bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Al2O3 and h-BN on Wear and Corrosion Performance of IN625 Nickel-Based Coating
Authors: Yan Huan , Li Lei , Hu HongLei , Huang Wen
Published: October 2024

IN625 offers high-temperature oxidation resistance, wear resistance, and stable chemical properties. To improve the corrosion and wear resistance of the Q345B steel surface, two types of metal matrix composites (IN625 + 1% Al2O3 and IN625 + 1% h-BN) were applied to the substrate surface using the laser cladding process. This study analyzed the hardness, electrochemical corrosion, friction, and wear properties of both the laser-clad specimens and the substrates. The results show that (1) the hardness and wear resistance of the fusion-coated coating were significantly improved compared with the base material. Notably, the hardness increased by 19%, and the coefficient of friction decreased by 41% compared with the IN625 + 1% h-BN coating. Furthermore, the hardness and wear resistance of the IN625 + 1% h-BN coating were superior to those of the IN625 + 1% Al2O3 coating, attributed to the formation of eutectic compounds such as NiB and Ni2B in the dendritic region. (2) The corrosion resistance of the IN625 + 1% Al2O3 coating exceeds that of the IN625 + 1% h-BN coating and is also superior to that of the substrate. This improvement is primarily attributed to the addition of Al2O3, which enhances solid solution strengthening within the dendritic crystals of the fused-coating layer, reduces the percentage content of inclusions, and elevates the corrosion resistance of the coatings.
β-Yb2CdSb2—A Complex Non-Centrosymmetric Zintl Polymorph
Authors: Watts Spencer R. , Najera Larissa , Ogunbunmi Michael O. , Bobev Svilen , Baranets Sviatoslav
Published: October 2024

The ternary Zintl phase, Yb2CdSb2, was discovered to exist in two different polymorphic forms. In addition to the orthorhombic α-Yb2CdSb2 (space group Cmc21) known for its excellent thermoelectric properties, we present the synthesis and characterization of the crystal and electronic structure of its monoclinic variant, β-Yb2CdSb2. Structural characterization was performed with the single-crystal X-ray diffraction method. β-Yb2CdSb2 crystallizes in a monoclinic crystal system with the non-centrosymmetric space group Cm (Z = 33, a = 81.801(5) Å, b = 4.6186(3) Å, c = 12.6742(7) Å, β = 93.0610(10)°) and constitutes a new structure type. The complex crystal structure of β-Yb2CdSb2 contrasts with the previously studied β-Ca2CdPn2 (Pn = P, As, Sb) polymorphs, although it shares similar structural features. It consists of three different layers, made of corner-sharing [CdSb4] tetrahedra and stacked in the ABC sequence. The layers are interconnected via [CdSb3] trigonal planar units. Multiple Yb and Cd atomic sites exhibit partial occupancy, resulting in extensive structural disorder. Valence electron partitioning within the Zintl–Klemm formalism yields the formulation (Yb2+)1.98(Cd2+)1.01(Sb3−)2(h+)0.02, highlighting the nearly charge-balanced composition. Detailed electronic structure calculations reveal the closed band gap and presumably semimetallic nature of β-Yb2CdSb2 with the band structure features hinting at potential topological properties.
Analysis of Energy Flow to the Interface Microstructure and Its Effect on Weld Strength in Ultrasonic Additive Manufacturing
Authors: Venkatraman Gowtham , Headings Leon M. , Dapino Marcelo J.
Published: October 2024

Ultrasonic additive manufacturing (UAM) is a process used for the three-dimensional printing of metal foil stock that can produce near-net-shaped metallic parts. This work details the development of an energy-based tool to identify the relationships between input energy, energy stored in the interface microstructure, and the strength of the weld interface in UAM. The stored energy in the grain boundaries of the crystallized grains in the interface microstructure are estimated using the Read–Shockley relationship. The energy stored in the interface is found to be positively correlated with the resulting weld strength. An energy flow diagram is developed to map the flow of energy from the welder to the workpiece and quantify the key participating energies such as the energy of plastic deformation, energy stored in the interface microstructure, energy required for asperity collapse, and heat generation. A better understanding of the flow of energy in UAM can assist in optimizing the process to maximize the portion of energy input by the welder that is used for bond formation.
Age Difference, Not Food Scarcity or Sibling Interactions, May Drive Brood Reduction in Wild Scarlet Macaws in Southeastern Peru
Authors: Vigo-Trauco Gabriela , Martínez-Sovero Gustavo , Brightsmith Donald J.
Published: October 2024

Avian brood reduction was initially thought to be driven by insufficient food supply. Now it is more commonly considered a consequence of asynchronous hatching and resulting siblicide, direct filial infanticide (where parents kill specific chicks) or indirect filial infanticide (where parents starve specific chicks). In psittacines, brood reduction has been reported, but the mechanisms and causes remain unexplored. In this paper, we test the hypotheses that Scarlet Macaw chick starvation is driven by (1) sibling aggression, (2) food scarcity, and (3) parental food allocation based on (a) chick hatch weight and (b) chick age differences. We documented wild Scarlet Macaw behavior in lowland Peru in 37 nests over 19 seasons using morphological measurements and nest videos. Chick starvation was the leading cause of chick mortality (27% of all second-hatched chicks starve, and nearly all third- and fourth-hatched chicks starve). We found no evidence that starvation was caused by (1) sibling conflicts or (2) food availability. We did find parental food distribution favors first-hatched chicks, with larger age differences increasing the chances of second chick starvation. This study offers insights into brood reduction among Neotropical cavity-nesting birds and enhances our capacity to develop scientifically informed management strategies to support endangered psittacines.
Improving Automatic Coronary Stenosis Classification Using a Hybrid Metaheuristic with Diversity Control
Authors: Gil-Rios Miguel-Angel , Cruz-Aceves Ivan , Hernandez-Aguirre Arturo , Hernandez-Gonzalez Martha-Alicia , Solorio-Meza Sergio-Eduardo
Published: October 2024

This study proposes a novel Hybrid Metaheuristic with explicit diversity control, aimed at finding an optimal feature subset by thoroughly exploring the search space to prevent premature convergence. Background/Objectives: Unlike traditional evolutionary computing techniques, which only consider the best individuals in a population, the proposed strategy also considers the worst individuals under certain conditions. In consequence, feature selection frequencies tend to be more uniform, decreasing the probability of premature convergent results and local-optima solutions. Methods: An image database containing 608 images, evenly balanced between positive and negative coronary stenosis cases, was used for experiments. A total of 473 features, including intensity, texture, and morphological types, were extracted from the image bank. A Support Vector Machine was employed to classify positive and negative stenosis cases, with Accuracy and the Jaccard Coefficient used as performance metrics. Results: The proposed strategy achieved a classification rate of 0.92 for Accuracy and 0.85 for the Jaccard Coefficient, obtaining a subset of 16 features, which represents a discrimination rate of 0.97 from the 473 initial features. Conclusions: The Hybrid Metaheuristic with explicit diversity control improved the classification performance of coronary stenosis cases compared to previous literature. Based on the achieved results, the identified feature subset demonstrates potential for use in clinical practice, particularly in decision-support information systems.
Histopathological Evaluation of Somatostatin Receptor 2 Expression in Myocarditis—Rationale for the Diagnostic Use of Somatostatin Receptor Imaging
Authors: Polte Christian L. , Visuttijai Kittichate , Vukusic Kristina , Sandstedt Joakim , Sandstedt Mikael , Bobbio Emanuele , Björkenstam Marie , Karason Kristjan , Bergh Niklas , Bollano Entela , Oldfors Anders
Published: October 2024

Background/Objectives: Myocarditis is an inflammatory disease of the myocardium and remains to this day a challenging diagnosis. A promising novel imaging method uses the expression of somatostatin receptors (SSTRs) on inflammatory cells to visualize myocardial inflammation. However, little is known about the histopathological correlate of SSTR imaging in different forms of myocarditis. Methods: In the present retrospective histopathological study, we systematically analysed the expression of SSTR subtype 2 (SSTR2) on inflammatory cells of 33 patients with biopsy- or explant-proven myocarditis (lymphocytic myocarditis (n = 5), giant-cell myocarditis (n = 11), and cardiac sarcoidosis (n = 17)), and in eight controls (multi-organ donors) without signs of myocardial inflammation and/or scars. Results: In all patients, immunohistochemical staining for SSTR2 was positive in areas with CD68-positive macrophages and multinucleated giant cells. Staining for SSTR2 was most prominent in the presence of multinucleated giant cells. The colocalization of both SSTR2 and CD68 on the same cell could be confirmed using immunofluorescence microscopy. Western blotting confirmed the upregulated expression of SSTR2 in cases of granulomatous inflammation (sarcoidosis) of the skeletal and heart muscle, in comparison with controls. Conclusions: In conclusion, our findings demonstrate the expression of SSTR2 on the protein level on CD68-positive macrophages and multinucleated giant cells in various forms of myocarditis, which provides a clear rationale for the diagnostic use of SSTR imaging in this patient group.
Clinical Performance of the LiquidArray® Gastrointestinal VER 1.0 Assay in Patients with Suspected Gastroenteritis
Authors: Jones Sophie , Pheasant Kathleen , Dalton Colette , Green Julie , Moore Catherine
Published: October 2024

Background/Objectives: Rapid and accurate pathogen identification is essential for the proper management of patients with infectious gastroenteritis, as well as for a better control of disease outbreaks. This observational, non-interventional, single-site study evaluated the diagnostic accuracy of LiquidArray® Gastrointestinal VER 1.0, a multiplex PCR syndromic panel capable of detecting up to 26 clinically relevant enteropathogens. Methods: Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and likelihood ratio (LR) were evaluated using stool samples from 1512 patients with suspected gastroenteritis and were compared to seven competitor assays. Results: LiquidArray® Gastrointestinal VER 1.0 showed a very low invalid rate (0.5% at initial testing, down to 0% after repeat) and high sensitivity (>90% for most detected targets) and specificity (>99% for all detected targets). Accordingly, the PPV and NPV were high (>90% for most targets and >99% for all targets, respectively). The analytical performance of LiquidArray® Gastrointestinal VER 1.0 was also excellent as to co-amplification capability, cross-reactivity and assay precision. Conclusions: This study demonstrates the excellent clinical performance of LiquidArray® Gastrointestinal VER 1.0 and its suitability for implementation in clinical routine for the rapid and accurate diagnosis of infectious gastroenteritis.
Sagittal Realignment Following Decompression for Lumbar Spinal Stenosis in Elderly Patients: A Comprehensive EOS Imaging Analysis
Authors: Park Hyung-Youl , Jung Ho-Young , Kim Geon-U , Lee Se-Heon , Lee Jun-Seok
Published: October 2024

Background/Objectives: This study investigated whether decompression surgery for lumbar spinal stenosis can effectively improve sagittal alignment in elderly patients. With the growing focus on sagittal balance in spinal surgery, this study aimed to evaluate post-decompression alignment changes and identify the factors influencing these changes using the EOS imaging system. Methods: A retrospective analysis was conducted on 49 elderly patients who underwent decompression surgery alone for lumbar spinal stenosis. Radiologic parameters, measured using the EOS system, and clinical outcomes were assessed preoperatively, at two weeks postoperatively, and at one year postoperatively. Patients were grouped based on the improvement of the sagittal vertical axis (SVA) by 25 mm or more. A multivariate analysis was performed to identify factors affecting sagittal alignment changes. Results: Significant sagittal alignment improvements were observed postoperatively, including a notable increase in thoracic kyphosis and a decrease in SVA observed at one year. Clinical outcomes, such as the Oswestry disability index (ODI) and EQ-5D, significantly improved at both two weeks and one year postoperatively compared to preoperative values (all p-values < 0.05). Multivariate analysis revealed that greater preoperative SVA and higher ODI were significant predictors of sagittal alignment changes (odds ratio [OR] for SVA = 1.014, OR for ODI = 1.034). Conclusions: Decompression surgery for lumbar spinal stenosis in elderly patients can result in significant improvements in sagittal alignment and clinical outcomes. The study suggests that decompression alone is a viable surgical option for elderly patients, particularly those with a greater preoperative sagittal imbalance and disability, even in the absence of major deformities.
Mammographic Breast Density at Breast Cancer Diagnosis and Breast Cancer-Specific Survival
Authors: Kanbayti Ibrahem , Akwo Judith , Erim Akwa , Ukpong Ekaete , Ekpo Ernest
Published: October 2024

Background: Breast density impacts upon breast cancer risk and recurrence, but its influence on breast cancer-specific survival is unclear. This study examines the influence of mammographic breast density (MBD) at diagnosis on breast cancer-specific survival. Methods: The data of 224 patients diagnosed with breast cancer were analyzed. Two area-based MBD measurement tools—AutoDensity and LIBRA—were used to measure MBD via a mammogram of the contralateral breast acquired at the time of diagnosis. These patients were split into two groups based on their percent breast density (PBD): high (PBD ≥ 20%) versus low (PBD < 20%). Breast cancer-specific survival in each of these PBD groups was assessed at a median follow-up of 34 months using Kaplan–Meier analysis and the Cox proportional hazards model. Results: The proportion of women with low PBD who died from breast cancer was significantly higher than that seen with high PBD (p = 0.01). The 5-year breast cancer-specific survival was poorer among women with low PBD than those with high PBD (0.348; 95% CI: 0.13–0.94) vs. 0.87; 95% CI: (0.8–0.96); p < 0.001)]. Women with higher breast density demonstrated longer survival regardless of the method of PBD measurement: LIBRA [log-rank test (Mantel–Cox): 9.4; p = 0.002)]; AutoDensity [log-rank test (Mantel–Cox) 7.6; p = 0.006]. Multivariate analysis also demonstrated that there was a higher risk of breast cancer-related deaths in women with low PBD (adjusted HR: 5.167; 95% CI: 1.974–13.521; p = 0.001). Conclusion: Women with <20% breast density at breast cancer diagnosis demonstrate poor survival regarding the disease. The impact of breast density on survival is not influenced by the method of measurement.
Cybersecurity Transformation: Cyber-Resilient IT Project Management Framework
Authors: Al-Janabi Samir , Jabbar Haidar , Syms Francis
Published: October 2024

In response to the escalating threats of cybersecurity attacks and breaches, ensuring the development and deployment of secure IT products has become paramount for organizations in their cybersecurity transformation. This work emphasizes the critical need for a comprehensive and secure IT project management life cycle that safeguards products from their initial development stages through decommissioning. The primary objective is to seamlessly integrate security considerations into every facet of IT project management life cycles. This work embraces a cyber-resilient IT project management framework and advocates the inclusion of cybersecurity measures in IT projects and their strategic, organized, continuous, and systematic integration throughout the entire product life cycle. It introduces a pioneering framework that harmonizes the cybersecurity risk management process with the IT project management life cycle. This framework delineates a methodical sequence of steps, each encompassing a distinct set of activities. The effectiveness and practical applicability of the proposed framework were validated through a comprehensive case study focused on the Personal Health Record (PHR) system. The PHR case study served as a real-world scenario to assess the framework’s ability to address cybersecurity challenges in a specific domain. The results of the experiment demonstrated the framework’s efficacy in enhancing the security posture of IT projects, showcasing its adaptability and scalability across diverse applications.
Direct vs. Indirect Digital Implant Impressions: A Time and Cost Analysis
Authors: Sampaio-Fernandes Manuel António , Pinto Ricardo Jorge , Almeida Paulo Rocha , Sampaio-Fernandes Maria Margarida , Silva Marques Duarte Nuno , Figueiral Maria Helena
Published: October 2024

Background/Objectives: This study aimed to compare the cost and time implications for implant-supported prosthesis comparing three digital impression techniques: digitization with an intraoral scanner, digitization of the conventional impression (without dental casts) and digitization of the stone models. Methods: To assess the time and cost of digital impression techniques on implants, time records on intraoral scans were consulted and three models were created with one, two and six implants to assess extraoral procedures time. Costs were evaluated based on material consumption, time expenditure and operator-related expenses. Time was recorded in three stages: (1) impression-taking, (2) model fabrication and (3) overall workflow completion. Statistical analysis was performed using ANOVA to compare cost and time differences across workflows. Results: Intraoral scanning presented a reduction in chair-side time between 4 and 20% when compared to extraoral techniques. For the three clinical situations evaluated, the intraoral scanning always presented the lowest cost. The extraoral digitization of impressions showed a reduction between 51.9% and 53.6% in laboratory time and between 3.5% and 7.6% in total cost compared to stone models digitization. Conclusions: The findings of this study indicate that intraoral scanning is a more cost-effective and time-efficient alternative to traditional impression methods, providing advantages in terms of reduced material use and shorter procedural durations.
Effects of Digital Elevation Model Resolution on Unmanned Aerial Vehicle-Based Topographic Change Detection in Human-Altered Landscapes
Authors: Dai Wen , Hu Jiahui , Wang Bo , Fan Mengtian , Zhou Yiyang , Zhang Mengmeng
Published: October 2024

UAV-based topographic change detection is widely used in geoscience communities. The change detection involves comparison of two digital elevation models (DEMs) produced by UAV surveys, which are affected by the DEM resolution. Coarse resolution DEMs introduce errors in change detection, but the DEM resolution effect remains poorly understood. Moreover, effective strategies for mitigating the resolution effect have yet to be investigated. This study generated UAV-based DEMs at resolutions ranging from 0.1 m to 10 m with various resampling methods. The impact of DEM resolution on topographic change detection was then evaluated by analyzing the difference of DEM (DoD) and volume budget errors with indices such as mean error (ME), standard deviation (STD), and Moran’s I. The results from two human-altered landscapes showed that the random errors of DoD increase rapidly with the DEM resolution coarsening, while DoD systematic errors (spatial distribution of errors) become stable after 4 m resolution. The volume budget errors also increase with DEM coarsening. Coarser resolution DEMs tend to underestimate the volume budget (gross erosion, gross deposition, and net changes). Moreover, selecting an appropriate method for generating DEM is beneficial in decreasing the errors caused by the resolution effect. Among the seven methods (MAX, MIN, MEAN, BIL, NEAR, NEB, and TIN), the BIL method is optimum for mitigating both DoD and volume errors. The NEAR, NEB, and TIN methods are equivalent, and they are superior to the aggregation methods (MAX, MIN, MEAN). The slope of DoD (SDoD) should be considered when selecting a resolution for change detection. Large errors tend to appear in areas with large SDoD and vice versa. Coarse resolution DEMs are tolerable in areas with low SDoD, while high resolution DEMs are necessary in areas with large SDoD.
Transforming Learning Orientations Through STEM Interdisciplinary Project-Based Learning
Authors: Seo Soobin , Van Orman Dustin S. J. , Beattie Mark , Paxson Lucrezia Cuen , Murray Jacob
Published: October 2024

Science, technology, engineering, and math (STEM) education is challenged by industries to incorporate business, engineering, and communication experiences to prepare students for workplace success. In this study, we outline an approach—the STEM Oriented Alliance for Research (SOAR)—to enhance student experience by offering interdisciplinary project-based learning (IPBL) for undergraduate students majoring in electrical engineering, communications, and marketing. We examined how students’ disciplinary and cooperative orientations toward learning shifted in response to their experiences in a semester-long interdisciplinary project-based learning experience with authentic industry outputs. Using a multi-method approach, we explored how interdisciplinary projects influenced student experiences in terms of five collaboration abilities: positive interdependence, accountability, promotive interaction, group processing, and social skills. Further, we observed a shift from fixed- to more growth-oriented mindsets, and from a primarily disciplinary to interdisciplinary focus for their future professional work. The outcomes of the SOAR project make clear that providing structure for professional cooperation on interdisciplinary projects can have profound effects on how students learn to cooperate and position themselves as learners. For most SOAR participants, the experience was deeply formative and contributed to their readiness to cooperate and learn within the interdisciplinary and STEM-oriented workforce.
New Perspectives on Collective Collaboration Within and Between Change Laboratory Sessions
Authors: Kaup Camilla Finsterbach , Dau Susanne
Published: October 2024

This article contributes new knowledge on collaboration within and between Change Laboratory sessions and how it offers the potential to support the zone of proximal development and the expansive learning of participants. The Change Laboratory is a formative intervention method that helps participants transform their practices. This qualitative study examines how six educators participating in a Change Laboratory intervention dealt with problems that arise when implementing digital artifacts in teaching mathematics. We collected data through participant observation between sessions and video recordings during sessions. We conducted the data analysis abductively, using the seven expansive learning actions as an analytical framework. The findings highlight how collaboration between the researcher and the participants, both during and between Change Laboratory sessions, helped support the participants’ zone of proximal development and expansive learning. This close collaboration enabled the educators to collectively reflect on and transform their teaching practices, specifically by incorporating digital artifacts into their educational routines. The study provides important insights into how digital artifacts can be successfully implemented in practice using Change Laboratories, emphasizing the importance of supporting educators in their zone of proximal development. Using a theoretical perspective grounded in cultural-historical activity theory, the study contributes to understanding how change occurs in the educational field.
Application of Digital Twins in Designing Safety Systems for Robotic Stations
Authors: Szybicki Dariusz , Pietruś Paulina , Burghardt Andrzej , Kurc Krzysztof , Muszyńska Magdalena
Published: October 2024

The aim of this paper is to present examples and original solutions related to the application of the digital twin concept in designing safety systems for robotic stations. This paper includes a review of publications on robot safety systems and digital twins. Based on this review, it was concluded that further work in this area is justified. This paper demonstrates the use of a digital model of a robotic casting mold preparation station to design safety components for an industrial cell. A key element of this paper is the presentation of developed algorithms and their applications in building digital twins of existing robotic stations. By characterizing advanced safety systems used in robotic stations, an example of using a digital twin of a robotic station to create safety zones and so-called restricted zones for the robot was developed. As part of the research conducted, a real, comprehensive example of creating safety zones based on the robot’s TCP paths was carried out.
Study of the Pure Deuterium Fuel Burning Rate in Z-Pinch Devices with Magneto-Inertial Confinement
Authors: Bayakhmetov Olzhas , Azamatov Assylkhan
Published: October 2024

The burning rate of pure deuterium (D-D) fuel in Z-pinch devices with magneto-inertial confinement was studied in this paper. The system of particle and energy balance equations for D-D fuel burning with a mixed D-T-3He fusion cycle (D-D, D-T, and D-3He reactions) was solved numerically, taking into account the densities of all reacted and produced ions (protons, deuterium, tritium, helium-3, and alpha-particles). The obtained results indicate that effective D-D fusion in Z-pinch devices can be successfully achieved under conditions of a hot, dense plasma with an initial temperature of 31 keV or higher. The initial ion density of deuterium and electron density were equal due to quasi-neutrality condition of the plasma, with both reaching 1024 m−3. Although the obtained results show that the burning rate of D-D fuel is approximately 2.3 times slower and its power density notably lower than that of D-T fuel, pure deuterium plasma can be considered as a promising alternative to well-studied deuterium–tritium plasma, with potential future applications in magneto-inertial fusion (MIF) facilities.
Towards Sustainable Energy Solutions: Evaluating the Impact of Floating PV Systems in Reducing Water Evaporation and Enhancing Energy Production in Northern Cyprus
Authors: Kassem Youssef , Gökçekuş Hüseyin , Gökçekuş Rifat
Published: October 2024

Floating photovoltaic systems (FPVSs) are gaining popularity, especially in countries with high population density and abundant solar energy resources. FPVSs provide a variety of advantages, particularly in situations where land is limited. Therefore, the main objective of the study is to evaluate the solar energy potential and investigate the techno-economic perspective of FPVSs at 15 water reservoirs in Northern Cyprus for the first time. Due to the solar radiation variations, solar power generation is uncertain; therefore, precise characterization is required to manage the grid effectively. In this paper, four distribution functions (Johnson SB, pert, Phased Bi-Weibull, and Kumaraswamy) are newly introduced to analyze the characteristics of solar irradiation, expressed by global horizontal irradiation (GHI), at the selected sites. These distribution functions are compared with common distribution functions to assess their suitability. The results demonstrated that the proposed distribution functions, with the exception of Phased Bi-Weibull, outperform the common distribution regarding fitting GHI distribution. Moreover, this work aims to evaluate the effects of floating photovoltaic systems on water evaporation rates at 15 reservoirs. To this aim, five methods were used to estimate the rate of water evaporation based on weather data. Different scenarios of covering the reservoir’s surface with an FPVS were studied and discussed. The findings showed that annual savings at 100% coverage can reach 6.21 × 105 m3 compared to 0 m3 without PV panels. Finally, technical and economic assessment of FPVSs with various scales, floating assemblies, and PV technologies was conducted to determine the optimal system. The results revealed that a floating structure (North orientation-tilt 6°) and bifacial panels produced the maximum performance for the proposed FPVSs at the selected sites. Consequently, it is observed that the percentage of reduction in electricity production from fossil fuel can be varied from 10.19% to 47.21% at 75% FPV occupancy.
Thermal–Hydraulic Performance Analysis of Combined Heat Sink with Open Microchannels and Embedded Pin Fins
Authors: Li Yifan , Wang Tianyu , Wang Zhipeng , Zhu Congzhe , Yang Junlan , Yang Bin
Published: October 2024

An open type of microchannel with diamond pin fins (OM-DPFs) is introduced for the cooling of high-performance electronic chips. For a Reynolds number (Re) of 247~1173, a three-dimensional model is established to explore the hydrothermal properties of the OM-DPF and compare it to traditional heat sinks with closed rectangular microchannels (RMs), heat sinks with open microchannels (OMs), and the results in the existing research. Firstly, the synergy between tip clearance and pin fins on the hydrothermal properties is discussed. Secondly, the entropy production principle is adopted to analyze the irreversible losses for different heat sinks. Lastly, the total efficiencies of different heat sinks are assessed. The RMs present the worst heat transfer with the lowest friction loss. For the OMs, the temperature and pressure drop are decreased slightly compared to those of the RMs, and the irreversible loss is reduced by 4% at Re = 1173 because of the small tip clearance. But the total efficiency is lower than that of the RMs because the pressure drop advantage is offset by the weak heat transfer. For the OM-DPF, the combined structure has a noticeable impact on the multiple physical fields and hydrothermal characteristics, which present the best thermal performance at the cost of the highest friction loss. The irreversible loss of heat transfer in the OM-DPF is reduced obviously, but the friction irreversible loss significantly increases at high Re values. At Re = 429, the total entropy production of the OM-DPF is reduced by 47.57% compared with the RM. Compared to the OM and the single-pin fin structure in the literature, the total efficiency of the OM-DPF is increased by 14.56% and 40.32% at Re = 614. For a pump power of 0.1 W, the total thermal resistance (Rth) of the OM-DPF is dropped by 23.77% and 21.19% compared to the RM and OM. For a similar Rth, the pump power of the combined structure is 63.64% and 42.86% lower than that of the RM and OM. Thus, the novel combined heat sink can achieve efficient heat removal while controlling the energy consumption of liquid cooling systems, which has bright application prospects.
Reinforcement Learning Model-Based and Model-Free Paradigms for Optimal Control Problems in Power Systems: Comprehensive Review and Future Directions
Authors: Ginzburg-Ganz Elinor , Segev Itay , Balabanov Alexander , Segev Elior , Kaully Naveh Sivan , Machlev Ram , Belikov Juri , Katzir Liran , Keren Sarah , Levron Yoash
Published: October 2024

This paper reviews recent works related to applications of reinforcement learning in power system optimal control problems. Based on an extensive analysis of works in the recent literature, we attempt to better understand the gap between reinforcement learning methods that rely on complete or incomplete information about the model dynamics and data-driven reinforcement learning approaches. More specifically we ask how such models change based on the application or the algorithm, what the currently open theoretical and numerical challenges are in each of the leading applications, and which reinforcement-based control strategies will rise in the following years. The reviewed research works are divided into “model-based” methods and “model-free” methods in order to highlight the current developments and trends within each of these two groups. The optimal control problems reviewed are energy markets, grid stability and control, energy management in buildings, electrical vehicles, and energy storage.
Grid Integration of Offshore Wind Energy: A Review on Fault Ride Through Techniques for MMC-HVDC Systems
Authors: Kumar Dileep , Shireen Wajiha , Ram Nanik
Published: October 2024

Over the past few decades, wind energy has expanded to become a widespread, clean, and sustainable energy source. However, integrating offshore wind energy with the onshore AC grids presents many stability and control challenges that hinder the reliability and resilience of AC grids, particularly during faults. To address this issue, current grid codes require offshore wind farms (OWFs) to remain connected during and after faults. This requirement is challenging because, depending on the fault location and power flow direction, DC link over- or under-voltage can occur, potentially leading to the shutdown of converter stations. Therefore, this necessitates the proper understanding of key technical concepts associated with the integration of OWFs. To help fill the gap, this article performs an in-depth investigation of existing alternating current fault ride through (ACFRT) techniques of modular multilevel converter-based high-voltage direct current (MMC-HVDC) for OWFs. These techniques include the use of AC/DC choppers, flywheel energy storage devices (FESDs), power reduction strategies for OWFs, and energy optimization of the MMC. This article covers both scenarios of onshore and offshore AC faults. Given the importance of wind turbines (WTs) in transforming wind energy into mechanical energy, this article also presents an overview of four WT topologies. In addition, this article explores the advanced converter topologies employed in HVDC systems to transform three-phase AC voltages to DC voltages and vice versa at each terminal of the DC link. Finally, this article explores the key stability and control concepts, such as small signal stability and large disturbance stability, followed by future research trends in the development of converter topologies for HVDC transmission such as hybrid HVDC systems, which combine current source converters (CSCs) and voltage source converters (VSCs) and diode rectifier-based HVDC (DR-HVDC) systems.
A Stochastic Approach to the Power Requirements of the Electric Vehicle Charging Infrastructure: The Case of Spain
Authors: Castillo Oscar , Álvarez Fernández Roberto , Porru Mario
Published: October 2024

Battery electric vehicles represent a technological pathway for reducing carbon emissions in personal road transport. However, for the widespread adoption of this type of vehicle, the user experience should be similar to that of combustion engine vehicles. To achieve this objective, a robust and reliable public charging infrastructure is essential. In Spain, the electric recharging infrastructure is growing quickly in metropolitan areas but much more slowly on roads and highways. The upcoming charging stations must be located along high-volume traffic corridors and in proximity to the Trans-European Transport Network. The main contribution of this research is to offer a method for examining the essential electricity infrastructure investments required in scenarios involving substantial electric vehicle adoption. The methodology includes a sensitivity analysis of fleet composition and market share, recharging user behavior, charging station density, and vehicle efficiency improvements. To this end, the authors have developed a simplified probabilistic model, addressing the effect of the involved parameters through a comprehensive scenario analysis. The results show that the actual number of high-capacity charging plugs on Spanish roads is significantly lower than the European regulation requirements for the year 2030 considering an electric vehicle market share according to the Spanish Integrated National Energy and Climate Plan 2021–2030 objectives and it is far from the necessary infrastructure to cover the expected demand according to the traffic flow. Under these circumstances, the charging peak power demand reaches over 7.4% of the current Spanish total power demand for an electric vehicle fleet, which corresponds to only 12% of the total.
Investigation of a Magnetic Levitation Architecture with a Ferrite Core for Energy Harvesting
Authors: Soares Igor Nazareno , Altafim Ruy Alberto Corrêa , Altafim Ruy Alberto Pisani , Moreira Melkzedekue de Moraes Alcântara Calabrese , Sousa Felipe Schiavon Inocêncio de , Afonso José A. , Carmo João Paulo , Flauzino Rogério de Andrade
Published: October 2024

This work presents the development of a magnetic levitation system with a ferrite core, designed for electromagnetic energy harvesting from mechanical vibrations. The system consists of a fixed enamel-coated copper coil and five neodymium-iron-boron permanent magnets housed within a PVC spool. To enhance magnetic flux concentration, a manganese-zinc ferrite (Mn-Zn) ring was employed within the spool. Experimental tests were conducted at frequencies up to 20 Hz, demonstrating the device’s potential for harvesting energy from small vibrations, such as those generated by human biomechanical movements, achieving operating voltages up to 3 V. Additionally, the architecture is scalable for larger systems and allows for the integration of multiple transducers without magnetic field interference, independent of the frequency or excitation phase of each transducer.
Low-Carbon Rural Areas: How Are Polish Municipalities Financing the Green Future?
Authors: Kozera Agnieszka , Standar Aldona , Stanisławska Joanna , Rosa Anna
Published: October 2024

The main aim of the research was to assess Polish rural municipalities’ investment activity connected with the development of a low-carbon economy, supported with EU funds in the 2007–2013 and 2014–2020 financial frameworks. The empirical study was based on data from Poland’s Ministry of Development Funds and Regional Policy, Ministry of Finance, and Statistics Poland, analysed through basic descriptive statistics and a logistic model to identify key factors influencing investment activity. The study showed that the greatest number of agreements on funding were, in fact, signed by rural municipalities in the period under analysis. The predominant measures undertaken during this time were the promotion of renewable energy sources and the improvement in energy efficiency. In the earlier financial framework, low-carbon economy projects in rural areas were more often implemented by municipalities with developing demographic potential, including those characterised by a higher level of enterprise development. In the subsequent financial framework, human capital turned out to be of key importance for the investment activity of rural municipalities. Experience gained from 2007–2013 positively influenced fund absorption in 2014–2020, improving project value, number, and support. The study confirmed that rural municipalities play a vital role in advancing a low-carbon economy, as local actions are key to achieving sustainable development and reducing greenhouse gas emissions.
Trend Analysis of Cross-Border Electricity Trading in Pan-European Network
Authors: Venizelou Venizelos , Poullikkas Andreas
Published: October 2024

The long-term global target of facilitating energy security and optimizing resource utilization while supporting the transition to sustainable energy systems has led the pathway towards regional cooperation in the context of energy infrastructures and trading. Recent trends highlight the development of transnational energy grids, pipelines, and renewable energy projects, facilitating efficient distribution of electricity, gas, and other energy forms. These advancements offer benefits such as increased reliability of energy supply, cost savings through shared resources, and strengthened relationships between countries. However, challenges persist, including regulatory differences, geopolitical tensions, alignment of market rules as well as substantial investment requirements in infrastructure and technology. Addressing these challenges necessitates harmonized policies, robust legal frameworks, and cooperative international governance, which are crucial for effective cross-border energy trading. The aim of the work is to present the current landscape as well as analyze the latest trends and developments in the dynamic field of electricity interconnectors, providing insights into its trajectory and implications for the European internal energy market.
Modulation Strategy with Minimum Switching Losses for Three-Phase Non-Isolated AC–DC Matrix Converters
Authors: Testa Riccardo , Vancini Luca , Rizzoli Gabriele , Mengoni Michele , Femia Antonio , Zarri Luca , Tani Angelo
Published: October 2024

This paper presents an analysis of the operational characteristics of three-phase AC–DC matrix converters, which operate as rectifiers but possess a range of additional capabilities. These include the ability to reverse the power flow, control the input power factor, and generate a multilevel output voltage. The analysis yields a modulation strategy that minimizes switching losses. The proposed modulation strategy is compared with seven well-known space vector modulation strategies in terms of efficiency and distortion of input and output current. The performance is experimentally validated.
Energy Quality of Corn Biomass from Gasoline-Contaminated Soils Remediated with Sorbents
Authors: Borowik Agata , Wyszkowska Jadwiga , Zaborowska Magdalena , Kucharski Jan
Published: October 2024

Soil contaminated with petroleum-derived products should be used to cultivate energy crops. One such crop is Zea mays. Therefore, a study was performed to determine the suitability of Zea mays biomass obtained from gasoline-contaminated soil for energy purposes. The analysis included determining the heat of combustion and calorific value of the biomass, as well as the content of nitrogen, carbon, hydrogen, oxygen, sulfur, and ash in the biomass. Additionally, the suitability of vermiculite, dolomite, perlite, and agrobasalt for the phytostabilization of gasoline-contaminated soil was evaluated. It was found that the application of sorbents to gasoline-contaminated soil significantly reduced the severe negative effects of this petroleum product on the growth and development of Zea mays. Gasoline contamination of the soil caused a significant increase in ash, nitrogen, and sulfur, along with a decrease in carbon and oxygen content. However, it had no negative effect on the heat of combustion or calorific value of the biomass, although it did reduce the energy production from Zea mays biomass due to a reduction in yield. An important achievement of the study is the demonstration that all the applied sorbents have a positive effect on soil stabilization, which in turn enhances the amount of Zea mays biomass harvested and the energy produced from it. The best results were observed after the application of agrobasalt, dolomite, and vermiculite on gasoline-contaminated soil. Therefore, these sorbents can be recommended for the phytostabilization of gasoline-contaminated soil intended for the cultivation of energy crops.
System-Level Dynamic Model of Redox Flow Batteries (RFBs) for Energy Losses Analysis
Authors: Anyanwu Ikechukwu S. , Buzzi Fulvio , Peljo Pekka , Bischi Aldo , Bertei Antonio
Published: October 2024

This paper presents a zero-dimensional dynamic model of redox flow batteries (RFBs) for the system-level analysis of energy loss. The model is used to simulate multi-cell systems considering the effect of design and operational parameters on energy loss and overall performance. The effect and contribution of stack losses (e.g., overpotential and crossover losses) and system losses (e.g., shunt currents and pumps) to total energy loss are examined. The model is tested by using literature data from a vanadium RFB energy storage. The results show that four parameters mainly affect RFB system performance: manifold diameter, stack current, cell standard potential, and internal resistance. A reduction in manifold diameter from 60 mm to 20 mm reduced shunt current loss by a factor of four without significantly increasing pumping loss, thus boosting round-trip efficiency (RTE) by 10%. The increase in stack current at a low flow rate increases power, while the cell standard potential and internal resistance play a crucial role in influencing both power and energy output. In summary, the modeling activities enabled the understanding of critical aspects of RFB systems, thereby serving as tools for system design and operation awareness.
Soundscapes in Urban Green Spaces of a Megacity Across an Urban–Rural Gradient: A Case Study of Shanghai
Authors: Liu Lu , Yang Xiao , Yan Jingli , Zhang Wenwen , Ke Yunzheng , Zhang Tong , Yin Shan
Published: October 2024

Urban soundscapes are valuable indicators of urban biodiversity and ecosystem health. This study investigated the spatial and temporal characteristics of soundscapes in megacity green spaces and their relationship with the urban environment. An acoustic index was formulated and calculated using long-term data from Shanghai’s urban green spaces. The results show a significant increase in the acoustic index during spring and summer, peaking during these periods, while a decrease was observed from December to February, dominated by abiotic sounds. Diurnal variations indicate a rapid increase in the acoustic index at sunrise, reflecting heightened avian activity during the dawn chorus. Human interference in the urban center limited acoustic activity, whereas the outer suburbs, with their more natural environments, supported greater acoustic richness.
Wood Quality and Mechanical Properties
Authors: Christoforo André Luis
Published: October 2024

The recent Special Issue (SI) of Forests on “Wood Quality and Mechanical Properties” offers an in-depth exploration of the complex relationship between the quality of wood and its mechanical properties, in addition to describing innovations in the field [...]