•Bacterial community structure and diversity in Baiyangdian Lake were assessed.•Dominant bacteria in different habitats at different seasons were assessed.•Main functional groups were ...sulfur-oxidizing, sulfur-reducing, nitrifying and pollutant-degrading bacteria.•Main factors affecting bacterial community composition were pH, phosphorus and heavy metals.•Bacterial community composition, evenness and diversity varied more significantly with habitat.
Benthic bacteria are drivers of aquatic ecosystem material circulation and energy flow, and are sensitive to environmental changes. In this study, a total of 79 sediment samples were collected from four representative habitat types (duck farm, fish farm, lotus pond and residential area) and one reference site (conservation district) of Baiyangdian Lake, North China, in three seasons (winter, spring and summer). The physical and chemical properties and the levels of contaminants in sediment were determined. Bacterial communities were studied by 16S rRNA high-throughput sequencing techniques. The result showed that, Proteobacteria, Chloroflexi, Bacteroidetes, Firmicutes and Actinobacteria were the dominant species at the phylum level in Baiyangdian. Sulfuricurvum, Thiobacillus Dechloromonas, Sulfurovum, Nitrospira and Desulfatiglans were the dominant species at the genus level. The dominant genus was different among different habitats. Proteobacteria exhibited the highest relative abundance in all seasons, and the relative abundance of dominant bacteria was highest in winter. The main functional group from the sampling sites were contamination tolerance bacteria, such as sulfur-oxidizing, sulfate-reducing and nitrifying bacteria. Sulfur-oxidizing bacteria were found mainly in duck farms and residential areas, whereas sulfate-reducing bacteria and nitrifying bacteria occurred in lotus ponds. Habitat type was the most important factor influencing the bacterial community composition, evenness and diversity. Sediment pH and the amount of active phosphorus played the most important role in the composition of the bacterial community, and the heavy metals (Zn, Mn and Cr) and organic pollutants (polycyclic aromatic hydrocarbons, PAH) also had moderate influence. As Baiyangdian Lake is the central of Xiong’an New Area, the water quality management has become the hottest topic. Plenty of researches about environmental variables and aquatic species were taken, but lacking report of bacteria. This study provide basic information of bacterial community composition in this area, and help to understand the response of the bacterial community to habitat and seasonal change, which provide a scientific basis for the recovery and reconstruction of the degraded ecosystem.
The active distribution network (ADN) can provide the reactive power ancillary service (RPAS) to improve the operations of the transmission network operations (such as voltage control and network ...loss reduction) as distribution generation grows. In this context, an RPAS market is required to motivate the ADN to provide the RPAS to the transmission network since the transmission system operator (TSO) and the distribution system operator (DSO) are different entities. Hence, to obtain the TSO–DSO coordination in the RPAS market, this study proposes a two‐stage market framework on the basis of the successive clearing of the energy and RPAS markets. Additionally, a distributed market‐clearing mechanism based on an alternating direction method of multipliers (ADMM) is adopted to guarantee TSO's and DSO's information privacy. Furthermore, a binary expansion (BE) method is used to linearise the non‐convex bilinear terms in the market‐clearing model. The effectiveness of the proposed RPAS market framework and distributed market‐clearing mechanism is validated using two different test systems with different system scales.
Power-to-gas (P2G) facilities and natural gas fired power units provide flexibility to integrated electricity and natural gas systems (IENGS) for wind power accommodation and ramp deployment. This ...paper proposes a stochastic coordinated scheduling model for IENGS considering ramping costs with P2G storage and wind power. The operation model of natural gas system with P2G is presented, and the benefits of P2G integration are analyzed. To address the uncertainties of wind power and energy loads, multiple representative scenarios are generated. The flexible ramping requirements and costs are incorporated and analyzed, and flexible ramp can be provided by P2G in this work. The coordinated scheduling model for IENGS is formulated as a two-stage stochastic programming problem, in which day-ahead scheduling for electricity systems is modeled in the first stage model and scheduling of natural gas systems is carried out in the second stage model. Numerical case studies on a modified PJM 5-bus electricity system with a 7-node natural gas system and the IEEE 118-bus system with a 20-node Belgian natural gas system verify that P2G can help accommodate wind power, provide additional flexible ramping capacities, and reduce the gas supply from gas suppliers and gas load shedding.
The increasing installment of distributed generations (DGs) and the tight coupling between active distribution system (ADS) and district heating system (DHS) enhance the flexibility of ...electricity-heat integrated energy system (IES) to participate in the operation of power transmission system. The operation of transmission system will be affected by distribution company (DISCO). In this paper, a collaborative optimal operation model of transmission system is proposed considering the interaction with the district electricity-heat integrated energy systems based on a semi-definite programming relaxation method. The optimal operation problem of ADS is modeled based on AC optimal power flow (ACOPF) with second order cone (SOC) relaxation, and network constraints of DHS are considered. An iterative semi-definite programming relaxation method is utilized to ensure the solution accuracy. The effectiveness of the proposed model on improving the utilization rate of DGs and the economy is verified based on case studies.
•A collaborative optimal operation model of the transmission system is proposed.•Optimal operation of integrated ADS and DHS is considered.•The coordination between DSO and TSO is considered.•A semi-definite programming relaxation method is introduced to ensure the accuracy.
•A distributed optimal scheduling of regional integrated energy system is proposed.•Thermal inertia of buildings is considered.•Different heating modes of buildings are taken into account.•ADMM with ...variable penalty parameters is adopted to enhance the convergence.
The coordinated operation of regional integrated electricity and district heating systems (RIEDHS) can significantly improve energy efficiency. This paper considers the dynamic characteristics of the pipelines in the district heating systems (DHS) and the thermal inertia of buildings with different heating modes, and establishes a distributed optimal scheduling model of RIEDHS. In addition, due to the computational complexity of large-scale integrated energy systems, heavy communication burdens, and the privacy-preserving difficulties of multiple operators, a centralized solution is actually not feasible for RIEDHS. Based on the Alternating Direction Method of Multipliers (ADMM) algorithm, a distributed method for solving the RIEDHS problem is proposed. In order to enhance the convergence of the algorithm, the ADMM with variable penalty parameters is adopted. The effectiveness and superiority of the method are verified by case studies. The results show that the optimal scheduling model can make full use of the thermal inertia of buildings, reduce system operating costs, and promote photovoltaic consumption.
•A local electricity-heat integrated energy market clearing method is proposed.•Local electricity and heat markets are cleared simultaneously.•The equilibrium between DSO and TSO is considered.•The ...model is transformed into an MISOCP problem.
With the increasing interconnection of active distribution network (ADN) with the integration of distributed generations (DGs) and district heating network (DHN), local electricity-heat integrated energy market provides the opportunity of coordinated energy pricing and trading with transmission system operator (TSO). The market clearing results of distribution system operator (DSO) on local electricity and heating markets will be affected wholesale market clearing. This paper proposes a bi-level optimization model for local electricity-heat integrated energy market clearing for integrated ADN and DHN, and distribution locational marginal pricing coordinated with the wholesale market clearing of transmission system. In the proposed model, the upper-level model indicates the local electricity-heat integrated market clearing by DSO and the lower-level model indicates the wholesale electricity market clearing by TSO. The locational marginal price (LMP) of the substation of the PCC point will affect the market clearing of ADN and DHN, and further affect the distribution locational marginal price (DLMP). Moreover, the market clearing actions of DSO would affect the wholesale electricity market clearing and LMP. The equilibrium of DSO and TSO is found by transforming the proposed bi-level model into a mathematical program with equilibrium constraint (MPEC) model. The MPEC formulation is further converted into mixed integer second order cone programming (MISOCP) for effectively solving. The effectiveness of the proposed model on reducing the DLMP and improving economy of ADN and DHN are demonstrated through case studies.
Eigenstates of observables such as the Hamiltonian play a central role in quantum mechanics. Inspired by the pure Nash equilibria that arise in classical game theory, we propose ''Nash states'' of ...multiple observables as a generalization of eigenstates of single observables. This generalization is mathematically natural for many-body quantum systems, which possess an intrinsic tensor product structure. Every set of observables gives rise to algebraic varieties of Nash state vectors that we call ''Nash varieties''. We present analytical and numerical results on the existence of Nash states and on the geometry of Nash varieties. We relate these ideas to earlier, pioneering work on the Nash equilibria of few-body quantum games and discuss connections to the variational minimization of local Hamiltonians.
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