bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequencies of β-casein variants and their influence on genetic merit for production traits in Holstein cows
Authors: Caffaro María Eugenia , Raschia María Agustina , Maizon Daniel Omar , Poli Mario Andrés
Published: December 2024

Context Traits considered for selection are influenced by social, consumer, and breeder demands. In the past decades, there has been increasing global interest in producing milk free from the β-casein (CSN2) A1 allele because of the health benefits it may have. This has encouraged many breeders to select A2A2 cows in their dairy cattle herds. Aims This study aimed to evaluate the genetic variation in the bovine CSN2 gene regarding A1-like and A2-like variants and to assess the potential association between these variants and production traits in Holstein cows. Methods In total, 2600 Holstein cows from three commercial dairy farms with different breeding objectives and phenotypic records taken over different seasons, periods, and lactations were genotyped for single-nucleotide polymorphism rs43703011, which distinguishes A1-like from A2-like β-casein variants. Allele and genotype frequencies were determined and their breeding values for milk, fat, and protein yields, and fat and protein percentages were estimated. The influence of CSN2 genotypes on these breeding values was studied through a one-way ANOVA. For the significant CSN2 genotype–breeding value associations, allele substitution effects were estimated. Key results We found allele frequencies for A1-like and A2-like alleles in the ranges 0.262–0.366 and 0.634–0.738 respectively, and genotype frequencies in the ranges of 0.043–0.125, 0.43–0.537, and 0.393–0.523 for A1A1, A1A2 and A2A2 genotypes respectively. We demonstrated that the A2-like CSN2 variant correlates with higher estimated breeding values (EBVs) for milk, protein, and fat yields, and lower EBVs for fat and protein percentages. Conclusions These results are valuable to visualize the trends in CSN2 allele and genotype frequency changes over the years and to analyze the effect of the different variants of β-casein on production performance. Implications Our findings contribute to evaluating the consequences on dairy performance of selection for the A2-like variant.
Comparing three filter-bag types for accuracy and precision of in sacco undigestible neutral detergent fibre determination of various dicotyledon forages
Authors: Jonker A. , Della Rosa M. M.
Published: December 2024

Context Internationally, undigestible neutral detergent fibre (uNDF) has become a standard feed analysis to quantify the potential digestible NDF fraction and to be an internal marker to estimate diet total-tract digestibility in animal studies. However, this analysis is labour-intensive/expensive and not commercially available in New Zealand and many other countries. Aim To compare the uNDF after rumen incubation determined for various forages by using filter bags that can be used sequentially for NDF and uNDF analysis with the standard method using Saatifil bags. Methods Freeze-dried material of 15 forage samples (mainly dicotyledons) was weighed into three types of bags (Saatifil, 12 μm; F57, 25 μm; F58, 6–9 μm) in sextuplicate and then incubated across two runs for 12 days in the rumen of a fistulated non-lactating pasture-fed dairy cow. After incubation, the NDF of the residue was determined. Key results Overall, the average (±within forage sample CV%) uNDF was 5.4% (9.8), 6.7% (15.2) and 6.3% (16.0) of DM for Saatifil, F57 and F58, respectively, and the mean bias (±95% confidence interval, CI) was 1.3 (0.3–2.3) and 1.2 (−0.1–2.5) for F57 and F58 versus Saatifil respectively. The 95% CI indicated that the intercept and slope for the orthogonal regression of F57 and F58 versus Saatifil were not different from zero and one, respectively, and the correlation for F57 with Saatifil was stronger than for F58 (r = 0.65 and 0.40 respectively). Conclusions Both F57 and F58 bags resulted in similar uNDF values as with the Saatifil bag; however, numerically uNDF values were greater and with a large within-sample CV. Implications The results of the current study suggest that the F57 bag is suitable for uNDF determination, but that some further modifications to the protocol need to be made to improve the accuracy and precision of the uNDF determination.
Understanding extractable metal species relationships with phosphorus sorption and organic carbon in soils
Authors: Amenkhienan Bright E. , Dijkstra Feike , Warren Charles , Singh Balwant
Published: December 2024

Context Iron and aluminium oxides are important in phosphate sorption capacity of soils and preservation of soil organic carbon (SOC). However, there is a complex interplay between among Fe/Al oxides, SOC, and P in soils. Aims We aimed to evaluate the relationships between extractable Fe and Al, SOC concentration and P sorption capacity using generalised additive mixed models. Methods We compiled and analysed data from 77 published articles from Scopus and Web of Science. Key results Ammonium oxalate extractable aluminium (Alox) had astrong significant relationship (P < 0.0001) with P sorption capacity, but this was stronger with dithionite-citrate-bicarbonate extractable aluminium (Ald). A positive 1:1 relationship between Alox and Ald suggests that the pool of Al dissolved by ammonium oxalate and dithionite citrate bicarbonate (DCB) was nearly similar. A strong significant relationship was found between ammonium oxalate extractable iron (Feox) and Alox, and SOC concentration, but Alox had a stronger statistically significant relationship with SOC concentration. This may be due to various interactions of SOC with Al oxides, which can directly or indirectly influence P sorption capacity in soils. Conclusions From these relationships, we show that: (1) that Ald is a better predictor for P sorption capacity than Alox; and (2) Alox is a better predictor of SOC than Feox. Implications DCB and ammonium oxalate extractable Al (and Fe) that represent Al in crystalline and poorly crystalline, or amorphous form of Al may be used as a routine soil test, and may be able to predict P sorption capacity and SOC preservation potential, particularly in acid soils.
Triple oxygen isotopes of lunar water unveil indigenous and cometary heritage
Authors: Thiemens Maxwell M. , Martinez Morgan H. Nunn , Thiemens Mark H.
Published: December 2024

The origin of water in the Earth-Moon system is a pivotal question in planetary science, particularly with the need for water resources in the race to establish lunar bases. The candidate origins of lunar water are an indigenous lunar component, solar wind water production, and the delivery of meteoritic and cometary material. Characterizing the oxygen isotopic composition of water provides information on lunar oxygen sources. The scarcity of lunar water required the development of a high-precision analytical technique for small samples. This method employs stepwise heating, fluorination, and oxygen isotopic measurements using a dual inlet isotope ratio mass spectrometer. The three heating steps were selected based on other extraterrestrial material studies to release loosely bound water that may have been terrestrially contaminated (50 °C), loosely bound water (150 °C), and tightly bound water (as OH) (1,000 °C). This method was applied to a suite of 9 Apollo samples (basalts, breccias, and a regolith), along with terrestrial and meteoritic controls. We present here measurements of the triple oxygen isotopic composition of this water. Our data predominantly show high Δ′
17
O values (≥ 0‰) for lunar water. These values are consistent with enstatite, ordinary, and CI chondrite-like signatures, although coupling Δ′
17
O with δ
18
O forms mixing trends that dominantly overlap enstatite signatures. The other end of the mixing line is in the positive Δ′
17
O space with cometary δ
18
O values, providing constraints for cometary Δ′
17
O between 0.75 to 1.75‰.
The present epoch may not be representative in determining the history of water on Mars
Authors: Jakosky Bruce M.
Published: December 2024

Understanding the history of water on Mars is important for understanding both its geological and potential biological history. The abundance and physical state of water has evolved through time, from the surface having an early warmer and wetter environment to the present-day colder and drier one. Although multiple lines of evidence support this change, attempts to determine the abundance of water on the planet, the history of water at the surface, and the sequestration into both permanent and exchangeable sinks have yielded a wide range of results. I explore the uncertainties in the processes and interpretation, to understand our ability to quantitatively determine the water inventory and its changes through time. Results indicate that the present state of models and of the data constraining them preclude determining a unique history for water. This uncertainty does not affect the conclusion that significant amounts of water have been lost to space and to other sinks and that these losses are consistent with the changes in climate and surface environment.
Cortisol awakening response prompts dynamic reconfiguration of brain networks in emotional and executive functioning
Authors: Zeng Yimeng , Xiong Bingsen , Gao Hongyao , Liu Chao , Chen Changming , Wu Jianhui , Qin Shaozheng
Published: December 2024

Emotion and cognition involve an intricate crosstalk of neural and endocrine systems that support dynamic reallocation of neural resources and optimal adaptation for upcoming challenges, an active process analogous to allostasis. As a hallmark of human endocrine activity, the cortisol awakening response (CAR) is recognized to play a critical role in proactively modulating emotional and executive functions. Yet, the underlying mechanisms of such proactive effects remain elusive. By leveraging pharmacological neuroimaging and hidden Markov modeling of brain state dynamics, we show that the CAR proactively modulates rapid spatiotemporal reconfigurations (state) of large-scale brain networks involved in emotional and executive functions. Behaviorally, suppression of CAR proactively impaired performance of emotional discrimination but not working memory (WM), while individuals with higher CAR exhibited better performance for both emotional and WM tasks. Neuronally, suppression of CAR led to a decrease in fractional occupancy and mean lifetime of task-related brain states dominant to emotional and WM processing. Further information-theoretic analyses on sequence complexity of state transitions revealed that a suppressed or lower CAR led to higher transition complexity among states primarily anchored in visual-sensory and salience networks during emotional task. Conversely, an opposite pattern of transition complexity was observed among states anchored in executive control and visuospatial networks during WM, indicating that CAR distinctly modulates neural resources allocated to emotional and WM processing. Our findings establish a causal link of CAR with brain network dynamics across emotional and executive functions, suggesting a neuroendocrine account for CAR proactive effects on human emotion and cognition.
Biofilm formation by
Staphylococcus aureus
is triggered by a drop in the levels of a cyclic dinucleotide
Authors: Syed Adnan K. , Baral Rishika , Van Vlack Erik R. , Gil-Marqués María Luisa , Lenhart Taliesin , Hooper David C. , Kahne Daniel , Losick Richard , Bradshaw Niels
Published: December 2024

The bacterial pathogen
Staphylococcus aureus
forms multicellular communities known as biofilms in which cells are held together by an extracellular matrix principally composed of repurposed cytoplasmic proteins and extracellular DNA. These biofilms assemble during infections or under laboratory conditions by growth on medium containing glucose, but the intracellular signal for biofilm formation and its downstream targets were unknown. Here, we present evidence that biofilm formation is triggered by a drop in the levels of the second messenger cyclic-di-AMP. Previous work identified genes needed for the release of extracellular DNA, including genes for the cyclic-di-AMP phosphodiesterase GdpP, the transcriptional regulator XdrA, and the purine salvage enzyme Apt. Using a cyclic-di-AMP riboswitch biosensor and mass spectrometry, we show that the second messenger drops in abundance during biofilm formation in a glucose-dependent manner. Mutation of these three genes elevates cyclic-di-AMP and prevents biofilm formation in a murine catheter model. Supporting the generality of this mechanism, we found that
gdpP
was required for biofilm formation by diverse strains of
S. aureus
. We additionally show that the downstream consequence of the drop in cyclic-di-AMP is inhibition of the “accessory gene regulator” operon
agr
, which is known to suppress biofilm formation through phosphorylation of the transcriptional regulator AgrA by the histidine kinase AgrC. Consistent with this, an
agr
mutation bypasses the block in biofilm formation and eDNA release caused by a
gdpP
mutation. Finally, we report the unexpected observation that GdpP inhibits phosphotransfer from AgrC to AgrA, revealing a direct connection between the phosphodiesterase and
agr
.
Intelligence artificielle et diversité linguistique
Authors: Mattioda Maria Margherita
Published: December 2024

L’IA a connu une évolution fulgurante au cours de ces dernières années. Sa propagation dans tous les
domaines s’accompagne d’un besoin urgent de réfléchir sur ses usages et, éventuellement
ses dérives, surtout lorsque le déploiement des systèmes intelligents peut se répercuter sur la vie et les droits des individus.
L’apparition de traducteurs automatiques neuronaux représente un pas en avant sur le plan de la qualité par rapport aux
systèmes de traduction de la génération précédente, mais peuvent-ils jouer un rôle fondamental dans la gestion équitable de la
diversité linguistique et garantir les droits linguistiques dans les contextes multilingues ? Dans cette contribution nous nous
interrogerons sur la relation entre droits linguistiques et traduction pour ensuite explorer l’impact de la traduction
automatique neuronale sur la diversité linguistique et sur la mise en œuvre des droits linguistiques.
Tense and agreement processing in native Spanish speakers with aphasia
Authors: Stecher Camila , Sánchez María Elina , Carden Julia Roberta , Jaichenco Virginia Irene
Published: December 2024

Several cross-linguistic studies have reported an impairment of verbal morphosyntax in People with Aphasia (PWA),
highlighting a greater impact on tense morphology in contrast to agreement-inflectional morphology (Benedet, Christiansen & Goodglass, 1998; Friedmann &
Grodzinsky, 1997, 2000; Gavarrò &
Martínez-Ferreiro, 2007; Kok et al., 2007; Wenzlaff & Clahsen, 2004). The Diacritical Encoding and Retrieval Hypothesis (DERH, Faroqi-Shah & Thompson, 2007) postulates that this deficit is due to a specific
difficulty projecting the semantic time information to the morphosyntax of verbs, related to processing limitations in PWA. This
study aimed to assess the processing of the tense and agreement inflection in Spanish-speaking PWA. A group of 9 PWA completed
four tasks designed to study verbal inflection production and comprehension in Spanish: Sentence Completion, Sentence Elicitation,
Grammaticality Judgements and Sentence-Picture Matching. As expected, PWA showed a significatively greater impairment in tense
inflection compared to agreement inflection. Furthermore, the analysis showed that this differential impairment manifested when
PWA were asked to encode semantic time information and retrieve the corresponding verb morphology. These findings are consistent
with the postulates of the DERH.
Behavioural Alterations in Heat-Stressed Cattle
Authors: Idris Musadiq
Published: December 2024

Heat stress is a major concern and a common cause of poor welfare in both dairy and feedlot cattle. Heat stress is expected to become a more challenging task with climate change for cattle industry in hot tropics of the world. In situations when there is an excessive heat load, cattle may initiate behavioural as well as physiological responses to preserve and restore thermal equilibrium. Increases in body temperature, respiration, and perspiration and modifications to liver, kidney, and hypothalamus function are examples of physiological reactions. Cattle that modify their behaviour are better able to adapt to their surroundings and maintain equilibrium. Shade seeking, crowding at the water trough, increased water consumption and water splashing, increased breathing and panting behaviour, and bunching and altered eating behaviour are the main behavioural changes in cattle that have been observed in response to a heat load condition. This case study aimed to review the importance of understanding various behavioural alterations to assess heat stress in cattle and to accelerate response time to these animals. The understanding of behavioural alterations for cattle experiencing hot environmental temperature will be helpful to establish future research horizon to ameliorate heat stress in cattle.

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© The Author 2024
Classification of entanglement distribution using machine learning
Authors: El Ayachi F , Ait Mansour H , El Baz M
Published: December 2024

A classification of multipartite entanglement is introduced for pure and mixed states. The classification is based on the distribution of entanglement between the qubits of a given system, with a mathematical framework used to characterize fully entangled states. Then we use current machine learning and deep learning techniques to automatically classify a random state of two, three, and four qubits without the need to compute the amount of the different types of entanglement in each run; rather this is done only in the learning process. The technique shows high, near-perfect, accuracy in the case of pure states. As expected, this accuracy drops, more or less, when dealing with mixed states and when increasing the number of parties involved.
Generalized susceptibilities of the net-baryon number based on the three-dimensional Ising universality class*
Authors: Pan 潘 Xue 雪
Published: December 2024

Assuming the equilibrium of the Quantum Chromodynamics (QCD) system, we investigate the critical behavior of the sixth-, eighth-, and tenth-order susceptibilities of the net-baryon number through mapping the results in the three-dimensional Ising model to that of QCD. Both the leading and sub-leading critical contributions from the Ising model are discussed. When considering only the leading critical contribution, the density plots of susceptibilities of the same order demonstrate a consistent general pattern independent of the values of the mapping parameters. As the critical point is approached from the crossover side, a negative dip followed by a positive peak is observed in the

dependence of the three different orders of susceptibilities. When sub-leading critical contribution is considered, modifications become apparent in the density plots of the susceptibilities. The emergence of negative dips in the

dependence of the susceptibilities is not an absolute phenomenon, whereas the positive peak structure is a more robust feature of the critical point.
Shadow and gravitational weak lensing around a quantum-corrected black hole surrounded by plasma*
Authors: Alloqulov Mirzabek , Isaqjonov Yokubjon , Shaymatov Sanjar , Jawad Abdul
Published: December 2024

In this study, we investigate the optical properties of a quantum-corrected black hole (BH) in loop quantum gravity surrounded by a plasma medium. First, we determine the photon and shadow radii resulting from quantum corrections and the plasma medium in the environment surrounding a quantum-corrected BH. Our findings indicate that the photon sphere and BH shadow radii decrease owing to the quantum correction parameter α, which acts as a repulsive gravitational charge. Further, we investigate the gravitational weak lensing by applying the general formalism used to model the deflection angle of the light traveling around the quantum-corrected BH within the plasma medium. We show, in conjunction with the fact that the combined effects of the quantum correction and non-uniform plasma frequency parameter can decrease the deflection angle, that the light traveling through the uniform plasma can be strongly deflected than the non-uniform plasma environment surrounding the quantum-corrected BH. Finally, we examine the magnification of the lensed image brightness under the effect of the quantum correction parameter α, including the uniform and non-uniform plasma effects.
New Insights on Gamma-Ray Burst Radiation Mechanisms from Multiwavelength Observations
Authors: Yao Yu-Hua , Min Fang-Sheng , Chen Shi , Guo Yi-Qing
Published: December 2024

The study of high-energy gamma-ray emission from gamma-ray bursts (GRBs) involves complex synchrotron radiation and synchrotron self-Compton (SSC) scattering mechanisms with multiple parameters exhibiting a wide distribution. Recent advancements in GRB research, particularly the observation of very high energy (VHE, >100 GeV) radiation, have ushered in a new era of multiwavelength exploration, offering fresh perspectives and limitations for understanding GRB radiation mechanisms. This study aimed to leverage VHE observations to refine constraints on synchrotron + SSC radiation from electrons accelerated by forward shocks. By analyzing two external environments—the uniform interstellar medium and stratified stellar wind medium, we conducted spectral and variability fitting for five specific bursts (GRB 180720B, GRB 190114C, GRB 190829A, GRB 201216C, and GRB 221009A) to identify the optimal parameters characterizing these events. A comparative analysis of model parameter distributions with and without VHE radiation observations reveals that the magnetic energy equipartition factor ϵ

B
is more concentrated with VHE emissions. This suggests that VHE emissions may offer greater constraints on this microphysical parameter. Additionally, we found that the energy budget between VHE and keV–MeV γ-ray emissions under the SSC radiation exhibits an almost linear relationship, which may serve as a tool to differentiate radiation mechanisms. We anticipate future statistical analyses of additional VHE bursts to validate our findings.
A control system design of wave power generation using HHT to realize maximum power control
Authors: Wang Hao , Yu Haitao , Zhong Wei
Published: December 2024

Ocean wave power generation can provide clean energy for offshore electrical equipment. However, the random changes in waves are not conducive to capturing energy efficiently. How to improve the capture of wave power has become a problem that wave energy power generation equipment needs to address. This study uses the Hilbert-Huang Transform (HHT) to predict the frequency of random waves and controls the motor according to the predicted frequency, enabling the wave energy power generation device to resonate with the waves to obtain the maximum power.
A simple method for common-mode voltage optimization in three-level three-phase four-leg inverters
Authors: Liu Guorui , Wang Fusheng , Zhang Hengkang , Wu Wei , Zuo Qingfeng
Published: December 2024

In response to the problem of large common-mode (CM) voltage magnitude and high-frequency variation under traditional modulation strategies for three-level three-phase four-leg (3L3P4L) inverters, this paper proposes a modulation strategy based on carrier combination and modulation wave splitting. Firstly, this paper establishes a CM model for the 3L3P4L inverter and derives mathematical expressions of the system’s CM voltage in terms of switch states and system parameters. Building upon this foundation, this paper explains the reasons for high-frequency variations in CM voltage under traditional schemes and provides a detailed introduction to the optimization process and principles of the proposed strategy. Finally, a simulation model is developed by using Matlab/Simulink software. Through comparison with traditional approaches, the effectiveness of the proposed strategy is validated.
An evaluation method for electromagnetic compatibility risks caused by the intelligent transformation of oil and gas field stations
Authors: Wen Zhang , Wang Jinshan , Wu Jinfeng , Zhang Shaofei , Wang Xue
Published: December 2024

With the development of the intelligentization of the petroleum and chemical industry, the application of wireless communication technology and a large number of communication devices in the construction of smart oil and gas fields may cause harmful interference to important electronic and electrical equipment within the oil and gas fields, leading to shutdowns or other serious safety accidents. This paper mainly studies the analysis and evaluation methods of electromagnetic safety risks that may arise after the deep integration of new generation information technology and oil and gas field engineering, so as to quickly analyse and locate the electromagnetic safety risks and risk levels that may arise in the process of building wireless communication networks in the oil and gas field areas. It provides guidance for the intelligent upgrade of oil and gas field projects and accelerates the construction of 5G communication networks in the petroleum and chemical industry.
Analysis of the evolution of power system scale and grid stability
Authors: Dong Wu , Zhou Qinyong , Zhang Libo , Zhang Jian , Hao Shaoxu
Published: December 2024

To address the challenges faced in grid planning during the development phase of new power systems, an evolution model of the grid was constructed based on historical and future planning data of a regional power grid. Adopting a systematic perspective, this study statistically analyzed the changes in several indicators strongly related to safety and stability within the model. It quantitatively examined the correlation patterns between grid development scale and safety stability, investigating the evolution of grid-scale effects. The study found that the positive correlation between grid-scale and system stability is gradually weakening and suggested the timely adoption of effective technical measures to maintain or even enhance the safety and stability level of the grid.
Radar and communication integration under FPGA platform: real-time waveform generation with time division multiplexing and waveform sharing strategy
Authors: Jia Guowen , Zhang Zhen , Tang Yiwen , Zhang Yue
Published: December 2024

The integration of radar and communication technologies is gaining prominence in electronic information systems. This paper explores advanced waveform strategies—LFM (Linear Frequency Modulation) + MSK (Minimum Shift Keying) based on time-division multiplexing and LFM-MSK utilizing waveform sharing. These methods enhance spectrum efficiency and system capabilities in detecting targets and transmitting data reliably amidst complex environments. Based on the FPGA (Field Programmable Gate Array) platform, this study proposes real-time waveform generation methods for integrated radar communication waveforms, specifically LFM+MSK and LFM-MSK. It focuses on discussing FPGA implementation solutions for these methods and validates their effectiveness. This research addresses a critical gap in the field and provides practical insights for radar communication integration systems.
Construction and identification of defect knowledge map for DC protection system
Authors: Yao Tao , Zhang Lie , Wang Ye , Ren Xuchao
Published: December 2024

With the continuous acceleration of DC engineering construction, the equipment scale of the DC protection system continues to expand. As the core part of DC transmission, the DC protection system has become an important factor affecting the safe and stable operation of the power grid. The diagnosis and handling of defects in DC protection system equipment often rely on expert experience and technical service support from manufacturers, making it difficult to detect and handle them in a timely manner. Defect analysis and handling are time-consuming and labour-intensive, and disposal experience cannot be shared, posing hidden dangers to the safe and stable operation of the power grid. The DC protection system contains a massive number of components and has extremely complex internal logic. Traditional data mining methods make it difficult to fully extract the semantic features of defect texts in DC protection devices. Therefore, this paper analyzes the types and causes of protection devices in DC transmission systems, uses the Word2Vec-Bootstrapping algorithm to extract the DC protection defect knowledge, uses the Bootstrapping algorithm to classify the word relation, and proposes a modeling method of DC protection device defect Knowledge map. By converting the extracted knowledge into triplet form and constructing a knowledge map, the causes and treatment measures of DC protection defects are diagnosed. An example shows that this method can fully extract the semantic features in the DC protection device defect record text, improve the utilization rate of the defect text record, and accurately identify the defect of the DC protection device.
Wide-range ZVS control technology of bidirectional dual-bridge series resonant DC/DC converters based on phase-shift frequency modulation control
Authors: Ye Yujie , Wang Fusheng , Wu Huijie , Cheng Shuai
Published: December 2024

Increasing the switching frequency helps optimize the performance of resonant DC-DC converters and reduces the size of resonant components, but it also increases the switching losses. To address the challenge of achieving soft switching in the medium to low power range, this paper proposes a new control strategy. In this paper, it achieves a wide range of Zero Voltage Switching (ZVS). It combines Variable Frequency Modulation (VFM) and Phase Shift Modulation (PSM), utilizing Minimum Current Trajectory (MCT) control to reduce the system’s conduction losses. Besides, VFM is used to extend the ZVS range and reduce switching losses.
Kinematics modeling and analysis of large parabolic cylindrical deployable antenna support mechanism
Authors: Fu Linhan , Chen Jinbao , Chen Chuanzhi , Zhang Yingxue , Song Zhicheng
Published: December 2024

A high deployment ratio, large aperture, lightweight design, and high precision are the trends in the development of future deployable antennas. To meet the mission requirements of spaceborne antennas, a large parabolic cylindrical deployable antenna support mechanism composed of multiple rectangular modules is constructed, and a kinematic modeling method for multi-module linkage is proposed. Based on the structure and deployment principles of the antenna, a spatial geometric model of the antenna support mechanism is constructed. By integrating the Denavit-Hartenberg (D-H) method and robotics theory, kinematic models for both the basic deployment unit and the overall mechanism are established. Finally, the models are validated and analyzed through geometric modeling and numerical simulation. The results show that this configuration design can fit different parabolic curves by adjusting the parameters of the rods and can be extended to a scale of hundreds of meters. Meanwhile, the accuracy and reliability of the kinematic models for both the basic deployment unit and the overall mechanism provide a theoretical foundation for subsequent dynamic studies and systematic optimization of the antenna support mechanism.
Design of optimal sliding mode control system for PMLSM
Authors: Zhu Chuanmin , Wang Dawei , Li Zhiyuan
Published: December 2024

To enhance the responsiveness and resilience against disturbances in the speed regulation system of Permanent Magnet Linear Synchronous Motors (PMLSM), an advanced control approach leveraging optimized sliding mode control is introduced. Initially, a foundation is laid by designing a PI-based speed control system and a conventional sliding mode control system within the framework of PMLSM vector control. Simulation models are then constructed to validate the efficacy of these systems. Subsequently, focusing on the traditional sliding mode controller, optimizations are implemented to refine the sliding mode convergence dynamics and the switching function, leading to the development of an optimal sliding mode controller model. Ultimately, simulation tests confirm that this optimized sliding mode speed controller achieves seamless transition without overshoot, swift response times, and robust disturbance rejection capabilities. Its performance in terms of responsiveness and anti-interference surpasses both the PI controller and the conventional sliding mode speed controller.
FIR noise reduction using GWO and Fast Kurtogram for extracting fault characteristic frequencies in rolling bearings
Authors: Jiang Shan , Li Minhui
Published: December 2024

Fast Kurtogram (FK) is a widely recognized method for detecting characteristic fault frequency bands. Nevertheless, its sensitivity to noise often causes diagnostic errors. This research seeks to enhance FK’s identification performance by implementing an adaptive FIR filter that mitigates noise. To validate this approach, single-point fault signals were obtained from the outer race, inner race, and rolling elements of bearings operating at four distinct motor speeds. These raw signals were then subjected to statistical analysis after normalization. To design the adaptive FIR filter, the study employs an enhanced Grey Wolf algorithm along with the Parks-McClellan algorithm to determine the optimal filter order and impulse response coefficients. Subsequently, band-pass filtering is applied to the fault characteristic frequency bands identified through FK. The fault characteristic frequencies are then extracted using envelope spectrum analysis. The bandwidth and fault characteristics derived from the processed signals are compared against those obtained from the unfiltered original signals. The findings indicate that optimal normalization preprocessing is crucial before filter design. The determined optimal order and impulse response coefficients enable the adaptive design of FIR filters. As a result, the FIR-filtered signal exhibits significantly fewer noise-induced anomalous peaks, thereby improving the signal-to-noise ratio and enhancing FK’s robustness against noise interference. Implementing an adaptive FIR filter for noise reduction significantly aids in more precise analysis and diagnosis of bearing conditions. Looking ahead, this study proposes integrating machine learning algorithms to further enhance the accuracy in identifying characteristic frequency bands associated with single-point faults in rolling elements.
Design and simulation analysis of a two-dimensional extended array structure
Authors: Lv Shibin , Tian Ye , Wang Liukai , Li Long
Published: December 2024

A compact and two-dimensional expandable extended array structure was designed to meet the electrical and structural compatibility requirements of a certain type of equipment. The transition from the distance between the RF component side RF channels A × B (mm) to the distance between the antenna array units a × b (mm) was achieved. The structural mechanical performance simulation was conducted. It was found that the deformation in the connector insertion direction was significant, which affected the reliability of the RF connection. Based on the simulation results, the original structural scheme was optimized and further improved to enhance the assembly, maintenance, and interchangeability of the extended array. The maximum structural deformation in the insertion direction of the RF connector was 0.19mm, which was reduced by 0.2mm compared to the previous optimized scheme with a structural deformation of 0.39mm. The large deformation area was significantly reduced. The stiffness of the structure was significantly improved, meeting the reliability requirements of multi-channel module RF blind insertion.
Empirical relationship with experimental model test results on change of blade number of Kaplan turbine on flow and efficiency characteristics
Authors: Mangla Mukesh
Published: December 2024

Axial flow Kaplan turbines with moveable guide vanes and rotating runner blades presents a complex flow. Turbine performance is dependent on loss and flow characteristics of different components. The runner is the heart of turbine and its design being the most dominant effect on performance of turbine characteristics in the turbine space. Blade design is combination of profile and solidity, the solidity was changed by changing number of blades and its effect on characteristics was investigated by model testing. In this paper an empirical relationship has been derived based on actual model test as per IEC 60193:2019 of all three types of Kaplan model with vertical runner, Tubular model with horizontal runner, and Bulb turbine model with horizontal runner. The relationship was investigated by changing the runner blade numbers 3, 4 or 5 on flow & efficiency characteristics. The experimental results analysis depicted a relationship in all three types of models having different blade profiles. Relationship among unit parameters like specific speed (nQE) Discharge factor (QED) and Speed factor (nED) were derived by regression analysis of test data.
Influence of cavitation simulation on Pelton turbine bucket performance
Authors: Liu Z , Liang Q , Xiao Y , Liu J , Qin C , Zhou Y , Li H , Du Q
Published: December 2024

Cavitation is one of the crucial problems faced by Pelton turbines operating under high water heads. To evaluate the influence of cavitation on the predicted Pelton turbine bucket performance, the conventional water-gas two-phase flow simulation and the water-vapor-gas two-phase three component flow simulation were carried out at the design operating point of a six-nozzle model Pelton turbine. The results showed that the inclusion of cavitation model might induce obvious influence on the bucket front surface torque curve after the peak, which was originated from the cavitation simulated at bucket back surface during the cut-in process of the next bucket, deteriorating the jet flow pattern with secondary flow enhanced. The inflow of deformed jet piece onto the bucket front surface finally affected the hydraulic performance of the bucket, accounting for the runner hydraulic loss of about 0.5% after the inclusion of cavitation model. This study provided the idea that for the types of buckets vulnerable with cavitation, cavitation phenomenon should be included in the simulation, so as to obtain the performance predicted closer to reality.
Experimental investigation of a FSFC variable speed pump-turbine prototype - Part1: penstock fatigue reduction and fast active power regulation
Authors: Nicolet C , Alligné S , Dreyer M. , Schmid J , Biner D , Münch-Alligné C , Lugon J , Hugo N
Published: December 2024

The Z’Mutt pumping station is located in Canton Valais-Wallis, in Switzerland and is part of the Grande Dixence hydroelectric scheme. The unit 5 of this station has recently been upgraded with a 5 MW variable speed reversible Francis pump-turbine equipped with Full Size Frequency Converter, FSFC, allowing the unit speed to be adjusted from −100% to +100%. This paper presents the methodology based on 1D numerical simulations including CFD/FEM runner damage hill chart to optimize the turbine start-up sequence to minimize both runner and penstock fatigue by taking advantage of the FSFC variable speed technology. FSFC allows for precise start-up trajectories in the n11-Q11 frame, to avoid runner high damage operating points, while reducing penstock pressure variations as compared to a classical fixed speed technology. This methodology resulted in the definition of 6 different FSFC start-up sequences, as well as the classical fixed speed start-up, which have been successfully implemented and tested on site. Site tests of fast transition from turbine to pump and vice versa are also showcased. Finally, fast active power regulation tests performed in pump mode are presented to show the ability of FSFC variable speed technology to provide ancillary grid service in pump mode.
Increasing grid flexibility – Implementation and testing of improved start and mode change procedures in a PSPP with double-fed induction machines and reversible pump-turbines
Authors: Weiser T , Fehringer F , Jung A R
Published: December 2024

Besides being a carbon-free and highly efficient energy storage technology, pumped-storage power plants (PSPP) offer operational flexibility which in turn eases the integration of volatile energy sources such as wind and solar energy into the electric grid. The flexibility to bring the power unit quickly to generation mode and thus to inject active power to the transmission grid involves various process transitions. In specific, this paper describes the implementation and respective site tests of the following mode changes: a) from standstill to generation mode by simultaneously accelerating the power unit to synchronization speed with the turbine and the voltage source inverter of a double-fed induction machine and b) from pump mode to generation mode. This work was part of the activities of the EU-funded H2020 project XFLEX HYDRO. The demonstration plant is the Frades 2 PSPP in Portugal, which is equipped with two reversible Francis-type pump turbines, each coupled to a 420 MVA double-fed induction machine. Based on recorded process values and additional measurements such as a turbine runner strain gauge measurement and shaft torque measurement, a detailed comparison of the different mode changes in terms of mechanical stress and vibrational behaviour was conducted. To a large extend, the obtained results and the applied methodology are valid as well for reversible pump-turbine sets with synchronous generators and start-up inverter technology. The outlook comprises a discussion about further improvements for the transition from pump mode to generation mode specifically for double-fed induction machines.
Numerical prediction of the fluid damping of a standing disc with a variable axial distance from a rigid wall
Authors: Khalfaoui K , Moraga G , Bareis J , Zorn M , Presas A , Riedelbauch S
Published: December 2024

Near-resonant flow-induced vibrations are a significant cause of fatigue damage in hydraulic impellers. The amplitude of these vibrations is limited mainly by the fluid damping, making its quantification paramount for the safety of hydraulic turbines. To study the fluid damping for low-specific-speed radial impellers, a submerged disc in still water with a variable vertical distance from a rigid wall is investigated. This setup serves as an abstraction of the axial gap between impeller hub and head cover, and of the modal behavior of impellers for the case of diametrical nodal lines. The fluid damping is computed numerically for the 3-nodal-diameters mode using the imposed modal motion approach for various axial gap sizes and vibration amplitudes. The results are contrasted with the experimental damping measured with the same setup. First, a simulation configuration that accurately replicates the experimentally measured damping in value and tendency is presented. The factors that would normally impede a valid numerical prediction are exposed and solutions are suggested. Second, the valid simulation results are thoroughly studied, and the flow field is visualized to gain insight into the physical mechanisms that cause the fluid mass and damping. As a result, the interaction between fluid and structure in this system is understood.
Advancing the Reliability of Residual Life Assessment for Turbines through Strain Gauge Measurements: Key Aspects and Latest Developments
Authors: von Locquenghien F , Fehringer F , Eissner M
Published: December 2024

With the need for flexible operation and an aging hydropower fleet, the importance of residual life assessment for turbines has been on the rise. While prediction methods are continuously improving, the most reliable data about the health status of a machine is obtained through measurement campaigns. Unlike fatigue evaluations during the design stage that include safety factors, residual life assessments require higher precision to enable owners to evaluate their assets and investments. The increased precision of a measurement campaign justifies the additional costs incurred.

This article emphasizes the significance of a careful review of all aspects, including load history, measurement data, transposition method, and material data. It also presents the latest developments in accordance with IEC 63230 and provides an example prototype measurement to underscore the importance of each aspect. Special attention is given to the transposition of strain data from the measurement location to the hot spot position and its impact on load sequences and stochastic loads. Through a sensitivity study, the article aims to provide a better understanding of the importance of each aspect in the residual life evaluation process.
Flow analysis and optimization study of main components of flow-type small hydro turbine system
Authors: Bae Seong-Han , Kim Subin , Kang Hyunsu , Kim Youn-Jea
Published: December 2024

Small hydro power generation refers to the production of electricity by harnessing the kinetic energy of water in small rivers or streams, typically generating up to 10 MW of power. The optimal shape combination of the watercone and turbine, according to the water flow rate, is crucial for maximizing the power generated. In this study, flow analysis using computational fluid dynamics was performed on Kaplan turbines to examine the effects of blade angle, volume flow rate and rotational speed on power generation. To ascertain the impact of variables on power generation, the internal flow field was examined. The findings demonstrated that an increased blade angle perpendicular to the flow direction resulted in a reduced incidence of vortices and cavitation formations within the turbine wake. A predictive model was generated using a design of experiment and response surface methodology to generate a predictive model to find the power generation for flow rates, blade angles and rotational speed within the experimental range.
Analysis of manganese (Mn) and copper (Cu) content in leachate water of Putri Cempo landfill, Surakarta
Authors: Matin H H A , Rachmawati S , Amira Z P , Purnamasari F , Ayuningtyas H R , Akromi M A I , Ainindyai D G
Published: December 2024

Leachate can contain hazardous components that can pollute the environment and health if not managed. This study aims to determine the content of heavy metals Mn and Cu in leachate from Putri Cempo Solo TPA and provide recommendations if the Mn and Cu values exceed the threshold. The method used is laboratory analysis. Analysis of Mn and Cu content was carried out using Atomic Absorption Spectroscopy by comparing the results of Mn and Cu content with quality standards according to PP 82/2001 Class IV concerning Water Quality Management and Water Pollution Control and PerMenKes 492/2010 concerning Mn content and PP 82/2001 Class IV concerning Water Quality Management and Water Pollution Control against Cu content. Laboratory test results showed that the Mn content was 33.7060 mg/l and Cu was 0.9294 mg/l. It is known that the maximum limit of heavy metal contamination Mn ranges from 0.1-0.4 mg/l and Cu is 0.2 mg/l. It was concluded that the heavy metal content of Putri Cempo landfill leachate has exceeded the quality standard. In order not to exceed the quality standard, it is recommended to treat leachate with coagulation-flocculation, adsorbent, and bioremediation processes.