Continuous and reliable power supply plays an important role for water leakage monitoring systems used in urban water supply pipes. Renewable energies powered water leakage monitoring system is ...becoming a promising way to reduce the dependence on traditional chemical batteries. In this study, an inline vertical cross-flow turbine was developed to harvest the potential hydropower inside water supply pipes for supplying power to the water monitoring systems. Specifically, numerical investigations are carried out on the block shapes of a water turbine system to determine an optimal model. The effects of tip clearance on the turbine performance are conducted and it is found that a smaller tip clearance can reduce the reversing torque on the returning blades and increase the pressure drop through the runner for improving the turbine performance. Besides, a self-adjustable vane is designed to avoid excess water head loss. The simulation results show that the proposed self-adjustable vane is effective to limit the water head loss at high flow velocities (1.5–2.0 m/s) to 5 m. Finally, the turbine prototype is fabricated and tested on a lab test rig. The experimental results indicate that the numerical method adopted in this research is accurate enough for such micro water turbine performance prediction. A month-long test shows that the daily electricity generation of the proposed turbine is about 600 Wh and the water head loss is always below 5 m, which means that the proposed turbine can provide sufficient power for any general water leakage monitoring system without influencing normal water supply.
•An inline vertical cross-flow turbine was proposed to harvest hydropower in water supply pipes.•Effects of block shape on turbine performance were investigated.•Effects of tip clearance on turbine performance were studied.•A self-adjustable vane was designed to avoid excess water head loss.•Lab tests were conducted to study the performance of proposed turbine
Recently, room‐temperature stationary sodium‐ion batteries (SIBs) have received extensive investigations for large‐scale energy storage systems (EESs) and smart grids due to the huge natural ...abundance and low cost of sodium. The SIBs share a similar “rocking‐chair” sodium storage mechanism with lithium‐ion batteries; thus, selecting appropriate electrodes with a low cost, satisfactory electrochemical performance, and high reliability is the key point for the development for SIBs. On the other hand, the carefully chosen elements in the electrodes also largely determine the cost of SIBs. Therefore, earth‐abundant‐metal‐based compounds are ideal candidates for reducing the cost of electrodes. Among all the high‐abundance and low‐cost metal elements, cathodes containing iron and/or manganese are the most representative ones that have attracted numerous studies up till now. Herein, recent advances on both iron‐ and manganese‐based cathodes of various types, such as polyanionic, layered oxide, MXene, and spinel, are highlighted. The structure–function property for the iron‐ and manganese‐based compounds is summarized and analyzed in detail. With the participation of iron and manganese in sodium‐based cathode materials, real applications of room‐temperature SIBs in large‐scale EESs will be greatly promoted and accelerated in the near future.
State‐of‐the‐art high‐abundance and low‐cost metal‐based cathode materials for sodium‐ion batteries are comprehensively summarized and analyzed, providing a step toward the real‐life, commercial application of sodium‐ion batteries. Constructive suggestions and guidance are provided and future prospects regarding this promising field are discussed.
The low salt adsorption capacities (SACs) of benchmark carbon materials (usually below 20 mg g–1) are one of the most challenging issues limiting further commercial development of capacitive ...deionization (CDI), an energetically favorable method for sustainable water desalination. Sodium superionic conductor (NASICON)-structured NaTi2(PO4)3 (NTP) materials, especially used in combination with carbon to prepare NTP/C materials, provide emerging options for higher CDI performance but face the problems of poor cycling stability and dissolution of active materials. In this study, we report the development of the yolk–shell nanoarchitecture of NASICON-structured NTP/C materials (denoted as ys-NTP@C) using a metal–organic framework@covalent organic polymer (MOF@COP) as a sacrificial template and space-confined nanoreactor. As expected, ys-NTP@C exhibits good CDI performance, including exemplary SACs with a maximum SAC of 124.72 mg g–1 at 1.8 V in the constant-voltage mode and 202.76 mg g–1 at 100 mA g–1 in the constant-current mode, and good cycling stability without obvious performance degradation or energy consumption increase over 100 cycles. Furthermore, X-ray diffraction used to study CDI cycling clearly exhibits the good structural stability of ys-NTP@C during repeated ion intercalation/deintercalation processes, and the finite element simulation shows why yolk–shell nanostructures exhibit better performance than other materials. This study provides a new synthetic paradigm for preparing yolk–shell structured materials from MOF@COP and highlights the potential use of yolk–shell nanoarchitectures for electrochemical desalination.
It is highly desired but still remains challenging to design and develop a Co‐based nanoparticle‐encapsulated conductive nanoarray at room temperature for high‐performance water oxidation ...electrocatalysis. Here, it is reported that room‐temperature anodization of a Co(TCNQ)2 (TCNQ = tetracyanoquinodimethane) nanowire array on copper foam at alkaline pH leads to in situ electrochemcial oxidation of TCNQ− into water‐insoluable TCNQ nanoarray embedding Co(OH)2 nanoparticles. Such Co(OH)2‐TCNQ/CF shows superior catalytic activity for water oxidation and demands only a low overpotential of 276 mV to drive a geometrical current density of 25 mA cm−2 in 1.0 m KOH. Notably, it also demonstrates strong long‐term electrochemical durability with its activity being retrained for at least 25 h, a high turnover frequency of 0.97 s−1 at an overpotential of 450 mV and 100% Faradic efficiency. This study provides an exciting new method for the rational design and development of a conductive TCNQ‐based nanoarray as an interesting 3D material for advanced electrochemical applications.
A Co(OH)2 nanoparticle‐encapsulating conductive tetracyanoquinodimethane (TCNQ) nanowire array on copper foam is prepared using an in situ electrochemical oxidation method to form a water‐insoluable conductive TCNQ nanoarray. This array effectively entraps Co(OH)2 nanoparticles at alkaline pH. Such Co(OH)2‐TCNQ/CF requires an overpotential as low as 276 mV to drive a geometrical current density of 25 mA cm−2 in 1.0 M KOH, with strong long‐term electrochemical durability.
Nickel-rich layered oxides are regarded as very promising materials as cathodes for lithium-ion batteries because of their environmental benignancy, low cost, and high energy density. However, ...insufficient cycle performance and poor thermotic characteristics induced by structural degradation at high potentials and elevated temperatures pose challenging hurdles for nickel-rich cathodes. Here, a protective pillaring layer, in which partial Ni2+ ions occupy Li slabs induced by gradient Mn4+, is integrated into the primary particle of LiNi0.815Co0.15Al0.035O2 to stabilize the surface/interfacial structure. With the stable outer surface provided by the enriched Mn4+ gradient concentration and the pillar effect of the NiO-like phase, Mn-incorporated quaternary cathodes show enhanced structural stability and improved Li+ diffusion as well as lithium-storage properties. Compared with the severe capacity fade of a pure layered structure, the cathode with gradient Mn4+ exhibits more stable cycling behavior with a capacity retention of 80.0% after 500 cycles at 5.0 C.
A theoretical model for the multi-span spinning beams with elastic constraints under an axial compressive force is proposed. The displacement and bending angle functions are represented through an ...improved Fourier series, which ensures the continuity of the derivative at the boundary and enhances the convergence. The exact characteristic equations of the multi-span spinning beams with elastic constraints under an axial compressive force are derived by the Lagrange equation. The efficiency and accuracy of the present method are validated in comparison with the finite element method (FEM) and other methods. The effects of the boundary spring stiffness, the number of spans, the spinning velocity, and the axial compressive force on the dynamic characteristics of the multi-span spinning beams are studied. The results show that the present method can freely simulate any boundary constraints without modifying the solution process. The elastic range of linear springs is larger than that of torsion springs, and it is not affected by the number of spans. With an increase in the axial compressive force, the attenuation rate of the natural frequency of a spinning beam with a large number of spans becomes larger, while the attenuation rate with an elastic boundary is lower than that under a classic simply supported boundary.
Electrocatalytic oxygen reduction reaction (ORR) provides an attractive alternative to anthraquinone process for H
2
O
2
synthesis. Rational design of earth-abundant electrocatalysts for H
2
O
2
...synthesis via a two-electron ORR process in acids is attractive but still very challenging. In this work, we report that nitrogen-doped carbon nanotubes as a multi-functional support for CoSe
2
nanoparticles not only keep CoSe
2
nanoparticles well dispersed but alter the crystal structure, which in turn improves the overall catalytic behaviors and thereby renders high O
2
-to-H
2
O
2
conversion efficiency. In 0.1 M HClO
4
, such CoSe
2
@NCNTs hybrid delivers a high H
2
O
2
selectivity of 93.2% and a large H
2
O
2
yield rate of 172 ppm·h
−1
with excellent durability up to 24 h. Moreover, CoSe
2
@NCNTs performs effectively for organic dye degradation via electro-Fenton process.
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•Carbon coating and Nb5+ substitution were simultaneously applied to modify Na3V2(PO4)3 composite.•Nb5+ doping could effectively enhance the electron conductivity of the ...materials.•The optimized material exhibits a high specific capacity and good cycling stability.
Featuring favorable ion transfer and high thermal stability, NASICON-structured Na3V2(PO4)3 has been regarded as a promising cathode candidate for sodium-ion batteries. However, this material might be impeded by inferior rate capability owing to its disappointing electron conductivity. To address this issue, a combined technique of carbon coating and Nb5+ doping was carried out for the first time. On one hand, the coated carbon nano-shell could construct an electron-conductive network and buffer the volume stain. On the other hand, the introduction of Nb5+ into the Na3V2(PO4)3 crystal could regulate the relevant crystal parameters and create more vacancies, further facilitating the transfer of sodium ions. As a result, the optimized Nb-doped Na3V2(PO4)3@C material achieved an excellent performance of 81.6 mA h g−1 at 50C and a high-capacity retention ratio of 80.8% even after 1600 cycles. This work not only highlights the significance of carbon coating and Nb5+ doping, but also shows promising opportunities in potential cathode alternatives for sodium-ion batteries.
Long non‐coding RNA MIF‐AS1 (lncMIF‐AS1) has been found to be upregulated in the tumor tissues of gastric cancer; however, its importance for the progression of gastric cancer remains unknown. Thus, ...the present study was designed to determine the role of the lncMIF‐AS1‐based signal transduction pathway in mediating the proliferation and apoptosis of gastric cancer cells. Differentially expressed lncRNAs and mRNAs were screened out using microarray analysis, based on the published data (GSE63288), and validated using quantitative RT‐PCR. Target relationships between lncRNA‐micro RNA (miRNA) and miRNA‐mRNA were predicted by bioinformatics analysis and verified by dual‐luciferase reporter assay. Protein expression of NDUFA4, COX6C and COX5B was detected by western blot. Cell proliferation, cell cycle and apoptosis were determined using colony formation assay and flow cytometry analysis. Oxidative phosphorylation in gastric cancer cells was assessed by levels of oxygen consumption and ATP synthase activity. Expression of lncMIF‐AS1 and NDUFA4 were upregulated in gastric cancer tissues and cells as compared with non‐cancerous gastric tissues and cells (P < .05). MiR‐212‐5p was identified as the most important miRNA linker between lncMIF‐AS1 and NDUFA4, which was negatively regulated by lncMIF‐AS1 and its depletion is the main cause of NDUFA4 overexpression (P < .01). The upregulated expression of NDUFA4 then greatly promoted the proliferation and decreased the apoptosis of gastric cancer cells through activation of the oxidative phosphorylation pathway. Taken together, the present study implies that inhibition of lncMIF‐AS1/miR‐212‐5p/NDUFA4 signal transduction may provide a promising therapeutic target for the treatment of gastric cancer.
Our findings showed that lncMIF‐AS1 is involved in gastric cancer tumorigenesis as a tumor activator gene. Through upregulation of NDUFA4, lncMIF‐AS1 promotes gastric cancer cell proliferation and repressed apoptosis. Moreover, we showed that lncMIF‐AS1 activates NDUFA4 expression by sponging to miR‐212‐5p in gastric cancer cells. And inhibition of lnvMIF‐AS1/miR‐212‐5p/NDUFA4 may provide an attractive therapeutic target for the treatment of gastric cancer.
Seawater electrolysis is an extremely attractive approach for harvesting clean hydrogen energy, but detrimental chlorine species (i.e., chloride and hypochlorite) cause severe corrosion at the anode. ...Here, we report our recent finding that benzoate anions-intercalated NiFe-layered double hydroxide nanosheet on carbon cloth (BZ-NiFe-LDH/CC) behaves as a highly efficient and durable monolithic catalyst for alkaline seawater oxidation, affords enlarged interlayer spacing of LDH, inhibits chlorine (electro)chemistry, and alleviates local pH drop of the electrode. It only needs an overpotential of 320 mV to reach a current density of 500 mA·cm–2 in 1 M KOH. In contrast to the fast activity decay of NiFe-LDH/CC counterpart during long-term electrolysis, BZ-NiFe-LDH/CC achieves stable 100-h electrolysis at an industrial-level current density of 500 mA·cm–2 in alkaline seawater. Operando Raman spectroscopy studies further identify structural changes of disordered δ (NiIII-O) during the seawater oxidation process.
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