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Plastic film mulching (FM) became a general practice to enhance crop productivity and its net primary production (NPP), but it can increase greenhouse gas (GHG) emissions. The proper addition of organic amendments might effectively decrease the impact of FM on global warming. To evaluate the feasibility of biomass addition on decreasing this negative influence, cover crop biomass as a green manure was incorporated with different recycling levels (0-100% of aboveground biomass) under FM and no-mulching. The net global warming potential (GWP) which integrated with soil C stock change and GHG (N2O and CH4) fluxes with CO2-equivalent was evaluated during maize cultivation. Under the same biomass incorporation, FM significantly enhanced the grain productivity and NPP of maize by 22-61 and 18-58% over no-mulching, respectively. In contrast, FM also highly increased the respired C loss, which was 11-95% higher than NPP increase, over no-mulching. Irrespective with biomass recycling ratio and mulching system, negative NECB which indicates the decrease of soil C stock was observed, mainly due to big harvest removal. FM decreased more soil C stock by 57-158% over no-mulching, but its C stock was clearly increased with increasing biomass addition. FM significantly increased total N2O and CH4 fluxes by 4-61 and 140-600% over no-mulching, respectively. Soil C stock changes mainly decided net GWP scale, but N2O and CH4 fluxes negligibly influenced. As a result, FM highly increased net GWP over no-mulching, while this net GWP was clearly decreased with increasing biomass application. However, cover cropping, and its biomass recycling was not enough to compensate the negative impact of FM on global warming. Therefore, more biomass incorporation might be essential to compensate this negative effect of FM.

Abstractπ‐Conjugated polyelectrolytes (CPEs) have been studied as interlayers on top of a separate hole transport layer (HTL) to improve the wetting, interfacial defect passivation, and crystal growth of perovskites. However, very few CPE‐based HTLs have been reported without rational molecular design as ideal HTLs for perovskite solar cells (PeSCs). In this study, the authors synthesize a triphenylamine‐based anionic CPE (TPAFS‐TMA) as an HTL for p‐i‐n‐type PeSCs. TPAFS‐TMA has appropriate frontier molecular orbital (FMO) levels similar to those of the commonly used poly(bis(4‐phenyl)‐2,4,6‐trimethylphenylamine) (PTAA) HTL. The ionic and semiconducting TPAFS‐TMA shows high compatibility, high transmittance, appropriate FMO energy levels for hole extraction and electron blocking, as well as defect passivating properties, which are confirmed using various optical and electrical analyses. Thus, the PeSC with the TPAFS‐TMA HTL exhibits the best power conversion efficiency (PCE) of 20.86%, which is better than that of the PTAA‐based device (PCE of 19.97%). In addition, it exhibits negligible device‐to‐device variations in its photovoltaic performance, contrary to the device with PTAA. Finally, a large‐area PeSC (1 cm2) and mini‐module (3 cm2), showing PCEs of 19.46% and 18.41%, respectively, are successfully fabricated. The newly synthesized TPAFS‐TMA may suggest its great potential as an HTL for large‐area PeSCs.

The potential of deoiled Azolla pinnata biomass (DAB) as electrode and substrate was evaluated for microbial fuel cell (MFC) operation. The anode electrode was fabricated using biochar obtained by subjecting DAB to pyrolysis at 600 °C, while the reducing sugars after hydrolysis of DAB by acid pretreatment was used as substrate. The post pyrolyzed biochar (P-DAB) was characterized for structural and elemental functionalities using SEM, XRD and Raman spectroscopy, whereas the reducing sugar obtained from hydrolyzed DAB (H-DAB) was analyzed for its composition. Experimental results indicated that at a given 3 g COD/L resulted in a voltage of 382 mV with 65.6% of COD reduction in closed circuit (CC) mode of operation. Cyclic voltammetric analysis depicted maximum oxidative and reductive peak currents of 3.42 mA and -4.0 mA. Noticeable peaks were also identified in CC (-0.2 V to +0.2 V and -0.19 V to -0.3 V) and OC (+0.2 V to +0.4 V and -0.1 V to -0.3 V) corresponding to complex IV cytochrome c couples (cytochrome Cox (Cyt Cox)/cytochrome Crd (Cyt Crd)), signifying the participation of electron carriers during electron transfer. The microbiome diversity showed dominance of Proteobacteria, a phylum known for exo-electrogenic bacterial species. The DAB-derived products account to environmental sustainability and support circular bioeconomy in a biorefinery mode.

Due to their high surface areas and large pore volumes, porous carbons (PCs) are valuable materials for use as electrodes in energy storage and conversion devices. Biomass is an ideal precursor for the preparation of PCs in part because it is sustainable and eco-friendly. Herein, new methodology for converting agarose, a naturally occurring type of biomass that forms robust hydrogels, into PCs with tunable pore structures and high electrochemical performance is described. The synthetic process is straightforward and entails heating a gel that is composed of agarose and potassium oxalate (K 2 C 2 O 4 ). Since the salt transforms into gaseous byproducts at elevated temperatures, the decomposition process was harnessed to create activated, open pores as the hydrogel underwent carbonization. For example, a PC with a surface area of 1754.9 m 2 g –1 and a pore volume of 2.643 cm 3 g –1 was obtained by heating a mixture of agarose and K 2 C 2 O 4 in a 1:3 weight ratio at 700 °C. The material was subsequently used as the electrode material in a supercapacitor and found to display a specific capacitance of 166.0 F g –1 at 0.125 A g –1 . Varying the quantity of added K 2 C 2 O 4 resulted in predictable changes in porosity and thus offered a means to tune the textural properties and the electrochemical performance of the PCs. For example, changing the feed ratio of agarose to K 2 C 2 O 4 to 1:6 afforded a PC that exhibited a high persistent specific capacitance (64.1 F g –1 at 5 A g –1 after 10,000 cycles) and a high-power density (20 kW kg –1 at 10 A g –1 ).

Abstract Membrane vapor separation processes are a promising technology for both removing water vapor and recovering the sensible heat of exhaust gas from the drying process. In this study, to investigate how the impact of membrane selectivity affects the efficiency of water vapor removal and sensible heat recovery, the performances were evaluated using 3 membrane modules. From the results, by increasing the membrane selectivity, the permeate vapor and the removal efficiency decreased. The air recirculation ratio for recovering sensible heat was not found to be entirely dependent on the membrane selectivity, in spite of the trade-off between permeability and selectivity. In addition, by increasing the partial pressure, the vapor removed increased, though the change of air recirculation was negligible regardless of membrane selectivity.

Public interest in and preferences for certain species can sometimes provide an opportunity for conservation and management. Here, we attempted to identify ‘popular’ anurans from YouTube data. In addition, the attractiveness of anuran advertisement-calling sounds were analyzed using acoustic data. By searching YouTube with the search term ‘frog calling’, 250 videos were selected. Of these, 174 videos could be classified according to species; these videos aided in extracting clean calling sounds, free from the overlapping calls of other male frogs, as well as other sounds. To assess the interests and preferences of viewers for different species, the numbers of videos, view counts, ‘likes,’ and ‘dislikes’ were recorded. From the videos, the calls of 78 species belonging to 17 families were identified. Viewer interest was highest for the Hylidae and Ranidae species, which are often discoverable in the field. In addition, invasive frogs had large numbers of videos and large numbers of ‘likes.’ People tended to prefer frogs calling with lower dominant frequencies. However, there were few videos on endangered species, and these garnered relatively less interest than other species. To manage and conserve invasive or endangered frog species, there is a need to increase ecological understanding by adjusting species awareness and charisma.

This research aimed to examine the willingness to pay (WTP) of the young generation (the age group from 18 to 29) for the participatory solutions and actions on fine particulate matter (PM2.5) pollution control and abatement in Daegu, Korea, and Beijing, China. This study found out that Korean respondents and Chinese respondents shared a wide range of similarities, both in terms of socio-demographic characters like age, family size, and house/apartment ownership, as well as a number of perceptions related to environmental and social responsibilities. Around one-third of the Korean respondents and one-fifth of the Chinese respondents expressed negative WTP due to primary reasons such as lack of trust in the effectiveness of PM2.5 control measures (Korea) and limitation of budget (China). The mean estimated values of WTP with and without explanatory variables in Korea were merely slightly higher than those in China. The mean WTP without control variables in Korea was 11,882.97 KRW/month (10.61 USD/month) and the one in China was 65.09 CNY/month (9.48 USD/month). The mean WTP with explanatory variables for Daegu, Korea, was KRW 11,982.33 (USD 10.70) per person per month, and the one for Beijing, China, was CNY 64.84 (USD 9.40) per person per month. The annual total WTP for Daegu, Korea, was assessed around KRW 47572 million (USD 42.45 million), whereas the estimated total WTP for Beijing, China, was around CNY 3260.14 million (USD 474.94 million) per year. Based on the results and the findings, this study proposes to further strengthen the comprehensive cooperation between China and Korea in the field of air quality improvement, with a particular focus on PM2.5 control and abatement and cooperation in academic circles and among the general public.

In general, severe load imbalances in small AC micro-grid systems can degrade their operational performance and their maintenance. This is because the unbalanced load in the micro-grid affects the energy flow and the voltage regulation functions of each phase. In order to solve the voltage imbalance problem, several algorithms for the 3-phase 4-leg CVCF inverter have been proposed, but the control algorithms are not enough to operate the 4-leg CVCF inverter in a stable manner. Therefore, this paper proposes a single-phase voltage and power control algorithm for the 3-phase 4-leg CVCF inverter based on a dq control in order to improve the voltage imbalance problem caused by a severely unbalanced load, where the single phase voltage control algorithm is composed of an αβ-dq and a dq-αβ transformer, a voltage and a current controller, and an off-set controller and a PWM, and the single-phase power control algorithm is also composed of an αβ-dq and a dq-αβ transformer, an active/reactive power and a current controller, and an off-set controller and a PWM. Additionally, this paper performs modeling of the single-phase voltage and the power controller for a 4-leg CVCF inverter using the Matlab/Simulink S/W. From the simulation results, it is confirmed that the transient stability of the proposed single voltage control algorithm can be improved compared to the conventional control algorithm, and voltage control can also be maintained in a stable manner under extremely unbalanced conditions. Further, it is confirmed that 3-phase currents of the proposed single-phase power control algorithm are controlled in a stable manner under extremely unbalanced conditions.