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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]

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]

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]

The theoretical specific impulse of Hall thrusters using a krypton propellant is much higher than that of those using xenon. However, the actual benefits of this improvement are limited by the difficulty in achieving krypton atom ionization, and its efficiency is much lower than that of xenon. In this study, the anode specific impulse and anode efficiency of Hall thrusters using krypton propellant were improved by adding a small quantity of xenon. A dual-channel supply of xenon and krypton was achieved by optimizing the discharge channel structure based on the design of the aft-loaded magnetic field. The effects of the xenon and krypton supply method and xenon fraction on the discharge characteristics of the Hall thruster were investigated by conducting discharge experiments using the mixed propellant. The results indicated that injecting a small quantity of xenon significantly improved the ionization of krypton, improved the ionization and acceleration efficiency of the thruster, and fully utilized the high specific impulse characteristics of krypton. Furthermore, the addition of a small quantity of xenon also significantly increased the upper limit of the discharge voltage for stable operation using krypton from 500 V. At the maximum tested xenon fraction, the maximum discharge voltage was loaded to 900 V. At a discharge voltage of 800 V, the optimal anode efficiency and anode specific impulse increased by 4.5 % and 534 s, respectively, compared with those for pure xenon propellant (with an anode efficiency of 54 % and anode specific impulse of 3034 s). The results of this study are of great significance for the design of high-efficiency, high-specific-impulse, and low-cost Hall thrusters. • A dual-channel gas supply structure is proposed, which can supply two kinds of gases into the discharge channel individually. • Thruster performance is optimal when krypton is supplied downstream and auxiliary xenon is supplied upstream. • High-voltage operating ability under krypton is greatly improved with the assistance of a small quantity of xenon. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) honeycomb-like hematite superstructure was successfully fabricated on 100 pixel per inch (ppi) Fe foam scaffold via a straightforward hydrothermal approach. Influencing factors including the reaction temperature, time and the dosage of precipitant were systematically studied. A self-assembly growth mechanism was proposed based on the results of hydrothermal reaction. The powder catalyst in the form of zero-dimensional (0D) hematite nanoparticles acted as a reference sample was also synthesized at the same reaction conditions without Fe foam substrate. The honeycomb-like hematite structure exhibited a higher CO conversion and lower methane selectivity than the traditional powder catalyst for Fischer–Tropsch synthesis (FTS). These enhancements can be mainly attributed to its distinctive structure with high specific surface area, large Fe3O4 content, promoted reducibility and uniform particle size distribution, as well as effective diffusion of feed gas and products. [ABSTRACT FROM AUTHOR]

Alkali-activated cementitious material (AACM) based on the utilization of solid waste is a new type of environmentally friendly inorganic material, which has the advantages of early strength, fast hardening, high strength, and better durability. The reactivity of solid waste powder is a key factor for its appropriate utilization in alkali-activated cementitious materials, necessitating a rational evaluation of its reactivity. The reactivity evaluation was conducted on various solid waste powders, including fly ash (FA), red mud (RM), recycled micro-powder (RMP), red brick powder (RBP), coal gangue powder (CGP), and cement kiln dust (CKD). The effects of NaOH concentration, weight ratio of water to solid waste powder (W/P) and curing humidity on the compressive strength were investigated，then the compressive strength under optimal conditions was determined based on response surface analysis. The compressive strength under optimal conditions was used to evaluate the reactivity of solid waste powders. Moreover, microscopic tests (e.g., XPS test, ICP test, and NMR test) were carried to evaluate the reactivity of the solid waste. The relative number of bridging oxygen (RBO) measured by the NMR method in conjunction with chemical composition analysis serves as an effective method for evaluating the reactivity of solid waste powders. The leaching rate of Silicon (Si) and Aluminum (Al) ions in the ICP method depended mainly on the NaOH concentration and the elemental content in the raw material. In addition, the binding energies of O1s, Si 2p, and Al 2p tested by the XPS method had no particular correlation with the compressive strength. • Based on response surface analysis to evaluate the reactivity of solid waste powders. • Compressive strength under optimum conditions was used as criteria for evaluation. • Combining NMR method with chemical composition could assess reactivity effectively. [ABSTRACT FROM AUTHOR]

In this study, the effect of pulse frequency on the discharge and plume characteristics of Hall thrusters under pulsating operation is investigated. The experimental results show that the discharge current and thrust decrease as the frequency increases to the range of 30–90 kHz. The efficiency of the thruster is negatively correlated with the pulse frequency, and the pulse frequency minimally affects the plume divergence angle and ion current. It is found that an increase in the pulse frequency decreases the secondary electron emission flux on the wall and the near-wall conduction rate of electrons in the channel, thus consequently decreasing the electron current. An increase in the electron current share improves the current-utilization efficiency. In addition, as the frequency increases, the ion power loss on wall increases and the ion acceleration becomes less effective, thus resulting in a decrease in thrust. The combined effect of these two factors results in an increase in the anode efficiency as the frequency increases. • The effect of pulse frequency on the discharge and plume characteristics of Hall thrusters under pulsating operation were investigated. • Increasing the pulse frequency decreases the secondary electron emission flux, which reduces the rate of electron-in-wall conduction in the channel, thus resulting in a lower electron current. • As the pulse frequency increases, the ions power loss on wall increases leading to poorer ion acceleration and a reduction in thrust. [ABSTRACT FROM AUTHOR]

Electric propulsion systems with high-specific impulses have replaced chemical propulsion systems in many space missions. The aft-loaded magnetic field technology of Hall thrusters moves the ionization and acceleration processes downstream of the channel by varying the magnetic field distribution. Consequently, ion bombardment of the channel walls is inhibited, and the service life of the Hall thrusters is substantially increased. However, neutral gas leaks because of the rapid diffusion near the channel outlet, where strong ionization occurs. Thus, the propellant atoms are ionized insufficiently, resulting in a decline in the performance. Therefore, an aft-loading design for the neutral gas flow field was developed to optimization distribution of the neutral gas in this study. A 1.5 kW Hall thruster was verified experimentally. The experimental results show that the aft-loaded neutral gas flow field significantly improved the ionization and acceleration processes. The propellant utilization efficiency increased by 4–8% within the discharge voltage range of 300–900 V. The ion energy distribution moved toward the high-energy direction significantly, promoting an overall improvement in the performance, with a thrust increase of 7.3–11.5 %. The anode efficiency increased from 49–57 % to 58–61 %. The results of this study are significant for the design of high-performance, long-life Hall thrusters. • The aft-loading design of gas flow is realized using the special topology of the hybrid-wall Hall thruster. • The ionization distribution of aft-loaded neutral gas flow field is concentrated in higher potential region. • The aft-loaded neutral gas flow moves the ionization region downstream of the channel. [ABSTRACT FROM AUTHOR]

Poor performance limits the wider application of 100-W-power class Hall thrusters. The effects of position matching between the anode and the zero-magnetic-field region (ZMFR) on the discharge process and performance improvement of 100-W Hall thrusters were investigated. The experimental results demonstrate that appropriately widening the ZMFR downstream of the anode improves the ion current and thrust, promotes plume focusing, and optimizes thruster performance. The thrust and anode efficiency is enlarged by 7.6 % and 20 % (relative value), respectively, when the ZMFR downstream of the anode is expanded by 0.2 L (L is the channel length). The simulation results indicated that widening the ZMFR promoted the expansion of the high-ionization zone to the bottom of the channel, and increased the overall ionization rate. Moreover, as the ZMFR increases, the effective ion acceleration voltage increases. However, widening the ZMFR also aggravated the ion-wall interaction and reduced the propellant utilization rate. Therefore, the performance of the thrusters exhibited an optimal range as the length of the ZMFR increased. In addition, increasing the ZMFR did not affect the life of the thrusters. • The effects of position matching between the anode and zero magnetic field region on discharge characteristics are studied. • The discharge characteristic parameters of thruster with different lengths of ZMFR downstream of the anode are given. • Appropriately increasing the ZMFR can improve the ion current and thrust, thereby improving the anode efficiency. • The position matching between the anode and ZMFR affects the ionization process and propellant utilization ratio. [ABSTRACT FROM AUTHOR]

In this study, the material loss relationship between the electrodes of a micro-cathodic arc thruster was investigated by adjusting the input voltage. The crater morphology of the micro-cathodic arc thruster was observed with a scanning electron microscope. The internal crater material was analyzed with an energy spectrum analyzer. On this basis, the arc path is obtained and the material loss of the structure between the electrodes of the micro-cathodic arc thruster was studied through further numerical simulation. The experimental and simulation results show that with a change in the Power processing unit (PPU) input voltage of the micro-cathodic arc thruster, the material distribution in the cathode crater and the discharge channel between the electrodes changed, affecting the bombardment of ions between the electrodes of the thruster on the insulating structure and conductive coating. In engineering applications, regulation of the arc breakdown path can effectively reduce the total energy of ion bombardment on the wall. • Study on micro-morphology and composition distribution characteristics of arc crater of micro-cathode arc thruster. • Study on the distribution characteristics of PPU input voltage and discharge channel between thrusters. • The ion bombardment on the wall under different discharge channels is simulated. • With the increase of PPU input voltage, the dominant factor of inter-electrode structure loss changes. [ABSTRACT FROM AUTHOR]