146 results on '"Chen, Weiming"'
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2. Effect of electromigration on microstructure and properties of CeO2 nanopartical-reinforced Sn58Bi/Cu solder joints.
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Chen, Weiming, Zhang, Keke, Fan, Yuchun, Zhang, Chao, and Wang, Nannan
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To mitigate the decrease in mechanical performance of Sn58Bi/Cu solder joints resulting from electromigration-induced damage. The CeO2 nanoparticles were incorporated into Sn58Bi solder by a melt-casting method, and their effects on the microstructure and properties of Sn58Bi/Cu solder joints under electromigration were investigated. The study results demonstrate that the addition of 0.125 ~ 0.5 wt% CeO2 nanoparticles refines the eutectic microstructure of Sn58Bi solder alloy. At an addition amount of 0.5 wt%, the composite solder alloy exhibits the maximum tensile strength of 68.9 MPa, which is 37% higher than that of the base solder. CeO2 nanoparticle-reinforced Sn58Bi solder can achieve excellent solderbility with Cu substrates and the joints can significantly inhibit the growth of the anodic Bi-rich layer, which is responsible for electromigration. With the extension of current stressing time, Bi-rich and Sn-rich layer are respectively formed on the anode and cathode in the joints. The intermetallic compound (IMC) layer grows asymmetrically, transitioning from a fan-shaped morphology to a flattened structure at the anode and to a thickened mountain-like morphology at the cathode. Adding the CeO2 nanoparticles helps to mitigate the decrease in mechanical performance caused by electromigration damage during current application to some extent. Over the current stressing period of 288 ~ 480 h, the fracture position shifts from the anodic IMC/Bi-rich interface to the cathodic Sn-rich/IMC interface. The fracture mechanism transitions from a brittle fracture characterized by plate-like cleavage to a ductile–brittle mixed fracture with fine dimples and cleavage. [ABSTRACT FROM AUTHOR]
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- 2024
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3. MSSDet: Multi-Scale Ship-Detection Framework in Optical Remote-Sensing Images and New Benchmark.
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Chen, Weiming, Han, Bing, Yang, Zheng, and Gao, Xinbo
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OPTICAL remote sensing , *REMOTE-sensing images , *OPTICAL images , *MARITIME shipping , *OBJECT recognition (Computer vision) , *SPATIAL resolution - Abstract
Ships comprise the only and most important ocean transportation mode. Thus, ship detection is one of the most critical technologies in ship monitoring, which plays an essential role in maintaining marine safety. Optical remote-sensing images contain rich color and texture information, which is beneficial to ship detection. However, few optical remote-sensing datasets are open publicly due to the issue of sensitive data and copyrights, and only the HRSC2016 dataset is built for the ship-detection task. Moreover, almost all general object detectors suffer from the failure of multi-scale ship detection because of the diversity of spatial resolution and ship size. In this paper, we re-annotate the HRSC2016 dataset and supplement 610 optical remote-sensing images to build a new open source ship-detection benchmark dataset with rich multi-scale ship objects named the HRSC2016-MS dataset. In addition, we further explore the potential of a recursive mechanism in the field of object detection and propose a novel multi-scale ship-detection framework (MSSDet) in optical remote-sensing images. The success of detecting multi-scale objects depends on the hierarchical pyramid structure in the object-detection framework. However, the inherent semantic and spatial gaps among hierarchical pyramid levels seriously affect detection performance. To alleviate this problem, we propose a joint recursive feature pyramid (JRFP), which can generate semantically strong and spatially refined multi-scale features. Extensive experiments were conducted on the HRSC2016-MS, HRSC2016, and DIOR datasets. Detailed ablation studies directly demonstrated the effectiveness of the proposed JRFP architecture and also showed that the proposed method has excellent generalizability. Comparisons with state-of-the-art methods showed that the proposed method achieves competitive performance, i.e., 77.3%, 95.8%, and 73.3% mean average precision accuracy on the HRSC2016-MS, HRSC2016, and DIOR datasets, respectively. [ABSTRACT FROM AUTHOR]
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- 2022
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4. Ultrathin Zn(002) textured zinc anodes for dendrite-free and hydrogen evolution-inhibited zinc batteries.
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Li, You, Chen, Weiming, Jia, Shengkun, Tang, Mulan, Zhai, Yuxin, Zhan, Lulu, and Chen, Weiyan
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ZINC , *INTERFACIAL reactions , *ZINC electrodes , *DENDRITIC crystals , *DENDRITES , *HYDROGEN , *ANODES - Abstract
For practical rechargeable aqueous zinc-ion batteries, the long-term cycling stability of the zinc anode remains significantly constrained by its low utilization efficiency and the persistent challenge of hydrogen evolution. This study demonstrates the fabrication of ultrathin zinc electrodes with a robust Zn (002) texture while ensuring an adequate supply of zinc metal for use as an anode material. This approach effectively suppresses the tendency of zinc atoms to undergo deposition transformation due to dislocation-induced phenomena. Compared to zinc foils with higher deposition amount, the ultrathin Zn anode exhibits enhanced resistance to dendrite growth and interfacial side reactions. Assembled symmetrical cells based on this ultra-thin Zn anode show a cycle life of 1750 h (1 mAcm−2, 0.5 mAhcm−2), maintaining stable cycling for over 100h even at a high depth of discharge (DOD) of 46.23%. Additionally, the full cell couple with V 10 O 24 exhibits a high initial capacity of 429.6 mAh g−1 and a capacity retention of 75.8% after 1000 cycles. [Display omitted] • Preventing Zn dendrite formation during cycling by precisely controlling the deposition amount. • Synthesis of ultrathin, strong Zn (002) textured zinc anodes to achieve high utilization, cycling at 46 % DOD for over 100 h. • Elucidates the mechanism underlying the influence of deposition amount on zinc anode performance. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Graphdiyne Nanospheres as a Wettability and Electron Modifier for Enhanced Hydrogenation Catalysis.
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Yu, Jia, Chen, Weiming, Li, Kaixuan, Zhang, Chunhui, Li, Mingzhu, He, Feng, Jiang, Lei, Li, Yuliang, Song, Weiguo, and Cao, Changyan
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WETTING , *MESOPOROUS silica , *CATALYSIS , *METAL catalysts , *WATER pressure , *HETEROGENEOUS catalysis , *HYDROGENATION , *CATALYTIC hydrogenation - Abstract
Owing to unique alkyne‐rich structure, graphdiyne (GDY) has been proven to be a superb support for anchoring metal catalysts. Herein we demonstrate a new role of GDY as the wettability modifier for enhanced hydrogenation catalysis. After loading a certain amount GDY nanospheres, the silica mesoporous channels become superaerophilic, which allows gaseous H2 to be directly stored inside, thus significantly increasing the H2 concentration around the palladium nanoparticles (NPs). At the same time, GDY nanospheres also alter the electronic structure of the Pd NPs via a strong d‐π interaction. Combining these two roles of GDY, allows the hydrogenation of benzaldehyde to proceed under ambient H2 pressure in water, with an impressive 4.3‐fold enhancement compared to the unmodified Pd/mSiO2 catalyst. This study demonstrates a new role of GDY in constructing wettability matched catalysts for gas‐liquid‐solid tri‐phase reactions. [ABSTRACT FROM AUTHOR]
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- 2022
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6. Graphdiyne Nanospheres as a Wettability and Electron Modifier for Enhanced Hydrogenation Catalysis.
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Yu, Jia, Chen, Weiming, Li, Kaixuan, Zhang, Chunhui, Li, Mingzhu, He, Feng, Jiang, Lei, Li, Yuliang, Song, Weiguo, and Cao, Changyan
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WETTING , *MESOPOROUS silica , *CATALYSIS , *METAL catalysts , *WATER pressure , *HETEROGENEOUS catalysis , *HYDROGENATION , *CATALYTIC hydrogenation - Abstract
Owing to unique alkyne‐rich structure, graphdiyne (GDY) has been proven to be a superb support for anchoring metal catalysts. Herein we demonstrate a new role of GDY as the wettability modifier for enhanced hydrogenation catalysis. After loading a certain amount GDY nanospheres, the silica mesoporous channels become superaerophilic, which allows gaseous H2 to be directly stored inside, thus significantly increasing the H2 concentration around the palladium nanoparticles (NPs). At the same time, GDY nanospheres also alter the electronic structure of the Pd NPs via a strong d‐π interaction. Combining these two roles of GDY, allows the hydrogenation of benzaldehyde to proceed under ambient H2 pressure in water, with an impressive 4.3‐fold enhancement compared to the unmodified Pd/mSiO2 catalyst. This study demonstrates a new role of GDY in constructing wettability matched catalysts for gas‐liquid‐solid tri‐phase reactions. [ABSTRACT FROM AUTHOR]
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- 2022
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7. Pickering emulsion stabilized by sugarcane leaf polyphenols-zein covalent nanoparticles for curcumin delivery: In-vitro and inhibition of oxidative hemolytic activity evaluation.
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Chen, Weiming, Pan, Haihui, Sheng, Yuanhao, Wang, Feilin, Jiang, Fengyu, Bi, Yongguang, and Kong, Fansheng
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CURCUMIN , *EMULSIONS , *ERYTHROCYTES , *SUGARCANE , *NANOPARTICLES , *OXIDANT status - Abstract
Pickering emulsion have been widely used to encapsulate bioactives with the aim of preventing degradation, improving bioavailability and achieving the effect of slow release. Curcumin (Cur), as a bioactive compound, was famous as its excellent beneficial human health functions. However, the low solubility and susceptibility to environmental influences limit the application of Cur. In our previous study, the covalent nanoparticles (sugarcane leaf polyphenols-zein, SGLpZ) with excellent antioxidant capacity were successfully fabricated. In addition, the pickering emulsion stabilized using SGLpZ with significance storage stability and antioxidant properties, which inspired us for Cur delivery application. Therefore, in this study, SZP (pickering emulsion stabilized by SGLpZ) were prepared and were firstly used to delivery Cur evaluation. Results exhibited that the mechanism of excellent stabilization of SZP may be due to the wide range of O/W phase interfaces with SGLpZ, which could be further used as a delivery system for Cur. An in-vitro simulated digestion suggested that SZP provided better protection to Cur under three different conditions (different Na+ concentration, temperatures and UV exposure times), compared to ZZP (pickering emulsion stabilized by zein nanoparticles alone). SZP was able to achieve a slow release of Cur as well as the high bioaccessibility of Cur during the in-vitro simulated digestion. Finally, Cur, Cur-ZZP and Cur-SZP inhibited respectively by 33.20±1.00%, 53.26±0.94% and 71.59±0.14% (p <0.05) at the Cur concentration of 20 μg/mL in the in-vitro inhibition of AAPH-induced erythrocyte hemolysis assay. The study indicated that the pickering emulsion stabilized by SGLpZ was a reliable Cur delivery system and provided a novel idea of food material application for bioacitive substances delivery. [Display omitted] • A green-sustainable pickering emulsion stabilized by Sugarcane leaf polyphenols-Zein nanoparticles was firstly prepared. • Cur-SZP for better results compared with curcumin and Cur-ZZP in three different external environments. • Cur-SZP achieved slow release and improved bioavailability of curcumin in in-vitro digestion. • The inhibitory effect of Cur-SZP on hemolysis of red blood cells was studied. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Oxidative carbon–carbon bond cleavage of 1,2-diols to carboxylic acids/ketones by an inorganic-ligand supported iron catalyst.
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Chen, Weiming, Xie, Xin, Zhang, Jian, Qu, Jian, Luo, Can, Lai, Yaozhu, Jiang, Feng, Yu, Han, and Wei, Yongge
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CARBON-carbon bonds , *IRON catalysts , *CARBOXYLIC acids , *CHEMICAL amplification , *SCISSION (Chemistry) , *HETEROGENEOUS catalysts , *KETONES , *KETONIC acids - Abstract
The carbon–carbon bond cleavage of 1,2-diols is an important chemical transformation. Although traditional stoichiometric and catalytic oxidation methods have been widely used for this transformation, an efficient and valuable method should be further explored from the views of reusable catalysts, less waste, and convenient procedures. Herein an inorganic-ligand supported iron catalyst (NH4)3[FeMo6O18(OH)6]·7H2O was described as a heterogeneous molecular catalyst in acetic acid for this transformation in which hydrogen peroxide was used as the terminal oxidant. Under the optimized reaction conditions, carbon–carbon bond cleavage of 1,2-diols could be achieved in almost all cases and carboxylic acids or ketones could be afforded with a high conversion rate and high selectivity. Furthermore, the catalytic system was used efficiently to degrade renewable biomass oleic acid. Mechanistic insights based on the observation of the possible intermediates and control experiments are presented. [ABSTRACT FROM AUTHOR]
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- 2021
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9. An Ortho-modification Strategy to Develop Brooker’s Merocyanine Probe for Precise Monitoring of pH Changes in Urine.
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Dai, Yanpeng, Chen, Weiming, Zhang, Jin, Cai, Yujie, and Zhang, Xiangting
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As a non-invasive body fluid, urine pH is one of the important biomarkers for diseases such as the kidneys. Therefore, rapid and accurate detection of urine pH is of great clinical significance. A novel fluorescent probe (SPPH-Cl) was developed based on Brooker’s merocyanine skeleton for pH detection. The pKa of SPPH-Cl was adjusted to 6.55 using a phenolic hydroxyl ortho substitution strategy, therefore, the fluorescence response range of SPPH-Cl to pH covers the urine physiological pH range (4.6-8.0). SPPH-Cl has excellent water solubility, stable recoverability, wide anti-interference capability, and sensitive reactions to pH fluctuations in pure aqueous solutions. SPPH-Cl has succeeded in applying to monitor the pH of volunteer urine samples based on a standard curve established in artificially simulated urine, and the detection results have accuracy comparable to pH meters. Therefore, this work provided a powerful molecule tool for detecting pH in urine samples. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Application of membrane separation technology in the treatment of leachate in China: A review.
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Chen, Weiming, Gu, Zhepei, Ran, Gang, and Li, Qibin
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MEMBRANE separation , *SEPARATION (Technology) , *LANDFILL management , *LEACHATE , *LANDFILLS , *WASTE management , *SOLID waste , *INCINERATION - Abstract
• Application of membrane separation process in China is comprehensively investigated. • Leachate treatment capacity of NF is the highest in landfill and incineration plant. • A combination of NF and RO exhibits the best efficiency for leachates treatment. • Membrane processes are more likely to be adopted in economically developed regions. • Operation costs of membrane process mainly depends on the pre-treatment process. To comprehensively investigate the application of membrane separation technology in the treatment of landfill leachate in China, the performance of nearly 200 waste management enterprises of different sizes in China were analyzed, with an emphasis on their scale, regional features, processes, and economic characteristics. It was found that membrane separation technologies, mainly nanofiltration (NF), reverse osmosis (RO), and NF + RO, have been used in China since 2004. The treatment capacity of the two most dominant membrane separation technologies, i.e., NF and RO, were both almost 60,000 m3/d in 2018, and both technologies are widely used in landfills and incineration plants. Their distribution is mainly concentrated in eastern and southwestern China, where the amount of municipal solid waste (MSW) is relatively high and the economy is developing rapidly. Membrane separation technology is the preferred technique for the advanced treatment of leachate because more contaminants can be effectively removed by the technology than by other advanced processes. However, the membrane retentate that is produced using this technology—commonly known as leachate concentrate—is heavily contaminated due to the enrichment of almost all the inorganic anions, heavy metals, and organic matter that remain after bioprocessing. An economic cost analysis revealed that the operating cost of membrane separation technology has stabilized and is between 1.77 USD/m3 and 4.90 USD/m3; electricity consumption is the most expensive cost component. This review describes the current problems with the use of membrane separation technology and recommends strategies and solutions for its future use. [ABSTRACT FROM AUTHOR]
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- 2021
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11. Hemoglobin-derived Fe-Nx-S species supported by bamboo-shaped carbon nanotubes as efficient electrocatalysts for the oxygen evolution reaction.
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Chen, Weiming, Luo, Xuanli, Ling, Sanliang, Zhou, Yongfang, Shen, Bihan, Slater, Thomas J.A., Fernandes, Jesum Alves, Lin, Tingting, Wang, Jianshe, and Shen, Yi
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OXYGEN evolution reactions , *CARBON nanotubes , *X-ray absorption near edge structure , *ALKALINE solutions , *DENSITY functional theory , *ELECTROCATALYSTS , *X-ray absorption - Abstract
Herein, we report a facile route to synthesize isolated single iron atoms on nitrogen-sulfur-codoped carbon matrix via a direct pyrolysis process in which hemoglobin, a by-product of the meat industry, was utilized as a precursor for iron, nitrogen and sulfur while bamboo-shaped carbon nanotubes served as a support owing to their excellent conductivity and numerous defects. The resulting metal-nitrogen complexed carbon showed outstanding catalytic performance for the oxygen evolution reaction (OER) in alkaline solutions. At an overpotential of 380 mV, the optimal sample yielded a current density of 83.6 mA cm−2, which is 2.5 times that of benchmark IrO 2 (32.8 mA cm−2), rendering it as one of the best OER catalysts reported so far. It also showed negligible activity decay in alkaline solutions during long-term durability tests. Control experiments and X-ray absorption fine structure analyses revealed that Fe-N x species in the samples are the active sites for OER. Further density functional theory calculations indicated that the presence of sulfur in the carbon matrix modified the electronic structures of active species, thereby leading to the superior activity of the sample. Image 1 • Fe-Nx-S species were formed by a direct pyrolysis of hemoglobin and carbon nanotubes. • The resulting sample showed outstanding performance for the OER in alkaline solutions. • The sample gave a current density of 83.6 mA cm−2 at 380 mV, which is 2.5 times that of IrO 2. • Density functional theory calculations were done to explore the role of the sulfur dopant. [ABSTRACT FROM AUTHOR]
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- 2020
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12. A comprehensive evaluation of the treatment of lead in MSWI fly ash by the combined cement solidification and phosphate stabilization process.
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Chen, Weiming, Wang, Fan, Li, Zhi, and Li, Qibin
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FLY ash , *SOLIDIFICATION , *INCINERATION , *HAZARDOUS substances , *CEMENT , *TREATMENT effectiveness , *POTASSIUM dihydrogen phosphate , *SOLID waste - Abstract
• Solidification and stabilization effect of Pb in MSWI fly ash was compared. • Pb leaching concentration, volume change ratio, and treatment cost were evaluated. • Combined solidification-stabilization process yielded the best treatment effect. • Optimal parameters are obtained through response surface methodology. Fly ash is a hazardous material that is produced from municipal solid waste incineration. It contains heavy metals and should be properly treated to meet landfill entry requirements. In this study, under the precondition that the leachable concentration of lead (Pb) exceeded the limit value for landfill disposal, the effects of cement solidification, chemical stabilization, and their combination on the leachable Pb concentration and the chemical state of Pb were systematically investigated. In addition, the reaction conditions were optimized by response surface methodology (RSM) in terms of leachable Pb concentration, volume change ratio, and treatment cost. The results indicated that the leachable Pb concentration decreased at lower cement or sodium dihydrogen phosphate (NaH 2 PO 4) dosages in cement solidification or NaH 2 PO 4 stabilization, and the liquid-to-solid ratio had a significant influence on cement solidification. The leachable Pb concentration met the limit value for landfill disposal in the individual processes with 20% cement or 5% NaH 2 PO 4 , and in the combined process with 10% cement + 2% NaH 2 PO 4. The combined process achieved the best treatment efficiency by enabling Pb to transform to a stable residual state. According to the RSM, a combined cement content of 11.64%, NaH 2 PO 4 content of 2.79%, and liquid-to-solid ratio of 0.48 were the optimal parameters, resulting in substantial decreases in the volume change ratio and treatment costs, while satisfying the preconditions for landfill disposal. In conclusion, the combined process can reduce the pollution risk to the environment, and is an efficient and cost-effective pre-treatment method for incinerator fly ash. [ABSTRACT FROM AUTHOR]
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- 2020
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13. A pilot-scale comparative study of bioreactor landfills for leachate decontamination and municipal solid waste stabilization.
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Gu, Zhepei, Chen, Weiming, Wang, Fan, and Li, Qibin
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BIOREACTOR landfills , *SOLID waste , *LEACHATE , *LANDFILLS , *COMPARATIVE studies , *FATTY acids , *POLLUTION - Abstract
• The performance differences of three pilot-scale landfills were investigated. • MSW stabilization in the SABL was greatly accelerated. • NH 4 +–N in SABL leachate was substantially lower than that from the other landfills. • SABL leachate exhibited the least chloride pollution risk. Many studies have sought to optimize operation parameters and enhance the treatment capacity of bioreactor landfills (BL) under ideal laboratory conditions. At pilot scale, conclusions drawn from laboratory-scale experiments will be different due to variations in actual landfill composition and changes in environmental conditions. However, comparative pilot-scale studies of traditional anaerobic landfills (AnL) and BLs are rare. In this study, three pilot-scale landfills, including an AnL, anaerobic BL (AnBL) and semi-aerobic BL (SABL), were monitored to examine the difference in performance at different scales and among types of landfills. Settlement amount followed the order SABL (25.45 cm) > AnBL (18.67 cm) > AnL (14.38 cm). Decomposition of organic matter (i.e., volatile fatty acids) was more rapid in SABL than in the other landfills and no hydrolytic acidification period was observed. Therefore, among the three landfills, SABL entered the methanogenic stage in a much shorter time and MSW stabilization was accelerated due to this landfill's unique combination of aerobic-anoxic-anaerobic ambient. In addition, NH 4 +–N concentration in leachate from the SABL (~19.96 mg/L) was substantially lower than from AnL (338.28 mg/L) and AnBL (233.22 mg/L), and SABL leachate exhibited the least chloride pollution risk. This study provides theoretical support and strong evidence for using SABLs to treat MSW in practical applications. [ABSTRACT FROM AUTHOR]
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- 2020
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14. Treatment of semi-aerobic aged-refuse biofilter effluent from treating landfill leachate with the Fenton method.
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Gu, Zhepei, Chen, Weiming, Li, Qibin, and Zhang, Aiping
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DISSOLVED organic matter , *LEACHATE , *LANDFILLS , *BIOCHEMICAL oxygen demand , *FLUOROPHORES , *CHEMICAL oxygen demand - Abstract
• Landfill leachate was effectively treated by SAARB combined Fenton method. • Fulvic- and humic-like substances were identified in SAARB effluent. • Two fluorescent substances were tracked with parameters varying in Fenton method. Semi-aerobic aged-refuse biofilter (SAARB) can achieve good treatment efficiency for organics and nitrogen ammonia, but the effluent of SAARB from treating landfill leachate (SAARB leachate) has high chemical oxygen demand (COD), compared to the discharge standard (100 mg/L), and high humification degree. In this study, the conventional Fenton method was used in the advanced treatment of SAARB leachate. Fluorescent components in SAARB leachate were identified and tracked with parallel factor (PARAFAC) analysis, and the influencing factors, i.e., Fe2+ dosage, n(H 2 O 2 /FeSO 4) ratio, initial pH, and reaction time, on the removal of fluorescent components were systematically investigated. UV–Vis spectra show the structural transformation of dissolved organic matter (DOM) in SAARB leachate. Results show that SAARB leachate mainly contains two fluorescent components: fulvic-like substances [C1; excitation (Ex)/emission (Em) (nm), (245)280/405] and humic-like substances [C2; Ex/Em (nm), (260)360/435]. A higher Fe2+ dosage, longer reaction time, and acidic conditions increased the degradation efficiency of organics, but excess H 2 O 2 inhibited the treatment process. Under optimum Fenton parameters (Fe2+ dosage of 5 mmol/L, n(H 2 O 2 /FeSO 4) ratio of 8, initial pH of 4, and reaction time of 60 min), removal rates of C1 and C2 were 52.97% and 77.81%, respectively. UV–Vis spectra indicate that the Fenton reaction can destroy unsaturated conjugated bonds, decreasing the humification degree, hydrophobicity, molecular weight, and condensation degree. Finally, the biodegradability (represented by BOD 5 (biochemical oxygen demand for 5-days)/COD) greatly increased (from 0.05 to 0.36), thus benefiting further biological treatment. The results provide suggestions and guidance for practical applications in landfill leachate treatment. [ABSTRACT FROM AUTHOR]
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- 2020
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15. NPBS database: a chemical data resource with relational data between natural products and biological sources.
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Xu, Tingjun, Chen, Weiming, Zhou, Junhong, Dai, Jingfang, Li, Yingyong, and Zhao, Yingli
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NATURAL products , *COMPUTABLE functions , *CHEMICAL structure , *DATABASES , *NONRELATIONAL databases , *DATA structures - Abstract
NPBS (Natural Products & Biological Sources) database is a chemical data resource with relational data between natural products and biological sources, manually curated from literatures of natural product researches. The relational data link a specific species and all the natural products derived from it and contrarily link a specific natural product and all the biological sources. The biological sources cover diverse species of plant, bacterial, fungal and marine organisms; the natural molecules have proper chemical structure data and computable molecular properties and all the relational data have corresponding references. NPBS database provides a wider choice of biological sources and can be used for dereplication to prevent re-isolation and re-characterization of already known natural products. Database URL : http://www.organchem.csdb.cn/scdb/NPBS [ABSTRACT FROM AUTHOR]
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- 2020
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16. Magnetic clay as catalyst applied to organics degradation in a combined adsorption and Fenton-like process.
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Xu, Ximeng, Chen, Weiming, Zong, Shaoyan, Ren, Xu, and Liu, Dan
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CLAY catalysts , *FISCHER-Tropsch process , *ADSORPTION (Chemistry) , *DRINKING water , *SCANNING electron microscopy , *TRANSMISSION electron microscopy - Abstract
• Magnetite nanoparticle supported on sepiolite (Fe 3 O 4 -Sep) was fabricated. • Fe 3 O 4 -Sep showed high adsorption ability toward BPA. • Adsorbed BPA can be degraded in-situ via Fenton-like process. • Columnar Fe 3 O 4 -Sep remained stable in the fixed-bed reactor under continuous-flow. • Influence of real water matrix on the combined processes was negligible. In this work, a magnetic sepiolite composite was prepared by chemical co-precipitation method and firstly applied as both adsorbent and catalyst for the removal of bisphenol A (BPA) through a heterogeneous Fenton process. The composite was characterized by XPS, XRD, SEM and TEM techniques. The results of the kinetics study indicate that BPA (50 mg·L−1) can be adsorbed onto the composite via electrons transfer as well as π-π interaction, and then be completely degraded at pH 6.0 within 30 min after the addition of H 2 O 2 (1000 mg·L−1). The analysis of FTIR confirms that the degradation occurred through a combined process of adsorption and oxidation. BPA was pre-concentrated and fixed onto the composite surface and then degraded in-situ by hydroxyl radicals, which were generated through the interaction between H 2 O 2 and surface active sites. To investigate the stability and regeneration properties of the catalyst, the powder composite was extruded into a small cylindrical sample and loaded in a fixed-bed reactor, which was operated under continuous-flow condition. The BPA removal efficiency after 4 h remained at 87%, while the leaching of Fe ions gradually increased. Further, degradation tests in different real waters including tap water and municipal wastewater spiked with BPA (50 μg·L−1) reveal that the influence of real matrix on the oxidation ability was very little. The findings of this study confirm the composite as a promising material for the catalytic removal of organics via the coupled adsorption-oxidation process. [ABSTRACT FROM AUTHOR]
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- 2019
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17. Pickering emulsions prepared using zein-sugarcane leaves polyphenol covalent crosslinking nanoparticles via ultrasonication: Capacities in storage stability, lipid oxidation, in vitro digestion and safety evaluation.
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Chen, Weiming, Pan, Haihui, Wang, Feilin, Sheng, Yuanhao, Jiang, Fengyu, Bi, Yongguang, and Kong, Fansheng
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PLANT polyphenols , *FOOD emulsions , *EMULSIONS , *SONICATION , *FREE fatty acids , *DIGESTION - Abstract
[Display omitted] • Zein/Sugarcane leaves polyphenols (SGLpZ) covalent nanoparticles were successfully prepared. • Pickering Emulsions stabilized by SGLpZ with ultrasound showed high stability in lipid oxidation during storage. • SGLp modification Pickering emulsions (SZP) exhibited low free fatty acids release in in-vitro digestion. • SZP showed high safety in hemocompatibility and cytotoxicity assays in-vitro. This study firstly used sugarcane leaf polyphenols (SGLp) to modify zein to form covalent nanoparticles (SGLpZ) and used SGLpZ as an emulsifier to stabilize pickering emulsions (SZP) via ultrasonic method. The results showed that the addition of SGLp could alter the physicochemical properties of zein, including improving increasing the hydrophilicity of zein and the antioxidant properties of zein (three basic antioxidant activities test in vitro). SGLpZ could be able to form a dense film on the surface of the pickering emulsions which inhibited lipid oxidation as the concentration of SGLp increased at 4 ℃ for 20 days, thus stabilizing pickering emulsions (SZP). Further assessment of storage stability of pickering emulsions stabilized by SGLp was evaluated via measuring the free fatty acids (FFA) release in vitro gastrointestinal digestion. The results showed that the FFA release of SZP decreased from 20.61 ± 0.10% to 16.14 ± 0.69%. In addition, SGLp gave SZP a yellow color, which inspired that SZP could be used in the food industry to make yellow-colored functional foods. Finally, the safety of SZP initially assessed by in-vitro hemocompatibility and cytotoxicity (MTT) assays. In conclusion, our fingdings were beneficial for the further design and development of SGLp in food fields and enabled the development a new type in functional protein-plant polyphenols food pickering emulsions. [ABSTRACT FROM AUTHOR]
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- 2023
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18. Compensation Network Optimal Design Based on Evolutionary Algorithm for Inductive Power Transfer System.
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Chen, Weiming, Lu, Weiguo, Iu, Herbert Ho-Ching, and Fernando, Tyrone
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EVOLUTIONARY algorithms , *CURRENT fluctuations , *EVOLUTIONARY computation , *ALGORITHMS , *MATHEMATICAL models , *EXPERIMENTAL design - Abstract
Conventional design and optimization of passive compensation network (PCN) for inductive power transfer (IPT) system are based on specific topologies. The demerits of this design method are: i) The topology is mostly chosen by experience; ii) The design parameters are not multi-objective optimal. Aiming at these issues, this paper proposes an optimal PCN design scheme based on evolutionary algorithm (EA) to synchronously optimize the topology and parameters of PCN for IPT system. Firstly, a unified mathematical model of the PCN is presented and derived by transmission matrix. Then, according to the mathematical model, the multi-objective functions (such as output fluctuation and efficiency) as well as the constraints (such as load and coupling coefficient) for the optimal PCN design are established. The EA based multi-objective optimal PCN design algorithm is further constructed. Six optimal results are obtained using the algorithm, and one optimized PCN having minimum output current fluctuation and high-efficiency is chosen to validate the effectiveness of the proposed design scheme in experiment. For the given IPT system with the optimized PCN, the maximum fluctuation of output current is no more than 11%, within 200% of load variation and about 77% of coupling variation. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
19. Opportunities for low-carbon socioeconomic transition during the revitalization of Northeast China: Insights from Heilongjiang province.
- Author
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Chen, Weiming, Lei, Yalin, Wu, Sanmang, and Li, Li
- Abstract
The Strategies of Reviving the Old Industrial Bases provide opportunities for low-carbon transition in Northeast China, which is one of the earliest regions to industrialize and the largest rustbelt in China, but study on the impacts of its socioeconomic factors on CO 2 emissions is still in short, though it is essential for guiding the pathways to achieve low-carbon socioeconomic transition. We adopted the structural decomposition analysis (SDA) to identify the main contributors to emissions increase in Heilongjiang province during 2002–2012, which is the heartland of Northeast revitalization. The results show that the increase in CO 2 emissions was mainly driven by growth in per-capita final demand, which generated 203.8 Mt (153.6%) upstream CO 2 emissions between 2002 and 2012. Changes in production structure and final demand structure had smaller impacts on CO 2 emissions increase (36.1 Mt and 27.0 Mt). However, the positive influences were largely overwhelmed by change in emission intensity, which avoided 135.4 Mt (−102%) CO 2 emissions. Therefore, appropriate measures related to energy structure optimization and efficiency improvement should be implemented. Especially, increasing the proportion of wind, solar and biomass energy in Heilongjiang, where renewable energy is abundant, would reduce the CO 2 emissions significantly. In addition, domestic export took the lead position in driving the CO 2 emissions in Heilongjiang, accounting for 37.6%–43.1% annual emissions between 2002 and 2012. Thus, some financial instrument, such as tax relief for less carbon intensive exports could be adopted to prompt upstream suppliers to decarbonize their production processes. Unlabelled Image • Structural decomposition analysis (SDA) is used to identify the main contributors of CO 2 emissions increase during 2002-2012 in Heilongjiang province. • Growth in per-capita final demand was main driver for CO 2 emissions Increase. • The positive influences were largely overwhelmed by change in emission intensity, which avoided 135.4 Mt (-102%) CO 2 emissions. • Domestic export took the lead position in driving the CO2 emissions in Heilongjiang, accounting for 37.6%-43.1% annual emissions between 2002-2012. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
20. Atrazine degradation using Fe3O4-sepiolite catalyzed persulfate: Reactivity, mechanism and stability.
- Author
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Xu, Ximeng, Chen, Weiming, Zong, Shaoyan, Ren, Xu, and Liu, Dan
- Subjects
- *
ATRAZINE , *CATALYTIC activity , *HETEROGENEOUS catalysts , *INTERMEDIATE goods ,CATALYSTS recycling - Abstract
• Fe 3 O 4 NPs supported on sepiolite was applied as persulfate activator. • Small size and good dispersion of Fe 3 O 4 NPs were observed by FESEM and TEM. • 71.6% of ATZ and 20% of solution TOC can be removed by Fe 3 O 4 -Sep/PS after 60 min. • The structure stability and catalytic activity were proved during recycle runs. • Pathways included dealkylation, chain oxidation and dechlorination-hydroxylation. In this study, with sepiolite as a support, a novel magnetic Fe 3 O 4 -sepiolite composite was fabricated by coprecipitation method. The characterization results reveal that the sepiolite support could anchor Fe 3 O 4 nanoparticles with good dispersion. The composite was used as a catalyst to activate persulfate (PS) for atrazine (ATZ) degradation. 71.6% of ATZ and 20.9% of solution TOC could be removed after 60 min with 92 mmol/L of PS ([ATZ] 0 = 10 mmol/L). Due to the good adsorption capacity of Fe 3 O 4 -sepiolite composite toward ATZ, the degradation was considered to be facilitated by an adsorption process, since the adsorbed ATZ can be more easily transported to the active sites and be degraded in situ. Operation factors, including PS dose and solution pH, were investigated and found to be influential for the ATZ removal. The Fe 3 O 4 -sepiolite composite maintained its catalytic activity and structural stability with negligible Fe leaching during the recycling batch experiments. The intermediate products were further identified and the possible transformation pathway was then proposed based on the results. The findings of this research promote the application of Fe 3 O 4 -sepiolite composite as efficient and recyclable heterogeneous catalyst for organic degradation, and provide insights into the development of alternative catalysts with good adsorptive properties. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
21. An investigation of refractory organics in membrane bioreactor effluent following the treatment of landfill leachate by the O3/H2O2 and MW/PS processes.
- Author
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Chen, Weiming, Luo, Yuanfeng, Ran, Gang, and Li, Qibin
- Subjects
- *
WATER purification , *LANDFILL management , *LEACHATE , *LANDFILLS , *HYDROGEN peroxide , *HYDROXYL group , *ORGANIC compounds - Abstract
• O 3 /H 2 O 2 and MW/PS processes for the MBR effluent are systematically compared. • MW/PS process has a better treatment effect on refractory organics in MBR effluent. • Ozone plays a major role in the degradation of aromatic organic compounds in the O 3 /H 2 O 2 process. • Hydroxyl and sulfate radicals are the main reactive oxygen species in the MW/PS process. • Chemical oxidation (i.e. O 3 /H 2 O 2 , MW/PS) is a viable technology to eliminate organics in leachate. In this study, refractory organics in a membrane bioreactor (MBR) effluent were investigated following the treatment of landfill leachate by the ozone combined hydrogen peroxide (O 3 /H 2 O 2) and microwave-activated persulfate (MW/PS) processes. The treatment efficiency and the transformation characteristics of refractory organics and reactive oxygen species were determined. It was found that an acidic environment and an increase in the O 3 dosage improved the organic removal efficiency in the O 3 /H 2 O 2 process, and the use of H 2 O 2 improved the treatment efficiency, while excessive H 2 O 2 inhibited it. In the MW/PS process, an increase in the PS dosage and MW power greatly improved the treatment efficiency, while an alkaline environment inhibited it. Under the optimized reaction parameters, the O 3 /H 2 O 2 and MW/PS processes effectively degraded refractory organics (i.e., humic acid and fulvic acid) into components with a smaller molecular weight and simpler structure. The humification, aromaticity, and conjugation of organics in wastewater were greatly reduced. Compared to the O 3 /H 2 O 2 process, the MW/PS process had a better treatment effect on refractory organics, and there were more low molecular weight organics (<1 kDa) in the treated wastewater. Because O 3 is the main selective oxidant in the O 3 /H 2 O 2 process, a large amount of organic acids were accumulated. A large amount of hydroxyl radicals and sulfate radicals with strong oxidation ability were produced in the MW/PS process, and therefore the combined action of hydroxyl and sulfate radicals can efficiently decompose humus and intermediate organics. Overall, the MW/PS process was more effective in treating the MBR effluent than the O 3 /H 2 O 2 process. The results of this study provide a reference for the selection of an advanced oxidation process to eliminate refractory organics in landfill leachate. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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22. An Auxiliary-Parallel-Inductor-Based Sequence Switching Control to Improve the Load Transient Response of Buck Converters.
- Author
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Lu, Weiguo, Chen, Weiming, Ruan, Yixiao, and Iu, Herbert Ho-Ching
- Subjects
- *
TRANSIENT responses (Electric circuits) , *SWITCHING circuits , *SEQUENCE analysis , *ELECTRIC inductors , *CONVERTERS (Electronics) - Abstract
In this paper, a sequence switching control (SSC) scheme based on an auxiliary parallel inductor is proposed to improve the transient performance of buck converters. The proposed SSC scheme introduces a small controlled inductor in parallel with the output inductor, so as to increase the inductor-current slew rate when it is activated during a load transient. Furthermore, an “n+ 1” sequence switching strategy is proposed to control the auxiliary parallel inductor. The proposed scheme divides the transient event inton+ 1 periods. In the formernperiods, the same small output voltage deviations are designed, while in the last period, a smaller deviation is done for a smooth transition from the transient to the steady state. The switching sequence is derived applying the capacitor–charge balance principle for each ofn+ 1 periods. For a given buck converter in the experiment, the settling time and the output voltage deviation of the proposed SSC scheme enhance more than 50% and 67%, respectively, over those of the time-optimal control for a 3-A load step. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
23. Transformation and degradation mechanism of landfill leachates in a combined process of SAARB and ozonation.
- Author
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Chen, Weiming, Zhang, Aiping, Jiang, Guobin, and Li, Qibin
- Subjects
- *
OZONIZATION , *LEACHATE , *BIODEGRADATION , *LANDFILLS , *BIOFILTERS - Abstract
Highlights • Coupling SAARB and ozonation was firstly applied to the treatment of leachates. • DOM in mature leachate is significantly different from that in young leachate. • Degradation and transformation mechanism were studied using 3D-EEM-PARAFAC model. • The combined process may provide suggestions and guidance for practical project. Abstract Dissolved organic matter (DOM) in mature landfill leachate is significantly different from that in young landfill leachate; the composition of DOM greatly influences both biological treatment and advanced treatment processes. In the present study, the transformation and degradation mechanisms of landfill leachates in a combined semi-aerobic aged refuse biofilter (SAARB) and ozonation process was investigated using organic removal analysis, molecular weight distribution (MWD), 3D-EEM-PARAFAC analysis, UV–Vis spectroscopy, and linear regression. Results revealed that the DOM in mature landfill leachate contained a greater amount of aromatic substances and had higher molecular weight than DOM in young landfill leachate. After the SAARB process, humus contained in the SAARB was discharged with effluent from both mature and young landfill leachate. Due to the differences in composition and structure of organic matter, the COD removal efficiency (17.89%) of SAARB effluent from treating mature landfill leachate (mature SAARB effluent) was much lower than that (45.91%) of SAARB effluent from treating young landfill leachate (young SAARB effluent) under the same operational parameters of the ozonation process. As indicated by PARAFAC analysis, better chemical stability of DOM in mature SAARB effluent resulted in inferior ozone treatment efficiency. Furthermore, the hydrophobicity and the concentration of benzene ring compounds in the mature and young SAARB effluent were reduced significantly by the ozonation process. Therefore, great improvements in the biodegradability of SAARB effluents were achieved in the ozonation process. Overall, the results of this study provide suggestions and guidance for practical applications of these technologies. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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- View/download PDF
24. Degradation of refractory organic contaminants in membrane concentrates from landfill leachate by a combined coagulation-ozonation process.
- Author
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Chen, Weiming, Gu, Zhepei, Wen, Peng, and Li, Qibin
- Subjects
- *
POLLUTANTS , *LEACHATE , *COAGULATION in industrial waste purification , *OZONIZATION , *ARTIFICIAL membranes , *FULVIC acids - Abstract
Abstract Landfill leachate is a typical refractory wastewater for which research into rapid and efficient treatment methods has become very topical. In this study, a coagulation-ozonation process was developed to treat the concentrate arising from membrane treatment of landfill leachate. The effect of coagulant type and initial pH on treatment efficiencies was investigated. Results showed that many of organics were effectively removed in the coagulation process. Thereafter, ozone was applied to further treat the coagulation-resistant organic substances. Our results revealed that the degradation rate of these coagulation-resistant substances followed the trend (color number) CN > (light absorbance at 254 nm) UV 254 > (chemical oxygen demand) COD, and the residual coagulation-resistant substances were oxidized rapidly in the ozone process. Ozone first destroyed the molecular structure of fulvic acid and the by-products generated, such as protein-like substances. In addition, the molecular weight, organic condensation degree, and concentration of benzene ring compounds were considerably decreased. Moreover, the macro molecular organics (i.e., humic acid and fulvic acid) within the size range 1–100 kDa were effectively degraded and partially transformed into bicarbonate. Overall, the combined coagulation-ozonation process reduced COD, UV 254 , and CN in the landfill leachate concentrate by 88.32%, 94.37%, and 98.83%, respectively, and thus the biodegradability of the treated leachate also was significantly improved. This excellent performance proved the feasibility of the combined coagulation-ozonation process for the removal of recalcitrant organic substances contained in landfill leachate concentrate, benefiting subsequent biological treatment. Highlights • Ozonation was applied to treat residual coagulation-resistant substances. • Residual coagulation-resistant substances were oxidized rapidly in the ozone process. • Degradation mechanism of coagulation-resistant organics was investigated using multiple ways. • The combined process significantly improved the biodegradability of the concentrates. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
25. Circuit modeling and efficiency analysis for wireless power transfer system with shielding.
- Author
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Chen, Weiming, Lu, Weiguo, and Wang, Xi
- Subjects
- *
WIRELESS power transmission , *MAGNETIC fields , *ELECTRIC coils , *SIMULATION methods & models , *FINITE element method - Abstract
Summary: It is an effective way to use magnetic shielding scheme in magnetic coupled wireless power transfer (WPT) system to reduce magnetic flux leakage. However, the additional shielding material would affect the equivalent circuit model and the power transmission efficiency of WPT system. Although the impact of some common shielding materials on the transmission efficiency has been studied using finite element simulation, there is still a lack of understanding about the impact to the equivalent model in theory. In this paper, the equivalent circuit and transmission efficiency of WPT system are analyzed theoretically under the influence of different shielding materials, and the relationship between material electrical characteristics and transmission efficiency is presented. In our WPT prototype with two 166‐mm diameter coils under ferrite shielding and aluminum shielding, the achieved maximum transmission efficiencies are 95.7% for 100‐kHz resonant frequency and 97.9% for 1‐MHz resonant frequency under the ferrite shielding, and the efficiency errors between the analytical and experimental results are less than 5% for 100‐kHz resonant frequency and 10% for 1‐MHz resonant frequency. The equivalent circuit and transmission efficiency of wireless power transfer system are analyzed theoretically under the influence of different shields, and the relationship between material electrical characteristics and transmission efficiency is presented. The analyzing and experimental results show that shields with high permeability and low electrical conductivity are beneficial for enhancing the transmission efficiency of WPT system. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
26. Kinetics study of dinitrodiazophenol industrial wastewater treatment by a microwave-coupled ferrous-activated persulfate process.
- Author
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Gu, Zhepei, Chen, Weiming, Li, Qibin, and Zhang, Aiping
- Subjects
- *
WASTEWATER treatment , *PERSULFATES , *FERROUS sulfate , *CHROMOPHORES , *SEWAGE , *CHEMICAL oxygen demand - Abstract
Abstract In this study, a ferrous-activated persulfate (PS) process induced by microwave (MW) energy was used to treat an industrial wastewater containing dinitrodiazophenol (DDNP). The effect of different operational parameters, such as PS dose, initial pH, MW power, and the mass ratio of ferrous to PS [i.e., n(Fe2+/PS)], on chemical oxygen demand (COD) removal and the pseudo first-order constant k was systematically studied. Results showed that the constant k and COD removal increased considerably with increasing PS dose, MW power, and n(Fe2+/PS); however, the constant k and COD removal decreased proportionally as the initial pH increased from 3 to 11. A base-activated PS system was formed when the initial pH further increased to 13, which resulted in a dramatic increase of k and COD removal. Controlled experiments demonstrated that the synergetic effect of MW, Fe2+, and PS were significant. The value of k was 0.2425 min−1, COD removal was 71.42%, and biodegradability remarkably increased from 0.056 to 0.6712 during treatment by MW-Fe2+/PS at a PS dose of 8 g/L, MW power of 600 W, initial pH of 3, n(Fe2+/PS) of 0.04, and reaction time of 14 min. Spectral analyses showed that the chromophores (including the diazo group and nitro group compounds) and benzene rings were greatly decomposed. Identification tests for reactive oxygen species showed that the predominant oxidizing species in the MW-Fe2+/PS process was the sulfate radical, and that the hydroxyl radical played a lesser role for color number elimination. From the perspective of both treatment efficiency energy consumption, the MW-Fe2+/PS process was confirmed to be an economical and promising pretreatment process for DDNP industrial wastewater. Graphical abstract Image 1 Highlights • MW-Fe2+/PS process was applied to the treatment of DDNP industrial wastewater. • A significant synergetic effect was observed among microwave, Fe2+, and persulfate in MW-Fe2+/PS process. • SO 4 – and OH were the dominant oxidizing species in the MW-Fe2+/PS process. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
27. Enhanced degradation of refractory organics in concentrated landfill leachate by Fe0/H2O2 coupled with microwave irradiation.
- Author
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Chen, Weiming, Zhang, Aiping, Gu, Zhepei, and Li, Qibin
- Subjects
- *
REFRACTORY materials , *LEACHATE , *LANDFILLS , *CHEMICAL decomposition , *IRRADIATION , *MICROWAVES - Abstract
Highlights • The MW-Fe0/H 2 O 2 process was used to treat concentrated landfill leachate. • Reaction parameters and the degradation mechanism were systematically studied. • Refractory organics were degraded by the synergistic effects of MW, Fe0 and H 2 O 2. • Various analyses proved that refractory organics were efficiently degraded. • The reaction mechanism of the MW-Fe0/H 2 O 2 process has wide applicability. Abstract To study the treatment effect and mechanism of a combined microwave (MW)-Fe0/H 2 O 2 Fenton-like process on concentrated landfill leachate, the effects of initial pH, Fe0 dosage, H 2 O 2 dosage, MW power and reaction time on the removal of organic substances were investigated. The phase change of Fe0 before and after reaction and its catalytic mechanism were investigated using multiple analytical techniques. Results showed that the removal efficiencies of chemical oxygen demand, UV 254 and color number were 58.70%, 85.69% and 88.30%, respectively, at initial pH of 2.0, Fe0 dosage of 0.5 g/L, H 2 O 2 dosage of 20 mL/L, MW power of 400 W and reaction time of 14 min. Comparison of different Fenton-like processes indicated that the MW-Fe0/H 2 O 2 Fenton-like process was the most efficient and significantly decreased the aromaticity degree, molecular weight and condensation degree of organic substances in the leachate. The fluorescence peak of concentrated leachate exhibited a blue-shift in the MW-Fe0/H 2 O 2 process, further indicating that the condensation degree of humic substances declined and molecular weight remarkably decreased. The mechanism exhibited an advanced oxidation effect of a heterogeneous Fenton reaction between iron oxide and H 2 O 2 , as well as of adsorption and precipitation effects of iron-based colloids, on organic substances. Moreover, thermal and non-thermal effects of MW accelerated these reactions, achieving fast removal of organic pollutants in the concentrated landfill leachate. Overall, the results of this study showe that the MW-Fe0/H 2 O 2 process is an effective and promising method to handle concentrated landfill leachate. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
28. Inter-regional economic-environmental correlation effects of power sector in China.
- Author
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Chen, Weiming, Zhang, Zhenjun, and Chen, Kaiyuan
- Subjects
- *
ENERGY industries , *SUPPLY & demand , *CARBON emissions , *WATER consumption , *GREENHOUSE gas mitigation , *ELECTRIC power consumption - Abstract
Power sector is the pillar industry to promote China's rapid economic growth. It is also one of the sectors with the largest carbon emissions and water consumption. The green transformation of the power sector has become the focus of China's provincial economic and environmental policies. However, due to the complex inter-provincial power sector linkage, provincial power policies have spillover and overlapping effects, making it difficult for policies to coordinate and complement each other. Here, we quantify the value-added, CO2 emissions and water consumption driven by inter-provincial power sector linkage in China, and proposes differentiated policies at provincial and sectoral levels for green transformation of power sector. By quantifying the economic and environmental correlation effects among China's provincial power sectors, we found that low-carbon transformation of power sector in industrial provinces have higher economic costs. East and North China's policies committed to emission reduction in power sector can save more water. [Display omitted] • The economic and environmental linkage effects between China's provincial power sectors are quantified. • Low-carbon transformation of power sector in industrial provinces have higher economic costs. • East and North China's policies committed to emission reduction in power sector can save more water. • Electricity policies in China's high-income provinces should focus on the demand side. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
29. A lightweight face-assisted object detection model for welding helmet use.
- Author
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Chen, Weiming, Li, Changfan, and Guo, Hailin
- Subjects
- *
OBJECT recognition (Computer vision) , *WELDING , *HELMETS , *FEATURE extraction , *CONSTRUCTION management , *FUSIFORM gyrus - Abstract
Automatic Welding Helmet Use (WHU) detection technology is of great significance for the safety management of construction site, then, this paper proposes a lightweight face-assisted model using YOLOv5s for the detection of WHU (WHU-YOLO). First, the Ghost module is introduced into YOLOv5s to optimize feature extraction parts of backbone and neck, reducing model complexity. Then, the neck of YOLOv5s is reconstructed based on Bi-directional Feature Pyramid Network (Bi-FPN). The experimental results implemented on established Welding helmet and Human face Detection (WHD) dataset indicate that the false positives have been greatly decreased with the assistance of face data and the mean average precision (mAP) reaches 83.65%. Meanwhile, under the environment of NVIDIA GeForce GTX 1070 and 640 × 640 input size, WHU-YOLO with inference time up to 5.7 ms achieves model compression with 35.7%, 34.4% and 30.1% reductions in parameters, weight size and Floating Point Operations (FLOPs) compared with YOLOv5s, respectively, which has no decline on detection performance. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
30. Temperature and composition dependent thermal conductivity model for U-Zr alloys.
- Author
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Chen, Weiming and Bai, Xian-Ming
- Subjects
- *
URANIUM alloys , *EFFECT of temperature on metals , *THERMAL conductivity , *METAL-base fuel , *FAST reactors - Abstract
Uranium-zirconium (U-Zr) based metallic fuels are promising fuel forms for next-generation fast reactors. The presence of temperature gradient and constituent redistribution in U-Zr based fuels can induce the formation of different phases that have different physical properties such as thermal conductivity. In this work, a semi-empirical model is developed to predict the thermal conductivities of U-Zr alloys for the complete composition range and a wide range of temperatures. The model considers the effects of different electron scattering mechanisms on the electronic thermal resistivity in pure metals and the model's parameters are empirically determined by fitting to the experimental data. A new mixing rule is used to predict the effective thermal conductivity in U-Zr alloys by taking the alloying effects into account. The thermal conductivity predictions by the new model show good agreement with many available experimental data. In comparison with previous models, the new model has further improvement, in particular for high-U alloys that are relevant to reactor fuel compositions and at the low-temperature regime for the high-Zr alloys. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
31. A Method to Control Curcumin Release from PELA Fibers by Heat Treatment.
- Author
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Chen, Weiming, Ei‐hamshary, Hany, Al‐deyab, Salem S., and Mo, Xiumei
- Subjects
- *
CURCUMIN , *HEAT treatment , *POLYMERS , *CANCER chemotherapy , *POROSITY - Abstract
Abstract: Poly(ethylene glycol ‐co‐ DL‐lactide) (PELA) is a biodegradable polymer, which has attracted considerable interest in the area of drug release due to its potential as drug carrier. Drug‐loaded electrospun PELA fibers tend to be a promising candidate for local chemotherapy application in the future. In this study, curcumin was encapsulated into PELA fibers (Cur@PELA) for drug delivery via electrospinning. It was found that the shrinkage ratio, porosity, water absorption and water contact angle of Cur@PELA fiber membrane could be changed by heat treatment with different heating temperature (45°C, 50°C) and heating time (5 min, 10 min, 20 min). Moreover, the release rate of curcumin from Cur@PELA fibers was influenced by the porosity, water absorption and water contact angle of the drug‐loaded membrane. Heat treatment is thought to be a novel method to control release of drug from electrospun PELA fibers. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
32. Application of first-order reliability method with orthogonal plane sampling for high-dimensional series system reliability analysis.
- Author
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Chen, Weiming, Gong, Changqing, Wang, Ziqi, and Frangopol, Dan M.
- Subjects
- *
MONTE Carlo method , *RELIABILITY in engineering , *ENGINEERING systems - Abstract
The increasing complexity of modern engineering systems has motivated a shift of research focus from component-level reliability to system reliability with interdependent components. There is a growing demand for efficient reliability methods to analyze high-dimensional systems that involve numerous dependent components and component variables. The first-order reliability method (FORM), which is widely used for component-level reliability analysis, becomes inaccurate for high-dimensional systems composed of numerous components, each with a nonlinear high-dimensional limit state function. By integrating the orthogonal plane sampling, this paper proposes an improved FORM-based method to tackle the curse of dimensionality for series systems. The idea is to construct secant hyperplanes using the orthogonal plane samples so as to reduce the FORM error for high-dimensional nonlinear limit state functions. The design points of secant hyperplanes are projected to high-dimensional system space using an efficient procedure based on the specified correlation matrix of variables. Finally, the series system reliability is computed as high-dimensional multi-normal integral, which is addressed by the equivalent component method. Four numerical examples are investigated to demonstrate the accuracy and efficiency of the proposed method. Results indicate that the proposed method is significantly more efficient than the Monte Carlo simulation and more accurate than the conventional FORM. • The OPS is leveraged for high-dimensional component reliability. • FORM is fused with OPS to analyze reliability of high-dimensional systems. • Solve high-dimensional Gaussian integral via equivalent component method. • The method can be orders more efficient than direct Monte Carlo simulation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
33. Interprovincial transfer of embodied energy between the Jing-Jin-Ji area and other provinces in China: A quantification using interprovincial input-output model.
- Author
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Chen, Weiming, Wu, Sanmang, Lei, Yalin, and Li, Shantong
- Subjects
- *
COMMERCIAL products , *ENERGY transfer , *ECONOMIC development , *ENERGY consumption , *AIR pollution - Abstract
Commodity trade between regions implies a large amount of energy transfer. As an important economic growth pole of China, the Jing-Jin-Ji area (Beijing-Tianjin-Hebei) is also one of the areas with the largest energy consumption in China. Moreover, the primary energy consumer goods in this area are fossil fuels, such as coal. This has led to serious air pollution in the area. Therefore, the reduction of energy consumption under the premise of maintaining sustained economic growth is an important task of the Jing-Jin-Ji area. In this study, an interprovincial input-output model was applied to quantitatively estimate the embodied energy transfer between Jing-Jin-Ji area and other provinces in China. The results indicated that the Metal and nonmetal mineral processing industry and the Electrical, gas and water industry in the Jing-Jin-Ji area exported a large amount of embodied energy to the Yangtze River Delta and the Pearl River Delta. However, the embodied energy export of the Jing-Jin-Ji area mainly exported by Hebei province. Beijing and Tianjin even have some net import of embodied energy. The embodied energy transfer between Tianjin, Hebei and other provinces was mainly driven by investment, while the main media of embodied energy transfer between Beijing and other provinces was consumption. Therefore, we suggest that the Jing-Jin-Ji area should further increase the degree of dependence on other provinces' energy-intensive products and reduce the export of energy-intensive products. In addition, there should be difference in the energy and industrial policies among Beijing, Tianjin and Hebei, and the problems of high energy consumption and high proportion of heavy industry in Hebei should be first resolved. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
34. Groove fibers based porous scaffold for cartilage tissue engineering application.
- Author
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Chen, Weiming, Sun, Binbin, Zhu, Tonghe, Gao, Qiang, Morsi, Yosry, El-Hamshary, Hany, El-Newehy, Mohamed, and Mo, Xiumei
- Subjects
- *
POROUS materials , *FIBERS , *TISSUE engineering , *TISSUE scaffolds , *SCANNING electron microscopy , *MECHANICAL behavior of materials - Abstract
A porous scaffold was prepared by gelatin groove fibers for cartilage tissue engineering. The morphology of groove fibers and porous scaffolds were observed by scanning electron microscopy (SEM). The water absorption property of scaffolds was tested which demonstrated values as high as 1187%. The compressive mechanical property of scaffolds was also evaluated. In wet state, this scaffold exhibited elastic behaviour, and could bear 100 cycles compressive fatigue test. Moreover, this scaffold could promote rat chondrocyte and bone marrow mesenchymal stem cells (BMSC) proliferation. The findings indicate that such scaffold could be valuable candidates for cartilage tissue engineering. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
35. China’s water footprint by province, and inter-provincial transfer of virtual water.
- Author
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Chen, Weiming, Wu, Sanmang, Lei, Yalin, and Li, Shantong
- Subjects
- *
ECOLOGICAL impact , *WATER shortages , *WATER distribution , *WATER supply , *WATER efficiency - Abstract
Water shortages and the uneven distribution of water resources restrict China’s sustainable development. The concepts of virtual water and water footprints provide a new approach to alleviate regional shortages of Chinese water resources by the inter-provincial allocation of commercial water resources. In this study, an interregional input-output model was applied to quantitatively estimate the water footprint of each province in China and to quantify the inter-provincial transfer of virtual water. The results indicated that there was considerable diversity in the water footprints of the various provinces. Provinces with larger populations and greater GDP had larger water footprints, and developed regions had higher proportions of external water footprints. From the perspective of final demand, local consumption was the main factor driving the water footprints of these provinces. From the perspective of sectoral structure, the agricultural water footprint had a larger proportion in these provinces. The transfer of virtual water in China did not occur from regions with abundant water resources to those suffering from water shortages, but it generally occurred from west to east, from inland to coastal areas, and from underdeveloped to developed regions. Many water-deficient regions also had large net virtual water exports. Water shortages in China will be alleviated by the enhancement of industrial water-use efficiency in water-deficient regions, the transfer of water-intensive industries to regions with abundant water resources, and the development of tertiary industries with low water consumption. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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36. Molecular-level transformation of refractory organic matter during flocculation-ultraviolet/peroxymonosulfate treatment of MBR-treated landfill leachate.
- Author
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Chen, Weiming, Gu, Zhepei, He, Chen, and Li, Qibin
- Subjects
- *
ION cyclotron resonance spectrometry , *ELECTROSPRAY ionization mass spectrometry , *DISSOLVED organic matter , *LEACHATE , *ORGANIC compounds , *FLOCCULATION , *LANDFILLS - Abstract
Refractory organic matter in membrane bioreactor effluent resulting from landfill leachate treatment has a complex composition. This paper identified the transformation mechanism of organic matter in a flocculation-ultraviolet (UV)/peroxymonosulfate (PMS) system at the molecular level using electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry. The results showed that the flocculation system was able to remove a large amount of dissolved organic matter (DOM) with high oxidation and unsaturation/saturation. UV radiation displayed a relatively strong reactivity for DOM with an electron-rich structure, which it can transform into DOM with lower aromaticity through photolysis and photosensitivity, although the effectiveness of the transformation was poor. In comparison, due to the action of reactive oxygen species, the UV/PMS system can enable reactions such as demethylation, dehydrogenation, decarboxylation, dehydroxylation, ring cleavage, and decarbonylation. It can remove approximately 60% quantity of the total DOM and produce DOM featuring a higher degree of oxidation and saturation than that of the UV system alone. The results showed that the UV/PMS system was a complementary of flocculation in DOM removal from the membrane bioreactor effluent, while the system also resulted in a large number of sulfuric compounds; thus, requiring further evaluation of its ecological effects. [Display omitted] • Flocculation removed most oxidized DOM and newly-produced sulfuric and aliphatic DOM. • UV radiation decreased the aromaticity of electron-rich DOM. • The combination of UV/PMS and flocculation ahieved effective DOM removal. • Sulfuric compounds were produced in the treated leachate, needing further evaluation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
37. Game-theoretic modeling of power supply chain coordination under demand variation in China: A case study of Guangdong Province.
- Author
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Tian, Xiaoge, Chen, Weiming, and Hu, Jinglu
- Subjects
- *
SUPPLY chains , *CHINA studies , *POWER plants , *PROVINCES , *CONSUMERS - Abstract
Entities in the power supply chain usually tend to cooperate with each other for higher profits. The inter mechanism between the entities and power supply chain is an urgent research subject. To consider the power supply chain and entities better, a extended model of bilateral contract mechanism is proposed in this paper. Utilizing a Stackelberg game, this paper studies dynamic coordination and strategic interactions between power plants, power retailers, and consumers in the electricity trading process under demand uncertainty. An improved coordination model is proposed to help entities get potential profits as well as improve the stability of the power supply. The model is applied to power trading data from Guangdong, China which imposes penalties for inaccuracies in demand variation. Simulations suggest the model's solution exhibits higher reliability and minimizes fines. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. Synthesis, characterization and in vitro digestion of folate conjugated chitosan-loaded proanthocyanidins nanoparticles.
- Author
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Ding, Zhendong, Chen, Weiming, Jiang, Fengyu, Mo, Mengmiao, Bi, Yongguang, and Kong, Fansheng
- Subjects
- *
FOLIC acid , *PROANTHOCYANIDINS , *DIGESTION , *ERYTHROCYTES , *NANOPARTICLES , *SCANNING electron microscopes - Abstract
[Display omitted] • • Folic acid-chitosan conjugate was synthesized by amidation. • • Characterization of PC-CS/FA-NPs were performed by DLS, FTIR, TGA and SEM. • • The inhibitory effect of PC-CS/FA-NPs on hemolysis of red blood cells was studied. • • The in vitro digestibility of PC-CS/FA-NPs were investigated. Proanthocyanidins have significant biological activity and pharmacological effects and are widely used in food, medicine, and cosmetics. Chitosan nanoparticles loaded with proanthocyanidins have been proven to improve their biological activity. Given some deficiencies of chitosan (CS), the modification of chitosan by folic acid (FA) can obtain new variants with different functions. For this objective, the folic acid conjugated chitosan was designed, and in vitro properties of proanthocyanidins loaded nanoparticles were studied systemically. Firstly, folic acid-chitosan conjugate (FA-CS) was synthesized and characterized. Folate-coupled chitosan-loaded proanthocyanidin nanoparticles (PC-CS/FA-NPs) were prepared by ionic gelation technique using FA-CS as a carrier. The successful nanoparticle synthesis was characterized by dynamic light scattering (DLS) techniques and Fourier transform infrared (FT-IR) spectroscopy. The synthesized nanoparticles exhibited a spherical shape and smooth and uniform distribution features with a size range of less than 300 nm, as observed by a scanning electron microscope (SEM). Meanwhile, PC-CS/FA-NPs had good thermal and gastrointestinal digestive stability and had a protective effect on AAPH-induced erythrocyte oxidative hemolysis. In conclusion, folic acid decorated chitosan nanoparticles improved the stability and bioavailability of proanthocyanidins in gastrointestinal digestion. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
39. A comparison of nanoscale and multiscale PCL/gelatin scaffolds prepared by disc-electrospinning.
- Author
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Li, Dawei, Chen, Weiming, Sun, Binbin, Li, Haoxuan, Wu, Tong, Ke, Qinfei, Huang, Chen, EI-Hamshary, Hany, Al-Deyab, Salem S., and Mo, Xiumei
- Subjects
- *
GELATIN , *ELECTROSPINNING , *TISSUE scaffolds , *NANOFIBERS , *SCANNING electron microscopy - Abstract
Electrospinning is a versatile and convenient technology to generate nanofibers suitable for tissue engineering. However, the low production rate of traditional needle electrospinning hinders its applications. Needleless electrospinning is a potential strategy to promote the application of electrospun nanofiber in various fields. In this study, disc-electrospinning (one kind of needleless electrospinning) was conducted to produce poly(ε-caprolactone)/gelatin (PCL/GT) scaffolds of different structure, namely the nanoscale structure constructed by nanofiber and multiscale structure consisting of nanofiber and microfiber. It was found that, due to the inhomogeneity of PCL/GT solution, disc-electrospun PCL-GT scaffold presented multiscale structure with larger pores than that of the acid assisted one (PCL-GT-A). Scanning electron microscopy images indicated the PCL-GT scaffold was constructed by nanofibers and microfibers. Mouse fibroblasts and rat bone marrow stromal cells both showed higher proliferation rates on multiscale scaffold than nanoscale scaffolds. It was proposed that the nanofibers bridged between the microfibers enhanced cell adhesion and spreading, while the large pores on the three dimensional (3D) PCL-GT scaffold provide more effective space for cells to proliferate and migrate. However, the uniform nanofibers and densely packed structure in PCL-GT-A scaffold limited the cells on the surface. This study demonstrated the potential of disc-electrospun PCL-GT scaffold containing nanofiber and microfiber for 3D tissue regeneration. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
40. Embodied carbon transfer between China and the Belt and Road Initiative countries.
- Author
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Zhang, Zhenjun and Chen, Weiming
- Subjects
- *
BELT & Road Initiative , *CLIMATE change , *CARBON emissions , *CARBON , *GREENHOUSE gas mitigation - Abstract
The Belt and Road Initiative was proposed by China in 2013 to promote the interconnected development and prosperity of all participating countries. In the context of global response to climate change, understanding the embodied carbon transfer change along economic trade before and after the Belt and Road Initiative is essential to reduce carbon overall emission. In this paper, we used a multi-regional input-output model to study the embodied carbon transfer in trade between the Belt and Road countries that have signed cooperation documents with China from 2004 to 2017. The results showed that from 2004 to 2017, the growth rate that China's carbon emissions imported from other Belt and Road Initiative countries was about 1.9 times that of its exports. From 2004 to 2017, the proportion of China's carbon imports from other Belt and Road countries in China's total carbon imports increased from 3.41% to 3.73%, and exports decreased from 6.52% to 6.03%. In both 2004 and 2017, Electricity, Gas and Water sector, Heavy Industry sector, Transport sector were the three largest carbon transfer sectors in China's multilateral trade. In 2017, the embodied carbon transfer by multilateral trade among other Belt and Road countries except China increased by 15.53% compared with 2004. By comparing the characteristics of carbon transfer between China and the Belt and Road countries from 2004 to 2017, this study will provide insights for carbon emission reduction policy setting of Belt and Road Initiative countries. • We took countries that have signed documents with China as research objects. • MRIO model was used to analyze the carbon transfer change from 2004 to 2017. • The embodied carbon transfer in 2017 of BRI increased by 15.53% compared with 2004. • The growth rate of China's carbon imports from BRI was 1.9 times that of exports. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
41. Superelastic, superabsorbent and 3D nanofiber-assembled scaffold for tissue engineering.
- Author
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Chen, Weiming, Ma, Jun, Zhu, Lei, Morsi, Yosry, EI-Hamshary, Hany, Al-Deyab, Salem S., and Mo, Xiumei
- Subjects
- *
NANOFIBERS , *NANOSTRUCTURED materials synthesis , *POLYLACTIC acid , *ELECTROSPINNING , *PHYSIOLOGICAL effects of collagen , *TISSUE engineering , *THERAPEUTICS - Abstract
Fabrication of 3D scaffold to mimic the nanofibrous structure of the nature extracellular matrix (ECM) with appropriate mechanical properties and excellent biocompatibility, remain an important technical challenge in tissue engineering. The present study reports the strategy to fabricate a 3D nanofibrous scaffold with similar structure to collagen in ECM by combining electrospinning and freeze-drying technique. With the technique reported here, a nanofibrous structure scaffold with hydrophilic and superabsorbent properties can be readily prepared by Gelatin and Polylactic acid (PLA). In wet state the scaffold also shows a super-elastic property, which could bear a compressive strain as high as 80% and recovers its original shape afterwards. Moreover, after 6 days of culture, L-929 cells grow, proliferate and infiltrated into the scaffold. The results suggest that this 3D nanofibrous scaffold would be promising for varied field of tissue engineering application. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
42. Valorization of food waste into hydrogen: Energy potential, economic feasibility and environmental impact analysis.
- Author
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Cudjoe, Dan, Chen, Weiming, and Zhu, Bangzhu
- Subjects
- *
ENVIRONMENTAL impact analysis , *HYDROGEN as fuel , *FOOD waste , *FOOD industrial waste , *POTENTIAL energy , *HYDROGEN production - Abstract
[Display omitted] • Economic and ecological analysis of food waste to hydrogen is conducted. • Hydrogen yield from food waste in China from 2004 to 2019 is 221.12 billion kg. • The power generation potential of the hydrogen gas is 661.97 TWh. • Usage of power from hydrogen could reduce global warming by 42,041.9 kt CO 2 eq. • The food waste to hydrogen project is economically feasible in all provinces. Hydrogen gas is widely acknowledged as a significant energy carrier worldwide. Hydrogen gas derived from sustainable sources could be used as an alternative to fossil fuel for electricity generation with zero emission of hazardous pollutants. Food waste valorization to hydrogen is a viable energy source with potential economic benefits. The current study examines the economic viability and environmental effect of producing hydrogen from food waste in China using biogas steam reforming for power generation. The key findings show that the steam reforming of biogas from food waste could produce 221.12 billion kg of hydrogen gas. The quantity of hydrogen gas yield could generate 661.97 TWh of electricity. It was found that the consumption of the available electricity from the hydrogen gas could displace 15,482.26 M liters of diesel fuel combustion. The amount of diesel fuel consumption avoided can reduce global warming by 42,041.90 kt CO 2 e. It was also discovered that hydrogen has an appealing ecological efficiency of 94.64% when used as a source of energy generation. According to the outcomes of the economic analysis, the food waste to hydrogen project is economically feasible in all of China's provinces. The average hydrogen production cost, return on investment, the payback period is $0.814/kWh, 29.8%, and 7.2 years. This study could provide scientific data for investment and decision-making on ecological sustainability in food waste to hydrogen initiatives in China and other emerging nations with a similar culture. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
43. Molecular insights into the transformation of refractory organic matter in landfill leachate nanofiltration concentrates during a flocculation and O3/H2O2 treatment.
- Author
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Gu, Zhepei, Chen, Weiming, He, Chen, and Li, Qibin
- Subjects
- *
DISSOLVED organic matter , *LEACHATE , *NANOFILTRATION , *CARBOXYLATION , *ORGANIC compounds , *LANDFILLS , *FLOCCULATION - Abstract
During leachate treatment, molecular information regarding the completely removed, partially removed, less-reactive, increased, and produced parts of dissolved organic matter (DOM) remains unknown. This study applied ESI FT-ICR MS to investigate the transformation characteristics of leachate nanofiltration concentrate (NFC) DOM during a combined flocculation–O 3 /H 2 O 2 process. The NFC contained 5069 compounds in four main classes (CHO, CHON, CHOS, and CHONS compounds). The DOM number decreased to 4489 during flocculation and to 2903 after the O 3 /H 2 O 2 process. During flocculation, the completely and partially removed DOM was mainly low-oxygen unsaturated and phenolic compounds. Saturated DOM was produced and remained in the flocculated effluent. During the O 3 /H 2 O 2 process, the completely and partially removed DOM were mainly low-oxygen unsaturated and phenolic compounds that were mainly in a reduced state. Flocculation can remove many (condensed) aromatic compounds, and methylation and hydrogenation reactions occurred during flocculation. In the O 3 /H 2 O 2 process, dearomatization, demethylation, carboxylation, and carbonylation reactions further achieved the degradation of DOM that was resistant to flocculation. Overall, the combined flocculation-O 3 /H 2 O 2 process collectively eliminated a broader range of DOM than the single processes could achieve. The results of this study provide an in-depth understanding of DOM transformation in an NFC treatment. [Display omitted] • Transformation of NFC DOM in flocculation-O 3 /H 2 O 2 process was studied by FT-ICR MS. • Removed, less-resistant, and produced parts of NFC DOM in flocculation-O 3 /H 2 O 2 were determined. • A Kendrick mass defect theory was used to study DOM transformation of NFC. • Flocculation-O 3 /H 2 O 2 collectively eliminated a broader range of DOM. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
44. Dexamethasone loaded core–shell SF/PEO nanofibers via green electrospinning reduced endothelial cells inflammatory damage.
- Author
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Chen, Weiming, Li, Dawei, EI-Shanshory, Ahmed, El-Newehy, Mohamed, EI-Hamshary, Hany A., Al-Deyab, Salem S., He, Chuanglong, and Mo, Xiumei
- Subjects
- *
DEXAMETHASONE , *NANOFIBERS , *ELECTROSPINNING , *ENDOTHELIAL cells , *INFLAMMATION , *SILK fibroin , *DRUG delivery systems , *TISSUE engineering - Abstract
Silk fibroin (SF)/PEO nanofibers prepared by green electrospinning is safe, non-toxic and environment friendly, it is a potential drug delivery carrier for tissue engineering. In this study, a core–shell nanofibers named as Dex@SF/PEO were obtained by green electrospinning with SF/PEO as the shell and dexamethasone (Dex) in the core. The nanofiber morphology and core–shell structure were studied by Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). The Dex release behavior from the nanofibers was tested by High Performance liquid (HPLC) method. The protective effect of drug loaded nanofibers mats on Porcine hip artery endothelial cells (PIECs) against LPS-induced inflammatory damage were determined by MTT assay. TEM result showed the distinct core–shell structure of nanofibers. In vitro drug release studies demonstrated that dexamethasone can sustain release over 192 h and core–shell nanofibers showed more slow release of Dex compared with the blending electrospinning nanofibers. Anti-inflammatory activity in vitro showed that released Dex can reduce the PIECs inflammatory damage and apoptosis which induced by lipopolysaccharide (LPS). Dex@SF/PEO nanofibers are safe and non-toxic because of no harmful organic solvents used in the preparation, it is a promising environment friendly drug carrier for tissue engineering. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
45. Mesoscale modeling of microstructure-dependent thermal conductivity in U-Zr fuels.
- Author
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Chen, Weiming and Bai, Xian-Ming
- Subjects
- *
INTERFACIAL resistance , *THERMAL resistance , *METAL-base fuel , *FINITE element method - Abstract
In uranium-zirconium (U-Zr) based metallic fuels, different phases can form at different compositions and temperatures. Typically, lamellar δ-UZr 2 and α-U phases are the dominant microstructures in U-rich U-Zr alloys at temperatures below 880 K. In this work, a finite element method based mesoscale modeling technique is used to calculate the effective thermal conductivities of such heterogeneous microstructures, using the thermal conductivities of two individual phases and their interphase thermal resistance (Kapitza resistance) as input parameters. The Kapitza resistance between δ-UZr 2 and α-U is determined at different temperatures, which shows an approximately T−3 dependence in the temperature range between 300 and 800 K. In addition, the Kapitza resistance exhibits a strong dependence on the aspect ratio of the δ-UZr 2 phase. An analytical model is therefore developed to quantify the effects of both temperature and δ-UZr 2 aspect ratio on the Kapitza resistance. Using this newly developed Kapitza resistance model, the effective thermal conductivities of a number of δ-UZr 2 + α-U heterogeneous microstructures in U-Zr alloys, including non-lamellar microstructures, can be estimated accurately. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
46. Riemannian Manifold Hamiltonian Monte Carlo based subset simulation for reliability analysis in non-Gaussian space.
- Author
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Chen, Weiming, Wang, Ziqi, Broccardo, Marco, and Song, Junho
- Subjects
- *
RIEMANNIAN manifolds , *PROBLEM solving , *DISTRIBUTION (Probability theory) , *MARKOV processes , *MARKOV chain Monte Carlo - Abstract
This paper proposes a Riemannian Manifold Hamiltonian Monte Carlo based subset simulation (RMHMC-SS) method to overcome limitations of existing Monte Carlo approaches in solving reliability problems defined in highly-curved non-Gaussian spaces. RMHMC is based on the second-order geometric information of a probability space. Specifically, it generates an optimized path for Markov chain evolutions in a Hamiltonian constructed on the Riemannian manifold. Compared with the recently proposed Hamiltonian Monte Carlo based subset simulation (HMC-SS) approach, the RMHMC-SS approach shows better performance in handling highly-curved probability distributions. After a brief review of HMC-SS, the theory and implementation details of RMHMC-SS are presented. Finally, various reliability examples are studied to test and verify the proposed RMHMC-SS method. • Riemannian Manifold Hamiltonian Monte Carlo based subset simulation is developed. • Second order geometric information is used for efficient MCMC evolution. • The method is designed for reliability problems in highly-curved non-Gaussian space. • The method is successfully demonstrated by applications to non-Gaussian problems. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
47. A 3D Ubiquitous-Multiple-Joint Model and Its Application to the Stability Analysis of TBM Excavated Roadway in Jointed Stratum.
- Author
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Xue, Xinran, Zhang, Kai, Chen, Weiming, Liu, Hiu, Ma, Bailong, Liu, Tao, and Cao, Heng
- Subjects
- *
MINES & mineral resources , *COAL mining , *RANGE of motion of joints , *ROADS , *AUDIO equipment - Abstract
Tunnel Boring Machines (TBMs) have been used in many underground coal mines in China with high constructive efficiency, sound equipment integration and low cost. A recent application of TBM in Yuandian No.2 Coal Mine in Huaibei, China, has shown that the surrounding rockmass spalled severely in stratum impacted by multiple joint sets. To analyze this problem, a new 3D ubiquitous-multiple-joint (UMJ) model was proposed in the present research, which comprised a rock matrix and multiple sets of joints according to geological conditions. Then, the yielding and deformation of the roadway excavated by TBM were analyzed. The results showed that the plastic zones, stress states and displacement of surrounding rockmass were significantly affected by the orientation of joint sets. The results could well indicate failure characteristics of the in-situ roadway and showed the advantages of UMJ model to simulate the excavation in jointed rockmass. The key factors influencing the roadway stability were discussed by the UMJ model. Based on the simulation results, suggestions on excavation-support schemes were proposed for TBM excavating roadways. Highlights: 3D Ubiquitous-Multiple-Joint model is proposed to handle rockmass with multiple joint sets The stability of roadway is significantly affected by orientation and strength of joint sets Some measures are suggested to control TBM excavated roadway in jointed stratum [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
48. Transcriptome profiling reveals a novel role for trichostatin A in antagonizing histone chaperone Chz1 mediated telomere anti-silencing
- Author
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Wan, Yakun, Chen, Weiming, Xing, Jie, Tan, Jinyin, Li, Bing, Chen, Huiying, Lin, Zhanxian, Chiang, Jung-Hsien, and Ramsey, Saleem
- Subjects
- *
TRANSCRIPTION factors , *STATINS (Cardiovascular agents) , *MOLECULAR chaperones , *HISTONES , *TELOMERES , *GENE silencing , *SACCHAROMYCES cerevisiae , *GENETIC regulation , *HISTONE deacetylase , *ENZYME inhibitors - Abstract
Abstract: The histone chaperones play an important role in chromatin assembly and disassembly during replication and transcription. We have assessed the global roles of histone chaperones in Saccharomyces cerevisiae. Microarray transcriptional analyzes indicate that histone chaperones have their own specific target genes, and various histone chaperones have partially overlapping functions during transcriptional regulation. The histone deacetylase inhibitor TSA and histone chaperones Asf1, Vps75 and Rtt106 can function in parallel pathways to regulate transcription. Moreover, TSA can specifically antagonize histone chaperone Chz1-mediated telomere anti-silencing. This study demonstrates that a mutual cross-talk mechanism exists between histone chaperones and histone deacetylation in transcriptional regulation. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
49. Synthesis and SAR of piperazine amides as novel c-jun N-terminal kinase (JNK) inhibitors
- Author
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Shin, Youseung, Chen, Weiming, Habel, Jeff, Duckett, Derek, Ling, Yuan Yuan, Koenig, Marcel, He, Yuanjun, Vojkovsky, Tomas, LoGrasso, Philip, and Kamenecka, Theodore M.
- Subjects
- *
ORGANIC synthesis , *STRUCTURE-activity relationship in pharmacology , *PIPERAZINE , *AMIDES , *JNK mitogen-activated protein kinases , *ENZYME inhibitors , *DRUG design , *DRUG development - Abstract
Abstract: A novel series of c-jun N-terminal kinase (JNK) inhibitors were designed and developed from a high-throughput-screening hit. Through the optimization of the piperazine amide 1, several potent compounds were discovered. The X-ray crystal structure of 4g showed a unique binding mode different from other well known JNK3 inhibitors. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
50. Effect of new epoxy matrix for T800 carbon fiber/epoxy filament wound composites
- Author
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Chen, Weiming, Yu, Yunhua, Li, Peng, Wang, Chengzhong, Zhou, Tongyue, and Yang, Xiaoping
- Subjects
- *
ATOMIC force microscopy , *SPECTRUM analysis , *INFRARED spectroscopy , *SCANNING electron microscopy - Abstract
Abstract: A new epoxy resin matrix with good adherence to T800 carbon fibers (T800 CFs) in filament winding was developed by addition of hardener and resin diluter. Interfacial behavior of the T800 CF/epoxy composites was analyzed according to the Naval Ordnance laboratory (NOL) ring test, short-beam-shear test and fracture surface observation. Meanwhile, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used in analysis of the interfacial behavior. The interfacial properties of the T800 CF/epoxy filament wound composites were improved by optimizing the matrices through increasing the toughness and reducing the viscosity, which is an important factor in influencing the wettability of T800 CFs. The Interlaminar shear strength (ILSS) of the unidirectional T800 CF/epoxy composites and the tensile strength of NOL-ring in this work reached to 123 and 2570MPa, respectively. Also, the interfacial adhesion was much improved by the chemical reactions between the new matrix and the sizing on the T800 CFs. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
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