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The non-degradable nature of petroleum-based plastics and the dependence on petroleum-based products in daily life and production are dilemmas of human development today. We hereby developed a plastic waste upcycling process to address these challenges. A multi-stream fraction strategy was developed to process poly (ethylene terephthalate) (PET) plastics into soluble and insoluble fractions. The soluble fraction was used as a sole carbon source for microbial fermentation to produce biodiesel precursor lipids with an appreciable bioconversion yield. The insoluble fraction containing fractionated polymers was used as the asphalt binder modifiers. The downsized PET additive improved the high-temperature performance of the asphalt binder by 1 performance grade (PG) without decreasing the low-temperature PG. Subsequent SEM imaging unveiled alterations in the micromorphology induced by PET incorporation. Further FTIR and 1H NMR analysis highlighted the aromatic groups of PET polymers as a crucial factor influencing performance enhancement. The results demonstrated the multi-stream fraction as a promising approach for repurposing plastic waste to produce biodiesel and modify asphalt. This approach holds the potential to tackle challenges in fuel supply and enhance infrastructure resilience to global warming. [ABSTRACT FROM AUTHOR]

Abstract The human intestinal microbiota has an important role in the maintenance of human health and disease pathogenesis. The aim of this research was to investigate the impact of four media on human intestinal microbiota metabolite and composition changes, we performed in vitro batch culture using intestinal microbiota samples from three fecal microbiota transplantation (FMT) donors. After 48 h culture, gut microbiota medium (GMM) had the highest production of acetic acid (73.00 ± 7.56 mM) and propionic acid (16.79 ± 1.59 mM), bacterial growth media (BGM) had the highest production of butyric acid (13.39 ± 0.56 mM). In addition, brain heart infusion (BHI) promoted (p

High accuracy and a high spatiotemporal resolution of precipitation are essential for the hydrological, ecological, and environmental fields. However, the existing daily gridded precipitation datasets, such as remote sensing products, are limited both by the coarse resolution and the low accuracy. Despite considerable efforts having been invested in downscaling or merging, a method of coupled and simultaneously downscaling and merging multiple datasets is currently lacking, which limits the wide application of individual popular satellite precipitation products. For the first time, in this study, we propose a simple coupled merging and downscaling (CMD) method for simultaneously obtaining multiple high-resolution and high-accuracy daily precipitation datasets. A pixel-repeated decomposition method was first proposed, and the random forest (RF) method was then applied to merge multiple daily precipitation datasets. The individual downscaled dataset was obtained by multiplying the result of merging by an explanatory rate obtained by RF. The results showed that the CMD method exhibited significantly better performance compared with the original datasets, with the mean absolute error (MAE) improving by up to 50%, the majority of the values of bias ranging between −1 mm and 1 mm, and the majority of the Kling–Gupta efficiency (KGE) values being greater than 0.7. CMD was more accurate than the widely used dataset, Multi-Source Weighted-Ensemble Precipitation (MSWEP), with a 43% reduction in the MAE and a 245% improvement in the KGE. In addition, the long-term estimation suggested that the proposed method exhibits stable good performance over time. [ABSTRACT FROM AUTHOR]

Variations in precipitation have a great influence on human society and the natural environment. Existing studies have provided substantial information regarding variations in the magnitude, frequency, and intensity of precipitation. However, little is known about how the start and end dates of precipitation change, which could offer crucial insights for related studies in agriculture, hydrology, and other related disciplines. Here, we present an analysis of variations in the start date, end date, and frequency of different precipitation intensities, using a widely used gauge-satellite-reanalysis-based merging product, during the latest period, 1980–2022, across China. The results show that the spatial–temporal variations in the start date, end date, and frequency of different precipitation intensities were complex among regions. For example, in northeast and northwest China, light precipitation (LP) started earlier and increased in frequency during the study period. In the Tibetan Plateau, precipitation at different intensities levels started earlier, heavy precipitation (HP) and violent precipitation ended earlier, and the frequency of LP and moderate precipitation increased significantly. The start date of HP shifted earlier in Southeast China (−0.28 days/year). Our findings could be helpful in providing a comprehensive understanding of precipitation changes under global warming and highlight the need to pay close attention to these precipitation changes in the future. [ABSTRACT FROM AUTHOR]

The multiactive-bridge (MAB) structure has obvious efficiency and cost advantages in multiport power electric transformer, but it brings the characteristics of strong current coupling of each transformer. To improve the dynamic response speed of MAB and reduce the coupling characteristics, a high-frequency current predictive control (CPC) method for MAB is proposed in this letter. The controller uses the enhanced single-phase shift modulation method to adjust the phase shift angle and duty cycle of four ports at the same time so that the high-frequency current can be adjusted in several switching cycles. In the proposed CPC method, the influence of control delay is analyzed and compensated, and the dc offset, which may occur in the dynamic process is analyzed and gives corresponding solutions. More importantly, the proposed CPC method can be extended to the power predictive control method to realize power decoupling of multiple ports of MAB. The parameter robustness of current and power predictive control is analyzed briefly in this letter. The proposed control method is validated on a hardware-in-loop simulation platform based on RT-lab. Experiment results show the superior dynamic performance and good robustness of the proposed method. [ABSTRACT FROM AUTHOR]

The wireless power supply solution has shown great advantages in rail transit applications, such as maglev trains and trams. However, research works on designing the magnetic coupler for wireless charging system in rail applications, which is a crucial problem, are not sufficient. Considering the high power and lightweight requirements, this article selects the coaxial M-shape magnetic coupler with LCL/S compensation for railway applications, which contains the transmitting rail and the receiving coil wound on an M-shape magnetic core. First, analysis was conducted on the requirements for inductance parameters of the magnetic coupler under the circuit constraints, including transmission power, input and output voltages, and component electrical stress, etc. Then, the influence of the geometric parameters of the coil structure and misalignment on its inductance parameters is analyzed. Based on these analysis results, the design method for the M-type magnetic coupler based on the lightweight principal is proposed. The geometric parameters are designed following a certain sequence to minimize the number of iterations and FEM simulation parameter sweeps, making the design procedure suitable for engineering practice. According to the proposed method, the magnetic coupler for a 360 kW wireless charging tram is designed and implemented. Through simulations and experiments, the magnetic coupler is verified to be feasible for the system with light weight. [ABSTRACT FROM AUTHOR]

The noninverting buck–boost (NIBB) converter is a step-up and step-down dc–dc converter suitable for applications with a wide input voltage range. However, this circuit will face the problem of operating mode switching when the input voltage is close to the output voltage. Considering this problem, the principles of the NIBB converter are analyzed in this article. The duty cycle combinations of an NIBB converter are analyzed, and an analysis method for the mode transition problem from a geometric perspective is proposed. Using the two-edge pulsewidth modulation method, a novel bumpless mode transition control method is proposed. A nonlinear feedforward controller with hysteresis is designed according to the state equation of the circuit. Moreover, the inductor current reference value is compensated when the mode is switched so that the mode transition problem of the NIBB circuit is effectively solved. In addition, a small-signal analysis of the proposed method is performed. The analysis shows that the proposed method has good stability and dynamic performance in various typical conditions. A 10-kW NIBB prototype is built in this article, and the corresponding experimental scenarios are designed. The experimental results show that compared with the results of unified PI control during the mode transition, the transient oscillation of the output voltage is smaller, and the duration of the transient process is shorter. [ABSTRACT FROM AUTHOR]

For the bidirectional wireless power transfer (BWPT) technology, the phase synchronization between the transmitting and receiving converters is very essential and difficult to achieve by wireless communication between two sides because the delay and data transfer interval of wireless communication severely influence the control performance. This article proposes a novel control strategy for BWPT, which can achieve the phase synchronization and maximum efficiency point tracking independent of the real-time wireless communication. To solve the overshoot and oscillation problem incurred by the proposed control strategy and the nature of the system itself, the dynamics of a series–series compensated BWPT system is then analyzed and a small-signal model of this system is derived based on the generalized state space averaging and extended describing function methods. Using the small-signal model, a BWPT control system based on the proposed control strategy is designed and optimized. The validity of the proposed strategy and the performance of the control system are verified experimentally using a 3.3-kW prototype system. [ABSTRACT FROM AUTHOR]

Multileg Class-D amplifiers (CDAs) with phase-shifted carrier modulation can increase the equivalent switching frequency and reduce the output current ripples, which further reduces the size of the output filter. However, these benefits are degraded by the tolerances in the phase inductance values. The phase inductance mismatches impact the ripple cancelation effects (the harmonic contents at switching frequency and its harmonics appearing in the output current ripple). Therefore, the quality of the output waveform can further be impacted. Current research works dealing with this issue mainly focused on the interleaved dc–dc converters, which does not cover the analysis in multileg CDAs or inverters, especially for the full-bridge configuration. This paper proposes a general analytical method to characterize the steady-state phase and the total current ripple in the multileg CDAs with full-bridge configuration under inductance mismatches. Monte Carlo simulation is used to study the impact of inductance mismatches on the harmonic contents of the total current ripple, and the distribution law of the inductances at the worst case is revealed. The analytical method is verified by simulation and experimental results of a four-leg full-bridge CDA. A design guideline is given to optimize the filter design based on the analytical method. [ABSTRACT FROM AUTHOR]

The wireless electric vehicle (EV) charging system is highly safe and flexible. To reduce the weight and cost of EVs, the wireless charging system, which simplifies the structure inside an EV and utilizes the transmitter-side control method, has become popular. This study investigates the transmitter-side control methods in a wireless EV charging system. First, a universal wireless charging system is introduced, and the function of its transfer power is derived. It is observed that the transfer power can be controlled by regulating either the phase-shift angle or the DC-link voltage. Further, the influence of the control variables is studied using numerical analysis. Additionally, the corresponding control methods, namely the phase-shift angle and the DC-link voltage control, are compared by calculation and simulation. It is found that: (1) the system efficiency is low with the phase-shift control method because of the converter switching loss; (2) the dynamic response is slow with the DC-link voltage control method because of the large inertia of the inductor and capacitor; (3) both the control methods have limitations in their adjustable power range. Therefore, a combined control method is proposed, with the advantages of high system efficiency, fast dynamic response, and wide adjustable power range. Finally, experiments are performed to verify the validity of the theoretical analysis and the effectiveness of the proposed method. This study provides a detailed and comprehensive analysis of the transmitter-side control methods in the wireless charging system, considering the sensitivity of parameters, converter losses, system efficiency, and dynamic performance, with the dead-time effect taken into consideration. Moreover, the proposed control method can be used to realize the optimal combination of the phase-shift angle and the DC-link voltage with good dynamic performance, and it is useful for the optimal operation of the wireless charging system. [ABSTRACT FROM AUTHOR]

In many practical applications of wireless power transfer, the battery, which can be modeled as a voltage source, is charged wirelessly from the voltage-source inverter via the transmitter and the receiver. Therefore, it is crucial to analyze such a wireless power transfer system. In this paper, the closed-form oriented modeling and analysis of the wireless power transfer system with the constant-voltage source and load are conducted. Two cases are studied: both the transmitter and the receiver are under resonance, and only the receiver is under resonance. In the latter case, the transmitter is set to be inductive for the implementation of zero voltage switching. The battery current, the output power, and the transfer efficiency of both cases are analyzed and compared in detail. The voltage gain, the power factor, and the output power of the latter case are studied to offer physical insights and design guidelines. An experimental prototype is implemented to verify the analysis. The experiments agree with the calculations. [ABSTRACT FROM AUTHOR]

The load coils are employed for multiple loads of resonant wireless power transfer in this paper. With the addition of the load coil, this three-coil structure has easy access to transferring power to multiple loads with the advantages of a compact structure and controllable power flow. Both single-load transfer and multiple-load transfer are modeled and analyzed by means of the circuit theory. The transfer quality factor and the load matching factor are utilized in the analysis of efficiency. In the single-load transfer, the load matching condition is fully explored. Based on the single-load transfer, the multiple-load transfer is researched. The double-load transfer, acting as an illustration, is studied with the uncoupled and coupled load coils. Equivalent reflected resistances are introduced to decouple the model of the double-load transfer with coupled load coils mathematically. An experimental prototype is implemented to verify the aforementioned analysis. The experimental results agree with the theoretical calculations. [ABSTRACT FROM AUTHOR]

In multiple receivers of resonant wireless power transfer, selective power flow among the loads is an important issue. This paper proposes a new method to control power division. The two-coil structure with different resonant frequencies of the sending and receiving loops is modeled and analyzed. The efficiency is proved to peak at the resonant frequency of the receiving loop, regardless of the resonant frequency of the sending loop. Using this feature, selective power transfer can be achieved by setting the receiving loops at different resonant frequencies. The efficiency of a particular load is greatly influenced by the driving frequency. The multiple-load system with different resonant frequencies is modeled and the efficiency expression of each load is deduced. The mutual inductances of the receiving coils have a small impact on the efficiency distribution. The closer the resonant frequencies of the receiving loops, the less isolated the related loads. The calculations and the experiments confirm the analysis. [ABSTRACT FROM AUTHOR]

The nonlinear junction capacitances of power devices are critical for the switching transient, which should be fully considered in the modeling and transient analysis, especially for high-frequency applications. The silicon carbide (SiC) MOSFET combined with SiC Schottky Barrier Diode (SBD) is recognized as the proposed choice for high-power and high-frequency converters. However, in the existing SiC MOSFET models only the nonlinearity of gate-drain capacitance is considered meticulously, but the drain–source capacitance, which affects the switching commutation process significantly, is generally regarded as constant. In addition, the nonlinearity of diode junction capacitance is neglected in some simplified analysis. Experiments show that without full consideration of nonlinear junction capacitances, some significant deviations between simulated and measured results will emerge in the switching waveforms. In this paper, the nonlinear characteristics of drain–source capacitance in SiC MOSFET are studied in detail, and the simplified modeling methods for engineering applications are presented. On this basis, the SiC MOSFET model is improved and the simulation results with improved model correspond with the measured results much better than before, which verify the analysis and modeling. [ABSTRACT FROM AUTHOR]

Based on four-coil magnetically coupled resonant wireless power transfer, this paper demonstrates, explains, and analyzes the frequency-splitting phenomenon by using the circuit theory. First, the complete and simplified models are built to describe the whole system. The numerical formulas of the system efficiency both at and away from the resonant frequency are presented. Then the frequency-splitting phenomenon is displayed and further explained mathematically and physically. An important factor for frequency splitting is introduced. The boundary condition for frequency splitting and its splitting frequency points are deduced. The amplitude–frequency and phase–frequency characteristics of the input impedance are measured and described to verify the explanation. Three related factors are studied, and the sensitivity analysis is conducted. A solution is proposed that helps improve the efficiency when frequency splitting occurs. The theoretical calculations and experimental results provide a sound basis. [ABSTRACT FROM AUTHOR]

Recent years have witnessed the booming development of resonant wireless power transfer (RWPT). Compared with conventional inductive power transfer, the frequency of RWPT is usually much higher. To reduce the resonant frequency while maintaining the transfer efficiency constant at the same transfer distances, two solutions are proposed and realized in this letter. Two fundamental structures for RWPT are analyzed and the expressions of the transfer efficiency are deduced. It is pointed out that the transfer quality factor and the load matching factor are two important factors of achieving high transfer efficiency. The larger the transfer quality factor, the higher the transfer efficiency. There is an optimal load matching factor to reach the highest transfer efficiency. The transfer efficiency can remain constant at the same distances if the transfer quality factor is kept at the same level and the load is matched. Theoretical calculations and experimental results provide a sound basis for decreasing frequency. [ABSTRACT FROM AUTHOR]

Resonant wireless power transfer has attracted much attention in recent decades. In some practical applications such as wireless sensor networks, multiple-load transfer over various distances is required. In this letter, the intermediate-coil structure is utilized to transfer the same power to multiple loads over various distances, which indicates that the intermediate coils work both as relay resonators and as power receivers. The mathematical model is built and in-depth analysis is conducted. Four important factors, namely the source matching factor, the load matching factor, the transfer quality factor, and the reflected impedance factor, are employed to build the mathematical model of n-load transfer. The conditions to transmit the same power to all the loads attached in each relay resonator are investigated. The optimal load resistance and the highest efficiency with the same load resistance are derived. The theoretical calculations and the experimental results of double-load and three-load transfer confirm the analysis. [ABSTRACT FROM PUBLISHER]

A solute-saturated supercritical fluid loading (SSFL) process was proposed to load 2-phenylethyl alcohol (PEA) in silica and activated carbon (AC). The adsorption and loading amounts of PEA in carries were investigated at different temperatures (50.0–60.0 °C) and pressures (8.0–14.0 MPa) by a column sampling method. By using a high-pressure quartz spring method, the adsorption amounts of the binary PEA and CO 2 in silica were determined. The retention of PEA in the SSFL powder flavors was evaluated by a nitrogen-purging method. Results revealed that, compared with AC, silica had high loading of PEA (maximum 0.484 g/g) and showed better results in PEA preservation from loss at room temperature and control release at higher temperature; PEA suppressed the adsorption of CO 2 at relatively high pressure. Discussion indicated that precipitation and adsorption contributed to the high loading of PEA in silica, while adsorption mainly contributed to that in AC. [ABSTRACT FROM AUTHOR]

Surface sterilization and hazardous chemical degradation under ambient conditions can provide significant benefits for public and environmental health. Materials with sterilization and chemical degradation capacity under sunlight can efficiently reduce infectious disease incidence rates and toxic chemical exposure. Utilizing renewable energy for sustainable sterilization and degradation is more desirable as it reduces the potential secondary contamination. Herein, we report functional structure design using lignin, a renewable carbon heterogeneous polymer, to synthesize a highly efficient and stable photocatalyst that degrades environmentally hazardous organic compounds rapidly. Through a hydrolysis reaction between Ti-OH and the hydroxyl groups of lignin, Ti-O-C and Ti-O-Ti bonds were established and a lignin based photocatalyst with a hollow sphere structure (C lignin @H-TiO 2 ) was formed. The presence of a homozygous carbon modified TiO 2 structure contributes to the enhanced photodegradation activity with solar light. The close hetero-interfacial contact between carbonized lignin and TiO 2 further improves the photocatalytic efficiency by facilitating effective charge carrier separation. After synthesis optimization, the resulting C lignin @H-TiO 2 photocatalyst exhibits excellent performance in the degradation of atenolol under solar light irradiation with 100% degradation within five minutes. Additionally, it efficiently removes approximately 50% of PFOA and kills about 90% of bacteria within three hours. The uniform distribution of lignin within the crosslinking structures ensures a durable carbon modified TiO 2 framework, which remains stable after 10 cycles of usage. The robustness of the lignin-based photocatalyst enables incorporating the catalyst into diversified material formats and various usages. Coating of the photocatalyst onto device surfaces shows bacterial killing efficacy under sunlight. The photocatalysts based on lignin valorization present a green chemistry approach for environmental remediation and surface sterilization, which has long-term environmental protection benefits, with broad applications in toxin treatment and health protection against pathogen infection., Competing Interests: The authors declare no competing interests., (This journal is © The Royal Society of Chemistry.)