bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient and easily repeatable organic solar cells in a high boiling point solvent by introducing a highly mixed tolerant guest acceptor
Authors: Shen Xiangyu , Wang Xiaoning , Wang Jianxiao , Wang Rulin , Li Yonghai , Bi Fuzhen , Bao Xichang
Published: September 2024

Efficient and easily repeatable organic solar cells were fabricated based on a highly mixed tolerant acceptor in a high boiling point solvent.
High-performance vinyl-flanked diketopyrrolopyrrole–selenophene polymer semiconductors with branched, linear and cyclic alkyl side chains
Authors: Chen Liangliang , Shangguan Zhichun , Li Mengsi , Zhang Guanxin , Wang Cheng , Zhang Deqing
Published: September 2024

Vinyl-containing conjugated polymers exhibiting extended conjugated skeletons with long-wavelength absorption and high carrier mobility have been widely investigated as polymer semiconductors.
Open‐source floating‐gate cell for analogue synapses
Authors: Chen Matthew , Sonnadara Charana , Shah Sahil
Published: September 2024

The floating‐gate transistor is commonly employed as a non‐volatile memory device, leveraging a floating node at its gate to store electrical charge over extended periods. This stored charge effectively alters the threshold voltage of the transistor. Utilizing standard CMOS technologies, floating‐gate transistors can be designed and fabricated using conventional CMOS processes. This study focuses on characterizing the performance of a PMOS‐based floating‐gate transistor, specifically fabricated using the open‐source Skywater 130 nm process. The modulation of charge on the floating node is explored through both hot‐electron injection and Fowler–Nordheim tunnelling, providing insight into the resolution of these programming mechanisms. Additionally, the study includes a preliminary analysis of the retention time of the programmed charge in these devices. This work contributes to the open‐source electronics community by detailing the design and programming techniques of floating‐gate transistors developed with an open‐source process design kit, and makes the corresponding FG cell designs available for public use.
9T fast‐write SRAM bit cell with no conflicts for ultra‐low voltage
Authors: Jiang Chenjie , Wen Junqi , Meng Siyu , Fu Kepu , Xia Changquan , Chen Haitao , Qian Qinyu , Cheng Liwen
Published: September 2024

With the development of processes and reduction of transistor size, transistor sensitivity to voltage changes has increased. Traditional SRAM bit cells struggle to function properly at low voltages, and the lengthy write time necessitated by the write conflict problem will inevitably result in write failure. As ultra‐low‐voltage SRAM has emerged as a significant direction of research for SRAM, this paper proposes an ultra‐low‐voltage 9T SRAM bit cell that is conflict‐free. By circumventing write conflicts and enabling rapid writing, the bit cell demonstrates its superiority, particularly at ultra‐low voltages, by eliminating the requirement for peripheral write‐assist circuitry to accomplish chip writing. To assess the performance of the conflict‐free 9T bit cell, simulation experiments are conducted utilizing the 28 nm process model. Simulation results indicate that the 9T bit cell proposed in this paper requires only 66% of the writing time of the traditional 6T cell. This enables the cell to accomplish fast writing and more stable writing performance.
Full‐angle beam scanning leaky‐wave antenna array based on spoof surface plasmon polaritons
Authors: Wang Jun , Yao Yuqi , Kong Xianglin , Xu Ruofeng , Zhao Lei
Published: September 2024

A design scheme of high‐gain and full‐angle frequency beam scanning leaky wave antenna (LWA) and array is proposed based on spoof surface plasmon polaritons (SSPPs) slow‐wave transmission line (TL) for radar field applications. A row of complementary split ring resonators is periodically etched near the SSPPs TL, which can transform the fundamental mode of SSPPs TL to the fast‐wave region and radiate electromagnetic waves, realising the full‐angle frequency beam scanning performance. A 1‐to‐2 microwave power divider is designed to feed the LWA array and realised good impedance matching covers 5.8–9.4 GHz bandwidth. Simulation and experimental results indicate that the designed LWA array can realise full‐angle beam scanning range of 180° (−90° to 90°) with a scanning rate of 3.83°/% performance. The peak gain values of the designed LWA element and array are 11.4dBi and 14.6 dBi, respectively, and the radiation efficiency of LWA array is maintained more than 80% within the operation frequency band.
Prospects of ultrafiltration in supporting the Development of Matabacillus sp. CS-2 antinecrosis protease as a wound debridement agent - A bibliography study
Authors: Pardosi Sola Grace Afika , Rahmani Nanik , Aji Muhammad Ziddan Bayu , Fitria Meutia Srikandi , Ethica Stalis Norma
Published: September 2024

Debridement is a critical step in wound healing, which involves removing necrotic or infected tissue from wounds Specific enzymes, including fibrinolytic protease from Metabacillus sp. CS-2 has shown anti-necrosis activity and potential as a wound debridement agent. However, efforts to enhance the enzyme’s activity to improve its performance as a debridement agent remain unexplored. This review highlights the potential of ultrafiltration to boost bacterial protease activity based on data from Google Scholar and PubMed. Using the dimension.ai database with keywords “ultrafiltration”, “bacterial protease”, and “protease activity”, a literature review over the last ten years was conducted, supported by network visualization via VOSviewer. The findings suggest that ultrafiltration is an important part of a study that should be conducted to support the development of Metabacillus sp. CS-2 protease as a debridement agent.
Residues of several active insecticide ingredients in spinach (Amaranthus tricolor L.) and kale (Ipomoea reptans (L.) Poir.) in Bogor, West Java
Authors: Suneth Risma Fira , Dadang  , Nurmansyah Ali
Published: September 2024

Spinach and kale are popular vegetables in Indonesia. Spinach and kale production in Indonesia in 2021 will be 341,196 tonnes and 171,706 tonnes respectively. Farmers generally use insecticides to maintain the quality and quantity of vegetable production. The main problem with inappropriate use of insecticides is that there are residues in vegetable products. An interval between the last application and harvest time that is too short can cause high insecticide residues on agricultural products. The aim of this research is to analyze residue data for several active insecticide ingredients used on spinach and kale. The research carried out included field tests using pesticide formulations containing the active ingredients deltamethrin, profenofos, imidacloprid, chlorantraniliprole and carbofuran. Next, the residues of several active ingredients will be analyzed in the GIS Laboratory using GC. Data from residue analysis of several active ingredients will be compared with the maximum residue limits in National Standardization agency of Indonesia. The results obtained were residues of profenofos, imidacloprid and deltamethrin in spinach plants below MRL. Meanwhile, the residues of profenofos, imidacloprid and deltamethrin in kale were above the BMR. The profenofos residue in water spinach is 3.6546 mg/kg above the BMR 1 mg/kg based on BSN, the imidacloprid residue is 0.5195 mg/kg above the BMR 0.5 mg/kg based on the BSN and the deltamethrin residue is 0.9084 mg/kg above the BMR 0, 5 mg/kg based on BSN. Meanwhile, the active ingredients chlorantraniliprole and carbofuran were not detected. This is influenced by spraying frequency and climatic conditions. Apart from that, spraying intervals of 3 hsp and 7 hsp also affect residues on spinach and kale plants. The closer the spraying time to harvest time will affect the residue level in the plant. The physical and chemical properties that cause degradation of the active insecticide ingredient influence the reduction in residue.
Exploring the potential of proteolytic bacteria for keratinase enzyme synthesis: Study on isolation and screening
Authors: Yuliatmo Ragil , Wibowo Raden Lukas Martindro Satrio Ari , Wahyuningsih Rina , Rahmawati Atiqa
Published: September 2024

Keratinase enzymes have garnered interest for their ability to degrade keratin-rich substrates. In this study, we focus on isolation and screening proteolytic bacteria capable of producing keratinase enzymes. By identifying novel bacterial sources of keratinases, This study aims to explore the potential proteolytic bacteria to produce keratinase enzymes, through isolation and screening processes, in order to harness their capability for keratinase synthesis. Proteolytic bacteria were isolated from the storage warehouse of hide and skin in Politeknik ATK Yogyakarta. Screening for keratinase producing bacteria were conducted by selection of proteolytic activity test and keratin degradation test. Six of the twelve isolates exhibited halo zones when they grew on proteolytic media. Among the bacteria isolates, bacterium ATK3 demonstrated the highest percentage of keratin degradation and keratinase activity. Based on the study, bacteria isolate of ATK3 had the most potential to be explored as a keratinase enzyme producing bacteria.
Food metabolomics for improvement of nutrition and well-being
Authors: Afifah Enik Nurlaili , Putri Sastia Prama
Published: September 2024

Food metabolomics is an emerging field that employs comprehensive analytical techniques, such as Gas Chromatography-Mass Spectrometry (GC-MS), Liquid Chromatography-Mass Spectrometry (LC-MS), and Nuclear Magnetic Resonance (NMR), to identify and quantify essential nutrients and bioactive compounds in foods, and to link their impact on human health. By integrating metabolomic data with nutritional science, researchers can better elucidate how dietary components influence metabolic processes and contribute to overall health and well-being. This review highlights recent studies in food metabolomics, providing a detailed understanding of its application in assessing nutritional value, optimizing dietary recommendations, and improving food quality. The role of food metabolomics in precision nutrition and well-being is significant, and recent advancements in this research area are discussed.
Numerical analysis of pantograph–catenary coupling vibration for high-speed railways
Authors: Pan Like , Peng Peihuo , Chen Liming , He Fan
Published: September 2024

There is a pronounced coupling vibration between the catenary and pantograph during operation for high-speed railways. In this paper, a pantograph–catenary coupling vibration model is constructed to investigate the vibration characteristics under various working conditions. Two different types of catenaries (simple and elastic chain types) are simulated and compared using the finite element method. The pantograph is simplified into a mass–spring–damping combination member, the contact and messenger wires are set to linear beam cells, and the dropper and stitch wire are set to truss cells. The results suggest that the vibration characteristics of the two types of catenaries and pantograph exhibit different trends. The maximum stresses of the messenger wire, dropper, and contact wire do not follow a monotonically increasing trend with the train speed. The maximum stress of the messenger wire under the simple chain type of catenary is higher when the initial contact force increases from 80 to 120 N. However, the maximum stress under the elastic chain type of catenary is higher when the initial contact force is 60 or 140 N. Except for the initial contact force of 140 N, the maximum stresses of the dropper and contact wire under the simple chain type of catenary are lower than those under the elastic chain type. This work provides a valuable reference for optimizing the design of pantograph–catenary systems.
Solid-state reactions at niobium–germanium interfaces in hybrid quantum electronics
Authors: Langa B. , Sapkota D. , Lainez I. , Haight R. , Srijanto B. , Feldman L. , Hijazi H. , Zhu X. , Hu L. , Kim M. , Sardashti K.
Published: September 2024

Hybrid superconductor–semiconductor materials systems are promising candidates for quantum computing applications. Their integration into superconducting electronics has enabled on-demand voltage tunability at millikelvin temperatures. Ge quantum wells have been among the semiconducting platforms interfaced with superconducting Al to realize voltage tunable Josephson junctions. Here, we explore Nb as a superconducting material in direct contact with Ge channels by focusing on the solid-state reactions at the Nb/Ge interfaces. We employ Nb evaporation at cryogenic temperatures (∼100 K) to establish a baseline structure with atomically and chemically abrupt Nb/Ge interfaces. By conducting systematic photoelectron spectroscopy and transport measurements on Nb/Ge samples across varying annealing temperatures, we elucidated the influence of Ge out-diffusion on the ultimate performance of superconducting electronics. This study underlines the need for low-temperature growth to minimize chemical intermixing and band bending at the Nb/Ge interfaces.
Microgel-based etalon membranes: Characterization and properties
Authors: Kontaxi G. , Wensink G. , Sberna P. M. , Rücker M. , Garbin V. , Serpe M. J. , Bazyar H.
Published: September 2024

We introduce Microgel-based Etalon Membranes (MEMs), based on the combination of stimuli-responsive microgels with an etalon, which is an optical device consisting of two reflecting plates and is used to filter specific wavelengths of light. The microgels are sandwiched between two reflective layers and, in response to a stimulus (e.g., temperature, pH, or biomarker concentration), swell or de-swell, thereby changing the distance between the two reflective layers and generating multiple peaks in the reflectance spectra. This property gives a MEM the unique capability of simultaneous separation and tunable responses to environmental changes and/or biomarker concentrations. We propose a design based on gold layers on a silicon nitride wafer membrane. Our comprehensive characterization, employing permeability experiments, in situ optical reflectance spectroscopy, in-liquid atomic force microscopy (AFM) analysis, and captive bubble contact angle measurements, elucidates the dynamic response of MEM to pH, temperature, and glucose stimuli and the corresponding effect of microgel swelling/de-swelling on the membrane properties, e.g., permeability. The AFM results confirm the dynamic changes of the microgel layer’s thickness on the membrane surface in response to the stimuli. Although the microgel’s swelling/de-swelling influences the effective pore radius, the decrease in the membrane’s permeance is limited to less than 10%. In the swollen state of the microgels, the etalon membranes show a prominent hydrophilic behavior, while they become less hydrophilic in the microgels’ de-swollen state. This work introduces MEM and provides novel insights into their behavior. The fundamental understanding that we reveal opens the way to applications ranging from point-of-care testing to continuous environmental monitoring.
Evidence for the quenching of rapid photoresponse by defect generation in ultraviolet illumination of CuSbS2 films
Authors: Takagaki Y.
Published: September 2024

Phototransients are investigated for CuSbS2 films with varying the illumination energy. The generation and recombination of photocarriers, which are manifested as changes in the sheet conductivity of the films, take place almost instantaneously for excitation wavelengths of 970 and 633 nm. These rapid responses are, in contrast, absent for the illumination at wavelengths of 375 and 280 nm. In particular, roughly no photoconduction occurs in the case of 280 nm. The sheet conductivity develops thereby random two-level fluctuations following the illumination. Ultraviolet irradiation is thus suggested to generate crystalline defects, giving rise to the quenching of the instantaneous photoresponse caused by their trapping of the photocarriers. The photoresponse in simultaneous illumination at multiple wavelengths is dependent upon the relative intensities of the ultraviolet and visible/infrared components in a nonlinear fashion unless the photo-generated defects are overwhelmed by photocarriers.
Evolution of the substrate specificity of an RNA ligase ribozyme from phosphorimidazole to triphosphate activation
Authors: DasGupta Saurja , Weiss Zoe , Nisler Collin , Szostak Jack W.
Published: September 2024

The acquisition of new RNA functions through evolutionary processes was essential for the diversification of RNA-based primordial biology and its subsequent transition to modern biology. However, the mechanisms by which RNAs access new functions remain unclear. Do RNA enzymes need completely new folds to support new but related functions, or is reoptimization of the active site sufficient? What are the roles of neutral and adaptive mutations in evolutionary innovation? Here, we address these questions experimentally by focusing on the evolution of substrate specificity in RNA-catalyzed RNA assembly. We use directed in vitro evolution to show that a ligase ribozyme that uses prebiotically relevant 5′-phosphorimidazole-activated substrates can be evolved to catalyze ligation with substrates that are 5′-activated with the biologically relevant triphosphate group. Interestingly, despite catalyzing a related reaction, the new ribozyme folds into a completely new structure and exhibits promiscuity by catalyzing RNA ligation with both triphosphate and phosphorimidazole-activated substrates. Although distinct in sequence and structure, the parent phosphorimidazolide ligase and the evolved triphosphate ligase ribozymes can be connected by a series of point mutations where the intermediate sequences retain at least some ligase activity. The existence of a quasi-neutral pathway between these distinct ligase ribozymes suggests that neutral drift is sufficient to enable the acquisition of new substrate specificity, thereby providing opportunities for subsequent adaptive optimization. The transition from RNA-catalyzed RNA assembly using phosphorimidazole-activated substrates to triphosphate-activated substrates may have foreshadowed the later evolution of the protein enzymes that use monomeric triphosphates (nucleoside triphosphates, NTPs) for RNA synthesis.
Maximizing L2 learning from captioned TV viewing
Authors: Popova Margarita , Miralpeix Imma
Published: September 2024

This study compares comprehension and vocabulary
gains in L1 Russian (upper)-intermediate adolescents who watched two
episodes of a Netflix series in L2 English for the same amount of time under
two conditions: Repeated Viewing (RV) with captions; and Viewing with the
Chrome extension Language Reactor (LR), with individually
regulated tools to enhance learning. Both conditions were equally helpful
for comprehension and vocabulary learning (relative gains up to 51%), suggesting the
comparability of effects of repeated viewing and watching
with LR if the watching time is the same. A qualitative analysis of
learners’ viewing behaviour revealed differences between the conditions:
while the RV group focused more on the episodes’ content, the LR group paid
closer attention to language.
Research on the impact of cascade water light storage complementary power generation on water rate
Authors: Zhang Yan , Su Huaying , Wang Rongrong , Wang Ning , He Xianqiang , Lu Yong
Published: September 2024

Fully leveraging the regulatory role of cascade hydropower in the watershed and achieving complementary joint power generation of cascade water solar systems is an important way to promote the consumption of clean energy. The article takes the water consumption rate of hydroelectric power generation as the starting point and combines pumping and storage with photovoltaic output as the characteristic. A cascade water solar storage complementary scheduling model is proposed, and the impact of pumping and storage on water consumption rate is studied. The scheduling objective of this model is to reduce water consumption while fully absorbing photovoltaic output, including mechanical and electrical constraints of water turbines and pumps, grid balance constraints, and hydraulic constraints. The study focuses on the four cascade hydropower stations on the Beipan River and the surrounding photovoltaic power station group.
Research on new energy control optimization scheme based on dynamic voltage stability index
Authors: Liu Mosi , Sun Zhiyuan , Li Jinzhao , Peng Boya , Zheng Kun
Published: September 2024

This article presents a new energy control parameter optimization method based on the dynamic stability feature. We determine the voltage stability degree of the clean energy access system through the dynamic stability feature and then optimize the control parameters of the clean energy station according to the voltage stability degree of the system. By modifying and optimizing the control parameters of the external loop of the wattless power control, the clean energy has a stronger reactive power support capacity during the low-voltage ride-through period, enhancing the stability of the clean energy access system.
Study on fracture potential at a high water-cut stage: a case study of block a of Daqing oilfield
Authors: Li Wenxiang
Published: September 2024

At the middle and final stages of oilfield development, outstanding interlayer contradictions and the water cut of the single well are high. At this conjuncture, the conventional fracturing method for wells and layers selection cannot meet the current needs. Through the application of reservoir modeling, fine characterization methods for reservoirs and the injection-production relationship of the well pattern are re-evaluated. Algorithm optimization problems in the process of establishing geological models, the correlation between structural location and measures for increasing production, and the constraints of different water injection flow lines on the development well network are deeply analyzed. A new method of tapping the potential for measures adapted to this block is created, which has guiding significance for the mid- to late-stage development of old oil fields to increase production.
Study and application of technical policy limits for layer system recombination in water drive sandstone reservoirs
Authors: Hu Qihao , Guo Fajun , Wang Yazhou , Wang Xiuwei , Zhou Zhenyong , Che Ying , Wang Hongtao , Wan Min , Liu Shasha , Cao Jiefeng
Published: September 2024

Layer system recombination is the combination of main layers and non-main layers into a new injection-production well pattern respectively, in order to reduce interlayer contradictions. The main factors restricting layer system recombination are reservoir physical properties, residual material basis, and economic benefits. In this study, according to the actual reservoir characteristics, a conceptual model is established to study the technical policy limits of layer system recombination. Through numerical simulation and mathematical statistics methods, the variation rules of permeability rank difference, recovery degree rank difference, pressure rank difference, viscosity rank difference, and effective thickness upper limit are studied. And the inflection point of the curve is identified as the technical policy limit of layer system recombination. At the same time, the lower limit of reserve abundance under different oil prices is calculated as the economic limit of layer system recombination. Through remaining oil research and well pattern adaptability evaluation, the well pattern reconstruction study is carried out to effectively expand the water drive sweep range and reconstruct efficient displacement flow field. On the basis of layer system recombination and well pattern reconstruction optimization study, the numerical simulation method is used to carry out the research of injection-production technology policy such as reasonable pressure maintenance level, reasonable injection-production ratio, and reasonable oil production rate, which effectively guides the reservoir injection and production control and consolidates the effect of layer system well pattern reconstruction.
Research on adjustable load potential of thermal storage electric heating based on new energy-carrying capacity
Authors: Long Yu , Wang Yongli , Ruan Wenjun , Zhu Mingyang , Zhang Yuze , Duan Meimei
Published: September 2024

To comprehensively examine how the capacity of new energy sources affects the regulatory capabilities of thermal storage electric heat loads within distribution networks, this study introduces a dynamic and optimal scheduling approach tailored for electric heat loads that takes into account the capacity of new energy. Firstly, the regulation model of thermal load is constructed; secondly, the regulation potential of thermal load in the distribution network is analyzed. Ultimately, this research puts forward a regulatory approach for thermal loads considering the capacity of new energy sources. The model is resolved by using an iterative approximation method based on the fast non-dominated sorting genetic algorithm (SA-NSGA-II). The case study outcomes demonstrate that the suggested technique effectively incorporates the regulatory potential of thermal loads, thereby enhancing the integration of new energy within power grids. Example findings indicate that the suggested approach is capable of fully considering the regulation potential of electric and thermal loads and improving the utilization of new energy in power grids.
Wavelet transform-based composite disturbance detection method for power quality in distribution networks
Authors: Guan Zhaoxiong , Huangfu Hancong , Pang Weilin
Published: September 2024

Changes in modal extremum points can result in a low signal-to-noise ratio. Therefore, it is necessary to design a new composite disturbance detection method for power quality in distribution networks based on wavelet transform. That is to say, the abnormal points of composite disturbances in the power quality of the distribution network have been identified, and wavelet transform has been used for detection and classification, thus achieving comprehensive disturbance detection of power quality in the distribution network. The experimental results show that under different types of disturbances, the designed distribution network electrical quality composite disturbance detection method has a high signal-to-noise ratio and reliability and has a certain application value. Has made certain contributions to improving the power quality of the distribution network and ensuring its stable operation.
Research on damping defects of composite insulator core rods
Authors: Zuo Meiyang , Li Lin , Li Xiaolei , Shao Mingyan , Wang Qirui , Chen Bin , Huang Xinghang , Zhu Yu
Published: September 2024

Infrared thermal imaging detection is an effective method to detect faults in composite insulators, but various reasons can cause abnormal heating of composite insulators. Therefore, distinguishing abnormal heating caused by different reasons is particularly important for the safety, stability, and economic operation of the power system. This article conducts in-depth analysis and testing on the heating fault of 220 kV composite insulators, establishes a three-dimensional model, and simulates and analyzes the moisture defects of the core rod at three different defect positions, providing a certain reference value for studying the fault mechanism of composite insulators.
Research on optimal operation of distribution network with unified power quality conditioner
Authors: Zhao Zhiyu , Liang Tianle , Cui Yu , Liu Jialin , Li Weiyu
Published: September 2024

The Unified Power Quality Conditioner (UPQC), as a new type of load regulation equipment, is connected with specific types of loads in low-voltage substations to form an adjustable intelligent load cluster, thereby improving the optimization operation level of the distribution network. This paper introduces a distribution network optimization operation model containing UPQC as a load regulator, based on the branch power flow model, considering the relaxation method and insect foraging intelligent algorithm as solving methods. The distribution network optimization operation model proposed in this paper is based on an improved IEEE 33 node model. Simulation results show that UPQC can optimize the voltage offset level of the distribution network, reduce line losses, and lower the operating costs of distribution network operators by adjusting the low-voltage substation load. This optimized operation model has a certain reference value for reducing the voltage offset of the distribution network and reducing costs and losses.
Design and development of a cable impedance spectrum testing system based on dual-path IV
Authors: Wu Tongbao , Gong Defeng , Yang Lei
Published: September 2024

In order to meet the demand of impedance spectrum measurement for cable fault detection, based on Line Resonance Analysis (LIRA), combined with the cable distribution parameter model, we improve the circuit structure of the traditional “half-bridge method” of impedance measurement by applying two symmetrical auto-balanced bridges to realize the impedance measurement in a wide frequency range from 100KHz to 10MHz. The system adopts the STM32FDNS to measure the impedance in a wide frequency range from 100KHz to 10MHz. The system adopts the STM32F103RCT6 as the core of the main control system, the excitation system, the core measurement system applying two symmetrical auto-balanced bridges, and the human-machine interface. The experimental results show that the design innovation of two-way symmetric automatic balanced bridge compensates for the amplitude and phase of the signal to be measured, realizes the stable output of the ratio of the signal to be measured, with the ratio error not exceeding 0.2%, and the resonance period of the cable impedance spectrum and the impedance amplitude obtained are in line with the accuracy requirements of the LIRA for locating cable faults, and ultimately realizes that the cable fault distance localization error The error of cable fault distance localization is not more than 0.37%.
An optimized criterion for line selection based on zero-sequence admittances for high-resistance SPG faults in the intelligent grounding distribution system
Authors: Mo Yuying , Mo Shixun , Tang Xianhang , Liu Qinghao
Published: September 2024

In the case of a single-phase grounding (SPG) fault in the intelligent grounding distribution system, this paper analyzes the change features of the fault lines’ and the non-fault lines’ zero-sequence admittance amplitudes and phase angles before and after the removal of the busbar grounding arc quenching device. Furthermore, the paper puts forward a new criterion for line selection for SPG faults based on the system’s and the lines’ zero-sequence admittances. Applicable to the intelligent grounding distribution system, this criterion fixes the problems of potential failure protection and poor sensitivity of existing protective methods in the case of high-resistance grounding. In addition, it is superior and exclusive for unifying the action thresholds for all lines in the system. In the simulation experiment, different transition resistances and different locations of the fault point are input to understand their impacts on the criterion and verify its effectiveness and reliability. The simulation results show that this criterion is insusceptible to the fault’s location and that the selection result will become more stable and reliable as the transition resistance rises. This criterion is highly serviceable in practical engineering.
Research on third-harmonic injection based on nonlinear active disturbance rejection
Authors: Wu Haozhe , Guo Qingbo
Published: September 2024

With the rapid development of power electronic technology and the permanent magnet industry, Permanent Magnet Synchronous Motor (PMSM) is widely used in high-tech industries such as aerospace and transportation with excellent performance. However, PMSM is a time-varying system with multiple variables and strong coupling, making its control strategy rather complex. It is becoming increasingly important to improve the control strategy. Addressing the issues of easy saturation, poor robustness in PI controllers, and the inconvenience of injecting third-harmonic from the outside into the three-phase three-leg topology to enhance torque density, which leads to insufficient control precision in the PMSM servo system, a nonlinear active disturbance rejection controller (NLADRC) is proposed as the control strategy for the third-harmonic injection-based field-oriented control (FOC). Compared to the PMSM servo system without the injection of third-harmonic, the proposed system exhibits better disturbance rejection capability and higher torque density. Through simulations of the PMSM servo system with the injection of third-harmonic, the proposed control strategy is verified to have good response speed and control performance.
Research on dynamic voltage restorer control based on αβ-Frame moving average filter phase-locked loop in non-ideal power network conditions
Authors: Ou Yangyue , Zhu Chongjing , Hu Qiuyu , Wei Jincheng , Qiu Xiaochu
Published: September 2024

The Dynamic Voltage Restorer (DVR) can swiftly and precisely synchronize with the grid’s phase and accurately determine the reference voltage of the DVR in the presence of three-phase unbalanced voltage sag, harmonic distortion, and DC offset in the grid. A stationary reference frame moving average filter phase-locked loop (αβMAF-PLL) can be utilized to efficiently and precisely synchronize the reference voltage of the DVR under less-than-ideal grid conditions. Simulation models of the dynamic voltage restorer under different power network scenarios are created in Matlab/Simulink, with the simulation results confirming the speed and effectiveness of the DVR based on αβMAF-PLL.
Research on the influence of bamboo pipe structure parameters on fluid heat transfer characteristics
Authors: Yan Han , Yan Guanghan , Sun Mingrui , Zhang Jun , Liu Kangjie , Liu Yu
Published: September 2024

In recent years, heat exchangers have been widely applied in the chemical, petroleum, and power industries, and pipe-type heat exchangers have the advantages of good heat transfer, strong structure, and flexible operation. The side reinforcement of pipe-type heat exchangers is usually achieved using asymmetric pipes, but the existing asymmetric pipes often need help with easy corrosion and difficult processing. To address this issue, this paper proposes a new reed pipe structure based on the reed pipe structure. Focusing on the structural variables of reed pipes and the influence of Reynolds number on the reed pipe flow heat transfer, the empirical correlation formula between each structural variable and Nu and f was fitted using multi-element non-linear regression. The results showed that in terms of heat transfer performance: node number>pharyngeal diameter>pharyngeal length; considering actual production manufacturing, the comprehensive heat transfer performance of the reed pipe has a pharyngeal diameter of 1.3 mm, a pharyngeal length of 3.0 mm, and a node number of 10 is the best.
Research on flow induced vibration characteristics of heat transfer tube plugs in nuclear power plant steam generators
Authors: Dong Haitao , Lai Yunting , Zhang Zhongwei
Published: September 2024

When the defect of the heat transfer tubes in the steam generator of a pressurized water reactor (PWR) nuclear power plant meets the damage repair standard, plugging must be implemented to prevent the leakage of radioactive coolant materials, but plugging will inevitably affect the flow field state of the original equipment. In order to evaluate the safety of the heat transfer tube plug, this paper takes the heat pipe plugging as the research object, carries out the fluid-solid coupling numerical simulation of the steam generator heat transfer tube plugging based on ANSYS Workbench platform, and analyzes the action law of the fluid at the feedwater end of the bottom of the steam generator on the solid-liquid contact surface in the area. The research shows that the pressure around the plug near the edge of the feedwater end is easy to cause uneven pressure distribution on the pipe-fluid contact surface, thus causing flow-induced vibration of the plug. At the same time, the pressure at the inflow of the pipe is greater due to the scouring of the fluid, which is more likely to cause vibration. In addition, under the action of alternating inflow, the stress value and pressure energy borne by the bottom end of the plug are larger, while the displacement at the top end is larger, and the local stress at the inflow of the plug is the largest. Attention should be paid to the reinforcement of the plug at the inflow, increasing the stiffness of the bottom of the plug, and improving its natural frequency, to prevent it from failing due to resonance.
Failure analysis of air-conditioning system of domestic rolling stock based on fuzzy fault tree
Authors: Li Zhongyang , Zhong Shisheng , Zhao Minghang , Wang Lin , Song Longlong , Shi Xiaoli
Published: September 2024

Air conditioning is an integral part of a moving train, and when it fails, it will affect passenger satisfaction and electrical safety on the train. By analyzing the principle and failure modes of the air-conditioning system of a certain type of domestic rolling stock, a fuzzy fault tree is constructed in this article, which has the 33 minimum cut sets, for further quantitative analysis. Then, according to the experience of relevant technical personnel and the analysis of air conditioning failure data, the occurrence probabilities of the bottom events are evaluated using the popular triangular fuzzy number. This fault tree can be analyzed quantitatively to find out the probability of the top event and the fuzzy probability importance of the bottom events. Accordingly, we can know the parts of the air-conditioning system of rolling stock that are relatively prone to failure. Through the verification and analysis of real data, it is proved that this is an effective method to locate the weak parts in the air-conditioning system, which can help to identify the possible failure modes and causes, and guide failure diagnosis and prediction of the air-conditioning system, as well as optimize the maintenance program.
Convective heat transfer characteristics from a linearly tapered cylinder at a subcritical Reynolds number
Authors: Zhang Yifan , Lu Luyi
Published: September 2024

This study conducted a numerical investigation of the flow past a linearly tapered cylinder in the subcritical flow regime. This study concentrated on the influence of this geometric perturbation on the flow and heat transfer characteristics by comparing them with those of a uniform circular cylinder. It is revealed that the linearly tapered cylinder effectively reduced the mean drag and fluctuating lift coefficients. The tapered cylinder presented different separation angle locations at different spans, gradually moving backward as the diameter increased. The linearly tapered cylinder provided a higher mean Nu than a uniform cylinder at the same Re of 3000, resulting in an increase of about 25.48% of that for a uniform cylinder. Furthermore, the variation in the Nu over time was correlated with the force coefficients. Different views of the 3D contours depicting the Nu made it evident that the Nu had a maximum at both ends of the cylinder. Characterized by high-speed velocities, the Nusselt number was notably higher in the wake region.
Research on heat dissipation optimization of servers in a computer room under different air supply modes
Authors: Huang Tao , Cao Liangqiang , Wu Yahui , Yan Yan , Wang Wenzhe , Yuan Kai
Published: September 2024

The computational fluid dynamics method is used to study the internal heat dissipation of the original computer room, analyze the reasons for unreasonable temperature distribution, and optimization is adopted. According to the optimized computer room, the flow field and temperature field of two air supply modes are studied, and the results under different inlet air temperatures and flow rates are compared. The results show that the local temperature on both sides of the original computer room is too high, which is because the center of the server on both sides is not effectively ventilated and dissipated. The heat dissipation effect is optimized by adding the upper and lower air vents on both sides of the room, respectively. The calculation shows that the optimization effect is obvious. The top-to-bottom air supply mode and bottom-to-top air supply mode can have a good effect on the heat dissipation of the computer room, but the top-to-bottom air supply mode has a better effect on the heat dissipation of the computer room. Considering factors such as energy saving and cooling effect, it is recommended to choose 44000 m3/h of air intake volume under the top-to-bottom air supply mode.
Enabling sustainable consumer choices with CarbonShunya: India’s first solution to measure and mitigate carbon impact of consumer transactions in real-time*
Authors: Nahar Devender , Unni Hrishidev , Verma Piyush
Published: September 2024

Among the myriad challenges facing humanity, air pollution and climate change emerge as the most formidable existential threats to our future. Ironically, both these are direct fallouts of human activities such as indiscriminate consumption of consumer products/services and burning of fossil fuels. Purchase of consumer goods in 2024 is projected to be in excess of $22.6 trillion worldwide. How these consumers buy, use or dispose consumer goods will profoundly impact all life on the planet. Therefore, it is an imperative to embed sustainability in every Rupee of consumer spending. Hence a robust digital solution, CarbonShunya, has been developed with the purpose to empower a billion consumers to make sustainable purchase and lifestyle choices. CarbonShunya is India’s 1st solution that can measure and mitigate the Greenhouse Gas (GHG) footprint of consumer transactions in real-time. It provides consumers with actionable insights at the point-of-purchase and post-purchase to shape a shift in consumer beliefs, attitudes and behavior. This paper presents the methodology, assumptions and processes which have been adopted to develop the CarbonShunya life-cycle assessment framework and solution in Indian context. It also presents a case study, using the CarbonShunya framework, to measure and mitigate GHG impacts of monthly consumer expenditure on several categories of products/services across various states of India, based on a primary survey of over 174 000 households. The results from the case-study provide actionable insights and conclusions for policymakers and practitioners. CarbonShunya has cross-cutting applications across sectors so as to enable consuming economies to embrace conserving behaviors.
Assessing the Techno-Economics of Solar-Assisted Absorption Air Conditioning in a University Building in Jordan
Authors: Altork Yousef , Salem Duaa
Published: September 2024

Adsorption chillers are environmentally friendly cooling systems that use non-hazardous refrigerants, such as CFCs or HCFCs, and are efficient and adaptable for various applications, particularly in utilizing waste heat or low-grade heat sources. The economic viability of a solar water-lithium bromide absorption system in large commercial university building with higher electricity rates in Jordan’s central province was assessed using the Payback Period (PBP) methodology. The system’s PBP was found to be 9.65 years, affirming its economic feasibility. To enhance economic viability, adjustments to the Coefficient of Performance (COP) were explored. Technical evaluations incorporating actual thermodynamic data revealed a COP of 0.785, an improvement from the assumed 0.70. Strategies such as lowering the condenser’s working temperature or increasing the evaporator’s operating temperature positively impacted the system’s performance. Notably, at a condenser temperature of 47.5°C, the COP reached 0.77 with a cooling capacity of 21.48 kW, while at an evaporator temperature of 15°C, the COP and cooling capacity were 0.78 and 21.36, respectively. The study demonstrated that increasing the generator temperature led to a rise in COP, with the highest values of 0.785 and 22.68 kW achieved at 95.0°C. Furthermore, a techno-economic analysis revealed a reduced payback period of 8.66 years, emphasizing the influence of increased COP on the absorption air conditioning system’s economic performance.
Effect of co-doping of CeO2 and Sc2O3 on mechanical properties and CMAS corrosion resistance of YSZ ceramics
Authors: Yuan Pei-Lin
Published: September 2024

Given the escalating demand for advanced materials capable of withstanding extreme temperatures in the aerospace and automotive industries, the development of enhanced thermal barrier coatings is critical. This study introduces a novel thermal barrier coating material synthesized via the co-doping of yttria-stabilized zirconia (YSZ) ceramics with ceria (CeO2) and scandia (Sc2O3). The aim is to enhance mechanical properties and resistance to calcium-magnesium-alumino-silicate (CMAS) corrosion, both crucial for high-temperature applications in aerospace and automotive industries. Through a comprehensive experimental approach involving solid-phase sintering, microhardness, fracture toughness, and nanoindentation tests, the research evaluates the effects of co-doping on the ceramics’ performance. Results demonstrate that CeO2 and Sc2O3 co-doping remarkably improves the corrosion resistance of CMAS and mechanical properties of YSZ, suggesting potential for next-generation thermal barrier coatings in high-temperature environments.
Birds save up to 25% of their energy when they follow a leader
Authors: Harris Margaret
Published: September 2024

Birds use significantly less energy when they fly behind a leader, say researchers in the US.
ITER hit by new decade-long delay
Authors: Banks Michael
Published: September 2024

The ITER fusion reactor will now cost €5bn more and not reach full operation with deuterium and tritium until 2039, as Michael Banks explains.
Diamond’s cutting edge
Authors: McEntee Joe
Published: September 2024

Gianluigi Botton, head of the Diamond Light Source in Oxfordshire, talks to Joe McEntee about the £519m Diamond-II upgrade and what it means for the UK’s national synchrotron science facility.
How to run on water
Authors: Sharp Nicole
Published: September 2024

Far too heavy to be supported by surface tension, basilisk lizards and western grebes can sprint for short distances on water. To mark the 2024 Paris Olympics, Nicole Sharp examines the physics behind water-running and asks whether human athletes could ever accomplish the same feat.
WIMPs versus axions
Authors: Cooper Keith
Published: September 2024

From the smallest of interactions to the most powerful galactic phenomena, scientists are searching far and wide for the signatures of dark matter. In the second of a three-part series, Keith Cooper discovers that with so little known about this mysterious part of the universe, scientists find their theories of dark matter pitted against each other.
Normal forms and moduli stacks for logarithmic flat connections
Authors: Bischoff Francis
Published: September 2024

We establish normal form theorems for a large class of singular flat connections on complex manifolds, including connections with logarithmic poles along weighted homogeneous Saito free divisors. As a result, we show that the moduli spaces of such connections admit the structure of algebraic quotient stacks. In order to prove these results, we introduce homogeneous Lie groupoids and study their representation theory. In this direction, we prove two main results: a Jordan–Chevalley decomposition theorem and a linearization theorem. We give explicit normal forms for several examples of free divisors, such as homogeneous plane curves, reductive free divisors, and one of Sekiguchi’s free divisors.