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Response of aquatic organisms to eutrophication have been well reported, while less studies are available for the recovery of eutrophic lakes following a reduction in the external loading, especially for systems where nitrogen is reduced but the phosphorus concentration is maintained high due to internal loading. Diatoms are nitrate (NO3-N) opportunists but can also use ammonium (NH4-N). They may, therefore, be more sensitive to nitrogen reduction than other algae that typically prefer NH4-N. We document the variations of nutrients and diatoms in subtropical, eutrophic Lake Taihu over 28 yr during which a reduction of the external loading resulted from lake management. According to the results of change point analysis, data on environmental variables were divided into two periods (P1: 1992-2006; P2: 2007-2019) with two different seasons (WS: Winter-Spring; SA: Summer-Autumn), respectively. Compared with P1-WS, the concentration of NH4-N decreased significantly whereas NO3-N showed no significant change in P2-WS. In contrast, NH4-N concentrations were low and showed no significant changes in P1-SA and P2-SA and NO3-N decreased significantly in the latter period. Accordingly, NO3-N: NH4-N mass ratios in P1-SA and P2-WS were all significantly higher than those in P2-SA and P1-WS, respectively. The biomass of WS diatom increased significantly and the timing of the peak biomass shifted from P1-SA to P2-WS since 2007. The SEM analysis showed that NO3-N was retained as a statistically significant predictor for diatom biomass in P1-SA and significant effects of windspeed, zooplankton and NH4-N on diatom biomass in P2-WS. Windspeed and zooplankton have further changed the biomass of diatoms in the case of declining inorganic nitrogen. We conclude that the magnitude of vernal suppression or stimulation of diatom assemblages has increased, concomitant with the variations of NH4-N and NO3-N: NH4-N mass ratios. Diatoms response to NH4-N or NO3-N is apparently changing in response to water temperature in this eutrophic shallow lake. Thus, parallel reductions in external nitrogen loading, along with variations in dominant inorganic nitrogen, will stimulate the growth of diatom and therefore increase the total biomass of phytoplankton in still high internal phosphorus loading, which is should be regarded as a good sign of restoration measures.

Glypican-3 (GPC3) is a serum marker for hepatocellular carcinoma (HCC) and has excellent specificity and sensitivity. Herein, the construction of an electrochemical aptasensor based on reduced graphene oxide-carboxymethyl chitosan-hemin-palladium nanoparticles (RGO-CMCS-Hemin/Pd NPs) and GPC3 aptamer (GPC3apt) has the function of GPC3 identification and analysis. RGO-CMCS-Hemin/Pd NPs has excellent biocompatibility, large specific surface area and good electrical conductivity, which is not only used as advanced sensing materials to modify the electrode surface to reduce the resistance and increase the signal amplitude, but also used as an electroactive substance to provide electrical signals. GPC3apt as a biometric element makes the aptasensor has good specificity and sensitivity. The GPC3apt can combine with GPC3 and form GPC3-aptamer conjugation, which increases the electron transfer impedance and changes the electrical signal. Under the optimum conditions, the aptasensor had a good linear relationship with the GPC3 concentration in the range of 1.0–100.0 ng ml−1 with R2 of 0.9573. The lower limit of detection was 1.0 ng ml−1. When the aptasensor was applied to GPC3 detection in human serum samples, the recovery was 93.73%–118.83%. In addition, the GPC3 aptasensor has excellent specificity, reproducibility and stability, which is anticipated to be applied for the clinical detection of GPC3.

Reliability evaluation of phasor measurement unit (PMU) is a primary key element in the reliability evaluation of wide-area monitoring system (WAMS). In this paper, a comprehensive reliability evaluation method based on Monte Carlo dynamic fault tree (MCDFT) analysis is proposed to conduct the reliability evaluation on PMU. The reliability model of PMU is constructed using dynamic fault tree modeling and analyzed using Monte Carlo simulation to evaluate the reliability indices of PMU. The validity and advantages of the proposed MCDFT reliability evaluation of PMU were verified with simulation and comparison studies. Importance analysis showed that basic components in the GPS receiver and CPU hardware modules have high impacts on the reliability of PMU. Sensitivity and redundancy design analysis are then applied to conclude that the redundancy design of GPS receiver and CPU hardware would be the best measure for improving the reliability of PMU. Finally, a self-adaptive wide-area damping control scheme is taken as an example for the application of PMU reliability.

Lithium-sulfur (Li-S) batteries with the merits of high theoretical capacity and high energy density have gained significant attention as the next-generation energy storage devices. Unfortunately, the main pressing issues of sluggish reaction kinetics and severe shuttling of polysulfides hampered their practical application. To overcome these obstacles, various strategies adopting high-efficient electrocatalysts have been explored to enable the rapid polysulfide conversions and thereby suppressing the polysulfide shuttling. This review first summarizes the recent progress on electrocatalysts involved in hosts, interlayers, and protective layers. Then, these electrocatalysts in Li-S batteries are analyzed by listing representative works, from the viewpoints of design concepts, engineering strategies, working principles, and electrochemical performance. Finally, the remaining issues/challenges and future perspectives facing electrocatalysts are given and discussed. This review may provide new guidance for the future construction of electrocatalysts and their further utilizations in high-performance Li-S batteries. [Figure not available: see fulltext.]. © 2022, Tsinghua University Press.

Robust mitigation options will play significant role in achieving the target of limiting global change to below 1.5 °C above pre-industrial levels by 2100. To support cooperation for mitigation development, we establish a real options-based model to evaluate the rational decisions of exercising the abandon option for carbon capture and storage-enhanced oil recovery (CCS-EOR) projects under oil market and geological uncertainties. Three possible cooperative mechanisms (fixed carbon dioxide (CO2) price, oil-indexed CO2 price, and joint venture contracts) among CO2-EOR stakeholders are evaluated. The results show that the conflicts in profit maximization targets for different stakeholders in cooperative mitigation are to a great extent unable to be avoided. A joint venture business model is preferred in cooperative mitigation as it can effectively weaken such conflicts. And it is more reasonable to provide incentives to the downstream of the CO2-EOR chain than compensating the adoption cost of carbon capture technologies in the upstream. From a global perspective, the inefficient cooperation can be a main barrier that hinders the development of deep-cutting options. Global mitigation strategies should not only focus on promoting technology progress but also the design of innovative business models to balance the benefits among stakeholders. A joint venture business model is recommended in both the developed and developing countries for seizing the early mitigation opportunities.

The cryogenic process is used for CO2 purification in oxy-fuel combustion power plant, and multi-stream heat exchanger is one of the most important components. Viscosity and thermal conductivity ar ...

Treatment of mice in vivo with 5% w/v ethanol given in a liquid diet causes marked changes in spleen, peripheral blood, and thymus lymphocytes. In both the thymus and spleen, there is an acute cellular depletion resulting in a significant decrease in gross tissue size and cell number. In spleen and peripheral blood, the percentage of T lymphocytes is increased relative to B lymphocytes, but the ratio of CD4+/CD8+ T cell sub‐populations remains unchanged. Splenic natural killer (NK) cell activity is increased in ethanol‐consuming mice, although the percentage of NK1.1+ cells is relatively unchanged.

Abstract The potential of using high metals containing coal gangue and lignite to prepare high-activity coal char-based catalysts is investigated for effective biomass tar decomposition. Loose structure and rough surface are formed for these char-based catalysts with heterogeneous distribution of a large number of inorganic particles. In the biomass tar decomposition, the performance of the coal char-based catalysts is significantly influenced by the content of the metals in the raw materials and coal gangue char (GC) with the ash content as high as 50.80% exhibits the highest activity in this work. A high biomass tar conversion efficiency of 93.5% is achieved at 800 °C along with a significant increase in the fuel gas product. During the five-time consecutive tests, the catalytic performance of GC increases a little at the second or third times reuse and remains relatively stable, showing the remarkable stability of the catalyst in biomass tar decomposition applications.

Abstract This article introduces an effective stochastic operation framework for optimal energy management of the shipboard power systems including large, nonlinear and dynamic loads. The proposed framework divides the ship power system into several agents, which coordinate with each other based on their demands/supplies until. The alternating direction method of multipliers (ADMM) is deployed as the multi-agent framework to solve the reformulated distributed energy management problem in the ship. Two types of turbo-generators are considered in the proposed system model, including single-shaft and twin-shaft models, to increase the part-load efficiency in certain times when facing variable speed operation. The proposed distributed framework is equipped with a recursive mechanism, which helps the ship system for running optimal load scheduling when facing insufficient power generation. In order to model the uncertainty effects associated with the forecast error in the interval-ahead load demand, a stochastic framework based on unscented transform is devised which can work in the nonlinear and correlated environments of shipboard power systems. Due to the nonlinear cost function in each agent, a powerful optimization algorithm based on modified θ-firefly algorithm (Mθ-FOA) is proposed. This is a phasor algorithm, which helps for escaping from premature convergence and getting trapped in local optima. The appropriate performance of the proposed stochastic model is examined on the real dataset of a ship power system. The simulation results show the high robustness, guarantied consensus, economic operation and feasible solution when power generation shortage based on load shedding in the system.