bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy of Wrist MRI in Detecting Synovitis and Correlation with Arthroscopy
Authors: Mahmood Bilal , Diamond Keith , Ayalon Omri , Paksima Nader , Glickel Steven
Published: February 2024

Hypothesis Wrist magnetic resonance imaging (MRI) has shown excellent diagnostic accuracy in evaluating soft-tissue pathology of the wrist including ganglion cysts, ligament tears, and triangular fibrocartilage complex (TFCC) pathology. However, it is unclear how often MRI detects synovitis that is subsequently encountered during wrist arthroscopy and may be a source of pain for patients with symptoms unresponsive to conservative treatment. The aim of this study is to assess the diagnostic accuracy of conventional MRI in the detection of wrist synovitis observed intraoperatively with wrist arthroscopy.

Materials and Methods A retrospective chart review was performed on 51 patients who underwent arthroscopy for chronic wrist pain and MRI confirmed wrist pathology that did not resolve with nonoperative treatment. Wrist arthroscopy was performed by three fellowship-trained hand surgeons. While the primary pathology like TFCC or scapholunate ligament tear was identified and treated arthroscopically, it was noted that many of the patients had concomitant synovitis observed arthroscopically that was not identified preoperatively on MRI. Therefore, the diagnosis of wrist synovitis on MRI scan was compared with the observed presence of synovitis at the time of wrist arthroscopy. Results of preoperative MRI without contrast were categorized as true positive, false positive, true negative, and false negative, based upon intraoperative arthroscopic findings.

Results In total, 45/51 patients were confirmed to have dorsal and ulnar synovitis on wrist arthroscopy. MRI identified 16/51 patients as having synovitis. Of those 16 patients, 2 were false positives.

Conclusion The results demonstrate that conventional MRI without contrast has poor diagnostic accuracy in detecting wrist synovitis. Patients with ligament or chondral pathology or no clearly identifiable pathology on MRI whose clinical symptoms persist despite conservative treatment may have underlying dorsal and ulnar wrist synovitis that is not detected on MRI. Wrist arthroscopy facilitates the identification and treatment of synovitis in patients with concomitant wrist pathology and pain refractory to nonoperative treatment. This study suggests that MRI may have a low sensitivity for identifying wrist synovitis when compared with wrist arthroscopy during the evaluation of patients presenting with wrist pain.
The Council of Europe, Russia, and the future of European cooperation: any lessons to be learned from the past?
Authors: Brummer Klaus
Published: February 2024

The Council of Europe (CoE) was among the first Western institutions to open its doors to Russia after the end of the Cold War. However, during Russia’s membership (1996–2022) hopes of socializing the country into the CoE’s standards, norms, and principles in the areas of democracy, human rights, and the rule of law never materialized. While the CoE’s norms and principles nowadays need to be secured from Russia, there might be a point in the (distant) future where Russia should be reintegrated into European structures, with the CoE then again being a likely forum to that end. Against this background, this paper analyses the CoE’s interaction with Russia from the mid-1990s until today, focusing on the accession period as well as the organization’s subsequent monitoring activities and (non-)use of sanctions during Russia’s membership. It concludes with lessons that could guide future interactions between the CoE and Russia.
A real-time energy dispatch strategy based on the energy cooperative optimization complementarity model of multi-microgrids
Authors: Wang Zhipeng , Wu Nan
Published: February 2024

With the wide application of high proportion of distributed clean energy in regional microgrids, the issue of maximizing the utilization of renewable energy among multi-microgrids has become a research hotspot. Based on the proposed multi-microgrids' energy collaborative optimization and complementation model, a multi-microgrids' energy real-time optimization management and dispatch strategy is proposed that fully considers the real-time complementarity of renewable energy between multi-microgrids and achieves the best coordinated dispatch of energy. Two typical scenarios were set up in the IEEE 33-bus network model for verification, and the synergistic effects of different schemes were compared and set up. The data obtained demonstrate that the dispatch and management strategy proposed in this paper can achieve the maximum integration of renewable energy and the lowest operating cost among multi-microgrids, and it also validates the real-time, feasibility, and effectiveness of the proposed strategy.
Parasitic fish embryos do a “front-flip” on the yolk to resist expulsion from the host
Authors: Yi Wenjing , Reichard Martin , Rücklin Martin , Richardson Michael K.
Published: February 2024

Embryonic development is often considered shielded from the effects of natural selection, being selected primarily for reliable development. However, embryos sometimes represent virulent parasites, triggering a coevolutionary “arms race” with their host. We have examined embryonic adaptations to a parasitic lifestyle in the bitterling fish. Bitterlings are brood parasites that lay their eggs in the gill chamber of host mussels. Bitterling eggs and embryos have adaptations to resist being flushed out by the mussel. These include a pair of projections from the yolk sac that act as an anchor. Furthermore, bitterling eggs all adopt a head-down position in the mussel gills which further increases their chances of survival. To examine these adaptations in detail, we have studied development in the rosy bitterling (
Rhodeus ocellatus
) using molecular markers, X-ray tomography, and time-lapse imaging. We describe a suite of developmental adaptations to brood parasitism in this species. We show that the mechanism underlying these adaptions is a modified pattern of blastokinesis—a process unique, among fish, to bitterlings. Tissue movements during blastokinesis cause the embryo to do an extraordinary “front-flip” on the yolk. We suggest that this movement determines the spatial orientation of the other developmental adaptations to parasitism, ensuring that they are optimally positioned to help resist the ejection of the embryo from the mussel. Our study supports the notion that natural selection can drive the evolution of a suite of adaptations, both embryonic and extra-embryonic, via modifications in early development.
cAMP binding to closed pacemaker ion channels is cooperative
Authors: Kuschke Stefan , Thon Susanne , Sattler Christian , Schwabe Tina , Benndorf Klaus , Schmauder Ralf
Published: February 2024

The cooperative action of the subunits in oligomeric receptors enables fine-tuning of receptor activation, as demonstrated for the regulation of voltage-activated HCN pacemaker ion channels by relating cAMP binding to channel activation in ensemble signals. HCN channels generate electric rhythmicity in specialized brain neurons and cardiomyocytes. There is conflicting evidence on whether binding cooperativity does exist independent of channel activation or not, as recently reported for detergent-solubilized receptors positioned in zero-mode waveguides. Here, we show positive cooperativity in ligand binding to closed HCN2 channels in native cell membranes by following the binding of individual fluorescence-labeled cAMP molecules. Kinetic modeling reveals that the affinity of the still empty binding sites rises with increased degree of occupation and that the transition of the channel to a flip state is promoted accordingly. We conclude that ligand binding to the subunits in closed HCN2 channels not pre-activated by voltage is already cooperative. Hence, cooperativity is not causally linked to channel activation by voltage. Our analysis also shows that single-molecule binding measurements at equilibrium can quantify cooperativity in ligand binding to receptors in native membranes.
Small-molecule inhibition of MAP2K4 is synergistic with RAS inhibitors in
KRAS
-mutant cancers
Authors: Jansen Robin A. , Mainardi Sara , Dias Matheus Henrique , Bosma Astrid , van Dijk Emma , Selig Roland , Albrecht Wolfgang , Laufer Stefan A. , Zender Lars , Bernards René
Published: February 2024

The Kirsten rat sarcoma viral oncogene homologue
KRAS
is among the most commonly mutated oncogenes in human cancers, thus representing an attractive target for precision oncology. The approval for clinical use of the first selective inhibitors of G12C mutant KRAS therefore holds great promise for cancer treatment. However, despite initial encouraging clinical results, the overall survival benefit that patients experience following treatment with these inhibitors has been disappointing to date, pointing toward the need to develop more powerful combination therapies. Here, we show that responsiveness to KRAS
G12C
and pan-RAS inhibitors in
KRAS
-mutant lung and colon cancer cells is limited by feedback activation of the parallel MAP2K4-JNK-JUN pathway. Activation of this pathway leads to elevated expression of receptor tyrosine kinases that reactivate KRAS and its downstream effectors in the presence of drug. We find that the combination of sotorasib, a drug targeting KRAS
G12C
, and the MAP2K4 inhibitor HRX-0233 prevents this feedback activation and is highly synergistic in a panel of

KRAS
G12C

-mutant lung and colon cancer cells. Moreover, combining HRX-0233 and sotorasib is well-tolerated and resulted in durable tumor shrinkage in mouse xenografts of human lung cancer cells, suggesting a therapeutic strategy for KRAS-driven cancers.
Application of a machine learning method to model-based library approach for critical dimension measurements using CD-SEM
Authors: Guo P , Miao H , Zou Y B , Mao S F , Ding Z J
Published: February 2024

A model-based library (MBL) method has already been established for the accurate measurement of the critical dimension (CD) of semiconductor linewidth using critical dimension scanning electron microscope (CD-SEM) images. In this work, the MBL method is further investigated by combining CD-SEM image simulation and a neural network algorithm. The secondary electron linescan profiles were first calculated using a Monte Carlo simulation method, enabling us to obtain the dependence of linescan profiles on the selected values of various geometrical parameters (e.g. top CD, sidewall angle and height) for Si and Au trapezoidal line structures. Machine learning methods have then been applied to predict the linescan profiles from a randomly selected training set of the calculated profiles. The predicted results agree very well with the calculated profiles with the standard deviations of 0.1% and 6% for the relative error distributions of Si and Au line structures, respectively. The findings show that the machine learning methods can be practically applied to the MBL method for reducing the library size, accelerating the construction of the MBL database and enriching the content of the available MBL database.
Comprehensive DFT investigation of X2MgSe4 (X = Dy, Tm) spinels for opto-spintronic and thermoelectric devices
Authors: Nasarullah  , Ishfaq Mudassir , Aldaghfag Shatha A , Kazim Muhammad Zafarullah , Hafsa  , Rauf Saba , Yaseen Muhammad , Dahshan A
Published: February 2024

Herein, a computational technique known as full potential linearized augmented plane wave (FP-LAPW) is applied for the analysis of magnetic, structural, optical, electronic, and thermoelectric features of X2MgSe4 (X= Dy, Tm) spinels within the density functional theory (DFT). Structural and thermodynamic stabilities are confirmed through the computation of tolerance factor (0.77) and formation enthalpies (-ve) for both spinels. Dy2MgSe4 behaves as a semiconductor with a 1.5 eV direct bandgap (Eg) in the majority spin state but as a metal in the minority spin state, resulting in its half-metallic ferromagnetic (HMF) nature. While Tm2MgSe4 demonstrated a semi-conducting nature in both spin up/down channels, with Eg of 1.41/1.34 eV, respectively. Absorption spectrum displays linear trend with peaks appearing at 6.10 eV for Dy2MgSe4 and 6.46 eV for Tm2MgSe4. Since peaks are appeared in the Ultraviolet (UV) region making them suitable materials for various optoelectronic application, including optical memory devices, sensors and optical filters. The calculated ZT values are 0.77 (at 800 K) and 0.766 (at 300 K), for Dy2MgSe4 and Tm2MgSe4, correspondingly. Overall, the study of X2MgSe4 (X = Dy, Tm) has shown a great potential for their potential usage in energy harvesting and spintronic applications.
Investigating the magnetic and hysteretic properties of graphyne-based nanostructures: a comparative study of shape effects on critical temperatures, coercivity, and remanence
Authors: Kantar Ersin
Published: February 2024

Our study aims to investigate the physical properties of graphyne-based nanostructures, with a particular focus on their magnetic and hysteretic features. We analyze the influence of shape on these properties in an Ising-type graphyne structure using the effective field theory (EFT) method. Our research focuses on the critical and compensation temperatures, coercivity, and remanence of the graphyne structure in different shapes, ranging from alpha (α) to beta (β) to gamma (γ). We use the magnetization curves and hysteresis loops obtained from central and intermediate spins. We also illustrate the behavior of the coercive field and remanent magnetization as well as hysteresis loop the effect of exchange interactions r and s as well as temperature. We observe N- and R- type compensation in the β graphyne, and L- and S- type compensations in the γ graphyne. We also find that the widest hysteresis is observed in γ graphyne.
Ferromagnetism in silver-doped single-walled zinc oxide nanotubes
Authors: Jafarova Vusala N , Jafarova Aynur N
Published: February 2024

In this paper, the electronic and magnetic properties of single-walled ZnO:Ag nanotubes with a chirality of (6,0) were investigated. Ab initio simulations were carried out using Atomistic ToolKit computer code implementing density functional theory within the local spin density approximation. To obtain an accurate energy band gap for related systems, we used the Hubbard U semiempirical corrections. The introduction of the Ag atom into the ZnO nanotube structure changes the electronic structure, the energy gap decreases with the silver concentration. The calculated value of total magnetic moments of the Ag-doped single-walled ZnO NT system is 1.0 μB. Our results predict that Ag-doped ZnO NT can be a potential candidate for optoelectronic and spintronic devices.
Optical, structural and morphology study of Cu2O/Cu and GO/Cu2O/Cu films prepared by pulsed electrodeposition and electrophoresis.
Authors: González-Moreno F I , Tolentino-Hernández R V , Espinosa-Faller F J
Published: February 2024

In this work, copper (I) oxide films were prepared by pulsed electrodeposition onto copper substrates. Graphene oxide was deposited on the Cu2O/Cu films by cathodic electrophoresis. The films were studied by X-ray diffraction, Raman spectroscopy, optical reflectance and atomic force microscopy. The bandgap of the Cu2O/Cu films is close to 1.8 eV due to the presence of defects and decreases to close to 1.1 eV with GO deposition due to the oxidation of Cu2O to CuO on the surface. When GO was deposited, a reduction in the mean height was observed, indicating coverage of the entire surface. A topographic transformation of the surface was also observed, consisting of an increase in grain size and homogenization of the grain shape after GO deposition, possibly due to phase transformation. This work is the first step to prepare fully wet deposited thin film ZnO/GO/Cu2O/Cu solar cells.
Impact of supporting power source on a high-proportion renewable energy generation base
Authors: Meng Xu
Published: February 2024

In recent years, China has organized three batches of high-proportion renewable energy generation bases, with the aim of resolving the geographical imbalance between renewable energy supply and consumption. Renewable electricity is transported from the resource-abundant western regions to the electricity-demanding eastern regions. Given the inherent variability and unpredictability of wind power and photovoltaic power generation, there is a pressing need for additional support from more reliable energy generation sources, including coal-fired power and concentrated solar power (CSP). This paper presents a power system optimization planning model that incorporates the internal energy transfer of CSP. It proposes strategies for establishing high-proportion renewable energy generation bases supported by both coal-fired power and CSP. Furthermore, it investigates the primary constraints affecting the energy generation base. The study also compares the peak shaving depth and output characteristics between coal-fired power and CSP. Moreover, this paper introduces the method of natural gas supplemental combustion to enhance the power supply stability of CSP, enabling the renewable energy generation base to supply electricity through conventional DC transmission.
Distributed control of energy storages for multi-time-step peak load shaving in a microgrid
Authors: Yu Peng , Sun Yong , Gu Ruonan
Published: February 2024

Distributed energy storages (ESs) will be widely used in the future smart microgrids due to their continuous technology improvement and cost reduction. Meanwhile, the distributed control method also gains increasing attention for controlling distributed devices to protect user privacy and reduce computation burden compared with the centralized scheme. In this paper, a distributed control method of ESs is proposed for multi-time-step peak load shaving in a microgrid. Considering the ES efficiency is related to its power, an optimization is constructed to minimize the power loss during ES operations when performing peak load shaving function. By analyzing the net load curve and the ES available capacity, the multi-time-step peak load shaving problem is transformed into single-time-step ES operations at each time step. The Combine-Then-Adapt diffusion strategy is united with the consensus + innovation strategy to realize the peak load shaving in a fully distributed way. Case studies verify the efficiency of the proposed method.
Robust optimization scheduling of microgrid considering carbon capture equipment
Authors: Qiao Sen , Meng Runquan , Wei Bin , Li Jiageng
Published: February 2024

To cope with the carbon dioxide generated during the operation of the microgrid and consider the wind power fluctuations, a robust optimization scheduling model for the microgrid is proposed, considering carbon capture equipment. Considering the large amount of carbon emissions caused by micro-turbine power generation and electricity purchase during the operation of microgrid, two operating modes of carbon capture equipment are considered, the carbon trading costs are considered in the objective function, and the output of all wind power is included through a box uncertain set. The C&CG algorithm was used to solve the constructed model and obtain the corresponding scheduling plan. Finally, the effectiveness of the model was verified through numerical examples. The results indicate that the total operating cost of microgrids can be further reduced by setting up carbon capture equipment to operate in flexible mode.
Stability assessment of forestry plant power system based on improved long short-term memory network
Authors: Zhang Liang , Meng Xin , Tian Guohui , Duan Qishen
Published: February 2024

The stability assessment of forestry power system plays a vital role in many aspects. First of all, the stability of the power system is directly related to the production efficiency, employee safety and environmental sustainability of the factory. If the power system is unstable, it may cause power outage or power fluctuations, which will interrupt the production and turn the production line, which will lead to a reduction in production capacity and the increase in production costs. In addition, the stability of the power system is directly related to the security of employees. Sudden power failure or voltage fluctuations may cause improper equipment operation, and may even cause accidents and damage. Therefore, by evaluating the stability of the power system, potential security risks can be reduced. In addition, unstable power systems may cause waste and increase environmental burden. In order to improve the stability of the power system, this article proposes an improved LSTM (long and short memory) model of improved stability prediction. This model uses the power system to operate data, including current, voltage, frequency, and other parameters, and external factors related to weather conditions and load changes to predict the stability of the power system. Compared with traditional methods, this method performs well in predicting the failure and abnormalities of the power system, and has the ability to evaluate high accuracy and stability. Therefore, the improved LSTM model method can be regarded as a powerful tool for power system management and maintenance.
Short-term prediction of wind power based on grey wolf optimization Elman neural network algorithm
Authors: Liu Shu , Sun Zihan , Sun Yi , Kong Deqiang
Published: February 2024

The intermittence and fugitiveness of wind power is one of the significance ekements affecting the quality of wind power. Aiming at the random characteristics of wind power, the output power of short-term wind electricity is forecasted by collecting historical wind speed, power and other parameters of wind farm. A model of Elman network optimized by grey wolf arithmetic (GWO) is proposed to realize short period accurate forecast for wind power. The pattern is verified and analyzed on matlab. Compared with other prediction models, the prediction accuracy is higher, which shows the effectiveness and advancement of the model.
The Capacity-to-load ratio optimization method considering collaborative planning of multi-voltage level power grids
Authors: Wang Kailiang , He Zhuoyi , Ye Jianpeng , Lin Yihan , Lin Lingxue , Ma Yuxin
Published: February 2024

The capacity-to-load ratio is an important indicator to guide power grid planning and has a decisive influence on the selection of substation capacities and the construction of power lines. A capacity-to-load ratio optimization method concerning collaborative planning of multi-voltage level power grids is proposed in this paper. This method aims to minimize the construction cost and takes into account the collaborative planning of substations and power lines of multiple voltage levels. By combining the Bayesian optimization algorithm (BOA) and genetic algorithms (GA), a BOA-GA solving algorithm for the planning model is proposed. This algorithm automatically generates planning schemes for multi-voltage level power grids, and obtains the optimal capacity-to-load ratio, as well as the optimal investment of the power grid construction. Case studies demonstrate that the proposed model can optimize the capacity-to-load ratio and automatically plan the network structure of multi-voltage level power grids. The construction cost is significantly reduced while various technical indicators are satisfied. Additionally, the study reveals that the relationship between the capacity-to-load ratio and the overall investment of multi-voltage level power grid construction is a quadratic function over a long-time scale. And the curve is a parabola going upwards.
Analysis of the impact of distributed photovoltaic grid integration on distribution network voltage
Authors: Chen Qian , Bai Jing , Chen Xiaoyue , Wang Yu , Wang Haiyun , Zhou Yunbin , Wang Fangyu , Dong Nan
Published: February 2024

With the vigorous development of the new power system, the penetration rate of distributed PV grid-connected continues to increase. Large quantities of distributed PV grid-connected will affect the distribution network trend direction on the node voltage, affecting the safe operation of the distribution network. The study aims to address this problem. Firstly, the effect of distributed photovoltaic power generation on distribution network voltage is analyzed by theoretically analyzing different locations and capacities of distributed PV access. Secondly, it establishes a simulation model based on a typical IEEE33 node and performs analysis through trend calculation. Finally, the study derives the voltage distribution law of a distributed PV grid-connected distribution network to ensure the safe and stable operation of the power grid.
Research on performance ratio composition and standard energy efficiency ratio correction method of photovoltaic power station
Authors: Peng Yonglong , Wang Yiyang , Lu Jiang , Li Yabin , Feng Hailong
Published: February 2024

The performance ratio (PR) of the system is used to quantify the power generation efficiency of the photovoltaic power generation system. The size of the index is affected by many factors. After the environmental impact is compensated, the standard energy efficiency ratio (PRstc) of the system is obtained. PRstc is an important index for evaluating the power generation efficiency of photovoltaic power stations. Improving the accuracy of PRstc is conducive to improving the state evaluation and analysis capabilities of power stations, providing a theoretical basis for comparative analysis of photovoltaic power stations in different regions, and improving the scientific operation and maintenance of power stations. The PRstc calculation method of the industry standard NB / T 10394-2020 does not consider the influence of the change of the power temperature coefficient of the component and the weak light response of the photovoltaic cell, which ultimately leads to the calculation result less than the actual value. In order to reduce the error in the calculation of PRstc, the mathematical relationship between PR and power loss of photovoltaic power station is discussed. The calculation method of power loss caused by the change of environmental factors is proposed, and the PRstc is calculated by using the variation. Finally, the PRstc is calculated according to the actual operation data of photovoltaic power station, and compared with the calculation method of industry standard NB / T 10394-2020. The results show that when the total irradiation dose is high, the difference between the two PRstc values is less than 2 %. When the total irradiation is low, the calculation result is larger than that of the standard method, and the difference between the two increases with the decrease of the total irradiation. Due to the consideration of the change of power generation caused by the characteristics of photovoltaic modules, the error caused by the change of power temperature coefficient and weak light response of modules is reduced, which is more advantageous than the calculation method of industry standard.
The impact of massive EV charging on distribution lines
Authors: Chen Wenwen , Wang Yanfei , Huang Yuchen , Chen Yongjin , Luo Shun , Deng Meiling
Published: February 2024

The large-scale charging of electric vehicles at the same time is bound to have a large impact on the distribution network and then reduce the stability of the grid, especially during peak hours when it is easy to overload the lines. In this paper, we combine battery capacity and charging power data of electric vehicles and user usage habits to model the charging load changes of electric vehicles at different scales. The impact of charging by EV owners on network load was also analyzed through case studies. Our results have a certain practical significance for the planning of power grid lines.
Research on relay protection technology of high temperature superconducting cable system
Authors: Zhuo Junjie
Published: February 2024

High-temperature superconducting cables have many advantages such as low line loss, large transmission capacity, small space occupation, and environmental friendliness, which provide a highly efficient, compact, reliable, and green way of power transmission for power grids, and have great potential for application in large-capacity power transmission and urban power grid expansion and reconstruction. However, high-temperature superconducting cables have a complex structure, which is quite different from traditional cable lines in terms of operating conditions and fault mechanisms, and the requirements for the secondary system are also more stringent. Relying on the project of China Power Grid, “Research and Demonstration Application of Superconducting Transmission Technology in Urban Distribution Networks”, the thesis carries out an in-depth research on relay protection technology adapted to the access of high-temperature superconducting cables.
Membrane-type acoustic meta-material-based low-frequency noise reduction design and verification for transformers
Authors: Ma Yuchao , Sun Fugui , Huang Yikang , Qiu Yongjun
Published: February 2024

In order to effectively reduce the radiated transformer noise, high sound insulation membrane-type acoustic meta-materials is designed based on CAE method and the main noise reduction frequency is typical 100Hz to make the maximum noise reduction of transformer. After a scale-reduced 500kV transformer semi an-echoic room noise tests comparison, the results show that the membrane-type acoustic meta-materials effectively suppressed the tonal noise of the transformer, providing a solid application foundation for the noise reduction design of transformer in the future.
Numerical simulation of the flow field inside mixer
Authors: Kang Yong , Sun Runyu
Published: February 2024

When transporting oil in the petroleum industry, due to its high viscosity, cooling can have an impact on the transportation process. It is usually necessary to use a mixer to mix it with cold and hot to increase the temperature of the oil during transportation. In order to study the influence of the inlet pipe diameter of the mixer on mixing efficiency, internal flow field, and temperature field, the temperature distribution and velocity vector in the horizontal and wall directions of the mixer under different pipe diameters are simulated and analyzed using Fluent software in this paper, and pressure and temperature curves are drawn. The following conclusion was drawn: increasing the inlet diameter can not only alleviate the vortex phenomenon caused by the high inlet speed inside the mixer, but also reduce energy loss during water mixing and control the phenomenon of uneven velocity distribution inside the fluid.
Electro-chemical effects on combustion chemistry in electric field fire suppression
Authors: Shu Qi , Liu Boyun , Li Shengnan , Zhao Shuai
Published: February 2024

In order to investigate the role played by electro-chemical effects in the combustion of flames under an external electric field, it is necessary to simulate the chain effect brought about by the increase of electron energy during the combustion reaction by modifying the electron energy according to the ethanol combustion mechanism containing ionic chemical reaction. Due to the large amount of computation involved in carrying out numerical simulations using detailed chemical reaction mechanisms, the mechanisms are simplified in this paper in order to save computational resources. Combining the simplified mechanism, a finite rate chemical reaction model is used to simulate the chemical reaction of ions during the transverse electric field fire extinguishing process, and the relationship between the concentration of intermediate components in ethanol air diffusion combustion and temperature is analyzed.
Improved thermal network model for hot spot location in traction transformer windings
Authors: Liang Xianlu , Fu Qiang
Published: February 2024

Obtaining accurate location information of the hot spot in advance is a prerequisite for locating the hot spot. To tackle this problem, we propose an improved thermal network model, which provides a quantitative method for placing fiber optic sensors at hot-spot locations. The initial step is to construct an enhanced thermal network model that takes into account the thermal resistance of the boundary layer using heat transfer theory. Then, we compare this model with Computational Fluid Dynamics (CFD) in example calculations to validate its effectiveness and precision. The results show that our proposed model can accurately and rapidly calculate temperature distribution within winding areas, enabling the identification of hot spots. This information is reliable for installing monitoring equipment to measure transformer temperatures.
Motor control technology based on fractional active disturbance rejection
Authors: Liu Wenyang , Zhang Yuhuan , Shi Junbiao , Zhang Bo , Li Huiyao , Zheng Sha
Published: February 2024

For non-linear, strongly coupled, multivariable and naturally unstable motor control systems to realize the rapid return of the motor to the original equilibrium point without overshoot, the traditional PID controller algorithm is prone to defects such as large overshoot and long response time. The study proposes fractional order active disturbance rejection control for the motor self-balancing control method. A novel controller composed of a fractional order controller and an active disturbance rejection controller is designed and its control characteristics are analyzed and simulated. The experimental results show that compared with the traditional PID control, the controller has better dynamic performance, steady-state performance and anti-interference ability so that the motor can reach the equilibrium position quickly, stably and accurately. The illustrations of the experimental verification have been modified and explained.
Matching analysis on flow limiting valve of marine diesel engine common rail system
Authors: Sun Lijing , Tian Bingqi , Mao Liwei
Published: February 2024

The flow limiting valve (FLV) designed for the high pressure common rail fuel system (CRS) was designed, the simulation model of the FLV and electronic controlled injector is established and the injector’s model was verified by experiment data. Through simulation, the maximum cycle injection quantity (CIQ) and close flow quantity (CFQ) of the CRS matched with the FLV are verified, and the influence of key FLV’s parameters on the matching performance was analysed. The maximum CIQ is 722mm3 and the CFQ is 1194.2mm3, which can satisfy the technical requirements of the CRS under overload conditions. The closing lift and orifice diameter of the FLV has a significant impact on the CFQ, which should be carefully designed according to the technical requirements, and the dimensional tolerance and processing accuracy should be guaranteed in the production and assembly process to ensure the consistency of the CFQ.
Research on energy coordinated control strategy for offshore wind power based on distributed consistency algorithm
Authors: Chen Deyang , Fan Wei , Liu Yu , Wang Xinwei , Sun Tao
Published: February 2024

Offshore wind power is clean and has a large capacity, making it an important component of the development of new power systems. However, the randomness of offshore wind power affects the stability of the power grid. A coordinated control strategy of offshore wind power and multi-source energy based on a distributed consistency algorithm is proposed for offshore wind farms’ energy coordination management and optimization. By constructing a source network storage load model and analyzing the output and load fluctuations of offshore wind power, energy storage, and power grid, the constraint equation and balance equation of source network load storage power are derived. An adaptive distributed consistency methodology is employed based on a proportional utilization micro growth function to preserve the stability of offshore wind power and the power grid. It can enhance the power distribution of offshore wind power, energy storage, and distribution networks. The outcomes of the simulation show that the suggested approach may quickly equalize power, decrease frequency variations of offshore wind power, and enhance the commercial viability of offshore wind power.
Analysis of a nuclear power plant’s responses to the open-phase fault of preferred power supply
Authors: Lu Jinjun , Wang Zhijian
Published: February 2024

This paper explores the phenomenon of open-phase fault of nuclear power plants for preferred power supply, focusing on three distinct scenarios, normal operation, start, and overhaul. For each scenario, the paper discusses the responses of existing relay protection devices, which are crucial for detecting and mitigating open-phase faults. These responses vary depending on the impedance at the fault location and the load rate of the plant. This paper highlights that open-phase faults can lead to three-phase imbalances in the power system, but their impact on voltage levels is not always straightforward due to the transformer and motor compensation effects. Additionally, the paper identifies blind zones in open-phase fault detection, where existing relays may fail to respond effectively, leading the plant to enter a station blackout state. In conclusion, the research underscores the importance of open-phase fault detection and protection in nuclear power plants. It reveals potential vulnerabilities in existing relay configurations and emphasizes the need for enhanced monitoring and safety measures to prevent extended plant operation under open-phase fault conditions.
The future of X-ray polarimetry towards the 3-dimensional photoelectron track reconstruction
Authors: Kim Dawoon E. , Di Marco Alessandro , Soffitta Paolo , Costa Enrico , Fabiani Sergio , Muleri Fabio , Ratheesh Ajay , La Monaca Fabio , Rankin John , Del Monte Ettore , Rubini Alda
Published: February 2024

The development of the first X-ray polarimeter, based on the photoelectric effect 20 years ago and implemented thanks to advances in gas amplification structures and readout techniques, had a significant impact in opening a new window for X-ray polarimetry. This system measures the X-ray polarization by reconstructing the initial direction of the photoelectron, emitted by the interaction of an incident photon with an atomic electron, in a gas mixture from an ionization track collected on a two-dimensional plane. However, actual X-ray polarimeters, are still requiring relatively long exposure time and cannot coupled with high effective area mirrors or concentrators. In this context, the high yield polarimetry experiment in X-rays (Hype-X) project is currently underway, aiming to improve the sensitivity of the next generation X-ray polarimetry detectors taking advantage of the recent advancements in imaging techniques for high-resolution time projection chambers. In particular, we are evaluating the use of TIMEPIX3 to be applied for the read-out of a gas detector, which will allow us to obtain a three-dimensional image of the photoelectron track. To evaluate the improvement achievable by using a 3D track reconstruction, in this paper, we have reproduced a three-dimensional photoelectron track from a `Geant4' Monte Carlo simulation and examined the sensitivity of X-ray polarimetry using a new three-dimensional track reconstruction algorithm. We report the improvement of the modulation factor with three-dimensional track reconstruction as ∼5% (relative) in the 2–8 keV range and ∼17% (relative) in the 2–4 keV range compared to the current two-dimensional polarimetry system. This is equivalent to add a further telescope to the three-telescope systems now employed in space on board the IXPE mission.
Wavelength-induced shedding frequency modulation of seal whisker inspired cylinders
Authors: Dunt Trevor K , Heck Kirby S , Lyons Kathleen , Murphy Christin T , Bayoán Cal Raúl , Franck Jennifer A
Published: February 2024

The spanwise undulated cylinder geometry inspired by seal whiskers has been shown to alter shedding frequency and reduce fluid forces significantly compared to smooth cylindrical geometry. Prior research has parameterized the whisker-inspired geometry and demonstrated the relevance of geometric variations on force reduction properties. Among the geometric parameters, undulation wavelength was identified as a significant contributor to forcing changes. To analyze the effect of undulation wavelength, a thorough investigation isolating changes in wavelength is performed to expand upon previous research that parameterized whisker-inspired geometry and the relevance of geometric variations on the force reduction properties. A set of five whisker-inspired models of varying wavelength are computationally simulated at a Reynolds number of 250 and compared with an equivalent aspect ratio smooth elliptical cylinder. Above a critical non-dimensional value, the undulation wavelength reduces the amplitude and frequency of vortex shedding accompanied by a reduction in oscillating lift force. Frequency shedding is tied to the creation of wavelength-dependent vortex structures which vary across the whisker span. These vortices produce distinct shedding modes in which the frequency and phase of downstream structures interact to decrease the oscillating lift forces on the whisker model with particular effectiveness around the wavelength values typically found in nature. The culmination of these location-based modes produces a complex and spanwise-dependent lift frequency spectra at those wavelengths exhibiting maximum force reduction. Understanding the mechanisms of unsteady force reduction and the relationship between undulation wavelength and frequency spectra is critical for the application of this geometry to vibration tuning and passive flow control for vortex-induced vibration (VIV) reduction.
Synthetic aperture radar (SAR) detects large gas seeps in Alaska lakes
Authors: Engram Melanie , Anthony Katey Walter
Published: February 2024

Reservoirs of 14C-depleted methane (CH4), a potent greenhouse gas, residing beneath permafrost are vulnerable to escape where permafrost thaw creates open-talik conduits. However, little is known about the magnitude and variability of this methane source or its response to climate change. Remote-sensing detection of large gas seeps would be useful for establishing a baseline understanding of sub-permafrost methane seepage, as well as for monitoring these seeps over time. Here we explored synthetic aperture radar’s (SAR) response to large sub-permafrost gas seeps in an interior Alaskan lake. In SAR scenes from 1992 to 2011, we observed high perennial SAR L-band backscatter (σ
0) from a ∼90 m-wide feature in the winter ice of interior Alaska’s North Blair Lake (NBL). Spring and fall optical imagery showed holes in the ice at the same location as the SAR anomaly. Through field work we (1) confirmed gas bubbling at this location from a large pockmark in the lakebed, (2) measured flux at the location of densest bubbles (1713 ± 290 mg CH4 m−2 d−1), and (3) determined the bubbles’ methane mixing ratio (6.6%), radiocarbon age (18 470 ± 50 years BP), and δ13CCH4 values (−44.5 ± 0.1‰), which together may represent a mixture of sources and processes. We performed a first order comparison of SAR σ
0 from the NBL seep and other known sub-permafrost methane seeps with diverse ice/water interface shapes in order to evaluate the variability of SAR signals from a variety of seep types. Results from single-polarized intensity and polarimetric L-band SAR decompositions as well as dual-polarized C-band SAR are presented with the aim to find the optimal SAR imaging parameters to detect large methane seeps in frozen lakes. Our study indicates the potential for SAR remote sensing to be used to detect and monitor large, sub-permafrost gas seeps in Arctic and sub-Arctic lakes.
Effect of damper mass on soil-structure displacement in dynamic response to earthquake vibration with finite element modelling
Authors: Amali S H N S K , Nujid M Md , Zaki M F M , Ghazaly Z M , Bawadi N F , Ahmad M M
Published: February 2024

Earthquake is a natural disaster that always occur inside the region of pacific ring of fire. Many structures such as high-rise buildings, bridges, dams and many more failed and take severe damage due to the impact of the strong vibration of the earthquake. A pile foundation is a type of deep footing which is suitable for high-rise buildings founded on clay soils where its function to prevent potential failures such as bearing capacity and collapse. In addition, the problem of tall buildings is prone to sway and damaged when earthquake strike and such vibrations cause the dynamic behaviour of structure to change significantly in terms of excessive lateral displacements and accelerations. Thus, the effect of damper mass on soil-structure displacement in dynamic response to earthquake vibration was determined. The effectiveness of vibration absorber to the single pile structured in clay soil was modelled and simulated in finite element program PLAXIS 3D version 20 with and without the presence of the damper where the inputs were taken from the Sumatera and Chi – chi earthquakes. The problem was modelled and simulated by drawing a geometry, assigning the soil and pile materials input, loading and boundary conditions, meshing generated and staged construction for calculations of displacement structure output in response to dynamic due to earthquake vibration. The displacement-time with the effect of mass of the vibration with and without absorber are presented. The results show a good performance of damper on the single pile structured on soft soil with different types of earthquakes.
Oxygen Functionalized Graphitic Carbon Nitride for Photocatalytic Degradation of Dye
Authors: Yee P L , Sim L C , Shuit S H , Leong K H , Chin Y H
Published: February 2024

Photocatalyst such as graphitic carbon nitride (g-C3N4) is being studied intensively due to its ability in photocatalysis. g-C3N4 is a metal-free semiconductor photocatalyst with a bandgap of approximately 2.7 eV which contributes to its good visible light harvesting ability. In this work, bulk g-C3N4 was produced via pyrolysis of melamine in a muffle furnace. Functionalized g-C3N4 with improved properties was synthesized via modified Hummers method. The powdered form of functionalized g-C3N4 were characterized using SEM and EDX to identify its physiological properties. The result showed that the introduction of oxygen into g-C3N4 is proven by the increased content of oxygen in the functionalized g-C3N4 upon oxidation using Hummers method. Besides, exfoliation of g-C3N4 to smaller particle size observed from the SEM images. Then, the phototcatalytic performances of the bulk g-C3N4 and functionalized g-C3N4 were evaluated by degrading of Methylene Blue (MB) dyes under LED light irradiation. The result revealed that the bulk g-C3N4 has a higher efficiency in removal of dyes (56.40 % in 150 minutes) than the functionalized g-C3N4 (22.60 % in 150 minutes) which indicates that it has a better photocatalytic degradation ability, which possibly due to the destruction of compound structure under strong acid treatment.