bluuebunny/crossref_metadata_2025 huggingface dataset:
Occurrence of Body Posture Abnormalities in Overweight and Obese Children Aged 5–6 Years—Pilot Study
Authors: Bober Alicja , Kopaczyńska Aleksandra , Puk Agnieszka , Chwałczyńska Agnieszka
Published: July 2024

Objectives: The study aimed to assess the occurrence of body posture disorders and their changes under the influence of a physioprophylactic program in children depending on body weight. Methods: In the examined children, the general and segmental body composition and body posture were determined using a physiotherapeutic assessment based on the Kasperczyk method. Mass, overall, and segmental body composition were determined using the bioelectrical impedance method using a TANITA body composition analyzer. The study group of 76 children was divided due to body weight disorders into Group I (n = 51), in which BMI and fat mass values were within the normative limits for age and gender, and Group II (n = 19), comprising children whose body weight exceeded the norm and/or fat mass exceeded normative values. The examined children underwent a physioprophylactic. The program was conducted by qualified physiotherapists for 12 weeks, once a week for 30 min. The therapeutic program was focused on physioprevention of being overweight and the correction of body posture. Results: A distal distribution of fat mass was observed in the examined group. Asymmetry in the sagittal plane was found in 35% of children. No statistically significant differences were found in the presence of asymmetry in the sagittal plane between the groups. No statistically significant differences were found in the occurrence of posture irregularities between the groups. Conclusions: There were no changes in the weight and body posture of the examined children under the influence of the physiotherapy program. The lack of correlation in the examined group between body weight and posture irregularities in 5–6-year-olds may suggest the acquisition of posture defects as a consequence of the persistence of overweight or obesity.
Energy Harvester Based on Mechanical Impacts of an Oscillating Rod on Piezoelectric Transducers
Authors: Islas-Herrera Marco Antonio , Sánchez-Luna David , Jaimes-Ponce Jorge Miguel , Córdova-Córdova Daniel Andrés , Lorenzo-Alfaro Christopher Iván , Hernández-Rivera Daniel
Published: July 2024

Energy harvesting is a clean technique for obtaining electrical energy from environmental energy. Mechanical vibrations are an energy source that can be used to produce electricity using piezoelectric energy harvesters. Vibrations and wind in bridges have the potential to produce clean energy that can be employed to supply energy to electronic devices with low consumption. The purpose of this paper was to validate the functioning of an energy harvester and test the electrical power generation potential of a system based on the oscillation of a rod with a tip mass to stimulate piezoelectric transducers by impact. The obtained results showed the electric energy productions for different test conditions. Experimentally, the proposed structure produced 0.337 µJ of energy after 14 s of testing. In addition, after one hour of operation, an estimated production of 10.4 mJ was obtained, considering four stacks of 25 piezoelectric disks each when periodic impacts of 50 N at 5.7 Hz stimulated the transducers. In future work, we will focus on taking advantage of the vibrations produced in the proposed structure induced by the mechanical vibration of bridges and vortex-induced vibration (VIV) through interaction with wind to produce clean energy that is useful for low-power applications.
Peruvian North Coast Climate Variability and Regional Ocean–Atmosphere Forcing
Authors: Jury Mark R. , Alfaro-Garcia Luis E.
Published: July 2024

This study analyses climate variability on the north coast of Peru to understand how the local weather is coupled with anomalous ocean conditions. Using high-resolution satellite reanalysis, statistical outcomes are generated via composite analysis and point-to-field regression. Daily time series data for 1979–2023 for Moche area (8S, 79W) river discharge, rainfall, wind, sea surface temperature (SST) and potential evaporation are evaluated for departures from the average. During dry weather in early summer, the southeast Pacific anticyclone expands, an equatorward longshore wind jet ~10 m/s accelerates off northern Peru, and the equatorial trough retreats to 10N. However, most late summers exhibit increased river discharge as local sea temperatures climb above 27 °C, accompanied by 0.5 m/s poleward currents and low salinity. The wet spell composite featured an atmospheric zonal overturning circulation comprised of lower easterly and upper westerly winds > 3 m/s that bring humid air from the Amazon. Convection is aided by diurnal heating and sea breezes that increase the likelihood of rainfall ~ 1 mm/h near sunset. Wet spells in March 2023 were analyzed for synoptic weather forcing and the advection of warm seawater from Ecuador. Although statistical correlations with Moche River discharge indicate a broad zone of equatorial Pacific ENSO forcing (Nino3 R~0.5), the long-range forecast skill is rather modest for February–March rainfall (R2 < 0.2).
Fractional-Order Degn–Harrison Reaction–Diffusion Model: Finite-Time Dynamics of Stability and Synchronization
Authors: Hammad Ma’mon Abu , Bendib Issam , Alshanti Waseem Ghazi , Alshanty Ahmad , Ouannas Adel , Hioual Amel , Momani Shaher
Published: July 2024

This study aims to address the topic of finite-time synchronization within a specific subset of fractional-order Degn–Harrison reaction–diffusion systems. To achieve this goal, we begin with the introduction of a novel lemma specific for finite-time stability analysis. Diverging from existing criteria, this lemma represents a significant extension of prior findings, laying the groundwork for subsequent investigations. Building upon this foundation, we proceed to develop efficient dependent linear controllers designed to orchestrate finite-time synchronization. Leveraging the power of a Lyapunov function, we derive new, robust conditions that ensure the attainment of synchronization within a predefined time frame. This innovative approach not only enhances our understanding of finite-time synchronization, but also offers practical solutions for its realization in complex systems. To validate the efficacy and applicability of our proposed methodology, extensive numerical simulations are conducted. Through this comprehensive analysis, we aim to contribute valuable insights to the field of fractional-order reaction–diffusion systems while paving the way for practical implementations in real-world applications.
The Influence of Process Parameters on the Microstructure and Microhardness of 304 Stainless Steel in Joule Heating Fused Filament Fabrication
Authors: Li Suli , Chen Jichao , Fan Longfei , Xiong Jie , Gao Zhuang , Yang Laixia
Published: July 2024

Using finite element simulation and single-variable experimental methods, this study analyzes the variations in the microstructure and hardness of a 304 stainless steel wire during Joule heating fused filament fabrication. The effects of current intensity, printing speed, and roller pressure on the macroscopic morphology, microstructure, and microhardness of a single-layer single-channel formation were investigated. The results indicate that when the current intensity is 400 A, the printing speed is 1000 mm/min, and the roller pressure is 0.3 N, the surface of the single-layer single-channel formation is smooth and exhibits optimal forming characteristics with a width-to-height ratio of 3.23, a dilution rate of 51.61%, and an average microhardness of 238.17 HV. As the current intensity increases, the microstructure in the fusion zone initially decreases in size and then increases; similarly, with the increase in printing speed, the microstructure in the fusion zone first decreases and then increases; as the roller pressure increases, the microstructure in the fusion zone initially increases in size and then decreases. The microhardness initially increases and then decreases with the increase in process parameters, resulting in uneven hardness distribution due to the variations in microstructure size. The optimal combination of process parameters achieves a balance between heat input, cooling rate, and growth rate, thereby achieving grain refinement and hardness improvement, ultimately enhancing the mechanical properties of the material.
Relic Vergilius Oak (Quercus virgiliana Ten.) Trees Could Preserve Microhabitats of Pannonian Forest–Steppe Vegetation
Authors: Bordács Sándor , Pintér Beáta , Horváth Csaba , Benedek Lajos , Ladányi Márta
Published: July 2024

In the framework of an ongoing gene conservation programme in the Tolna Hills Region, Hungary, a total of 41 site plots were selected on agricultural land that had recently been used as grassland, meadow or vineyard. Aims of our study were (i) to test the taxonomic status of relic oak trees growing out of forested lands; (ii) to verify the origin of relic trees whether they regenerated by sprouts and suckers or by seeds in order to estimate their age and origin (nativeness); (iii) to test their microhabitats to see if forest-specific plant and fungal species were presented; (iv) and to test species to see if their presence linked to any forest vegetation in the past. Furthermore, the land-use type did not show a significant effect on the abundance of woody, dicot herbaceous, or monocot herbaceous plants recorded on sites based on maps from 1941 or earlier. The follow-up univariate ANOVA revealed a significant direct effect of recent land-use type (of 2022) on monocot herbaceous plants (F(3,33) = 5.21, p < 0.01). Additionally, a significant but weaker effect was observed on woody plants (F(3,33) = 3.22, p < 0.05). The overall past effect of land-use type showed a significantly high positive correlation between the abundance of woody plants and the number of times the maps showed forest or forest boundary land-use types (R = 0.46, p < 0.01). The plots have likely preserved and sustained the microhabitats of the native forest vegetation that was once distributed in the region. The site plots of relic oak trees, considered as flagstone habitats, create opportunities for gene flow, not only for the species with dispersal or discontinuous distribution, but also for the Vergilius oak populations. Therefore, relic trees and their microhabitats might have an important role in the mating system of various species and might also be valuable resources for genetic conservation programmes.
Mechanical Transmissions with Convex–Concave Multipair Contact of Teeth in Precessional Gearing
Authors: Bostan Viorel , Bostan Ion , Vaculenco Maxim
Published: July 2024

In this study, we propose a new toothed gear for mechanical transmissions built from a satellite wheel with two toothed conical crowns, one of which conjugates with a fixed central conical wheel mounted in the transmission housing and the other with a movable conical wheel installed on the flange of the driven shaft. The satellite wheel is mounted on the inclined portion of the crankshaft and performs spherospatial motion around a fixed point. When the crankshaft rotates, the teeth of the wheels engage with spherospatial interaction in two lateral gearings of the satellite wheel, yielding kinematic ratios dependent on the correlation of the number of teeth. The teeth of the satellite wheel are used with circular arc profiles, and the teeth of the central wheel have flank profiles with variable curvatures increasing continuously from the root to the tip, so that, in meshing, the teeth form multipair contacts with convex–concave geometry with a small difference in flank curvatures. The flank profile geometry and pairs of teeth simultaneously engage depending on the configurational parameters of the gearing and can use up to 100% of pairs of simultaneously conjugated teeth.
Insights into the Cardioprotective Effects of Pyridoxine Treatment in Diabetic Rats: A Study on Cardiac Oxidative Stress, Cardiometabolic Status, and Cardiovascular Biomarkers
Authors: Mutavdzin Krneta Slavica , Gopcevic Kristina , Stankovic Sanja , Jakovljevic Uzelac Jovana , Todorovic Dušan , Labudovic Borovic Milica , Rakocevic Jelena , Djuric Dragan
Published: July 2024

The aims of this study were to examine the effects of pyridoxine administration on the activities of cardiac antioxidant stress enzymes superoxide dismutase (SOD) and catalase (CAT) and enzyme indicators of cardiometabolic status, lactate and malate dehydrogenase (LDH, MDH), as well as LDH and MDH isoforms’ distribution in the cardiac tissue of healthy and diabetic Wistar male rats. Experimental animals were divided into five groups: C1—control (0.9% sodium chloride—NaCl—1 mL/kg, intraperitoneally (i.p.), 1 day); C2—second control (0.9% NaCl 1 mL/kg, i.p., 28 days); DM—diabetes mellitus (streptozotocin 100 mg/kg in 0.9% NaCl, i.p., 1 day); P—pyridoxine (7 mg/kg, i.p., 28 days); and DM + P—diabetes mellitus and pyridoxine (streptozotocin 100 mg/kg, i.p., 1 day and pyridoxine 7 mg/kg, i.p., 28 days). Pyridoxine treatment reduced CAT and MDH activity in diabetic rats. In diabetic rats, the administration of pyridoxine increased LDH1 and decreased LDH4 isoform activities, as well as decreased peroxisomal MDH and increased mitochondrial MDH activities. Our findings highlight the positive effects of pyridoxine administration on the complex interplay between oxidative stress, antioxidant enzymes, and metabolic changes in diabetic cardiomyopathy.
Role of the Stress Index in Predicting Mortality among Patients with Traumatic Femoral Fractures
Authors: Huang Ching-Ya , Chou Sheng-En , Huang Chun-Ying , Tsai Ching-Hua , Hsu Shiun-Yuan , Hsieh Ching-Hua
Published: July 2024

Background: Traumatic femoral fractures, often resulting from high-energy impacts such as traffic accidents, necessitate immediate management to avoid severe complications. The Stress Index (SI), defined as the glucose-to-potassium ratio, serves as a predictor of mortality and adverse outcomes in various trauma contexts. This study aims to evaluate the prognostic value of the SI in patients with traumatic femoral fractures. Methods: This retrospective cohort study included adult trauma patients aged 20 or above with traumatic femoral fractures from the Trauma Registry System at a level 1 trauma center in southern Taiwan between 1 January 2009 and 31 December 2022. At the emergency room, serum electrolyte levels were assessed using baseline laboratory testing. By dividing blood glucose (mg/dL) by potassium (mEq/L), the SI was calculated. The best cut-off value of the SI for predicting mortality was determined using the Area Under the Curve (AUC) of Receiver Operating Characteristic (ROC). Results: A total of 3717 patients made up the final group, of which 3653 survived and 64 died. In comparison to survivors, deceased patients had substantially higher blood glucose levels (199.3 vs. 159.0 mg/dL, p < 0.001) and SIs (53.1 vs. 41.6, p < 0.001). The optimal SI cut-off value for predicting mortality was 49.7, with a sensitivity of 53.1% and a specificity of 78.7% (AUC = 0.609). High SI was associated with increased mortality (4.2% vs. 1.0%, p < 0.001) and longer hospital stays (12.8 vs. 9.5 days, p < 0.001). The adjusted odds ratios of mortality, controlled by comorbidities, the Glasgow Coma Scale, and the Injury Severity Score, were significantly higher in patients with a higher SI (AOR 2.05, p = 0.016) than those with a lower SI. Conclusions: Elevated SI upon admission correlates with higher mortality and extended hospital stay in patients with traumatic femoral fractures. Although the SI has a moderate predictive value, it remains a useful early risk assessment tool, necessitating further prospective, multi-center studies for validation and standardization.
A Survey on Error Exponents in Distributed Hypothesis Testing: Connections with Information Theory, Interpretations, and Applications
Authors: Espinosa Sebastián , Silva Jorge F. , Céspedes Sandra
Published: July 2024

A central challenge in hypothesis testing (HT) lies in determining the optimal balance between Type I (false positive) and Type II (non-detection or false negative) error probabilities. Analyzing these errors’ exponential rate of convergence, known as error exponents, provides crucial insights into system performance. Error exponents offer a lens through which we can understand how operational restrictions, such as resource constraints and impairments in communications, affect the accuracy of distributed inference in networked systems. This survey presents a comprehensive review of key results in HT, from the foundational Stein’s Lemma to recent advancements in distributed HT, all unified through the framework of error exponents. We explore asymptotic and non-asymptotic results, highlighting their implications for designing robust and efficient networked systems, such as event detection through lossy wireless sensor monitoring networks, collective perception-based object detection in vehicular environments, and clock synchronization in distributed environments, among others. We show that understanding the role of error exponents provides a valuable tool for optimizing decision-making and improving the reliability of networked systems.
Color Image Encryption Based on an Evolutionary Codebook and Chaotic Systems
Authors: Cao Yuan , Song Yinglei
Published: July 2024

Encryption of images is an important method that can effectively improve the security and privacy of crucial image data. Existing methods generally encrypt an image with a combination of scrambling and encoding operations. Currently, many applications require highly secure results for image encryption. New methods that can achieve improved randomness for both the scrambling and encoding processes in encryption are thus needed to further enhance the security of a cipher image. This paper proposes a new method that can securely encrypt color images. As the first step of the proposed method, a complete bit-level operation is utilized to scramble the binary bits in a color image to a full extent. For the second step, the bits in the scrambled image are processed with a sweeping operation to improve the encryption security. In the final step of encryption, a codebook that varies with evolutionary operations based on several chaotic systems is utilized to encrypt the partially encrypted image obtained in the second step. Experimental results on benchmark color images suggest that this new approach can securely encrypt color images and generate cipher images that remain secure under different types of attacks. The proposed approach is compared with several other state-of-the-art encryption approaches and the results show that it can achieve improved encryption security for cipher images. Experimental results thus suggest that this new approach can possibly be utilized practically in applications where color images need to be encrypted for content protection.
Could the Roadside Shrines Be a Source of Alien Plant Introductions? The Example of the ‘Difunta Correa’ Shrine in Almería (Spain)
Authors: López-Pujol Jordi , Gómez-Bellver Carlos , Herrera Ileana
Published: July 2024

Ornamental gardens are probably the most important source of invasive alien plants. However, the role of roadside shrines as a source of alien plant introductions remains unexplored. Herein, we are reporting the cultivated alien flora of a roadside shrine (devoted to the ‘Difunta Correa’) in south-eastern Spain, while making a prior assessment of the risk of spreading in the surroundings. In an area of less than 50 m2, up to 20 plant taxa were identified, with the vast majority of them being alien. Some of the observed alien taxa can be very problematic (e.g., Kalanchoe × houghtonii) and are even included in the Spanish catalogue of invasive species (such as Opuntia ficus-indica). Although the shrine is not affecting the local biodiversity yet (though a few taxa are showing the first signs of spread), it is located just 1 km away from a valuable protected area (included within the Natura 2000 network of the European Union and also recognized as a Ramsar site). Roadside shrines and similar places (e.g., memorials or calvaries) should be, thus, regarded as a potential source of alien plant introductions; thus, monitoring is recommended, particularly when close to protected areas.
Latina and Black Women Collegians’ Paternal Relationships: A Chicana and Black Feminist Interpretive Phenomenological Analysis
Authors: Reyes Hannah L. , Mills Kristen J. , Cadet Danielle M. , Johnson Deborah J.
Published: July 2024

In the current qualitative study, we explored father (and varying father figures’) ethnoracial and gendered socialization messages toward Latina and Black college women. We conducted six focus group interviews with Black (n = 3 groups) and Latina (n = 3 groups) college women. Guided by Chicana and Black feminist interpretive phenomenological analysis, we identified four clusters which detailed perceived paternal influences in the lives of these college women: (a) paternal caring, (b) gender socialization, (c) value of education, and (d) developing platonic and romantic relationships.
Impact of Pre-Service Teacher Education Programme on Mathematics Student Teachers’ Teaching Practices during School Experiences
Authors: Olawale Babawande Emmanuel
Published: July 2024

While the pre-service teacher education (PSTE) programme holds global significance, there is a lack of evidence regarding its impact on the teaching practices of mathematics student teachers. Therefore, this study examines the impact of PSTE programmes on mathematics student teachers’ teaching practices during school experiences. Grounded in a post-positivist paradigm, the study employs a mixed-methods research approach and a sequential explanatory mixed-methods design to gather data through questionnaires and semi-structured interviews. The research findings indicate that PSTE programmes have a significant impact on mathematics student teachers’ ability to teach mathematical content that aligns with curriculum standards, enhances their subject knowledge, and increases their confidence. However, the programmes have minimal influence on their ability to implement differentiated instruction during their teaching practices. Based on these findings, the study concludes that although mathematics student teachers may lack the necessary skills to implement differentiated instruction, high-quality teacher education programmes can build their confidence and enable them to effectively manage their classrooms and adapt teaching practices to meet diverse learner needs. Therefore, the study suggests that stakeholders involved in PSTE programmes should provide continuous guidance and constructive feedback to help student teachers overcome challenges and improve their teaching practices. This support system is crucial for the success of the PSTE programme and has a direct impact on the quality of mathematics instruction in schools.
Characteristic Mode-Based Dual-Mode Dual-Band of Single-Feed Antenna for On-/Off-Body Communication
Authors: Li Tong , Gao Jinwei , Rasool Nouman , Basit Muhammad Abdul , Chen Chen
Published: July 2024

A dual-band, dual-mode button antenna is proposed for emerging fifth-generation (5G) networks and Industrial, Scientific, and Medical (ISM) communication systems, as it operates at 3.5 GHz and 5.8 GHz, respectively. At the lower band, a monopole-like omnidirectional radiation pattern is achieved by loading shorting pins on curved strips for on-body communication. At the higher band, broadside circularly polarized radiation is achieved by loading an asymmetric U-shaped slot in the central chamferd patch for off-body communication. By using Characteristic Modal Analysis (CMA), a clear physical insight into the formation of dual polarization is provided. The −10 dB impedance bandwidth ranges from 3.48 to 3.60 GHz and 5.65 to 6.03 GHz, respectively. The 3 dB axial ratio (AR) bandwidth ranges from 5.71 to 5.85 GHz in the high band. Additionally, the antenna achieves a peak gain of 1.2 dBi in on-body mode and 6.9 dBi in off-body mode. The maximum specific absorption rate (SAR) calculated on the body tissues is below the US/EU standard thresholds of 1.6 W/kg and 2 W/kg. The measured results indicate that the antenna experiences only slight impact from human body loading and structural deformations. Given its notable features, the proposed design is well suited for Wireless Body Area Network (WBAN) applications.
PGE-YOLO: A Multi-Fault-Detection Method for Transmission Lines Based on Cross-Scale Feature Fusion
Authors: Cai Zixuan , Wang Tianjun , Han Weiyu , Ding Anan
Published: July 2024

Addressing the issue of incorrect and missed detections caused by the complex types, uneven scales, and small sizes of defect targets in transmission lines, this paper proposes a defect-detection method based on cross-scale feature fusion, PGE-YOLO. Firstly, feature extraction is enriched by replacing the convolutional blocks in the backbone network that need to be cascaded and fused using the Par_C2f network module, which incorporates a parallel network (ParNet). Secondly, a four-layer efficient multi-scale attention (EMA) mechanism is incorporated into the network’s neck to address long and short dependency issues. This enhancement aims to improve global information retention by employing parallel substructures and integrating cross-space feature information. Finally, the paradigm of generalized feature fusion (GFPN) is introduced and reconfigured to develop a novel CE-GFPN. This model effectively integrates shallow feature information with deep feature information to enhance the capability of feature fusion and improve detection performance. Using a real transmission line multi-defect dataset from UAV aerial photography and the CPLID dataset, ablation and comparison experiments with various models demonstrated that our model achieved superior results. Compared to the initial YOLOv8n model, our model increased the detection accuracy by 6.6% and 1.2%, respectively, while ensuring there is no surge in the number of parameters. This ensures that the real-time and accuracy requirements for defect detection in the industry are satisfied.
Remaining Useful Life Prediction of Aero-Engine Based on KSFA-GMM-BID-Improved Autoformer
Authors: Wei Jiashun , Li Zhiqiang , Li Yang , Zhang Ying
Published: July 2024

Addressing the limitation of traditional deep learning models in capturing the spatio-temporal characteristics of flight data and the constrained prediction accuracy due to sequence length in aero-engine life prediction, this study proposes an aero-engine remaining life prediction approach integrating a kernel slow feature analysis, a Gaussian mixture model, and an improved Autoformer model. Initially, the slow degradation features of gas path performance parameters over time are extracted through kernel slow feature analysis, followed by the establishment of a Gaussian mixture model to create a health state representation using Bayesian inferred distances for quantifying the aero-engine’s health status. Moreover, a spatial attention mechanism is introduced alongside the autocorrelation mechanism of the Autoformer model to augment the global feature extraction capacity. Additionally, a multilayer perceptron is employed to further elucidate the degradation trends, which enhances the model’s learning and predictive capabilities for extended sequences. Subsequently, experiments are conducted using authentic aero-engine operational data, comparing the proposed method with the standard Autoformer and Transformer models. The results demonstrate that the proposed method outperforms both models in swiftly and accurately predicting the remaining life of aero-engines with robustness and high prediction accuracy.
LMD-DARTS: Low-Memory, Densely Connected, Differentiable Architecture Search
Authors: Li Zhongnian , Xu Yixin , Ying Peng , Chen Hu , Sun Renke , Xu Xinzheng
Published: July 2024

Neural network architecture search (NAS) technology is pivotal for designing lightweight convolutional neural networks (CNNs), facilitating the automatic search for network structures without requiring extensive prior knowledge. However, NAS is resource-intensive, consuming significant computational power and time due to the evaluation of numerous candidate architectures. To address the issues of high memory usage and slow search speed in traditional NAS algorithms, we propose the Low-Memory, Densely Connected, Differentiable Architecture Search (LMD-DARTS) algorithm. To expedite the updating speed of the optional operation weights during the search process, LMD-DARTS introduces a continuous strategy based on weight redistribution. Furthermore, to mitigate the influence of low-weight operations on classification results and reduce the number of searches, LMD-DARTS employs a dynamic sampler to prune underperforming operations during the search process, thereby lowering memory consumption and simplifying the complexity of individual searches. Additionally, to sparsify the dense connection matrix and mitigate redundant connections while maintaining optimal network performance, we introduce an adaptive downsampling search algorithm. Our experimental results show that the proposed LMD-DARTS achieves a remarkable 20% reduction in search time, along with a significant decrease in memory utilization within NAS process. Notably, the lightweight CNNs derived through this algorithm exhibit commendable classification accuracy, underscoring their effectiveness and efficiency for practical applications.
A Low-Profile Wide-Angle Coverage Antenna
Authors: Guo Jingli , Zhang Huanhuan , Liao Wenhao , Huang Youhuo , Qu Lanying
Published: July 2024

A low-profile wide-angle coverage antenna for Ad Hoc communication networks is presented in this letter, which consists primarily of a rotationally symmetrical structure with a microstrip patch antenna positioned at its center. Utilizing two orthogonal coupling feeds, the microstrip antenna produces circularly polarized radiation in the broadside direction. Meanwhile, the rotationally thin structure is driven by the coupling of the microstrip patch, and a linearly polarized radiation out of the range of ±15° is generated. Due to this parasitic structure, the radiation of the whole antenna at the upper hemisphere is balanced greatly, which leads to the wide-angle coverage ability enhancement of the low-profile antenna. A prototype operating at 2.7 GHz is fabricated and tested, demonstrating an impedance bandwidth of 15% (2.4 to 2.8 GHz). Measurement results show a 6 dB difference between the maximum and minimum gain in the upper hemisphere. With an overall antenna height of just 6 mm, all gains in the upper hemisphere exceed −3.5 dB.
A Review on the Impact of Transmission Line Compensation and RES Integration on Protection Schemes
Authors: Mazibuko Ntombenhle , Akindeji Kayode T. , Moloi Katleho
Published: July 2024

South Africa is currently experiencing an energy crisis because of a mismatch between energy supply and demand. Increasing energy demand necessitates the adequate operation of generation and transmission facilities to maintain the reliability of the power system. Transmission line compensation is used to increase the ability to transfer power, thereby enhancing system stability, voltage regulation, and reactive power balance. Also, in recent years, the introduction of renewable energy sources (RES) has proven to be effective in supporting the grid by providing additional energy. As a result, the dynamics of power systems have changed, and many developing nations are adopting the integration of renewable energy into the grid to increase the aspect ratio of the energy availability factor. While both techniques contribute to the grid’s ability to meet energy demand, they frequently introduce technical challenges that affect the stability and protection of the systems. This paper provides a comprehensive review of the challenges introduced by transmission line compensation and the integration of renewable energy, as well as the various techniques proposed in the literature to address these issues. Different compensation techniques, including fault detection, classification, and location, for compensated and uncompensated transmission lines, including those connected to renewable energy sources, are reviewed. This paper then analyzes the adaptive distance protection schemes available in the literature to mitigate the impact of compensation/integration of RES into the grid. Based on the literature reviewed, it is essential for protection engineers to understand the dynamics introduced by network topology incorporating a combination of RES and heavily compensated transmission lines.
Using Crested Porcupine Optimizer Algorithm and CNN-LSTM-Attention Model Combined with Deep Learning Methods to Enhance Short-Term Power Forecasting in PV Generation
Authors: Fan Yiling , Ma Zhuang , Tang Wanwei , Liang Jing , Xu Pengfei
Published: July 2024

Due to the inherent intermittency, variability, and randomness, photovoltaic (PV) power generation faces significant challenges in energy grid integration. To address these challenges, current research mainly focuses on developing more efficient energy management systems and prediction technologies. Through optimizing scheduling and integration in PV power generation, the stability and reliability of the power grid can be further improved. In this study, a new prediction model is introduced that combines the strengths of convolutional neural networks (CNNs), long short-term memory (LSTM) networks, and attention mechanisms, so we call this algorithm CNN-LSTM-Attention (CLA). In addition, the Crested Porcupine Optimizer (CPO) algorithm is utilized to solve the short-term prediction problem in photovoltaic power generation. This model is abbreviated as CPO-CLA. This is the first time that the CPO algorithm has been introduced into the LSTM algorithm for parameter optimization. To effectively capture univariate and multivariate time series patterns, multiple relevant and target variables prediction patterns (MRTPPs) are employed in the CPO-CLA model. The results show that the CPO-CLA model is superior to traditional methods and recent popular models in terms of prediction accuracy and stability, especially in the 13 h timestep. The integration of attention mechanisms enables the model to adaptively focus on the most relevant historical data for future power prediction. The CPO algorithm further optimizes the LSTM network parameters, which ensures the robust generalization ability of the model. The research results are of great significance for energy generation scheduling and establishing trust in the energy market. Ultimately, it will help integrate renewable energy into the grid more reliably and efficiently.
Performance Improvement of an MR-Damper-Based Vibration-Reduction System with Energy Harvesting at Sprung Mass Changes
Authors: Sapiński Bogdan , Jastrzębski Łukasz
Published: July 2024

The present paper is concerned with a magnetorheological (MR)-damper-based vibration-reduction system with energy harvesting capability considering sprung mass changes. The system represents a mechanical harmonic oscillator with electrical coupling, set in motion by kinematic excitation. The authors examine the system performance in the case when the MR damper control coil (damper control coil) is powered directly by the alternating current resulting from the voltage generated in an electromagnetic harvester in the assumed frequency range of sine excitation. Such a system is able to attenuate vibration in the near-resonance frequency range when the current in the damper control coil increases; however, its drawback is vibration amplification at higher frequencies. To eliminate this negative feature, it is proposed to connect shunt capacitors in parallel with the damper control coil. Then, the system can be tested experimentally in terms of current in the damper control coil, sprung mass, and the capacity of shunt capacitors in order to evaluate system performance according to the assumed performance index. The obtained results demonstrate significant improvement in system performance at higher frequencies of excitation.
Enhancing Electrode Efficiency in Proton Exchange Membrane Fuel Cells with PGM-Free Catalysts: A Mini Review
Authors: Martinaiou Ioanna , Daletou Maria K.
Published: July 2024

Proton Exchange Membrane Fuel Cells (PEMFCs) represent a promising green solution for energy production, traditionally relying on platinum-group-metal (PGM) electrocatalysts. However, the increasing cost and limited global availability of PGMs have motivated extensive research into alternative catalyst materials. PGM-free oxygen reduction reaction (ORR) catalysts typically consist of first-row transition metal ions (Fe, Co) embedded in a nitrogen-doped carbon framework. Key factors affecting their efficacy include intrinsic activity and catalyst degradation. Thus, alternative materials with improved characteristics and the elucidation of reaction and degradation mechanisms have been the main concerns and most frequently explored research paths. High intrinsic activity and active site density can ensure efficient reaction rates, while durability towards corrosion, carbon oxidation, demetallation, and deactivation affects cell longevity. However, when moving to the actual application in PEMFCs, electrode engineering, which involves designing the catalyst layer, and other critical operational factors affecting fuel cell performance play a critical role. Electrode fabrication parameters such as ink formulation and deposition techniques are thoroughly discussed herein, explicating their impact on the electrode microstructure and formed electrochemical interface and subsequent performance. Adjusting catalyst loading, ionomer content, and porosity are part of the optimization. More specifically, porosity and hydrophobicity determine reactant transport and water removal. High catalyst loadings can enhance performance but result in thicker layers that hinder mass transport and water management. Moreover, the interaction between ionomer and catalyst affects proton conductivity and catalyst utilization. Strategies to improve the three-phase boundary through the proper ionomer amount and distribution influence catalyst utilization and water management. It is critical to find the right balance, which is influenced by the catalyst–ionomer ratio and affinity, the catalyst properties, and the layer fabrication. Overall, understanding how composition and fabrication parameters impact electrode properties and behaviour such as proton conductivity, mass transport, water management, and electrode–electrolyte interfaces is essential to maximize electrochemical performance. This review highlights the necessity for integrated approaches to unlock the full potential of PGM-free materials in PEMFC technology. Clear prospects for integrating PGM-free catalysts will drive cleaner and more cost-effective, sustainable, and commercially viable energy solutions.
Prediction of Global Solar Irradiance on Parallel Rows of Tilted Surfaces Including the Effect of Direct and Anisotropic Diffuse Shading
Authors: Pereira Sara , Canhoto Paulo , Salgado Rui
Published: July 2024

Solar photovoltaic power plants typically consist of rows of solar panels, where the accurate estimation of solar irradiance on inclined surfaces significantly impacts energy generation. Existing practices often only account for the first row, neglecting shading from subsequent rows. In this work, ten transposition models were assessed against experimental data and a transposition model for inner rows was developed and validated. The developed model incorporates view factors and direct and circumsolar irradiances shading from adjacent rows, significantly improving global tilted irradiance (GTI) estimates. This model was validated against one-minute observations recorded between 14 April and 1 June 2022, at Évora, Portugal (38.5306, −8.0112) resulting in values of mean bias error (MBE) and root-mean-squared error (RMSE) of −12.9 W/m2 and 76.8 W/m2, respectively, which represent an improvement of 368.3 W/m2 in the MBE of GTI estimations compared to the best-performing transposition model for the first row. The proposed model was also evaluated in an operational forecast setting where corrected forecasts of direct and diffuse irradiance (0 to 72 h ahead) were used as inputs, resulting in an MBE and RMSE of −33.6 W/m2 and 169.7 W/m2, respectively. These findings underscore the potential of the developed model to enhance solar energy forecasting accuracy and operational algorithms’ efficiency and robustness.
Life Cycle Assessment in Renewable Energy: Solar and Wind Perspectives
Authors: Portillo Francisco , Alcayde Alfredo , Garcia Rosa Maria , Fernandez-Ros Manuel , Gazquez Jose Antonio , Novas Nuria
Published: July 2024

The growing urgency for sustainable energy solutions necessitates a deeper understanding of the environmental impacts of renewable technologies. This article aims to synthesize and analyze Life Cycle Assessments (LCA) in this domain, providing a comprehensive perspective. We systematically categorized 2923 articles into four sectors: (1) photovoltaic systems, (2) wind energy systems, (3) solar thermal systems, and (4) materials for auxiliary industry supporting these systems. A comparative analysis was conducted to identify methodological consistencies and disparities across these sectors. The findings reveal diverse methodological approaches and a range of environmental impacts, highlighting the complexities in assessing renewable energy systems. The article underscores the significance of material selection in photovoltaic, solar, and wind systems, providing a critical overview of the current state of LCA research in renewable energy and stressing the need for standardized methodologies. It also identifies gaps in recent research, offering insights for future studies focused on integrating environmental, economic, and social considerations in renewable energy assessments. Integrating environmental assessments provides a robust framework for making informed decisions on sustainable technologies. The findings are critical for projects that balance technological needs with sustainability goals.
Air-Polluting Emissions from Pyrolysis Plants: A Systematic Mapping
Authors: Pivato Alberto , Gohar Hamad , Antille Diogenes , Schievano Andrea , Beggio Giovanni , Reichardt Philipp , Maria Francesco , Peng Wei , Castegnaro Stefano , Lavagnolo Maria
Published: July 2024

There is a growing interest in the use of pyrolysis plants for the conversion of solid waste into useful products (e.g., oil, gas, and char) and the analysis of air-polluting emissions associated with such a process is an emerging research field. This study applied a systematic mapping approach to collating, describing, and cataloging available evidence related to the type and level of air pollutants emitted from pyrolysis plants, the factors affecting emissions, and available mitigation strategies that can be adopted to reduce air pollution. The scientific literature indexed in Scopus and Google Scholar, as well as available industry reports, was interrogated to document the evidence. A database comprising 63 studies was synthesized and cataloged from which 25 air pollutants from pyrolysis plants were considered, including volatile organic compounds and persistent organic pollutants. Air pollutant levels varied depending on the scale of the pyrolysis plants, their operating conditions, and the feedstock used. Various technologies, such as wet scrubbers, electrostatic precipitators, and baghouse filters, are available and have been utilized to reduce emissions and comply with the existing EU regulations for waste incineration (2010/75/EU). The systematic mapping identified several knowledge gaps that need to be addressed to inform relevant environmental policymaking, technology development, and the adoption of best practices for the mitigation of emissions from pyrolysis plants.
Optimization of the Process of Chinese Hamster Ovary (CHO) Cell Fed-Batch Culture to Stabilize Monoclonal Antibody Production and Overall Quality: Effect of pH Control Strategies
Authors: Liang Kexue , Luo Hongzhen , Li Qi
Published: July 2024

Monoclonal antibodies (mAbs) used in biomedical research and therapeutic applications are primarily produced by Chinese hamster ovary (CHO) cells via fed-batch culture. The growing need for elevated quantities of biologics mandates the continual optimization of the mAb production process. The development of an effective process control method is indispensable for the production of specified mAbs by CHO cells. In this study, the effects of the pH control strategy on CHO cell fed-batch culture to produce an antibody (EA5) were first investigated in a 3 L bioreactor. The results indicate that controlling the culture pH at 7.2 during the fed-batch stage could produce a higher EA5 titer of 6.1 g/L with a lower Man5 ratio of 2.2% by day 14. Based on this, an optimized CHO cell fed-batch culture was conducted in a 15 L bioreactor to verify its effectiveness and stability. In this case, on day 14, an EA5 titer of 6.5 g/L was achieved with productivity of 0.46 g/L/day, which was 1.07-fold higher compared to that of the culture in the 3 L bioreactor. Furthermore, regarding the product quality, a monomer abundance of 96.0%, a main peak of 55.0%, and a Man5 proportion of 2.4% were maintained in the 15 L bioreactor. In addition, different cell clarification processes were evaluated using the CHO cell culture broth from the 3 L and 15 L bioreactors to further improve productivity and economic performance. Overall, this study provides some directions for process intensification and improving the quality of mAbs produced by CHO cells in the biopharmaceutical industry.
Analysis of Microbial Community Changes and Their Correlations with Volatile Flavouring Substances during Autonomous Fermentation of Western Sichuan Yi Suancai Based on High-Throughput Sequencing
Authors: Fang Yuli , Bian Minghong , Wu Xuan , Yuan Lemei , Xu Qiang , Zhou Weitao , Han Baolin
Published: July 2024

Western Sichuan Yi suancai contains a group of highly functional microorganisms in an alpine and high-altitude ecological environment. Due to its unique salt-free fermentation process, it is nutritious and has a crispy texture. Six periods were established during fermentation: day 0, day 2, day 5, day 8, day 11, and day 14. The results showed that the antioxidant capacity and organic acid content increased during the fermentation process, while the pH gradually decreased, indicating that suancai from the later periods was better for supplementing the human body with acid substances and eliminating free radicals. Twenty-six flavour compounds were identified, including alcohols, esters, ketones, and acids. Ethyl alcohol, 3-methyl-1-butanol, ethyl methanoate, and acetic acid were the main contributors to the flavour, imparting floral and fruity notes to the suancai. Five dominant bacterial genera (Lactobacillus, Leuconostoc, Weissella, Klebsiella, and unclassified_o__Lactobacillales) were identified via high-throughput sequencing during the fermentation process, and there were nine dominant fungal genera (Dipodascaceae_gen_Incertae_sedis, Mucor, Pichia, unclassified__f__Dipodascaceaet, Cyberlindnera, Diutina, Trichosporon, Saccharomycopsis, and Wickerhamomyces). Correlation analysis showed that the antioxidant capacity was positively correlated with genera such as Lactobacillus, Mucor, and Alternaria, indicating that these microorganisms have important roles in enhancing the antioxidant properties of suancai. Meanwhile, some genera, such as Microbacterium, Herbaspirillum, Mortierella, and Sampaiozyma, promote the synthesis of alcohols, esters, acids, and ketones. This study revealed the interactions between microorganisms and metabolites during the fermentation of western Sichuan Yi suancai and provided a scientific basis for further understanding the fermentation mechanism of traditional suancai and improving the fermentation process.