Search

Appropriate water injection volume is the most basic parameter required to maintain stable formation pressure and ensure the development effect of water flooding in oilfields. However, the determination of appropriate water injection volume has always been a major problem in oilfield water injection management. Based on the Grey relational algorithm, this paper determines the optimal connected injection-production well group through the study of the dynamic relationship between oil and water wells. To specifically predict water injection, a Sparrow search algorithm optimisation model based on Sine mapping is proposed. A Sine-SSA-BP algorithm was devised to predict water injection volume and both the improved algorithm and the original BP algorithm were applied to real-world data to assess their predictive accuracy. The prediction results of the Sine-SSA-BP algorithm were found to be closer to the true value than the results of the original BP algorithm, and the average error percentage is reduced by 23.86%. Therefore, the new algorithm can predict and calculate the water injection volume more accurately. The research content of this paper can provide a theoretical basis for advising adjustment measures in the block to slow down the rise of water content, maintain stable production, and improve the efficiency of the mechanical mining system.

As the adoption of renewable energy sources grows, ensuring a stable power balance across various time frames has become a central challenge for modern power systems. In line with the "dual carbon" objectives and the seamless integration of renewable energy sources, harnessing the advantages of various energy storage resources and coordinating the operation of long-term and short-term storage have become pivotal directions for future energy storage deployment. To address the complexities arising from the coupling of different time scales in optimizing energy storage capacity, this paper proposes a method for energy storage planning that accounts for power imbalance risks across multiple time scales. Initially, the Seasonal and Trend decomposition using the Loess (STL) decomposition method is utilized to temporally decouple actual operational data. Subsequently, power balance computations are performed based on the obtained data at various time scales to optimize the allocation of different types of energy storage capacities and assess the associated imbalance risks. Finally, the effectiveness of the proposed approach is validated through hourly applications using real-world data from a province in southern China over recent years. [ABSTRACT FROM AUTHOR]

Recently, the power systems with a high penetration of renewables and power electronics have come into being. In these power systems, complex system dynamics, emergency faults, and insufficient frequency regulation reserve pose threats to system frequency stability. Based on the clustering development of energy storage, to ensure the system frequency stability when emergency faults occur, this paper proposes a decentralized frequency emergency control (FEC) strategy considering the participation of energy storage clusters (ESCs). First, the overall framework of the optimal-droop-based FEC strategy is introduced, which achieves the coordination between FEC and conventional frequency regulation strategies. Second, to appropriately allocate the unbalanced power among the generators and ESCs, a general design method for optimal droop coefficients is proposed, which is applicable to various control objectives. The optimality of the droop coefficients is rigorously proven. This case study is carried out on an electromagnetic transient simulation platform, and the simulation results verify the effectiveness and optimality of the proposed FEC strategy. [ABSTRACT FROM AUTHOR]

In order to study the operating characteristics of variable speed constant frequency wind turbine under different working conditions and the monitoring system of wind turbine. In this paper, the simulation model of each component system of wind turbine is established by MATLAB/Simulink module, and the influence law of different wind speed and ground fault types on the output power of wind turbine is studied. The active power of wind turbines under different short-circuit fault types is compared. At the same time, in order to realize real-time monitoring of wind turbine speed and output power, an online monitoring system for wind turbine operation based on industrial Internet of Things is proposed, and the composition and operation characteristics of this remote monitoring system are given. The practical application shows that the on-line monitoring system can accurately and remotely monitor the running status of the wind turbine and avoid the unstable running of the wind turbine. The research conclusions of this paper can provide reference for the design and construction of wind turbines and the operation of connecting to the power grid. [ABSTRACT FROM AUTHOR]

In the process of constructing deep natural gas wells in Sichuan and Chongqing, gas wells encounter various technical challenges such as high temperature, high pressure, and a corrosive environment containing H2S and CO2. The corrosion of rubber materials in these acidic environments can easily lead to seal failure in downhole tools. To better investigate the corrosion resistance of rubber materials in acidic environments, we utilized a dynamic cyclic corrosion experimental device capable of simulating the service conditions experienced by downhole tools under high-temperature, high-pressure multiphase flow. Corrosion-resistance tests were conducted on fluororubbers (FKM) 1, 2, 3, and HNBR (hydrogenated nitrile-butadiene rubber) under acidic conditions (80 °C and 160 °C), along with sealing corrosion tests on O-rings. These tests aimed to analyze the mechanical properties, hardness, and corrosion resistance before and after exposure to acid media as well as the sealing performance of O-rings. Ultimately, our goal was to identify suitable rubber materials for acidic pressure environments. Experimental results revealed that all four types of rubber exhibited decreased elongation at break after undergoing corrosion testing; however, fluororubber 3 demonstrated significant susceptibility to temperature effects while the other three types showed minimal impact from temperature variations. Fluororubber 1 and fluororubber 3 displayed substantial deformation levels whereas mechanical properties greatly deteriorated for fluororubber 2. Overall, HNBR showcased superior comprehensive performance. [ABSTRACT FROM AUTHOR]

The high pressure in some gas wells, such as those in the Xushen gas field in Daqing, China, makes them susceptible to freezing and hydrate blockages. Downhole throttling technology is widely used to reduce costs during well construction, however, due to the limitations of temperature, pressure and depth structure, this technology is sometime applied independently in some gas wells in which freezing and blockages are a frequent problem that can seriously affect production capacity. Moreover, artificial alcohol injection of 'passive plugging' to prevent hydrate formation not only consumes significant amounts of methanol but its efficiency is also dependent on factors such as weather, personnel and equipment, so it is not a continuous solution. In order to solve the above problems, the mechanism of hydrate formation was analyzed in this study, from which a combined mechanical and chemical hydrate control process was developed. OLGA software was used to design the process parameters of the novel mechanical and chemical inhibition technology for hydrate prevention and control, and also to simulate and analyze the wellhead temperature, pressure and hydrate generation once the process was implemented. Based on the results of the parameters calculation, the downhole throttle and hydrate inhibitor automatic filling device are used to realize the functions of downhole throttle depressurization and hydrate inhibitor continuous filling, reduce the wellhead pressure and hydrate generation temperature, and ensure the continuous production of gas well. This novel combination process was subsequently tested in three wells in the Daqing gas oilfield. Measurements showed that the average daily gas increase from a single well was 0.5×104m3, methanol consumption was reduced from the original maximum daily amount of 1750 kg to just 60 kg, the manual maintenance workload was reduced by 80%, and the rate of the well openings was increased from 45% to 100%. These results proved that this technology is feasible and efficient for applications in gas wells with high downhole pressure and low wellhead temperature, and, thus, provides important technical support for the prevention of gas hydrate and improvement of gas well production. [ABSTRACT FROM AUTHOR]

Synthetic messenger RNA (mRNA) switches are powerful synthetic biological tools that can sense cellular molecules to manipulate cell fate. However, their performances are limited by high output signal noise due to leaky output protein expression. Here, we designed a readout control module that disables protein leakage from generating signal. Aptamer array on the switch guides the inactive output protein to self‐assemble into functional assemblies that generate output signal. Leaky protein expression fails to saturate the array, thus produces marginal signal. In this study, we demonstrated that switches with this module exhibit substantially lower signal noise and, consequently, higher input sensitivity and wider output range. Such switches are applicable for different types of input molecules and output proteins. The work here demonstrates a new type of spatially guided protein self‐assembly, affording novel synthetic mRNA switches that promise accurate cell manipulation for biomedical applications. [ABSTRACT FROM AUTHOR]

The system efficiency of pumping units in the middle and late stages of oil recovery is characterized by several factors, complex data and poor regulation. Further, the main control factors that affect system efficiency in different blocks vary greatly; therefore, it is necessary to obtain the block characteristics to effectively improve system efficiency. The k-means algorithm is simple and efficient, but it assumes that all factors have the same amount of influence on the output value. This cannot reflect the obvious difference in the influence of several factors in the block on the efficiency. Moreover, the algorithm is sensitive to the selection of the initial cluster centre point, so each calculation result that reflects the efficiency characteristics of the block system cannot be unified. To solve the aforementioned problems affecting the k-means algorithm, the correlation coefficient of all the factors was first calculated, followed by extracting the system efficiency of the positive and negative indicators of standardization. Next, the moisture value was calculated to obtain the weight of each factor used as a coefficient to calculate the Euclidean distance. Finally, the initial centre point selection of the k-means algorithm problem was solved by combining the dbscan and weighted k-means algorithm. Taking an oil production block in the Daqing Oilfield as the research object, the k-means and improved algorithm are used to analyse the main control factors influencing mechanical production efficiency. The clustering results of the two algorithms have the characteristics of overlapping blocks, but the improved algorithm's clustering findings are as follows: this block features motor utilization, pump efficiency and daily fluid production, which are positively correlated with system efficiency. Further, low-efficiency wells are characterized by the fact that the pump diameter, power consumption, water content, daily fluid production, oil pressure and casing pressure are significantly lower than the block average; high-efficiency wells are characterized by pump depths lower than the block average. For this block, it is possible to reduce the depth of the lower pump and increase the water-injection effect to increase the output under conditions of meeting the submergence degree, which can effectively improve the system efficiency. [ABSTRACT FROM AUTHOR]

A three-step synthesis of 2-arylamino-5-formyl-pyrimidines is developed by condensation of the bis(hexafluorophosphate) Arnold salt with N -arylguanidines. This method conveniently provides the corresponding 2-arylaminopyrimidine derivatives in good yields. [ABSTRACT FROM AUTHOR]

Geometry and topology are fundamental concepts, which underlie a wide range of fascinating physical phenomena such as topological states of matter and topological defects. In quantum mechanics, the geometry of quantum states is fully captured by the quantum geometric tensor. Using a qubit formed by an NV center in diamond, we perform the first experimental measurement of the complete quantum geometric tensor. Our approach builds on a strong connection between coherent Rabi oscillations upon parametric modulations and the quantum geometry of the underlying states. We then apply our method to a system of two interacting qubits, by exploiting the coupling between the NV center spin and a neighboring 13C nuclear spin. Our results establish coherent dynamical responses as a versatile probe for quantum geometry, and they pave the way for the detection of novel topological phenomena in solid state. [ABSTRACT FROM AUTHOR]

Aim: In this study, we investigate the mechanistic link between rheumatoid arthritis (RA) and periodontitis to identify a novel target (cathepsin K; Ctsk) for the treatment of comorbid periodontitis and RA. Methods: An experimental model of periodontitis with arthritis was established in DBA/1 mice. We then tested the effect of BML‐244, a specific inhibitor of Ctsk, by quantifying several inflammatory markers of TLR9 signalling both in vivo and in vitro. Results: Our results showed that periodontitis–rheumatoid arthritis comorbidity causes severer periodontal bone and joint cartilage destruction than either disease alone. Inhibition of Ctsk reduced infiltration by dendritic cells and T cells and inflammatory cytokine production; these improvements alleviated the hard‐tissue erosion in periodontitis and RA as measured by bone erosion in periodontal lesions and cartilage destruction in knee joints. Inhibition of Ctsk also decreased the expression of TLR4 and TLR9 in vivo, whereas in vitro experiments indicated that Ctsk is involved specifically in the production of cytokines in response to TLR9 engagement. Conclusion: Our data reveal that periodontitis and RA may have additive pathological effects through dysregulation of the TLR9 pathway and that Ctsk is a critical mediator of this pathway and contributes to the pathogenesis of RA and periodontitis. [ABSTRACT FROM AUTHOR]

Abstract: Chemical functionalization of covalent organic frameworks (COFs) is critical for tuning their properties and broadening their potential applications. However, the introduction of functional groups, especially to three‐dimensional (3D) COFs, still remains largely unexplored. Reported here is a general strategy for generating a 3D carboxy‐functionalized COF through postsynthetic modification of a hydroxy‐functionalized COF, and for the first time exploration of the 3D carboxy‐functionalized COF in the selective extraction of lanthanide ions. The obtained COF shows high crystallinity, good chemical stability, and large specific surface area. Furthermore, the carboxy‐functionalized COF displays high metal loading capacities together with excellent adsorption selectivity for Nd3+ over Sr2+ and Fe3+ as confirmed by the Langmuir adsorption isotherms and ideal adsorbed solution theory (IAST) calculations. This study not only provides a strategy for versatile functionalization of 3D COFs, but also opens a way to their use in environmentally related applications. [ABSTRACT FROM AUTHOR]

In recent years, the energy storage system (ESS) has been demonstrated to be involved in many aspects of the integration of wind power. For ESS application, ESS allocation of the installation location, power rating, and energy rating is the first concern. Different from previous studies, this study emphasises the significance of the ESS operation in the study of ESS allocation. A bi‐level‐programming‐based model is proposed to take the interaction of allocation and operation into consideration at the same time, with the external level optimising allocation and the internal level optimising operation. The complexity assessment and solution algorithm of the model is also discussed. Next, a genetic numerical algorithm is proposed to solve the bi‐level model. The authors' results were tested on a modified IEEE 39 bus system and a provincial regional power system to verify both the flexibility and applicability of the proposed model and algorithm. This model is useful for various types of ESS and provides a foundation for ESS application. [ABSTRACT FROM AUTHOR]

ABSTRACT Cross-linked α-methylstyrene and acrylonitrile (MStAN) copolymer particles in a latex form were synthesized by free radical emulsion polymerization. The particles showed a narrow size distribution and an average diameter of 65 nm. The amount of the vinyl groups at the surface of the (MStAN) copolymer particles resulted from varied amount of the initiator (APS) and the cross-linking agent (DVB) was detected by iodine titration method. When filled into ethylene propylene rubber (EPR), the MStAN nano-particles exhibited excellent reinforcing capabilities, and with the increase of the vinyl groups at the surface of MStAN particles, the tensile stress of MStAN/EPR increased. Results demonstrated that the vinyl groups at the surface of the (MStAN) copolymer particles provided certain chemical interactions between the filler particles and the macromolecular chains of rubber matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41914. [ABSTRACT FROM AUTHOR]

Multi-station integration is motivated by the requirements of distributed energies interconnection and improvements in the efficiency of energy systems. Due to the diversity of communication services and the complexity of data exchanges between in-of-station and out-of-station, multi-station integrated systems have high security requirements. However, issues related to cyber security for multi-station integrated systems are seldom explored. Hence, this paper designs the secondary system architecture and proposes cyber security protection solutions for smart energy stations (SESt) that integrate the substation, photovoltaic station, energy storage station, electric vehicle charging station, and data center station. Firstly, the composition of SESt and functions of each substation are presented, a layered architecture of SESt is designed, and data exchanges of SESt are analyzed. Then, the cyber security threats and requirements of SESt are illustrated. Moreover, the cyber security protection principle and a cyber security protection system for SESt are proposed. On this basis, a security zoning and isolation scheme for SESt is designed. Finally, a traffic isolation scheme based on virtual local area networks (VLANs), a real-time guarantee scheme for communications based on service priority, and an enhancing cyber security scheme based on improved IEC 62351 are proposed for SESt. [ABSTRACT FROM AUTHOR]

Objectives: The mechanisms underlying the effects of Toll‐like receptor 9 (TLR9) and autophagy on rheumatoid arthritis (RA)‐aggravated periodontitis are unclear. We aimed to explore a novel target, cathepsin K (Ctsk)‐mediated TLR9‐related autophagy, during the progress of periodontitis with RA. Materials and Methods: DBA/J1 mouse model of periodontitis with RA was created by local colonization of Porphyromonas gingivalis (Pg) and injection of collagen. The expression of Ctsk was inhibited by adeno‐associated virus (AAV). Micro‐CT, immunohistochemistry (IHC), Western blot and quantitative real‐time polymerase chain reaction (qRT‐PCR) were used to detect the expression of TLR9‐related autophagy in periodontitis with RA. Small interfering RNA (siRNA) and CpG oligodeoxynucleotides (CpG ODN) were applied in macrophages. Western blot, immunofluorescence (IF) and qRT‐PCR were used to verify the in vivo results. Results: RA can promote periodontitis bone destruction in the lesion area, while inhibiting Ctsk could effectively alleviate this effect. The infiltration of macrophages, TLR9, autophagy proteins (TFEB and LC3) and inflammatory cytokines increased in the periodontitis‐with‐RA group and was reduced by the inhibition of Ctsk in the periodontal region. Macrophage stimulation confirmed the in vivo results. With the activation of TLR9 by CpG ODN, inhibition of Ctsk could suppress both TLR9 downstream signalling proteins and autophagy‐related proteins. Conclusions: This study advanced a novel role for Ctsk in TLR9 and autophagy to explain the interaction between periodontitis and RA. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) and periodontitis share many epidemiological and pathological features, with emerging studies reporting a relationship between the two diseases. Recently, RA and periodontitis have been associated with autophagy. In the present study, we investigated the effects of cathepsin K (CtsK) inhibition on RA with periodontitis in a mouse model and its immunological function affecting autophagy. To topically inhibit CtsK periodontitis with arthritis in the animal model, adeno-associated virus (AAV) transfection was performed in periodontal and knee joint regions. Transfection of small interfering RNA (siRNA) was performed to inhibit CtsK in RAW264.7 cells. The effects of CtsK inhibition on the autophagy pathway were then evaluated in both in vivo and in vitro experiments. RA and periodontitis aggravated destruction and inflammation in their respective lesion areas. Inhibition of CtsK had multiple effects: (i) reduced destruction of alveolar bone and articular tissue, (ii) decreased macrophage numbers and inflammatory cytokine expression in the synovium, and (iii) alleviated expression of the autophagy-related transcription factor EB (TFEB) and microtubule-associated protein 1A/1B-light chain 3 (LC3) at the protein level in knee joints. Inhibition of CtsK in vitro reduced the expression of autophagy-related proteins and related inflammatory factors. Our data revealed that the inhibition of CtsK resisted the destruction of articular tissues and relieved inflammation from RA with periodontitis. Furthermore, CtsK was implicated as an imperative regulator of the autophagy pathway in RA and macrophages., (Copyright © 2020 American Society for Microbiology.)