This paper presents a stochastic model for the long-term solution of security-constrained unit commitment (SCUC). The proposed approach could be used by vertically integrated utilities as well as the ...ISOs in electricity markets. In this model, random disturbances, such as outages of generation units and transmission lines as well as load forecasting inaccuracies, are modeled as scenario trees using the Monte Carlo simulation method. For dual optimization, coupling constraints among scenarios are relaxed and the optimization problem is decomposed into deterministic long-term SCUC subproblems. For each deterministic long-term SCUC, resource constraints represent fuel and emission constraints (in the case of vertically integrated utilities) and energy constraints (in the case of electricity markets). Lagrangian relaxation is used to decompose subproblems with long-term SCUC into tractable short-term MIP-based SCUC subproblems without resource constraints. Accordingly, penalty prices (Lagrangian multipliers) are signals to coordinate the master problem and small-scale subproblems. Computational requirements for solving scenario-based optimization models depend on the number of scenarios in which the objective is to minimize the weighted-average generation cost over the entire scenario tree. In large scale applications, the scenario reduction method is introduced for enhancing a tradeoff between calculation speed and accuracy of long-term SCUC solution. Numerical simulations indicate the effectiveness of the proposed approach for solving the stochastic security-constrained unit commitment
Experiments have demonstrated the regulation of long noncoding RNA (lncRNA) in tuberculosis (TB), and negative pressure treatment has been associated with the alleviation of TB. Here, we investigated ...the interaction of negative pressure and the lncRNA X‐inactive specific transcript (XIST) in modulating Mycobacterium tuberculosis (MTB) infection. Initially, we established an in vitro cell model of MTB infection and an in vivo mouse model of MTB infection, followed by treatment with negative pressure. Then, we examined the expression of XIST, followed by analysis of the downstream miRNA of XIST. XIST was overexpressed or underexpressed through cell transfection to examine its effects on macrophage polarization via the miR–125b–5p/A2 axis. The MTB models were characterized by upregulated XIST and downregulated miR‐125b‐5p. XIST bound to miR‐125b‐5p, leading to its downregulation, and thus causing higher MTB survival in an ESAT‐6–dependent manner. Additionally, negative pressure treatment decreased MTB‐driven XIST expression through downregulation of A20 (an NF‐κB repressor) via miR‐125b‐5 expression, promoting the M1 polarization program in macrophages through activation of the NF‐κB pathway. In summary, negative pressure treatment after MTB infection can promote the polarization of macrophages to the proinflammatory M1 phenotype by regulating the XIST/miR–125b–5p/A20/NF–κB axis.
Experiments have demonstrated the regulation of long noncoding RNA (lncRNA) in tuberculosis (TB), and negative pressure treatment has been associated with the alleviation of TB. Here, we investigated the interaction of negative pressure and the lncRNA X‐inactive specific transcript (XIST) in modulating Mycobacterium tuberculosis (MTB) infection.
This paper proposes an integrated model for assessing the impact of interdependency of electricity and natural gas networks on power system security. The integrated model incorporates the natural gas ...network constraints into the optimal solution of security-constrained unit commitment. The natural gas network is modeled by daily and hourly limits on pipelines, sub-areas, plants, and generating units. The application of fuel diversity (e.g., generating units with fuel switching capability) is presented as an effective peak shaving strategy for natural gas demand which could hedge price volatilities of natural gas and electric power. The proposed model can be used by a vertically integrated utility for the commitment and dispatch of generating units and the allocation of natural gas for the next day utilization. The proposed model can also be used for measuring the security of social services by modeling the interdependency of natural gas and electric power system infrastructures. If the proposed model is used by GENCOs, gas constraints will be submitted to electricity markets as energy constraints. Illustrative examples show the impact of natural gas supply infrastructure on the economic operation of a vertically integrated utility. The examples also discuss the impact of generating units with fuel switching capability on the power system security when the supply of natural gas is limited.
Renewable energy technology has been considered as a “MUST” option to lower the use of fossil fuels for industry and daily life. Designing critical and sophisticated materials is of great importance ...in order to realize high‐performance energy technology. Typically, efficient synthesis and soft surface modification of nanomaterials are important for energy technology. Therefore, there are increasing demands on the rational design of efficient electrocatalysts or electrode materials, which are the key for scalable and practical electrochemical energy devices. Nevertheless, the development of versatile and cheap strategies is one of the main challenges to achieve the aforementioned goals. Accordingly, plasma technology has recently appeared as an extremely promising alternative for the synthesis and surface modification of nanomaterials for electrochemical devices. Here, the recent progress on the development of nonthermal plasma technology is highlighted for the synthesis and surface modification of advanced electrode materials for renewable energy technology including electrocatalysts for fuel cells, water splitting, metal–air batteries, and electrode materials for batteries and supercapacitors, etc.
Designing critical and sophisticated electrode materials is of great importance to realize high‐performance renewable energy technology, such as fuel cells, water‐splitting devices, metal–air batteries, Li–ion batteries, and supercapacitors, etc. The recent progress in the development of nonthermal plasma technology for the synthesis and surface modification of advanced nanomaterials for electrochemical devices is highlighted.
The commercialization of fuel cells, such as proton exchange membrane fuel cells and direct methanol/formic acid fuel cells, is hampered by their poor stability, high cost, fuel crossover, and the ...sluggish kinetics of platinum (Pt) and Pt‐based electrocatalysts for both the cathodic oxygen reduction reaction (ORR) and the anodic hydrogen oxidation reaction (HOR) or small molecule oxidation reaction (SMOR). Thus far, the exploitation of active and stable electrocatalysts has been the most promising strategy to improve the performance of fuel cells. Accordingly, increasing attention is being devoted to modulating the surface/interface electronic structure of electrocatalysts and optimizing the adsorption energy of intermediate species by defect engineering to enhance their catalytic performance. Defect engineering is introduced in terms of defect definition, classification, characterization, construction, and understanding. Subsequently, the latest advances in defective electrocatalysts for ORR and HOR/SMOR in fuel cells are scientifically and systematically summarized. Furthermore, the structure–activity relationships between defect engineering and electrocatalytic ability are further illustrated by coupling experimental results and theoretical calculations. With a deeper understanding of these complex relationships, the integration of defective electrocatalysts into single fuel‐cell systems is also discussed. Finally, the potential challenges and prospects of defective electrocatalysts are further proposed, covering controllable preparation, in situ characterization, and commercial applications.
The latest advances in the development of fuel‐cell electrocatalysts by defect engineering are systematically introduced. Such defects modulate electronic structure and improve electrical conductivity, consequently enhancing the activities of electrocatalysts.
The reasonable design of electrode materials for rechargeable batteries plays an important role in promoting the development of renewable energy technology. With the in‐depth understanding of the ...mechanisms underlying electrode reactions and the rapid development of advanced technology, the performance of batteries has significantly been optimized through the introduction of defect engineering on electrode materials. A large number of coordination unsaturated sites can be exposed by defect construction in electrode materials, which play a crucial role in electrochemical reactions. Herein, recent advances regarding defect engineering in electrode materials for rechargeable batteries are systematically summarized, with a special focus on the application of metal‐ion batteries, lithium–sulfur batteries, and metal–air batteries. The defects can not only effectively promote ion diffusion and charge transfer but also provide more storage/adsorption/active sites for guest ions and intermediate species, thus improving the performance of batteries. Moreover, the existing challenges and future development prospects are forecast, and the electrode materials are further optimized through defect engineering to promote the development of the battery industry.
Recent advances regarding defect engineering on electrode materials for rechargeable batteries are systematically summarized, with a special focus on application in metal‐ion batteries, lithium–sulfur batteries, and metal–air batteries. The defects can not only promote diffusion of ions and charge transfer, but also maintain structural stability and provide more energy storage/adsorption/active sites, thus improving the performance of the batteries.
Defects have been found to enhance the electrocatalytic performance of NiFe‐LDH for oxygen evolution reaction (OER). Nevertheless, their specific configuration and the role played in regulating the ...surface reconstruction of electrocatalysts remain ambiguous. Herein, cationic vacancy defects are generated via aprotic‐solvent‐solvation‐induced leaking of metal cations from NiFe‐LDH nanosheets. DFT calculation and in situ Raman spectroscopic observation both reveal that the as‐generated cationic vacancy defects tend to exist as VM (M=Ni/Fe); under increasing applied voltage, they tend to assume the configuration VMOH, and eventually transform into VMOH‐H which is the most active yet most difficult to form thermodynamically. Meanwhile, with increasing voltage the surface crystalline Ni(OH)x in the NiFe‐LDH is gradually converted into disordered status; under sufficiently high voltage when oxygen bubbles start to evolve, local NiOOH species become appearing, which is the residual product from the formation of vacancy VMOH‐H. Thus, we demonstrate that the cationic defects evolve along with increasing applied voltage (VM → VMOH → VMOH‐H), and reveal the essential motif for the surface restructuration process of NiFe‐LDH (crystalline Ni(OH)x → disordered Ni(OH)x → NiOOH). Our work provides insight into defect‐induced surface restructuration behaviors of NiFe‐LDH as a typical precatalyst for efficient OER electrocatalysis.
Along with increasing voltage during the OER process, the structural evolution of cationic defects within NiFe‐LDH, where the simple vacancy VM changes to VMOH and then to the most reactive VMOH‐H, and the surface restructuration, where surface crystalline Ni(OH)x is converted to disordered Ni(OH)x and then to the surface local NiOOH species, are voltage‐regulated concurrent events defining the eventual catalytic performance of the precatalyst.
Binders have been reported to play a key role in improving the cycle performance of Si anode materials of lithium‐ion batteries. In this study, the biopolymer guar gum (GG) is applied as the binder ...for a silicon nanoparticle (SiNP) anode of a lithium‐ion battery for the first time. Due to the large number of polar hydroxyl groups in the GG molecule, a robust interaction between the GG binder and the SiNPs is achieved, resulting in a stable Si anode during cycling. More specifically, the GG binder can effectively transfer lithium ions to the Si surface, similarly to polyethylene oxide solid electrolytes. When GG is used as a binder, the SiNP anode can deliver an initial discharge capacity as high as 3364 mAh g−1, with a Coulombic efficiency of 88.3% at the current density of 2100 mA g−1, and maintain a capacity of 1561 mAh g−1 after 300 cycles. The study shows that the electrochemical performance of the SiNP anode with GG binder is significantly improved compared to that of a SiNP anode with a sodium alginate binder, and it demonstrates that GG is a promising binder for Si anodes of lithium‐ion batteries.
Guar gum is used as a robust binder for a silicon nanoparticle anode of a lithium‐ion battery for the first time. With a large number of polar hydroxyl groups, the guar gum binder can provide effective transport pathways for lithium ions, which significantly improves the electrochemical performance.
PDF
