distribution in the near-field plume region. Two different magnetic field distributions were designed. The influence of the magnetic inclination in the plume region on the performance of a low-power Hall thruster was investigated using a particle-in-cell (PIC) numerical simulation and experimental study. The results indicate that the magnetic field with inclined inward can effectively improve the performance of Hall thrusters, relatively increasing the thrust by 3.6%–9.6%, anode specific impulse by 3.8%–9.8%, and anode efficiency by 2.5%–5.5% at a fixed flow rate. It can also reduce the plume divergence angle, and the maximum decrease in the plume divergence half-angle is approximately 7°. The main reason is that the radial electric field in the plume region under an inward-inclined magnetic field is lower than that with an outward-inclined magnetic field, thus making the radial velocity of ions in the former magnetic field lower than that in the latter magnetic field, ultimately driving more ions to the thruster center. • The inclination of magnetic field lines in the plume region can affect performance of Hall thrusters. • The magnetic field with inclined inward in the plume region can enhance performance and reduce plume divergence angle of Hall thrusters. • When designing Hall thrusters, the magnetic field lines in the plume region should be kept inclined towards the center of thruster. [ABSTRACT FROM AUTHOR]

Abstract: A new convenient method for the synthesis of dimethyl carbonate from dimethoxymethane and O2 in the presence of catalytic amounts of Cu-MCM-48 was described. The XRD results indicate that the structure of Cu-MCM-48 is gradually distorted with the increase in the copper content, whereas the framework structure of Cu-MCM-48 is basically retained until the incorporated copper content reaches to 0.62wt%. The SEM, TEM and N2 adsorption studies show that copper content of 9.51wt% completely changes the morphology and structure of Cu-MCM-48. Effects of the amount of the incorporated copper in catalyst, catalyst amount used and other reaction conditions on the catalytic activity are investigated in details to obtain the optimized reaction conditions. Short reaction time, easy recycling of the catalyst and excellent yields are the main advantages of this process. [Copyright &y& Elsevier]

Introduction: Lung cancer is a major global health problem because of its high incidence and mortality. Targeted therapies have transformed treatment of driver-mutated metastatic non-small cell lung cancer (NSCLC). Nevertheless, recent studies demonstrated that cardiovascular disease (CVD) was the second leading cause of mortality in cancer survivors now, management of patients' cardiovascular health during the course of anticancer therapy has become a great challenge faced by the oncologists. Anticancer related cardiovascular (CV) complications are not limited to traditional chemotherapy, but are also increasingly recognized in targeted therapy. Case Report: We present a case of pulmonary embolism (PE) and bradycardia in a 91-year-old NSCLC patient treated with crizotinib for a rare MET Y1003S mutation. To our knowledge, this is the second report to show antitumor response of crizotinib in lung cancer patients with such a rare mutation. However, the patient complained chest tightness and shortness of breath after a month of standard dose crizotinib therapy. Non-invasive examination revealed new onset bradycardia and PE. Management & Outcome: Such clinical manifestations were associated with targeted therapy-related CV toxicity, on which the emerging discipline cardio-oncology focused, and a multidisciplinary investigation and treatment was conducted. Discussion: This case highlights the CV adverse events of novel therapies and the current challenges to be tackled in cardio-oncology. [ABSTRACT FROM AUTHOR]

The modified boiling test based on image processing has gained significant attention in recent years, aimed at replacing subjective visual observation with an objective measurement. However, there are still some unsolved problems influencing the accuracy of the test such as the shadow between aggregate particles and the selection of threshold values for binary image conversion. Based on these challenges, an innovative modified boiling test procedure based on digital imaging has been successfully developed for the purpose of rating asphalt mix ingredients via moisture susceptibility. The new method focuses on a single piece of aggregate with a newly cut smooth surface, and then the aggregate coated by asphalt is subjected to the boiling test. Changes to the thickness of the asphalt coating on the fresh surface before and after boiling can be captured indirectly by digital images and reflected by the changing average grayscale values. The experimental results of 20 asphalt-aggregate combinations clearly showed the moisture damage resistance of different samples and the effect of liquid antistripping agent. In addition, the test results correlated well with energy ratios based on the surface free energy measurements of asphalt and aggregate. A decreased stripping rate over time were also observed for all samples and no significant stripping was found after 90 min of boiling. The selection of a suitable boiling time is critical to the accuracy of the test, which can be determined by trial-and-error methods. The proposed modified boiling test avoids the disadvantages of previously developed methods and provides a quick way to evaluate the asphalt mixture ingredients by moisture susceptibility, making it possible to test a large amount of samples within a short period of time. The new method can be used to generate an initial selection of asphalt-aggregate combinations in place of the surface free energy method. [ABSTRACT FROM AUTHOR]

In this work, we designed and synthesized two new phenothiazine dyes CBPTZ-BTD1 and CBPTZ-BTD2 , which employed the electron-accepting moiety of benzothiadiazole (BTD). The structural difference between the two new dyes is due to the presence of an ethynyl unit between BTD and the benzoic acid. With respect to its congener CBPTZ-BTD1 , CBPTZ-BTD2 with the insertion of ethynyl group shows a more coplanar molecular skeleton, which endows CBPTZ-BTD2 with a higher dye loading and a strengthened ICT effect, resulting in a red-shifted ICT absorption with a higher molar extinction coefficient. Besides, CBPTZ-BTD2 has a longer electron lifetime in comparation with CBPTZ-BTD1 without the linear ethynyl unit, as reveled by OCVD and EIS measurements. Therefore, CBPTZ-BTD2 exhibits a better photovoltaic performance with an enhanced J SC of 14.04 mA cm−2 and V OC of 0.82 V, leading to an improved PCE of 7.33 %. [Display omitted] • Two new phenothiazine dyes with benzothiadiazole (BTD) acceptor based on acceptor moiety of benzothiadiazole (BTD) without or with the insertion of ethynyl group were reported for dye-sensitized solar cells (DSSCs). • Dye properties and their DSSC application were investigated experimentally and theoretically. • The DSSC device based on dye with an ethylnyl-group in the acceptor moiety exhibited the insertion of ethynyl-group exhibits a better efficiency of 7.33 %. [ABSTRACT FROM AUTHOR]

Waste asphalt shingle (WAS) has traditionally been disposed of by landfilling due to environmental concerns surrounding Polycyclic aromatic hydrocarbons in WAS, which may potentially leach out, causing environmental pollution. However, this disposal method has been less environmentally acceptable and less cost effective than in the past due to concern on land resources. This study evaluates the potential of degradation of WAS, therefore reducing the polycyclic aromatic hydrocarbons (PAHs) content, by exploiting microbial biodegradation. The white rot fungus Phanerochaete chrysosporium was tested for its potential to degrade waste asphalt shingle binder. The biodegradation process was analyzed and quantified by both Fourier-transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). Results illustrate that P. chrysosporium can degrade WAS binder. GPC analysis indicates that the small asphaltic molecules were biodegraded preferentially by P. chrysosporium. The PAHs content of the WAS binder increased initially during fungal biodegradation, but subsequently decreased with the progression in biodegradation to a level lower than that of the original shingle binder. Results from this study could be used to develop solutions to the sustainable management of waste asphalt shingles. [ABSTRACT FROM AUTHOR]

The energy supply mode of a micro-cathodic arc thruster (μ-CAT) was adjusted based on the charge and discharge characteristics of the energy storage element, and the cathode discharge characteristics of μ-CAT were studied under different energy supply modes. We applied an electrical method to measure the discharge characteristics of μ-CAT, with an enhanced intensified charge coupled device spectrum detector to measure the plasma parameters of μ-CAT, allowing analysis of the internal logic among thruster plasma parameters, arc discharge characteristics, and thruster energy supply mode. The mechanisms of μ-CAT were analyzed and characteristics of accumulated discharge, energy distribution, and ion velocity distribution of thruster were compared under different energy supply modes to obtain the effect of the energy supply mode on the discharge characteristics of the interelectrode of μ-CAT. The results show that the energy supply mode of μ-CAT affected the ionization characteristics and ionization stability of the micro-cathodic arc thruster, causing a multistage ionization difference in the cathode metal target. This would not only affect the propulsion performance of the thruster, but also affect the change of the number of particles in the cathode region in a single discharge cycle. [ABSTRACT FROM AUTHOR]

• A novel quinoline derivative chemosensor (QN) as dual chemosensor was designed, synthesized and characterized. • The chemosensor QN exhibits highly selectivity fluorescence enhancement to Al3+ and colorimetric sensing for Fe2+. • The plausible binding modes of QN -Al3+ and QN -Fe2+ were supported by theoretical calculations. A simple and novel quinoline derivative (QN), based on quinoline-8-carboxaldehyde and 3‑hydroxy-2-naphthoic hydrazide was synthesized. The structure of chemosensor QN was confirmed by X-ray Crystallography. The chemosensor QN as dual chemosensor showed selective fluorescence recognition of Al3+ and colorimetric detection of Fe2+. In the presence of Al3+, the sensor QN generated a noticeable fluorescence enhancement accompanied with obvious color change from colorless to yellowish green. Moreover, QN was successfully used for colorimetric sensing for Fe2+, while the solution color changed from pale yellow to dark green. The detection limit was obtained to be 1.22 × 10−8 mol L−1 for Al3+ and 1.04 × 10−7 mol L−1 for Fe2+. The sensing mechanism of sensor QN toward Al3+ and Fe2+ were investigated by 1H NMR, ESI-MS and IR. Moreover, the coordination modes of QN -Al3+ and QN -Fe2+were confirmed by theoretical calculations. Image, graphical abstract [ABSTRACT FROM AUTHOR]

This paper proposes increasing the width of the discharge channel to improve the specific impulse of Hall thrusters. In our study, we significantly increased the achievable channel width by optimizing the magnetic circuit topology, and the design freedom of the Hall thruster was improved. A prototype of a wide-channel high-specific-impulse Hall thruster was designed and experimentally verified. The effects of channel width on the discharge process and the characteristics of an aft-loaded magnetic field Hall thruster were investigated. The high-intensity luminous region did not diffuse radially with an increase in the channel width, and the plasma was always concentrated near the channel centerline. A wider channel is more conducive for improving the propellant utilization efficiency, thereby effectively improving the specific impulse of the Hall thruster. By optimizing the discharge channel width, the upper limit of the discharge voltage was increased, and the maximum specific impulse was increased from 3170 to 3794 s, a relative improvement of 20%. The effect of the specific impulse improvement at the same discharge voltage was analyzed and discussed. The results of this study are significant for the design of high-specific-impulse Hall thrusters. [ABSTRACT FROM AUTHOR]

[Display omitted] • A ultra-thin wearing course with high skid and wear resistance using polyurethane as binder was developed. • The performance and the nano-adhesion behavior of PUTWC were investigated using experimental, molecular dynamics (MD) simulation methods and characterization test. • The relationship between performances test and nano-interaction of PUTWC was established. This study can provide certain guidance for the coming application of PUTWC on pavements. An ultra-thin wearing course is a promising maintenance method for prolonging the service life of the pavement. This study used polyurethane (PU) as a binder to develop an ultra-thin wearing course with high skid and wear resistance (named as PUTWC). The performance and nano-adhesion behavior of PUTWC were investigated by experimental and molecular dynamics (MD) simulation methods. The relationship between the mechanical properties of aggregates and the skid resistance of PUTWC was further analyzed using the grey correlation method. Results indicated that PUTWC using the emery with a particle size of 2–3 mm as the aggregate expressed a more favorable wear and skid resistance, also higher structural stability. The impact and polishing value of aggregates showed a more significant effect on the wear resistance of PUTWC. The adhesive bonding property between the PU and aggregates was investigated using the MD simulation by comparing the interfacial interaction energy, fraction of free volume, and relative concentration distribution of the PU component. Results showed that a stronger adhesion existed between the PU and emery compared with the ceramic particles, which was consistent with the performance test results. The conclusions of MD simulation were confirmed by the test results of scanning electron microscopy (SEM) and positron annihilation lifetime spectroscopy (PALS). [ABSTRACT FROM AUTHOR]

Bio asphalt is an organic polymer derived from biomass resources, which has the potential to partially or completely replace petroleum asphalt. This study used lignocellulose to prepare bio oil by hydrothermal liquefaction method. A mixed solvent of ethanol and ethylene glycol was introduced to increase the oil yield and decrease the reaction temperature. The oil yield reached the highest when solvent mixing ratio of 1:1, liquid-solid ratio of 6:1, catalyst dosage of 3%, and reaction temperature of 250 °C respectively. The bio oil and 50# asphalt were mixed in proportion sheared for 30 min (1000 rpm) under the condition of 135 °C to produce bio asphalt. The chemical structures and rheological properties of bio oil and bio asphalt were investigated and compared with petroleum asphalt. Fourier transform infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance analysis indicate that the bio oil expressed a lower H/C ratio, higher O content and more light components including liquid compounds comparing to the petroleum asphalt. The content of the polar group including O–H and C=O of bio oil was higher than that of petroleum asphalt. Gas Chromatography-Mass Spectrometry (GC-MS) was used to prove the presence of olefins and alcohols in bio oil. Thermogravimetric analysis showed that the bio oil expressed better thermal stability than that of petroleum asphalt, which expressed a potential of using as a pavement material. The dynamic shear rheometer (DSR) results showed that the complex shear modulus, G∗ decreased as the content of bio oil. The Glass transition temperature Tg indicated that the bio asphalt with 10% bio oil content showed similar performance with that of 70# asphalt. [ABSTRACT FROM AUTHOR]

Phosphors-in-glass films (PiGFs) with thermally conductive substrates are considered to be an efficient color inorganic color conversion material for laser lighting. However, due to the contradiction between the light extraction and heat dissipation, achieving high brightness and excellent color quality simultaneously is still a big challenge. Herein, a unique architecture of bicolor PiGF with highly reflective interface design was proposed for high-quality laser lighting. The TiO 2 -glass films with different thicknesses were prepared on highly heat-conducting AlN substrates to obtain the TiO 2 –AlN (TA) substrates with various reflectance. In addition, mixed green/red, stacked green-red, and stacked red-green phosphor glass films were printed and sintered on the TA substrates to prepared three bicolor PiGF converters of M-PiTA, G-R-PiTA, and R-G-PiTA. At the TiO 2 -glass film thickness of 100 μm, the M-PiTA enables a luminous flux of 2053 lm@24.8 W/mm2, which is 1.9 times that of traditional M-PiGF-AlN converter (1077 lm@17.6 W/mm2). The M-PiTA converter realizes a high-quality white light with a CRI of 82.7 and a chromaticity coordinate of (0.3378, 0.3297). Furthermore, the M-PiTA converter enables higher luminance and light quality compared with the stacked G-R-PiTA and R-G-PiTA converters. With the laser power of 4.2 W, the working temperature of M-PiTA converter is only 59.2 °C, while that of R-G-PiTA and G-R-PiTA converters rises to 499 °C and 301 °C. The results demonstrate that the bicolor PiTA converters have broad prospects in the application of laser lighting. [ABSTRACT FROM AUTHOR]

In Hall thrusters, the electron velocity distribution function is not only depleted at high energies, but also strongly anisotropic. With these electrons interacting with the channel wall, the sheath will be changed in its dynamic characteristics. In the present letter, a two dimensional particle-in-cell code is used to simulate these effects in a collisionless plasma slab. The simulated results indicate that the sheath changes from steady regime to temporal oscillation regime when the electron velocity distribution function alters from isotropy to anisotropy. Moreover, the temporal oscillation sheath formed by the anisotropic electrons has a much greater oscillating amplitude and a much smaller average potential drop than that formed by the isotropic electrons has. The anisotropic electrons are also found to lower the critical value of electron temperature needed for the appearance of the spatial oscillation sheath. [ABSTRACT FROM AUTHOR]

Micro-nano satellites show considerable potential in the application of low-orbit satellite networks, and low-power Hall effect thrusters (HETs) that provide the impetus for them have also attracted considerable attention worldwide. However, the relatively large surface-to-volume ratio of low-power HETs leads to significant loss of ions on the wall surface. After the channel width is increased or the ionization area is moved outward, ensuring sufficient ionization of the propellant is very difficult, and thus its integrated performance is not high. Thus, in this study, a 100-W permanent magnet HET with an aft-magnetic field is considered as the carrier to investigate the effect of gas supply direction on the thruster discharge characteristics through a simulation and experiments. Results indicate that under the same working conditions, adopting the circumferential direction gas supply mode effectively increases the density of the propellant in the ionization zone (up to 7%), improves the propellant ionization rate (up to 12.7%), and improves integrated discharge performance (the anode efficiency can be increased by up to 5.3%). In addition, the performance optimization effect of this mode is more evident under the working condition of low flow. When combined with an aft-magnetic field, this method is an effective means to ensure high-efficiency discharge of a low-power HET, which can be used as a reference for the miniaturization development of HETs. • The circumferential direction gas supply mode increases the density and ionization rate of propellant. • The performance optimization effect is more evident under the working condition of low flow. • The circumferential direction gas supply mode is an effective means to ensure high-efficiency discharge of low-power HET. [ABSTRACT FROM AUTHOR]

The recycling of asphalt shingles in pavement construction is beneficial to the environment and industry by reducing the consumption of virgin materials. However, current approaches of utilizing recycled asphalt shingle (RAS) by mixing with soft asphalt or rejuvenator were questionable for the anti-aging problems. This study developed a new approach to recycle asphalt shingles, in which the RAS binder was dissolved and extracted by a mixed solvent of heptane and trichloroethylene (TCE). In the proposed process, the viscosity of the extracted RAS binder was controlled by the polarity and composition of the mixed solvent. Results indicate that heptane dissolved the soft part and trichloroethylene (TCE) could dissolve the stiff part of RAS binder. The use of the mixed solvent of heptane and TCE with a certain proportion through the proposed method could prepare asphalt binder with desired properties. The current approaches of utilizing RAS were compared with the proposed method. Results indicate that the anti-aging properties of extracted RAS binder using the proposed method were better since the soft asphalt could not dissolve RAS binder at 170 °C, and the binder blend of RAS binder and rejuvenator had a potential anti-aging problem because an obvious loss of rejuvenator existed during the aging process. The performance test suggests that the high and low temperature region of the extracted RAS binder was close to 75.2–28 °C, which could be used as a common asphalt in pavement engineering. • RAS binder was extracted and used as common asphalt. • Heptane and TCE were mixed to prepare the mixed solvent. • Soft asphalt could not dissolve RAS binder. • Rejuvenator was evaporated seriously during the short aging process. [ABSTRACT FROM AUTHOR]