The paper presents an overview of the state of the art in energy-efficient techniques in the domain of discrete part manufacturing, focusing on the techniques including energy assessment model for ...machining process and the energy efficiency analysis and evaluation for machine tools, important components, and machining systems. The main motivation is to review the existing works related to reduce energy consumption in machining processes, to discuss the challenges towards energy-efficient manufacturing, and identify the major barriers from both technologies and approaches.
The present work is focused on the use of electrochemical cathode-reduction method for leaching LiCoO2 produced by spent lithium-ion batteries. The thermodynamics, kinetics, and electrochemical ...impedance spectroscopy analyses are used to determine the probable control mechanism involved in the leaching of cobalt from spent LiCoO2. The leaching efficiencies reached about 90% for cobalt and nearly 94% for lithium using 1.25 mol/L of malic acid and a working voltage of 8 V for 180 min at 70 °C. Kinetics analysis indicates that the leaching process of cobalt could be divided into two stages: the first stage is controlled by a surface chemical reaction, and the second stage is controlled by a combination of the surface chemical reaction and diffusion. Electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy analysis show that the combination control at the second stage is related to the form of Co(OH)3 produced during the leaching process of spent LiCoO2. Finally, a novel process for the leaching of cobalt from spent LiCoO2 is proposed.
•A novel process of electrochemical cathode reduction is designed for leaching of spent LiCoO2 batteries.•The thermodynamics, kinetics and EIS are analyzed for understanding the controlling mechanism of leaching process.•The SEM, XPS and TEM are analyzed for clarifying the combination control at second stage of leaching process.
In order to achieve the large-scale, long-distance and high-efficiency trans-regional electricity transmission, it is of significance to construct a strong and national smart grid with ultra-high ...voltage (UHV) transmission system as its backbone and the coordinated development of power grids at all levels, which will enhance the resources allocation capacity of grid, promote the large-scale integration into grid of renewable energy, and further mitigate the power shortage in eastern and southern China. This paper starts with the analysis of the regional grids' supply and demand situation in China, and then analyzes the development status and existing issues of China's trans-regional electricity transmission. Finally, strategies and recommendations are proposed.
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•2D mesoporous CoN NSs nitrided from Co(OH)2 NSs as enzyme-free glucose sensors.•Excellent electroconductibility facilitating the Co4+ formation along CoN NSs surfaces.•A wide linear ...range of 0.01–8.0mM with a large sensitivity of 921.18 uA cm−2mM−1 for CoN NSs.•Excellent anti-interference ability and stability of CoN NSs toward glucose detection.
In this paper, we have designed and facilely synthesized the novel mesoporous cobalt nitride nanosheets modified by the pyrolytic carbon conductor (denoted as Co2N0.67 NSs). By the hydrothermal method, we successfully grown the precursor nanosheets (i.e. Co(OH)2 NSs) under the regulate and control of hexamethylenetetramine (HMT) weak base. Through a simple nitridation process in NH3 atmosphere at 400°C, the as-prepared smooth Co(OH)2 NSs were thoroughly transformed into the mesoporous Co2N0.67 NSs modified by pyrolytic carbon of HMT. Thanks to a synergistic effect between the metallic character of Co2N0.67 phase and good electroconductibility of carbon, the as-prepared hybrid Co2N0.67 NSs can boost electron transfer from catalyst surfaces and then form abundant Co4+ active sites on electrode surfaces in electrochemical reaction processes. Meanwhile, vast mesoporous structures appeared in Co2N0.67 NSs further promoted the dispersion of Co4+ active sites and enhanced the mass transfer rate. Benefitting from the above mentioned factors, Co2N0.67 NSs therefore exhibit excellent glucose oxidation ability than another two control samples (i.e. Co(OH)2 NSs and Co3O4 NSs). When used for glucose detection after the electrochemical activation process, the optimal Co2N0.67 NSs display excellent detection parameters: a wide linear range of 0.01–8.0mM, a large sensitivity of 921.18 uA cm−2mM−1 glucose, a low detection limit of 0.1μM, a response time within 3s, good reproducibility, considerable long-term stability, and excellent anti-interference to electroactive molecules and Cl−. Upon utilized for measuring glucose concentrations in serum samples, the detection results on Co2N0.67 NSs are similarly satisfying and accurate. This work opens a new possibility for the sensitive and fast glucose concentration detection in human blood serum samples.
p-Toluenesulfonyl isocyanate (PTSI) is introduced as electrolyte additive in a bid to enhance the electrochemical performances of LiNi0.5Co0.2Mn0.3O2 cathode materials under high voltage. A less ...resistive and stable film on the cathode surface derived from PTSI oxidation which taken place prior to the carbonate solvents is formed. As a result, the discharge capacity retention of Li/LiNi0.5Co0.2Mn0.3O2 cell is elevated from 71.4% to 86.2% after 100 cycles at room temperature, and from 32.3% to 54.5% after 100 cycles at 55 °C. In addition, the Li/LiNi0.5Co0.2Mn0.3O2 half cell with PTSI exhibits superior rate capability compared to that in baseline electrolyte. The improved performance is not only ascribed to the thin protective layer originated from PTSI decomposition which prevent the successive breakdown of the electrolyte on cathode surface, but it is also attributed to the SO group in PTSI serves as the weak base site to restrain the reactivity of PF5, resulting in the suppression of LiF formation and HF generation.
•PTSI is proposed as film forming additive for layered cathode for the first time.•The cyclic stability and rate capability are obviously enhanced with PTSI additive.•PTSI additive tends to be oxidized before the carbonate solvents.•The electrolyte decomposition is suppressed by PTSI derived passivation film.
In recent years, the interest in the relationship between urban green space and residents’ mental health has gradually risen. A number of researchers have investigated the causal relationship and ...possible mediators between the two, although few have summarized these mediators. For this reason, we searched for relevant studies and filtered them by criteria and quality score, and analyzed the mediators and paths of the impact of urban green space on residents’ mental health. The mediators can be divided into environmental factors, outdoor activity, and social cohesion. From the perspective of heterogeneity, both individual characteristics (e.g., age and gender) and group characteristics (e.g., level of urban development and urban density) of residents are considered to be the cause of various mediating effects. Types of urban green space tend to affect residents’ mental health through different paths. Furthermore, this review discusses the details of each part under the influence paths. Finally, the policy implications for urban green space planning from three mediator levels are put forward based on an analysis of the situation in different countries.
Mesenchymal stem cells (MSCs) are effective for the management of experimental ischemia-reperfusion acute kidney injury (IRI-AKI). Immune modulation is one of the important mechanisms of MSCs ...treatment. Interleukin-17A (IL-17A) pretreated MSCs are more immunosuppressive with minimal changes in immunogenicity in vitro. Here, we demonstrated that administration of IL-17A-pretreated MSCs resulted in significantly lower acute tubular necrosis scores, serum creatinine, and BUN of mice with IRI-AKI, compared with the administration of MSCs. Of the co-cultured splenocytes, IL-17A-pretreated MSCs significantly increased the percentages of CD4+Foxp3+ Tregs and decreased concanavalin A-induced T cell proliferation. Furthermore, mice with IRI-AKI that underwent IL-17A-pretreated MSC therapy had significantly lower serum IL-6, TNF-α, and IFN-γ levels, a higher serum IL-10 level, and higher spleen and kidney Treg percentages than the mice that underwent MSCs treatment. Additionally, the depletion of Tregs by PC61 (anti-CD25 antibody) reversed the enhanced treatment efficacy of the IL-17A-pretreatedMSCs on mice with IRI-AKI. Additionally, IL-17A upregulated COX-2 expression and increased PGE2 production. The blockage of COX-2 by celecoxib reversed the benefit of IL-pretreated 17A-MSCs on the serum PGE2 concentration, spleen and kidney Tregs percentages, serum creatinine and BUN levels, renal acute tubular necrosis scores, and serum IL-6, TNF-α, IFN-γ, and IL-10 levels of IRI-pretreated mice with AKI, compared with MSCs. Thus, our results suggest that IL-17A pretreatment enhances the efficacy of MSCs on mice with IRI-AKI by increasing the Treg percentages through the COX-2/PGE2 pathway.
The lithium-ion battery is the key power source of a hybrid vehicle. Accurate real-time state of charge (SOC) acquisition is the basis of the safe operation of vehicles. In actual conditions, the ...lithium-ion battery is a complex dynamic system, and it is tough to model it accurately, which leads to the estimation deviation of the battery SOC. Recursive least squares (RLS) algorithm with fixed forgetting factor is widely used in parameter identification, but it lacks sufficient robustness and accuracy when battery charge and discharge conditions change suddenly. In this paper, we proposed an adaptive forgetting factor regression least-squares–extended Kalman filter (AFFRLS–EKF) SOC estimation strategy by designing the forgetting factor of least squares algorithm to improve the accuracy of SOC estimation under the change of battery charge and discharge conditions. The simulation results show that the SOC estimation strategy of the AFFRLS–EKF based on accurate modeling can effectively improve the estimation accuracy of SOC.
Currently, the energy structure with coal is given priority to in China. This situation would not change in a short time which results in massive CO2 emissions and increased pressure to natural ...environment. Carbon capture and storage technology (known as CCS) is a carbon abatement technology that separates CO2 from industrial production or energy conversion, transports to the storage site after compression, and injects to the deep underground to make long-term isolation from the atmosphere. This technology achieves zero emission during fossil energy extraction and conversion, so the Intergovernmental Panel on Climate Change (IPCC) regarded it as one of the effective methods reducing greenhouse gas emissions in 2005. First, based on the development status of CCS in China, in terms of policies, technology research and CCS projects are described. SWOT is an analysis method that analyses objects all-around from four main aspects of strength, weakness, opportunity and threat. By SWOT, this paper focuses on analyzing the development environment currently in order to find the main stimulatives and obstacles and confirm the feasibility of CCS development in China. Finally, recommendations are proposed addressing the problems and obstacles. The results show that CCS is an effective way to reduce future emissions in China, as with the huge market, and the general support by Chinese government and green groups. However, relevant departments should strengthen economic and policy support at the same time.
Secondary organic aerosol (SOA) constitutes a large fraction of OA, yet remains a source of significant uncertainties in climate models due to incomplete understanding of its formation mechanisms and ...evolutionary processes. Here we evaluated the effects of photochemical and aqueous-phase processing on SOA composition and oxidation degrees in three seasons in Beijing, China, using high-resolution aerosol mass spectrometer measurements along with positive matrix factorization. Our results show that aqueous-phase processing has a dominant impact on the formation of more oxidized SOA (MO-OOA), and the contribution of MO-OOA to OA increases substantially as a function of relative humidity or liquid water content. In contrast, photochemical processing plays a major role in the formation of less oxidized SOA (LO-OOA), as indicated by the strong correlations between LO-OOA and odd oxygen (O
= O
+ NO
) during periods of photochemical production (R
= 0.59-0.80). Higher oxygen-to-carbon ratios of SOA during periods with higher RH were also found indicating a major role of aqueous-phase processing in changing the oxidation degree of SOA in Beijing. Episodes analyses further highlight that LO-OOA plays a more important role during the early stage of the formation of autumn/winter haze episodes while MO-OOA is more significant during the later evolution period.
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