bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal Chemistry and Structural Complexity of the Uranyl Molybdate Minerals and Synthetic Compounds
Authors: Kuporev Ivan V. , Kalashnikova Sophia A. , Gurzhiy Vladislav V.
Published: December 2023

This paper reviews not the largest, but at the same time quite an interesting, group of natural and synthetic uranyl molybdate compounds. Nowadays, nine minerals of U and Mo are known, but the crystal structures have only been reported for five of them. Almost an order of magnitude more (69) synthetic compounds are known. A significant discrepancy in the topological types for natural and synthetic phases is shown, which is most likely due to elevated temperatures of laboratory experiments (up to 1000 °C), while natural phases apparently grow at significantly lower temperatures. At the same time, the prevalence of dense topologies (with edge-sharing interpolyhedral linkage) among natural phases can be noted, which is fully consistent with other recently considered mineral groups. Uranyl molybdates demonstrate several similarities with compounds of other U-bearing groups; however, even topological matches do not lead to the appearance of completely isotypic compounds. Structural complexity calculations confirm, in general, crystal chemical observations. Considering the prevalence of dense structures in which coordination polyhedra of uranium and molybdenum are connected through common edges as well as framework architectures, one can expect a less significant influence of interlayer species on the formation of the crystal structure than the main U-bearing complexes. The more structural complexity of the uranyl molybdate units, the more complex of the entire crystal structure is. In addition, there is a tendency for complexity to increase with increasing density of the complex; the simplest structures are vertex-shared, while the complexity increases with the appearance of common edges.
Metamaterial Perfect Absorbers for Controlling Bandwidth: Single-Peak/Multiple-Peaks/Tailored-Band/Broadband
Authors: Zheng Haiyu , Pham Thanh Son , Chen Liangyao , Lee Youngpak
Published: December 2023

Metamaterial absorbers have garnered significant interest due to their unique electromagnetic properties, which facilitate the efficient absorption of electromagnetic radiation in a specific frequency range or multiple frequency ranges. The metamaterial absorbers are designed based on artificially engineered structures that enable tailored absorption properties. These structures might include multiple resonances or incorporate electrical resistive components to achieve broadband absorption. This review paper provides a comprehensive analysis of the progress made in the field of the bandwidth of metamaterial absorbers, encompassing the underlying design principles, key performance characteristics, diverse applications, and perspectives for further research. The paper draws to a conclusion by outlining the potential future directions for further advancements in this exciting area of research, and highlighting the challenges that need to be addressed for the widespread adoption of metamaterial absorbers.
Sleep and Adolescent Depression
Authors: Castiglione-Fontanellaz Chiara E. G. , Tarokh Leila
Published: December 2023

Adolescence is a pivotal period of development marked by significant physiological and psychological changes, making youth particularly susceptible to mental health challenges, including depression. A growing body of research has highlighted the important role of sleep in the etiology and exacerbation of adolescent depression. Disruptions in sleep patterns, including insomnia and irregular sleep-wake cycles, are prevalent among depressed adolescents and can exacerbate depressive symptoms. In this review, we examine alterations to sleep behavior and physiology in adolescent depression. Furthermore, we introduce a theoretical model of hypersomnia in adolescent depression. This manuscript explores the intricate relationship between sleep and adolescent depression, with a focus on future directions for research and intervention.
The Evaluation of the Suitability, Quality, and Readability of Publicly Available Online Resources for the Self-Management of Fear of Cancer Recurrence
Authors: Wu Verena Shuwen , Sabud Tiyasha , Smith Allan ‘Ben’ , Lambert Sylvie D. , Descallar Joseph , Lebel Sophie , Bamgboje-Ayodele Adeola
Published: December 2023

Cancer survivors often rely on the internet for health information, which has varying levels of readability, suitability, and quality. There is a need for high-quality online self-management resources for cancer survivors with fear of cancer recurrence (FCR). This study evaluated the readability, suitability, and quality of publicly available online FCR self-management resources. A Google search using FCR-related keywords identified freely available FCR self-management resources for cancer survivors in English. Resource readability (reading grade level), suitability, and quality were evaluated using relevant assessment tools. Descriptive statistics and cluster analysis identified resources with higher suitability and quality scores. Mean resource (n = 23) readability score was grade 11 (SD = 1.6, Range = 9–14). The mean suitability score was 56.0% (SD = 11.4%, Range = 31.0–76.3%), indicating average suitability and the mean quality score was 53% (SD = 11.7%, Range = 27–80%), indicating fair quality. A cluster of 15 (65%) resources with higher suitability and quality scores was identified. There were no significant associations between suitability or quality scores and the type of organisation that published the resources. Online FCR self-management resources varied in readability, suitability and quality. Resources with higher quality and suitability scores relative to other resources are identified for use by healthcare professionals and cancer survivors. Resources that are more culturally appropriate, with lower reading grade levels and detailed self-management strategies are needed.
Non-Indigenous Freshwater Fishes as Indicators of Ecological Quality in Running Waters
Authors: Gkenas Christos , Vardakas Leonidas , Koutsikos Nicholas
Published: December 2023

The European Union Water Framework Directive (WFD) is a comprehensive initiative guiding river basin water management, addressing pressures such as pollution from diffuse and point sources, and hydromorphological alterations. However, pressures that can deteriorate the ecological quality of water bodies through biotic changes (i.e., by the introduction of non-indigenous species) are not rigorously addressed by the WFD. This study explores associations between conventional ecological quality indices based on physicochemical and biotic quality elements (fish and macroinvertebrates) against the presence and densities of non-indigenous freshwater fish species (NIFS) in lotic ecosystems of Greece, aiming to unravel the potential usage of NIFS in future ecological assessments. The dataset comprises 277 samplings at 115 sites, covering physicochemical and biotic (fish and macroinvertebrate) quality indices, and anthropogenic pressure variables. Based on our findings, the occurrence and densities of four NIFS (Lepomis gibbosus, Pseudorasbora parva, Gambusia holbrooki, and Carassius gibelio) were highly associated with the ecological quality assessments of the applied indices. Higher occurrences and densities of these NIFS were related to samplings of lower ecological quality. In addition, NIFS exhibited a positive association with anthropogenic pressures, likely due to their adaptability to less optimal environmental conditions or higher tolerance to pollution and other stressors. Our findings underscore the need for a paradigm shift in ecological quality assessments, emphasizing the use of NIFS either as a potential indicator of ecosystem health or as a pressure that deteriorates ecological quality.
Usurpation and Brooding of Least Tern (Sternula antillarum) Chicks by Common Terns (Sterna hirundo)
Authors: Sullivan Jeffery D. , Irons Jonathan , Treadway Anna , McDonough Ayla , Lee Alyssa , O’Donnell Amy , Callahan Carl R. , McGowan Peter C. , Prosser Diann J.
Published: December 2023

While nest usurpation and subsequent incubation of eggs and even brooding of chicks from other species has been reported for Common Terns (Sterna hirundo), such behavior is considered rare. We report an observation of a Common Tern pair usurping the Least Tern (Sternula antillarum) nest and brooding the Least Tern chicks. While the Least Tern pair attempted to provide care for the chicks, the Common Terns displayed aggressive behavior and defended the nest. Though both species attempted to feed the chicks, no feeding events were observed due to harassment from the other species. Neither pair was observed nesting prior to or following this event, and all chicks are believed to have been lost to predation. We discuss the possible scenarios leading to the observed usurpation event, the possibility that usurpations are more common than previously believed, and the need for different monitoring methods to elucidate the causes of usurpations.
Orthoptera Community Dynamics and Conservation in a Natura 2000 Site (Greece): The Role of Beta Diversity
Authors: Stefanidis Apostolis , Zografou Konstantina , Tzortzakaki Olga , Kati Vassiliki
Published: December 2023

Greece is a European hotspot for Orthoptera (378 species), yet it has been scarcely explored. We investigated the diversity patterns of Orthoptera and the ecological mechanisms shaping them by sampling 15 sites (30 plots of 1ha) across five habitats in Mount Mitsikeli, a Natura 2000 site. The mountain is deemed rich (0.4 species/km2), hosting 34 species, including a species of European interest (Paracaloptenus caloptenoides). The grassy openings in the beech–fir forest and rural mosaics were found to be important habitats for Orthoptera, while the mountain grasslands were poorer but hosted a greater abundance of grasshoppers. The three main environmental factors shaping diversity patterns (with an explained variance of 51.34%) were grass height, the cover of woody vegetation and the cover of bare ground. Beta diversity was high (with a Bray–Curtis of index 0.45 among habitats). Species turnover prevailed among all sites and within agricultural land, beech–fir forest and Mediterranean scrub, while nested patterns prevailed within mountain grasslands and mixed thermophilous forest. Conservation actions should target sites in ecosystems driven by species turnover, but primarily the most species-rich sites are driven by nestedness. Such actions should include the implementation of biodiversity-inclusive grazing schemes to hamper forest encroachment and the restoration of mountain grassland quality from cattle overgrazing.
Frost Cracks Show a Slight Effect on Fungal Richness in Stem Wood of Hybrid Aspen Trees in Latvia
Authors: Kļaviņa Dārta , Matisons Roberts , Auniņa Annija , Striķe Zane , Ciseļonoka Laima , Krastiņa Keitlīna , Zeps Mārtiņš , Jansons Āris , Bitenieks Krišs , Ruņģis Dainis Edgars , Gaitnieks Tālis
Published: December 2023

Hybrid aspen Populus tremula L. × Populus tremuloides Michx. is fast-growing and a potential source of biomass for bioenergy production in Europe. However, knowledge about the phytopathological risks to hybrid aspen clones, particularly about frost crack damage as a possible infection gateway of fungal infections, is scarce. Five clones, represented by 205 trees from three trials in Latvia, were studied; two wood samples (at root collar and 1.3 m height) were obtained from each tree. Wood-inhabiting fungi were isolated and identified by the morphology and sequencing of the ITS region with fungal-specific primers, and fungal communities were compared using PERMANOVA. Fungal communities from trees with stem cracks were richer in species, especially pathogens, and species richness was higher in samples collected at 1.3 m height. Plant pathogens were isolated from 52% of all samples. Soft rot-causing Alternaria and Fusarium were dominant; Alternaria was more common at the height of 1.3 m, while Fusarium was more common at the root collar. White rot fungi were isolated from less than 2% of all samples, indicating a low degree of tree infection in the 15- to 16-year-old plantations. Clonal differences were not significant for fungal communities in general; nevertheless, for the occurrence of the genus Cladosporium, clonal differences were observed. In conclusion, the differences in fungal communities in relation to stem cracks implied only indirect clonal effects on phytopathological risks, emphasizing the resistance to stem cracking as a crucial trait for the sustainability of hybrid aspen plantations.
Widespread Occurrence of Coral Growth Anomalies in the Republic of Maldives
Authors: Bises Chiara , Dehnert Inga , Aeby Greta , Dennis Michelle , Gobbato Jacopo , Hodge Jessica , Staiger Miriam , Siena Federica , Galli Paolo , Montano Simone
Published: December 2023

In the last decades, there has been a concerning increase in the frequency and severity of coral disease outbreaks on a global scale, resulting in significant damage to the coral reef ecosystem and biodiversity. Growth anomalies (GAs) have been increasingly observed, with significantly higher occurrences in larger and older coral colonies compared to their smaller counterparts. However, there is a notable lack of knowledge and reports regarding growth anomalies in the Maldivian region. Here, we provide the first evidence of four distinct growth anomalies on three coral species, respectively on Acropora sp., Montipora sp., and Pachyseris speciosa, observed across four different locations across three atolls within the Maldivian Archipelago.
Amniotic Band Syndrome—Prenatal Diagnosis
Authors: Gică Nicolae , Apostol Livia Mihaela , Gică Corina , Huluță Iulia , Vayna Ana Maria , Panaitescu Anca Maria , Gana Nicoleta
Published: December 2023

This is a case of a fetus affected by an amniotic band detected at 20 weeks of gestation. A presumptive diagnosis was made based on the ultrasound features. The ultrasound showed an abnormally developed right lower limb and no other associated fetal abnormalities. The unilaterality of the defect decreases the chances of genetic abnormality or an early vascular insult. The postnatal examination of the newborn concluded that the prenatal diagnosis was right.
Maxillary Anterior Teeth Dimensions and Relative Width Proportions: A Narrative Literature Review
Authors: Cinelli Francesca , Piva Francesco , Bertini Fabio , Russo Daniele Scaminaci , Giachetti Luca
Published: December 2023

Predictable results in the aesthetic treatment of anterior teeth can be obtained by resorting to the concept of dental aesthetics and, in particular, defining the ideal tooth dimensions and proportions to obtain a harmonious smile. Considering the great variety of articles dealing with the topic, and the lack of updated reviews, this narrative literature review aims to evaluate current knowledge on anterior teeth dimensions and to verify the existence and the potential applications of the anterior teeth proportioning theories (Golden Proportion, Golden Percentage, RED Proportion, and Golden Rectangle). PubMed, Embase, Cochrane Library, and Google Scholar databases were comprehensively searched using different keywords and term combinations. The research includes articles published up to June 2023, no time limits were set, and only articles in English were included. Inclusion criteria comprehended reviews, clinical studies, and in-vitro studies. A total of 66 articles were selected. Two main topics were identified: “Anterior teeth dimensions”, “Golden Proportions, Golden Percentage, RED Proportions, and Golden Rectangle”. As far as tooth dimensions are concerned, different width ranges are recognized for men and women and for different ethnic groups. Perfectly symmetric contralateral elements are found in low percentages of subjects. The correlation between dental dimensions and facial parameters is not always present, and it strongly depends on the sample’s ethnicity and gender. Ideal tooth proportions were only partially identified.
Early Childhood Teachers’ Support of Children’s Play in Nature-Based Outdoor Spaces—A Systematic Review
Authors: Smedsrud Tor Mauritz , Kleppe Rasmus , Lenes Ragnhild , Moser Thomas
Published: December 2023

Early Childhood Education and Care (ECEC) places value and benefits on children’s play in nature-based outdoor spaces. However, there is a lack of knowledge regarding teachers’ support of play in environments with rugged terrains and natural materials. Therefore, this systematic review aims to locate, present, and discuss research literature on how teachers in ECEC settings can support children’s play in nature-based outdoor spaces. According to the review, teachers’ support of children’s play was described in the literature as encouraging children’s free and unstructured play through facilitating actions addressing the children’s perspectives and the opportunities offered by the physical environment. Furthermore, teacher support was also described as teacher-led and teacher-guided interactions where teachers and children communicate or collaborate in playful situations. Differences and overlapping elements of types of teacher support are discussed, and implications for researchers, practitioners, and ECEC teacher education are provided.
Moving toward Inclusive Practices for Children and Families: A Preschool’s Journey
Authors: Damjanovic Victoria , Ledford Elyse
Published: December 2023

As a college of education was charged with transforming a campus preschool program into a teacher-educator lab school, a community of practice was formed to look at current practices and make changes to create a more inclusive program using culturally relevant pedagogy and blended practices. Using a qualitative case study, data were collected for one year to determine what was taking place in the program. In years two through five, changes were implemented and reflected upon. Transformative learning guided data collection and analysis to support the process of reflecting critically on experiences, engaging in reflective dialogue, and taking action toward increasingly deep levels of authentic inclusive practices. Findings indicate that changes in the environment, curriculum frameworks, considerations for teachers, and bringing families in were the keys to developing a more inclusive program for elevating children and families.
Adaptability and Social Support: Examining Links with Engagement, Burnout, and Wellbeing among Expat Teachers
Authors: Vincent Michelle K. , Holliman Andrew J. , Waldeck Daniel
Published: December 2023

(1) Background: Expatriate (expat) teachers, i.e., those living and working outside of their own country, face several unique challenges. Without sufficient protective resources, these challenges threaten to negatively impact upon their workplace engagement and psychological wellbeing, and lead to burnout. In the present study, we utilise the ‘conservation of resources’ (COR) theory to examine the influence of expat teachers’ adaptability (a personal resource) and social support (a conditional/situational resource) on their workplace engagement, burnout, and psychological wellbeing. (2) Methods: A sample of expat teachers (N = 88), mostly working and residing in Middle Eastern countries, completed a series of validated self-report scales to measure each substantive construct. (3) Results: Results revealed that adaptability, but not social support, was a significant positive predictor of both work engagement and psychological wellbeing. There were no significant interaction effects observed. Moreover, neither adaptability nor social support were associated with burnout in this study. Personal resources, such as adaptability, may be more significant determinants of workplace engagement and psychological wellbeing among expat teachers relative to conditional/situational resources, such as social support, according to this research. (4) Conclusions: These findings have important implications for researchers, practitioners, and businesses/organisations, underlining the need to concentrate on strengthening personal resources such as adaptability to improve workplace engagement and psychological wellbeing outcomes among expat teachers.
The Promotion of Originality Perceived in Two Multimodal Storytelling Applications: Storybird and Scratch
Authors: Peña-Acuña Beatriz , Navarro-Martínez Óscar
Published: December 2023

This mixed research aimed to determine if, in their initial training, teaching students consider Scratch and Storybird, digital storytelling applications, as contributing to promoting originality after an intervention in which they previously experimented with them. It was studied whether they considered it convenient to encourage children’s creativity by combining them to create stories in Spanish and English (as EFL) and then having the teacher adapt these two applications. The participants included 134 university students, teachers in initial training at Huelva’s Campus in Spain. The quantitative results as a whole showed significant differences regarding the different dimensions of originality analysed. In the qualitative ones, it was recognised that these apps encourage cognitive development, creativity, learning, communicative competence, and learning attitude, recognising the apps as didactic tools. When cross-examining the data, it was deduced that the digital storytelling applications preferably provide the benefits of encouraging, in a specific way, originality, imagination, and the production of stories in a multimodal manner. Thus, the emerging variables are cognitive.
Multitrack Educational Programs as a Method of Educational Process Personalization at Universities
Authors: Volkov Aleksandr , Rishko Yury , Boboshko Diana , Eliseeva Evgeniya , Treistar Dmitrii , Kulapova Antonina
Published: December 2023

This study analyzes the approach towards educational process organization at a university. We study existing practices of educational program personalization (and the relevant existing limitations) in the Russian system of university-level education. This study reviewed the general trends in university program personalization and performed an in-depth analysis of actual cases of personalized study plan implementation at Russian universities (we compared the declared objectives of such programs with their real-life implementation results). In this article, the authors also highlight the limitations affecting the maximum attainable level of personalization of study programs (such as the minimum number of students enrolled in a course in a given semester, problems of resource reallocation between different chairs at the university and administration costs of digitalization of a personalized study process). Based on our research, a model of study process organization (based on multitrack educational programs) has been developed and implemented. The article describes an algorithm for implementation of multitrack educational programs, highlights the limitations that this model of educational process complies with and formulates the advantages of this approach towards organization of the university-level study process compared to models employing individual educational trajectories.
Semi-Analytical Approach versus Finite Element Method for Analysis of Propagation Properties in Rectangular Waveguides: Silica-Titania Technological Platform
Authors: Janaszek Bartosz , Butt Muhammad A. , Piramidowicz Ryszard
Published: December 2023

This work explicitly demonstrates a semi-analytical effective index approximation (EIA) approach for the description of the propagation properties of rib and ridge waveguides. By using the example of waveguides realized on a low-cost silica-titania (SiO2:TiO2) technological platform, we present that EIA may be successfully applied for the approximate determination of modal effective indices and single mode propagation conditions. All obtained results have been confirmed to be convergent with the finite element method (FEM) simulations at low relative error. Due to the tremendously fast execution time of EIA simulations in comparison with the FEM solver, we believe that the presented approach may be applied in a preliminary step of designing functional blocks in new and existing photonic integrated circuit technologies, which often require complex and multi-parameter calculations.
Threshold/Multi Adaptor Signature and Their Applications in Blockchains
Authors: Ji Yunfeng , Xiao Yuting , Gao Birou , Zhang Rui
Published: December 2023

Adaptor signature is a variant of digital signatures and useful for fair excheng in financial applications such as cryptocurrencies, to name a few, off-chain transaction protocols, atomic swaps and other privacy-enhancing mechanisms. However, similar to normal digital signatures, an adaptor signature also suffers from the loss of the secret key and single-point failure, which is insufficient in practice. In this paper, we address this constraint by introducing two new concepts as enhancements: multi-adaptor signatures and threshold adaptor signatures. First, we propose the formal security models for multi-adaptor signature and threshold adaptor signature. Then, we present specific schemes for these two primitives based on the commonly used blockchain signature scheme Schnorr and the post-quantum signature scheme Dilithium, respectively. Furthermore, we provide security proofs for these four schemes. Finally, we demonstrate interesting applications for blockchains, such as oracle-based conditional payment and n to n atomic swap.
Development and Studies of VR-Assisted Hand Therapy Using a Customized Biomechatronic 3D Printed Orthosis
Authors: Górski Filip , Grohs Aleksandra , Kuczko Wiesław , Żukowska Magdalena , Wichniarek Radosław , Siwiec Sabina , Băilă Diana-Irinel , Zelenay Martin , Păcurar Răzvan , Sanfilippo Filippo
Published: December 2023

This article presents the process of development, testing, and use of wrist–hand orthosis in the hand therapy of a teen patient with congenital paresis disease. A regular 3D-printed anatomically adjusted orthosis is modified with a set of sensors, to work as motion and interaction controller in virtual reality (VR). As the patient with this condition cannot operate VR controllers due to wrist and hand defects, the corrective orthosis was converted to a VR controller, by introducing custom-made electronics and commercially available motion trackers, linking them to the orthosis. A VR game scenario, with typical input from the VR controllers replaced by input from the custom-made controllers is then designed. The VR game scenario is prepared with involvement of physiotherapists, to incorporate the most important exercises for patients with the same condition. The scenario is tested with a group of human patients and assessed by an expert physiotherapist, for determining its efficiency, as well as to determine a set of necessary improvements for future development of the orthosis.
Towards Agrirobot Digital Twins: Agri-RO5—A Multi-Agent Architecture for Dynamic Fleet Simulation
Authors: Gutiérrez Cejudo Jorge , Enguix Andrés Francisco , Lujak Marin , Carrascosa Casamayor Carlos , Fernandez Alberto , Hernández López Luís
Published: December 2023

In this paper, we propose a multi-agent-based architecture for a Unity3D simulation of dynamic agrirobot-fleet-coordination methods. The architecture is based on a Robot Operating System (ROS) and Agrobots-SIM package that extends the existing package Patrolling SIM made for multi-robot patrolling. The Agrobots-SIM package accommodates dynamic multi-robot task allocation and vehicle routing considering limited robot battery autonomy. Moreover, it accommodates the dynamic assignment of implements to robots for the execution of heterogeneous tasks. The system coordinates task assignment and vehicle routing in real time and responds to unforeseen contingencies during simulation considering dynamic updates of the data related to the environment, tasks, implements, and robots. Except for the ROS and Agrobots-SIM package, other crucial components of the architecture include SPADE3 middleware for developing and executing multi-agent decision making and the FIVE framework that allows us to seamlessly define the environment and incorporate the Agrobots-SIM algorithms to be validated into SPADE agents inhabiting such an environment. We compare the proposed simulation architecture with the conventional approach to 3D multi-robot simulation in Gazebo. The functioning of the simulation architecture is demonstrated in several use-case experiments. Even though resource consumption and community support are still an open challenge in Unity3D, the proposed Agri-RO5 architecture gives better results in terms of simulation realism and scalability.
Large-Scale Subspace Clustering Based on Purity Kernel Tensor Learning
Authors: Zheng Yilu , Zhao Shuai , Zhang Xiaoqian , Xu Yinlong , Peng Lifan
Published: December 2023

In conventional subspace clustering methods, affinity matrix learning and spectral clustering algorithms are widely used for clustering tasks. However, these steps face issues, including high time consumption and spatial complexity, making large-scale subspace clustering (LS2C) tasks challenging to execute effectively. To address these issues, we propose a large-scale subspace clustering method based on pure kernel tensor learning (PKTLS2C). Specifically, we design a pure kernel tensor learning (PKT) method to acquire as much data feature information as possible while ensuring model robustness. Next, we extract a small sample dataset from the original data and use PKT to learn its affinity matrix while simultaneously training a deep encoder. Finally, we apply the trained deep encoder to the original large-scale dataset to quickly obtain its projection sparse coding representation and perform clustering. Through extensive experiments on large-scale real datasets, we demonstrate that the PKTLS2C method outperforms existing LS2C methods in clustering performance.
A Low-Cost Detection Method for Nitrite Content in a Mariculture Water Environment Based on an Improved Residual Network
Authors: Pei Zhiqiang , Cai Zonghai , Meng Jingfei , Bai Yang , Cai Weiming , Fan Shengli
Published: December 2023

Nitrite content is one of the key indicators for measuring the quality of mariculture water and has a crucial impact on the benefits of aquaculture. Most of China’s fisheries are small-scale domestic aquaculture. For economic reasons, farmers generally use chemical colorimetry or rely on life experience (such as whether the water bodies have become turbid or whether aquatic organisms have abnormal or died) to determine the nitrite content in water; however, both methods can easily lead to misjudgment and cause losses. Another more accurate method is spectrophotometry, but the spectrophotometer used is more expensive. This article aims to propose a low-cost and high-precision nitrite detection method. The new method we propose is to first perform a color development reaction using chemical detection reagents, and then use an improved residual network instead of human eyes to determine the nitrite concentration in the water sample. The advantages of this method are the fast response of the chemical reagents and the high accuracy of the machine vision recognition. Our network can achieve an accuracy of 98.3% on the test set. The experimental results indicate that this method can be applied to practical mariculture.
A Study on EMI Noise Countermeasure Design of a Dishwasher
Authors: Lee Soongkeun , Joo Changdae , Kim Taekue
Published: December 2023

In this paper, we introduce and propose a design strategy implemented to mitigate electromagnetic interface (EMI) issues arising from the switching circuitry of dishwashers, encompassing components such as inverters and switched-mode power supplies (SMPSs). The focus lies on addressing conducted emissions (CEs) by analyzing the impedance of the load and core characteristics at the current level to implement enhancements. Additionally, we describe the incorporation of a common mode (CM) core attachment design aimed at the resonance frequency of the motor, effectively blocking noise generated by this resonant frequency and thereby enhancing radiated power (RP). Also, we discuss the modeling of noise filters and the overall system, comparing impedance characteristics, and validating the effectiveness of the proposed improvements through standardized tests. Furthermore, practical application to mass-produced products is demonstrated by eliminating internal harness cores and designing noise filters to reduce their size, all within the context of dishwasher EMI countermeasures.
Determination of Estimation Accuracy of Voltage Profiles Required for Proper Voltage Control by On-Load Tap Changer in Distribution Systems
Authors: Akasaka Riku , Hara Ryoichi , Kita Hiroyuki , Sugimura Shuhei , Kurihara Toshiharu
Published: December 2023

The introduction of a large number of photovoltaic systems to distribution systems has increased the complexity of the voltage profile. It is thus necessary to manage voltage at a higher system level. For this purpose, the voltage profile of the distribution system can be calculated using state estimation and the voltage can be controlled based on the estimated values. Many methods for estimating voltage profiles using state estimation have been developed. However, the estimation accuracy of voltage profiles required for proper voltage control has not been discussed. If the assumed required estimation accuracy is too high, then more meters than necessary will be installed, unnecessarily increasing costs. Conversely, if the assumed required estimation accuracy is too low, voltage control equipment will not operate properly, and voltage violations may occur. Thus, it is important to determine the required estimation accuracy of voltage profiles for proper voltage control. In this paper, the estimation error of the voltage profile is expressed using a probability density function, and the estimation accuracy of voltage profiles required for proper voltage control is examined. A numerical case study was performed on a distribution network model with 2160 consumers, and revealed the following. To prevent voltage violations, an estimation accuracy of voltage profile that is approximately 10 times lower than that of the estimation accuracy based on current measurement equipment data is sufficient. To minimize the number of tap operations, an estimation accuracy needs to be improved by 70% compared with the estimation accuracy based on current measurement equipment data.
Analysis of Flexibility Potential of a Cold Warehouse with Different Refrigeration Compressors
Authors: Khorsandnejad Ehsan , Malzahn Robert , Oldenburg Ann-Katrin , Mittreiter Annedore , Doetsch Christian
Published: December 2023

The research into new approaches to shift from fossil fuels to renewable energy sources (RES) has surged as environmental issues are on the rise, and fossil fuel sources are becoming scarce. The flexibility potential of cold supply systems has been discussed widely in the literature, firstly due to their high share of electricity consumption worldwide and secondly because of their potential to store thermal energy in the form of cold energy. However, finding a clear definition of flexibility and a concise approach for its quantification is still under progress. In this work, a comprehensive definition of the flexibility of energy systems and a novel methodology for its quantification are introduced. The methodology was applied on a cold warehouse with real data regarding its cold energy demand. The cold warehouse was first modeled via oemof, which is a modular open source framework developed in Python 3.8 using a mixed integer linear programming (MILP) optimization approach. The operation optimization of the cold warehouse was conducted for three goals, namely “minimization of electricity costs”, “minimization of CO2 emissions”, and “minimization of maximum used electric power (peak load minimization)”. Additionally, the effect of using different types of refrigeration compressors on the optimized operation of the cold warehouse was investigated. The results suggest that a cold warehouse possesses a high level of flexibility potential, which can be taken advantage of to reduce the electricity cost by up to 50%, the CO2 emissions between 25% to 30%, and the maximum used electric power by 50%. Different compressor types produced very similar results, although their flexibility level may vary.
Heat Extraction Evaluation of CO2 and Water Flow through Different Fracture Networks for Enhanced Geothermal Systems
Authors: Sun Zhixue , Song Wentong , Zhang Hao , Li Xueyuan , Xie Shuang , Nie Haifeng
Published: December 2023

Enhanced geothermal system (EGS) technologies have been developed to improve geothermal energy production from hot dry rock (HDR). In this study, discrete fracture network models for geometric topological networks that consider different parameters (the fracture density and the fracture length index) were built on the basis of fractal geometry theory. The heat extraction processes of CO2 and water as the working fluid through different discrete fracture networks were simulated with the application of the thermal–hydraulic–mechanical (THM) coupled method. A series of sensitivity analyses were carried out to reveal the influences of fracture parameters on heat transfer processes. Based on the simulation results, heat extraction efficiencies and temperature distributions in the reservoir of CO2 and water as the working fluid were compared, which showed that CO2 as the working fluid can bring a faster thermal breakthrough. It was found that the fracture length index a = 2.5 and the fracture density I = 5.0 can provide the highest heat extraction rate compared with other cases. This study provides a detailed analysis of fracture parameters and working fluids, which will contribute to the optimized management of geothermal energy production.
Closed-Form Expressions for Local Absorbing Boundary Conditions in Electromagnetic Scattering Problems and Their Implementation into Commercial FEM Software
Authors: Ziolkowski Marcin , Gratkowski Stanislaw
Published: December 2023

When solving open-region electromagnetic scattering problems using the standard finite element method, the infinite region exterior to the scatterer must be truncated with an artificial outer boundary. In the interior or finite part of the domain, finite elements can be used, but a boundary condition must be introduced at this artificial boundary to obtain a unique finite element solution. One class of boundary conditions designed for this purpose is called absorbing boundary conditions (ABCs). Several ABCs have been reported in the literature. These can be broadly classified into two categories: local and non-local. In this paper, we present new closed-form expressions for Nth-order local ABCs, equivalent to the well-known sequences of the Bayliss, Gunzburger, and Turkel boundary operators. To the best of our knowledge, these expressions have not yet been reported in the literature. Two- and three-dimensional problems are considered in this study. We also discuss the problem of incorporating custom ABCs into commercial finite element method programs, which are usually closed-source software packages. Two 2D electromagnetic scattering and radiation problems with known analytical solutions are analyzed.
Multi-Objective Short-Term Optimal Dispatching of Cascade Hydro–Wind–Solar–Thermal Hybrid Generation System with Pumped Storage Hydropower
Authors: Li Jie , Shi Linjun , Fu Hao
Published: December 2023

Aiming to mitigate the impact of power fluctuation caused by large-scale renewable energy integration, coupled with a high rate of wind and solar power abandonment, the multi-objective optimal dispatching of a cascade hydro–wind–solar–thermal hybrid generation system with pumped storage hydropower (PSH) is proposed in this paper. Based on the proposed system, the scheduling operation strategy takes into account the complex restrictions of cascade hydropower as well as the flexibility of the PSH. According to various scenarios, the NSGA-II approach is adopted to address the optimization problem, minimizing the system’s residual load variation and operation cost. The Pareto solution sets are contrasted and evaluated, applying the TOPSIS with CRITIC weighting. Additionally, the scheduling output of thermal power, cascade hydropower, and PSH is given in terms of different scenarios. The results demonstrate that the allocation of PSH to a hybrid energy system can significantly reduce the operation cost and the fluctuation in the residual load.
Paleotectonic Stress and Present Geostress Fields and Their Implications for Coalbed Methane Exploitation: A Case Study from Dahebian Block, Liupanshui Coalfield, Guizhou, China
Authors: Wang Jilin , Wang Youkun , Zhou Xiaozhi , Xiang Wenxin , Chen Changran
Published: December 2023

The macroscopic structural fractures (joints) and geostress distribution characteristics of coal reservoirs are important factors affecting the exploitation of coalbed methane (CBM). In this study, the joints in the sedimentary strata of the Dahebian block in Liupanshui area, Guizhou Province were investigated. Directional coal samples were collected for observation and statistical analysis of coal microfractures, the paleotectonic stress fields of the study area were reconstructed, and the tectonic evolution was elucidated. The geostress distribution characteristics of the target coal seam (coal seam No. 11, P3l) in the study area were analyzed using the finite element numerical simulation method. The results indicate that the structural evolution of the Dahebian syncline in the study area can be divided into two stages. The Late Jurassic–Early Cretaceous stage (Early Yanshanian) is the first stage. Affected by the sinistral strike slip of the Weining–Ziyun–Luodian (WZL) fault zone, the derived stress field in the study area exhibits maximum principal stress (σ1) in the NEE–SWW direction. The Late Cretaceous stage (Late Yanshanian) is the second stage. Affected by the dextral strike slip of the WZL fault zone, the derived stress field exhibits σ1 in the NNW–SSE direction. The folds and faults formed in the first stage were modified by the structural deformation in the second stage. The dominant strikes of joints in the sedimentary strata are found to be in the NW–NNW (300°–360°) and NE (30°–60°) directions, with dip angles mostly ranging from 60° to 90°. The dominant strikes of coal microfractures are in the NW (285°–304°) and NE (43°–53°) directions. The distribution of geostress in the study area is characterized by high levels of geostress in the syncline center, decreasing towards the surrounding periphery. The overall trend of the geostress contour line is similar to the shape of the syncline and is influenced by folds and faults. The σ1 of coal seam No. 11 is vertical stress. The prediction results show that the joint density of coal seam No. 11 in the block is 36–50 joints/m, and the shape of the joint density contour line is also affected by the axial direction of the Dahebian syncline and the surrounding faults. The variation in coal seam joint density and the control effect of geostress on joints opening or closing affects the permeability of coal reservoirs. The study results provide significant guidance for the exploitation of CBM.
Effect of Carboxyl-Doped Graphene Nanoplatelets as an Electrode for Supercapacitors According to Surface Property Changes via the Control of Conditions
Authors: Park Ji-Woo , Jeon In-Yup , Ju Young-Wan
Published: December 2023

Energy storage systems (ESSs) are attracting increasing attention for the development of sustainable and renewable energy technologies owing to limited fossil fuels. Supercapacitors are gaining significant interest as energy storage devices owing to their high-power density and long-term cycle stability. The use of suitable electrode materials affects the performance of supercapacitors. In this study, we fabricated a carboxyl-doped graphene nanoplatelet (CGnP) via a mechanochemical reaction. Additionally, CGnP was activated by controlling parameters such as temperature, flow rate, and maintenance period and evaluated as an electrode material for supercapacitors. The effect of the specific surface area (SSA) and functional groups of the fabricated samples on the capacitance was confirmed by controlling the activation parameters. The activated CGnP with 300 mL/min of CO2 at 1173 K for 4 h exhibited a high SSA of 1300 m2/g. The activated CGnP (180 F/g), with a high SSA, showed an increased capacitance of 46% compared to pristine CGnP (123 F/g). Additionally, activated CGnP1100 demonstrated good wettability and exhibited excellent stability with a low capacitance decrease of 6.1%, even after 10,000 cycles.
The Significance of Considering Battery Service-Lifetime for Correctly Sizing Hybrid PV–Diesel Energy Systems
Authors: Omar Moien A.
Published: December 2023

This study emphasizes how crucial it is to consider battery service lifetime when determining the optimal battery size in PV–diesel hybrid systems. It investigates how battery size influences the evaluation of hybrid systems and their lifetime due to battery cycling. Unlike previous research that relies on assumed battery lifetimes, this study delves into the tangible impact of battery cycling, revealing the intricate relationship between battery size, cycling behavior, and service lifetime. Utilizing HOMER Pro version 3.14.2 software, a case study assessed three battery capacities (300 Ah, 800 Ah, and 1000 Ah) in a hybrid PV system catering to a 24 kWh daily demand. Across varying assumed lifetimes (5, 10, and 20 years), the study found that a 300 Ah battery was the most feasible under a 5-year assumed battery lifetime. However, for 10-year and 20-year battery lifetimes, the 800 Ah system emerged as the optimal choice, emphasizing the influence of assumed lifetime on determining the optimal battery size. Throughput battery lifetime analysis estimated service lifetimes of 4.9, 10.96, and 13.64 years for the 300 Ah, 800 Ah, and 1000 Ah batteries, respectively. Notably, smaller-rated batteries exhibited shorter estimated service lifetimes linked to usage patterns. Among the systems assuming a 20-year calendar lifetime, the optimal 800 Ah system, with a service lifetime of 10.96 years, yielded an energy cost of 0.312 USD/kWh, annual costs of USD 2736.5, and a total cost of USD 37,450. Considering service lifetime, the 800 Ah system emerged as optimal, contrasting the initially favored 300 Ah system under a 5-year assumed lifetime. This underscores the crucial significance of comprehending and integrating service lifetime considerations to optimize the economic feasibility of PV hybrid systems.
A Study and Optimization of the Unsteady Flow Characteristics in the Last Stage Impeller of a Small-Scale Multi-Stage Hydraulic Turbine
Authors: Yang Jun , Peng Tao , Xu Gang , Hu Wenli , Zhong Huazhou , Liu Xiaohua
Published: December 2023

The demand for small-size multi-stage hydraulic turbines is experiencing rapid growth due to the ongoing efforts towards energy conservation and emission reduction. On account of their compact structural design, these turbines feature a more intricate internal flow configuration, rendering them prone to the creation of low-pressure zones, resulting in vapor–liquid two-phase flow, accompanied by the development of intense vibrations and noise, thereby adversely affecting the safety and stability of turbine operations. Concurrently, an innovative method for analyzing flow fields has been formulated combined with two-dimensional frequency domain visualization technology and proper orthogonal decomposition, serving to establish a diagnostic and optimization framework for the unsteady flow structures within rotating machinery by considering the features related to frequency distribution, spatial distribution, and energy contributions. It was found that there are two main unsteady flow structures which are the areas with high risks of vaporization under this study condition. According to the flow characteristics of the analysis, an optimization scheme was proposed to improve the two-phase flow problem in the secondary impeller, and the preliminary results were satisfactory.