bluuebunny/crossref_metadata_2025 huggingface dataset:
Internet of things towards environmental performance: a scientometrics and future research avenues
Authors: Edi Arsawan I Wayan , Hariyanti Ni Kadek Dessy , Azizah Amiril , Suryantini Ni Putu Santi , Darmayanti Ni Putu Ayu
Published: August 2024

The emerging contribution of the Internet of Things and technology in promoting sustainability and environmental protection is substantial. However, the empirical literature that studies the linkage between the three constructs is far from well-mapped. Accordingly, this study aims to map the literature associated with the Internet of Things and technology in establishing environmental performance by analyzing 1294 articles that underwent rigorous peer review on the Scopus and WOS databases. The finding demonstrated that there were six significant clusters to guide future research. The resulting visual trend is a guide for international collaboration between researchers in diverse academic fields, resulting in more enhanced research in terms of quality and quantity. Further implications are discussed in the paper.
Drone navigation system based on QR code recognition using fast component-based two-staged algorithm
Authors: Pratomo Awang Hendrianto , Thariq Habib Muhammad , Prasetyo Dessyanto Boedi
Published: August 2024

Kontes Robot Terbang Indonesia (KRTI) is a robotics competition organized by the National Achievement Center (Puspresnas). One of the branches of this competition is Vertical Takeoff and Landing (VTOL), which challenges participants to develop autonomous drones for package delivery based on QR code recognition. This research focuses on improving the accuracy of QR code recognition and drone navigation using a fast component-based two-stage method. Various image recognition methods for QR codes are discussed, including multi-threshold method, canny edge detection method, and fast componentbased two-stage method. The selected methods are modified to overcome the problems of rotation and perspective distortion. This research uses a quantitative and practical approach and is conducted indoors due to the limitations of drones on wind, light, and patterns on the ground. The fast component-based two-step method achieved 90.74% accuracy in QR code recognition, with certain challenges such as dark colored images. The navigation system relies on the drone’s position relative to the QR code in the image. The drone is instructed to approach the QR code for decoding. Test results showed 83.07% accuracy in matching commands, with problems due to QR code recognition failure. Strategies to overcome the recognition failure included rotation during takeoff and matching commands based on previous instructions. In addition, lag issues during drone navigation were addressed by optimizing the number of frames processed. The drone’s environmental requirements, such as well-lit areas and patterned floors, are described to ensure stable flight. This research provides insight into improving autonomous drone systems for package delivery through improved QR code recognition and navigation methods.
Comparative analysis of image enhancement techniques for braintumor segmentation: contrast, histogram, and hybrid approaches
Authors: Saifullah Shoffan , Pranolo Andri , Dreżewski Rafał
Published: August 2024

This study systematically investigates the impact of image enhancement techniques on Convolutional Neural Network (CNN)-based Brain Tumor Segmentation, focusing on Histogram Equalization (HE), Contrast Limited Adaptive Histogram Equalization (CLAHE), and their hybrid variations. Employing the U-Net architecture on a dataset of 3064 Brain MRI images, the research delves into preprocessing steps, including resizing and enhancement, to optimize segmentation accuracy. A detailed analysis of the CNN-based U-Net architecture, training, and validation processes is provided. The comparative analysis, utilizing metrics such as Accuracy, Loss, MSE, IoU, and DSC, reveals that the hybrid approach CLAHE-HE consistently outperforms others. Results highlight its superior accuracy (0.9982, 0.9939, 0.9936 for training, testing, and validation, respectively) and robust segmentation overlap, with Jaccard values of 0.9862, 0.9847, and 0.9864, and Dice values of 0.993, 0.9923, and 0.9932 for the same phases, emphasizing its potential in neuro-oncological applications. The study concludes with a call for refinement in segmentation methodologies to further enhance diagnostic precision and treatment planning in neuro-oncology.
Bidirectional Long Short-Term Memory (Bi-LSTM) Hourly Energy Forecasting
Authors: Wibawa Aji Prasetya , Fadhilla Akhmad Fanny , Iffat Paramarta Andien Khansa’a , Triono Alfiansyah Putra Pertama , Setyaputri Faradini Usha , Akbari Ade Kurnia Ganesh , Utama Agung Bella Putra
Published: August 2024

The growing demand for energy, especially in urban and densely populated areas, has driven the need for smarter and more efficient approaches to energy resource management. One of the main challenges in energy management is fluctuations in energy demand and production. To overcome this challenge, accurate and careful forecasting of hourly energy fluctuations is required. One method that has proven effective in time series forecasting is using deep learning. The research phase uses the CRISP-DM data mining methodology as a common problem solver for business and research. The scenarios tested in the study used 5 attribute selection scenarios based on correlation values based on target attributes and 2 normalization scenarios. Then, the deep learning model used is Bi-LSTM with hyperparameter tuning grid search. Performance measurement evaluation is performed with MAPE, RMSE, and R2. Based on the tests conducted, it was found that the Bi-LSTM model produced the best MAPE of 7.7256%. RMSE of 0.1234. and R2 of 0.6151 at min-max normalization. In comparison, the results on the z-score normalization are lower with the best MAPE value produced at 10.5525%. RMSE of 0.7627. and R2 of 0.4186.
Exploring usage-based and usability metrics for user experience for sustainable e-learning systems
Authors: Manik Lindung Parningotan
Published: August 2024

The digital revolution has ushered in a new era of education, characterized by the widespread adoption of e-learning systems. While these systems offer unprecedented opportunities for knowledge dissemination, the challenge lies in ensuring an effective and sustainable user experience. Although many studies have investigated the usability of e-learning systems, limited works have addressed a combination of usage-based metrics and Usability Metrics for User Experience (UMUX). This research article explores the intersection of usage-based and usability metrics within sustainable e-learning systems, aiming to develop a comprehensive framework for assessment and improvement. The study was conducted in a vocational school and participated by 64 teachers. They were invited to complete four tasks in an e-learning system and asked to fill out the questionnaires afterward. Besides calculating UMUX and UMUX-Lite scores, three usage-based metrics were also measured: completion rate, task duration, and the number of mouse clicks. The results showed that UMUX and UMUX-Lite had the potential to replace the System Usability Scale (SUS), which contains ten-item questionnaires and has been the industry standard over time. Shorter questionnaires, like UMUX, which includes four items, and UMUX-Lite, which even has only two items, would be preferred when the usability study has a limited time. In addition, the UMUX and UMUX-Lite scores correlated highly with the selected usage-based metrics, like the SUS score.
An application of spatial analysis and GIS in Tuberculosis (TB) cases in Central Luzon, Philippines
Authors: Atibagos-Nacion Nelda , Gonzaga Alex C.
Published: August 2024

According to WHO (2022), tuberculosis (TB) is the primary cause of ill health and the leading cause of death globally. It is estimated that approximately a quarter of the world’s population has been infected. With 372,367 cases of tuberculosis in 2022, the Philippines is among the top eight countries that accounted for more than 66% of all TB cases worldwide. Region III, along with NCR and Region IV-A, is one of the regions in the Philippines with the highest incidence of TB. This paper utilized the geographical information system (GIS) for easier visualization, and Getis-Ord Analysis, a type of spatial analysis tool for quick interpretations to provide an evidence-based framework for TB response. The spatial analysis was conducted to (1) determine if there are clusters of TB cases in the region across various periods and (2) determine if there are hot spots of TB cases in the most recent TB data covering 2019, 2020, and 2021. The results indicate that only the 2019 TB cases exhibit significant non-random clusters. It is recommended that further investigation be conducted to determine if the spatial clustering in 2019 is associated directly or indirectly with the El Niño event that occurred that year. On the other hand, the non-significance of the results for the years 2020 and 2021 may be attributed to the underreporting due to the implemented health protocols implemented to minimize the spread of COVID-19 which affected the accuracy of the reported cases. The results of the paper may be used for optimal resource allocation in addressing the spread of the disease.
Enhancing the efficiency of the remote service process
Authors: Zakirov Vakhid , Abdullaev Eldor
Published: August 2024

At the moment, two of the fastest growing industries are remote services and the remote organization of work and study activities. It follows that this calls for the area to be appropriately organized and that its users have access to a suitable working space. One of the most crucial elements in this situation is the response time for user queries, and it’s critical that it satisfies legal benchmarks. As a result, the key to cutting down on repair time is choosing system service techniques correctly. The benefits of accommodating remote teams’ requests for service time in order of priority are also examined in this article. An further mathematical model of customer service with priority has been created.
Development of android application for charity management using design thinking approach method
Authors: Hidayat Wahyu Nur , Syahri Esa Maydi , Afdlol Mochammad , Zahiro Ayu
Published: August 2024

Charity management is a critical aspect of supporting the sustainability and effectiveness of charitable organizations. In today’s digital era, mobile application development has become a relevant solution to increase efficiency and involvement in charitable activities. This research aims to design and develop an innovative Android application for charity management by applying the Design Thinking approach method. The Design Thinking approach method is used as a framework to better understand user needs and design intuitive, user-focused solutions. This process includes four main pillar stages: empathy, definition, ideation, and implementation. By deeply understanding the needs and challenges faced by charitable organizations and donors, the app is designed to provide a satisfying and effective experience. The app provides features like donation tracking, charity project management, real-time notifications, and transparent reports. The user-friendly and intuitive interface design ensures that users from various backgrounds can easily access and use this application. Apart from that, the integration of the latest technology such as artificial intelligence for data analysis and prediction of donation trends is also an integral part of this application. Prototype testing results show that this application is able to increase charity management efficiency, provide a positive user experience, and increase donor participation levels. Thus, it is hoped that the development of this Android application can make a positive contribution to the world of charity, create a greater social impact, and provide innovative solutions in technology-based charity management.
Exploring association of the psychological well-being, work life balance with technological stressors
Authors: Sharma Swati , Sharma Kavita
Published: August 2024

The intent of this study was to look into how doctors in northern India are feeling psychologically and how work-life balance and technological stressors affect it. Descriptive correlational analysis was the method used in this non-experimental quantitative study design. The study’s specific objectives were reflected in the design of the questionnaires employed. Eighty-three physicians in all, chosen via stratified sample, provided responses to the researcher. The statistical methods used for the data analysis and interpretation were mean and Pearson’s r. The essential information was gathered using an online survey application called Google Forms. Based on the study’s results, doctors’ assessments of psychological wellbeing, work-life balance, and techno stressors were all rated as quite high. Notably, no meaningful association between technostress producers and the results was found. The implications of these findings warrant further exploration and discussion, offering insights into the complex interplay between workrelated factors, personal well-being, and the use of technology in the professional lives of doctors. Additionally, these results can inform strategies for promoting the psychological well-being of doctors, considering the specific challenges identified in the context of work-life balance and technostress creators.
Speaking Up and Being Heard: The Importance of Functional Communication and Discourse Principles in Aphasia Intervention
Authors: Armstrong Elizabeth , Hersh Deborah
Published: August 2024

This article acknowledges Audrey Holland's influence on aphasiology as it specifically relates to the emergence of a strengths-based perspective on the everyday communication of people with aphasia. We explore a historical perspective, as well as current ways in which everyday communicative events are approached in both clinical and research practice. The term “functional communication” is synonymous with Audrey's work, with linguistically-based discourse analysis and therapy both viewed as natural companions and extensions of the concept within aphasiology. Audrey's focus on the interactional side of communication and psychosocial impacts of aphasia, as well as her expertise in analysis and measurement, contributed to the coalescing of impairment-based and social communication approaches, encompassing a true sense of humanity and connectedness. Her application of these in international contexts was also noteworthy. In this article, we hope to capture principles of aphasia management that underpin current clinical practice, and also move beyond the traditional clinic context to consider aphasia groups that have had such a key role in promoting successful social communication by and with people with aphasia. We suggest future directions to further promote the principles advocated by Audrey Holland in assisting people with aphasia to move forward with confidence with their conversation partners, friends, and communities.
Thin or thick? Populist and radical right politics across European cities, suburbs, and countryside
Authors: Crulli Mirko
Published: August 2024

The surge of populist and radical right phenomena reshaped European political geography. Yet the connections between places of residence and populist or radical right politics tended to be neglected until recently. This paper addresses the gap by exploring how residency relates to support for populism and the radical right in contemporary Europe. Focusing on the distinction between ‘cities’, ‘towns–suburbs’, and ‘countryside’, I conduct an individual-level investigation of populist and radical right votes and attitudes across different residential contexts. The analysis is based on European Social Survey data (2020–22) from 23 countries, in both Western (WE) and Central–Eastern (CEE) Europe. The key finding is that the cleavage between cities and suburban–rural areas is much more related to the thick ideological underpinnings of the radical right—authoritarianism and nativism—than the thin, purely populist, dimension. Nativism particularly is stronger the more rural the place of residence, irrespective of the individual’s socio-economic profile, political orientations, the extent to which their region is left-behind, and whether they live in WE or CEE. Hence, future research on the geographical polarization of politics may turn its attention to the radical right, more than to populism per se.
A new bilevel algorithm for UUV global path planning
Authors: Pan Xin , Feng Guoli , Huang Lin , Zeng Haiyan
Published: August 2024

Global path planning is one of the key technologies in unmanned underwater vehicle (UUV) intelligent control. At present, research on UUV global path planning technology tends to choose long-distance and large-scale 3D space as the research environment, which leads to a sharp increase in the amount of data and search range for 3D spatial path planning. Therefore, an efficient and relatively small data volume 3D spatial path planning method is an urgent problem that needs to be solved for UUV engineering applications. To solve this problem, a new bilevel path planning algorithm for UUV is proposed. In the upper level of the algorithm, a Max Min Ant System-Elite Genetic (MMAS-EGA) algorithm is put forward, which is a hybrid ant colony optimization/genetic algorithm, in order to improve the convergence speed of the algorithm. In the lower level of the bilevel algorithm, a function optimization algorithm and the MMAS algorithm are used to minimize the number of variables to be optimized. To verify the effectiveness of the algorithm, we conducted simulation experiments in a three dimensional environment. The simulation results in the three-dimensional environment show that, compared with the existing bilevel algorithm, the time to search the global optimal solution is reduced by 9%, and the number of iterations is reduced by 4.4%. Furthermore, the new algorithm we proposed is more efficient and suitable for global path planning for different tasks.
Analysis of the impact of electromagnetic fields on UAV flight control systems in EHV–UHV DC overhead transmission lines
Authors: Li Jie , Kong Lingkai , Chu Minghao
Published: August 2024

The impact of operating voltage on Unmanned Aerial Vehicle (UAV) inspection and control is mainly manifested as electromagnetic interference, where the electric field mainly affects the distribution of space charges and ions, exhibiting adsorption effects on UAVs, and the magnetic field interferes with airborne magnetometers, disrupting the navigation system of UAVs. Under power frequency conditions, the electromagnetic field of alternating current exhibits alternating characteristics, and it only polarizes near the wire to form space charges or ion currents, with little effect at further distances. However, the variation in the magnetic field in one cycle is zero (positively correlated with alternating current), so its impact on UAVs is not particularly significant. Under direct current conditions, a constant current is introduced into the wire, and the electric field polarized around the wire generates a constant property of charge or ion current, resulting in a relatively larger electric field strength and a wider range of influence. At the same time, the constant current generates a constant magnetic field, which is applied to the airborne magnetometer, equivalent to adding a constant interference source, thus having a significant impact on the inspection and control of UAVs. This article uses ANSYS software to conduct electromagnetic field simulation analysis on DC transmission lines of different voltage levels.
A computational study of how an α- to γ-motoneurone collateral can mitigate velocity-dependent stretch reflexes during voluntary movement
Authors: Niyo Grace , Almofeez Lama I. , Erwin Andrew , Valero-Cuevas Francisco J.
Published: August 2024

The primary motor cortex does not uniquely or directly produce alpha motoneurone (α-MN) drive to muscles during voluntary movement. Rather, α-MN drive emerges from the synthesis and competition among excitatory and inhibitory inputs from multiple descending tracts, spinal interneurons, sensory inputs, and proprioceptive afferents. One such fundamental input is velocity-dependent stretch reflexes in lengthening muscles, which should be inhibited to enable voluntary movement. It remains an open question, however, the extent to which unmodulated stretch reflexes disrupt voluntary movement, and whether and how they are inhibited in limbs with numerous multiarticular muscles. We used a computational model of a Rhesus Macaque arm to simulate movements with feedforward α-MN commands only, and with added velocity-dependent stretch reflex feedback. We found that velocity-dependent stretch reflex caused movement-specific, typically large and variable disruptions to arm movements. These disruptions were greatly reduced when modulating velocity-dependent stretch reflex feedback (i) as per the commonly proposed (but yet to be clarified) idealized alpha-gamma (α-γ) coactivation or (ii) an alternative α-MN collateral projection to homonymous γ-MNs. We conclude that such α-MN collaterals are a physiologically tenable propriospinal circuit in the mammalian fusimotor system. These collaterals could still collaborate with α-γ coactivation, and the few skeletofusimotor fibers (β-MNs) in mammals, to create a flexible fusimotor ecosystem to enable voluntary movement. By locally and automatically regulating the highly nonlinear neuro-musculo-skeletal mechanics of the limb, these collaterals could be a critical low-level enabler of learning, adaptation, and performance via higher-level brainstem, cerebellar, and cortical mechanisms.
Structure-driven development of a biomimetic rare earth artificial metalloprotein
Authors: Thompson Peter J. , Boggs David G. , Wilson Charles A. , Bruchs Austin T. , Velidandla Uditha , Bridwell-Rabb Jennifer , Olshansky Lisa
Published: August 2024

The 2011 discovery of the first rare earth–dependent enzyme in methylotrophic
Methylobacterium extorquens
AM1 prompted intensive research toward understanding the unique chemistry at play in these systems. This enzyme, an alcohol dehydrogenase (ADH), features a La
3+
ion closely associated with redox-active coenzyme pyrroloquinoline quinone (PQQ) and is structurally homologous to the Ca
2+
-dependent ADH from the same organism. AM1 also produces a periplasmic PQQ-binding protein, PqqT, which we have now structurally characterized to 1.46-Å resolution by X-ray diffraction. This crystal structure reveals a Lys residue hydrogen-bonded to PQQ at the site analogously occupied by a Lewis acidic cation in ADH. Accordingly, we prepared K
142
A- and K
142
D-PqqT variants to assess the relevance of this site toward metal binding. Isothermal titration calorimetry experiments and titrations monitored by UV–Vis absorption and emission spectroscopies support that K
142
D-PqqT binds tightly (
K
d
= 0.6 ± 0.2 μM) to La
3+
in the presence of bound PQQ and produces spectral signatures consistent with those of ADH enzymes. These spectral signatures are not observed for WT- or K
142
A-variants or upon addition of Ca
2+
to PQQ ⸦ K
142
D-PqqT. Addition of benzyl alcohol to La
3+
-bound PQQ ⸦ K
142
D-PqqT (but not Ca
2+
-bound PQQ ⸦ K
142
D-PqqT, or La
3+
-bound PQQ ⸦ WT-PqqT) produces spectroscopic changes associated with PQQ reduction, and chemical trapping experiments reveal the production of benzaldehyde, supporting ADH activity. By creating a metal binding site that mimics native ADH enzymes, we present a rare earth-dependent artificial metalloenzyme primed for future mechanistic, biocatalytic, and biosensing applications.
Structural basis for DNA recognition by a viral genome-packaging machine
Authors: Chechik Maria , Greive Sandra J. , Antson Alfred A. , Jenkins Huw T.
Published: August 2024

DNA recognition is critical for assembly of double-stranded DNA viruses, particularly for the initiation of packaging the viral genome into the capsid. The key component that recognizes viral DNA is the small terminase protein. Despite prior studies, the molecular mechanism for DNA recognition remained elusive. Here, we address this question by identifying the minimal site in the bacteriophage HK97 genome specifically recognized by the small terminase and determining the structure of this complex by cryoEM. The circular small terminase employs an entirely unexpected mechanism in which DNA transits through the central tunnel, and sequence-specific recognition takes place as it emerges. This recognition stems from a substructure formed by the N- and C-terminal segments of two adjacent protomers which are unstructured when DNA is absent. Such interaction ensures continuous engagement of the small terminase with DNA, enabling it to slide along the DNA while simultaneously monitoring its sequence. This mechanism allows locating and instigating packaging initiation and termination precisely at the specific
cos
sequence.
AFRIMETS supplementary comparison on calibration of dial gauge
Authors: ElMelegy Ahmed , Mechkour Lhossain , Date Paul , Obayi Bede , Gergiso Tadesse , Tesfaye Birhan , Bore Calvin , James Joseph , Charles Angela , Mutale Daniel , Gandah Burnhard , Kame Modiriemang , Ntima Pamidzani , Pryam Tomeswar , Pallut Ramasawmy , Nzimande Zanele , Masina Patrick
Published: August 2024

Main text

National Metrology Institutes from 11 African countries, namely Egypt, Morocco, Nigeria, Ethiopia, Kenya, Tanzania, Zambia, Zimbabwe, Botswana, Mauritius and South Africa have participated in an international supplementary comparison on the calibration of Dial Indicators.

This comparison was a part of larger supplementary comparison between 13 African countries for the calibration of hand measuring instruments. This larger comparison which was carried out during the period between December 2019 - December 2022 has been piloted by NIS, Egypt and has been registered in BIPM-KCDB database on December 2019. The artifacts have been prepared by NIS, Egypt and measured before sent to circulate between all participant countries in round-robin scheme and returned back again for NIS, Egypt where a final measurement was made for stability check.

The main purpose of these comparisons is to support submission of CMCs for calibration of hand length measuring instruments in BIPM-KCDB.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
AFRIMETS supplementary comparison on calibration of external micrometer
Authors: ElMelegy Ahmed , Mechkour Lhossain , Date Paul , Obayi Bede , Gergiso Tadesse , Tesfaye Birhan , Bore Calvin , James Joseph , Charles Angela , Mutale Daniel , Gandah Burnhard , Kame Modiriemang , Ntima Pamidzani , Pryam Tomeswar , Pallut Ramasawmy , Nzimande Zanele , Masina Patrick
Published: August 2024

Main text

National Metrology Institutes from 12 African countries, namely Egypt, Morocco, Ghana, Nigeria, Ethiopia, Kenya, Tanzania, Zambia, Zimbabwe, Botswana, Mauritius and South Africa have participated in an international supplementary comparison on the calibration of External Micrometer.

This comparison was a part of larger supplementary comparison between 13 African countries for the calibration of hand measuring instruments. This larger comparison which was carried out during the period between December 2019 - December 2022 has been piloted by NIS, Egypt and has been registered in BIPMKCDB database on December 2019. The artifacts have been prepared by NIS, Egypt and measured before sent to circulate between all participant countries in round-robin scheme and returned back again for NIS, Egypt where a final measurement was made for stability check.

The main purpose of these comparisons is to support submission of CMCs for calibration of hand length measuring instruments in BIPM-KCDB.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
AFRIMETS supplementary comparison on calibration of caliper
Authors: ElMelegy Ahmed , Mechkour Lhossain , Date Paul , Obayi Bede , Gergiso Tadesse , Tesfaye Birhan , Bore Calvin , James Joseph , Charles Angela , Mutale Daniel , Gandah Burnhard , Kame Modiriemang , Ntima Pamidzani , Pryam Tomeswar , Pallut Ramasawmy , Nzimande Zanele , Masina Patrick
Published: August 2024

Main text

National Metrology Institutes from 12 African countries, namely Egypt, Morocco, Ghana, Nigeria, Ethiopia, Kenya, Tanzania, Zambia, Zimbabwe, Botswana, Mauritius and South Africa have participated in an international supplementary comparison on the calibration of caliper.

This comparison was a part of larger supplementary comparison between 13 African countries for the calibration of hand measuring instruments. This larger comparison which was carried out during the period between December 2019 - December 2022 has been piloted by NIS, Egypt and has been registered in BIPM-KCDB database on December 2019. The artifacts have been prepared by NIS, Egypt and measured before sent to circulate between all participant countries in round-robin scheme and returned back again for NIS, Egypt where a final measurement was made for stability check.

The main purpose of these comparisons is to support submission of CMCs for calibration of hand length measuring instruments in BIPM-KCDB.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Abnormal behavior of the plasma potential in an inductively coupled plasma with a DC-biased grid
Authors: Kim Min-Seok , Jung Jiwon , Park Junyoung , Chung Chin-Wook
Published: August 2024

The formation of the plasma potential and the generation mechanism of very low electron temperature plasma are investigated in an inductively coupled plasma with a DC biased grid. The electron temperature is controlled from 2.4 eV to 0.2 eV according to the grid voltage (10 V to −40 V). Interestingly, when the grid voltage is negatively biased, the electron temperature decreases and the plasma potential decreases with the grid voltage, but then increases below −10 V which is abnormal. This behavior of the plasma potential is abnormal since the plasma potential is generally proportional to the electron temperature. The main reason for the abnormal increase of the plasma potential is the difference in the flux of electrons and ions below the grid. As the grid is negatively biased, the electron flux is greatly reduced compared to the ion flux, leading to an increase in plasma potential. After −20 V, the plasma potential saturates, because although the number of electrons entering the grid decreases, the electron flux is maintained by secondary electrons generated in the grid mesh. This abnormal increase in plasma potential decreases with pressure. An increase in plasma potential with gas species is also observed. The same behavior is observed for Ar, He, and N2 gases. The abnormal behavior of the plasma potential is explained with the current continuity.
Design of diesel engine vibration signal acquisition system based on Zynq
Authors: Wang Huishuai , Gao Haibo , Zuo Wen
Published: August 2024

The vibration signal of a diesel engine contains a large amount of fault information, and an accurate collection of vibration signals will provide reliable data support for diesel engine condition monitoring. This paper designs a diesel engine vibration signal acquisition system based on the powerful Zynq chip. IEPE piezoelectric acceleration sensors are selected to collect diesel engine vibration signals, and a signal conditioning circuit is designed to filter out interference during signal transmission using the characteristics of differential signals and to adjust the voltage amplitude of the signal to ensure compliance with the input voltage level requirements of the AD conversion module. Considering the excellent performance of the AD7771, it is selected as the AD conversion chip, and the peripheral circuit design is completed. With the help of Vivado software, the software and hardware design based on the Zynq chip is completed, controlling the AD7771 to sample 8 channels of vibration signals. Finally, a signal conditioning circuit simulation model is established in Multisim 14.1 software to verify its good performance, and upper computer software is developed to monitor the fault information of the diesel engine.
Image segmentation based on improved hybrid krill herd algorithm
Authors: Zhang Peng , Tian Ye
Published: August 2024

Image segmentation is an important problem in the field of image processing. Traditional multi-threshold image segmentation faces the problems of inefficiency and lack of real-time performance. In order to improve these problems, a Kapur multi-threshold segmentation algorithm based on the improved hybrid krill herd algorithm is proposed, which adopts a novel population iterative approach limited to the top krill to effectively alleviate the phenomenon of excessive aggregation of krill. Building on this foundation, the differential evolutionary algorithm is combined with the krill herd algorithm, which provides a sufficient search range to strengthen the ability of the algorithm to jump out of the local optimum. The experimental results of multi-threshold segmentation on three classical test images show that the proposed improved algorithm can achieve higher segmentation accuracy and quality, and the convergence rate is mostly above 90%, which verifies the reliability and effectiveness of the algorithm in multi-threshold image segmentation problems.
Study on environmental monitoring classification system based on improved bayesian algorithm
Authors: Guo Xiaoyan
Published: August 2024

The commonly used methods for classifying water quality data are based on water quality parameters. The naive Bayesian classification method can be applied to substitute different evaluation criteria and selected water quality parameters for different water bodies. Compared to other water quality data classification methods, naive Bayesian classification methods have advantages such as simple calculation, high classification accuracy, and strong universality. However, this method overlooks the correlation between various water quality parameters and categories. To address the issues of poor universality, computational complexity, and low accuracy of traditional water quality data classification methods, a water quality data classification method based on weighted naive Bayes is proposed. This method comprehensively considers the impact of water quality attributes and their values on the classification results and replaces the original naive Bayes with weighted attribute conditional probabilities to make the classification results as close as possible to the actual category of the sample. The results indicate that this method exceeds 94% accuracy and can be directly utilized as a water quality classification module in water quality monitoring systems.
Improved image segmentation method based on Otsu thresholding and level set techniques
Authors: Jing Zhipeng , Tang Bo
Published: August 2024

Image segmentation is a complex task in the field of image processing and computer vision, as it faces challenges such as noise, low contrast, and intensity variations. Due to the simplicity, efficiency, and ease of implementation of the Otsu algorithm, as well as its ability to improve accuracy in complex scenarios and enhance robustness against noise and lighting variations, a new grayscale pixel probability selection method has been proposed based on the classic Otsu method and Chan-Vese level set. By applying the Bayesian probability formula, the probability of a grayscale pixel is determined by the global prior and non-local prior. This improved Otsu method is combined with the Chan-Vese level set curve evolution method, resulting in a better image segmentation approach. Comparative experiments have demonstrated the advantages of this method.
Some properties of effect algebra
Authors: Li Wei , Han Wen , Sun Yiyue , Li Jiangtao , Wang Jiaying
Published: August 2024

As a kind of algebraic structure, effect algebra is the foundation of quantum structure and quantum measurement. Sequential effect algebra is a special type of effect algebra that plays an important role in the fundamental research of Quantum Computation. Therefore, we study the related theory of effect algebra in this paper. Finally, four properties and special examples of effect algebra and sequence effect algebra are presented, as well as three properties of effect algebra level sum.
Investigation of a cross-flow wind turbine with a hybrid frontal guiding device
Authors: Iliev Rossen , Tsalov Tsvetan
Published: August 2024

The research results of a new type of frontal guide device for vertical axis wind turbines are presented. The guiding device is composed of cylindrical guide vanes and deflector. The design is derived from two different guiding devices: cylindrical guiding apparatus and so-called omni-directional guiding apparatus, which consists of plates evenly placed around the turbine’s runner. The experiments were carried out on the laboratory test bench No. 7 (wind turbines) in the Laboratory of Hydropower and Hydraulic Turbomachinery at the Technical University of Sofia. According to the obtained data, the new guiding device increases the efficiency of the turbine up to 2.5 times. A comparison is made between the obtained operating curves and those of similar wind turbines, published in various reputable journals.
CFD Analysis of the Behavior of a Submersible Vehicle in Multiple Flow Directions and Elevator and Rudder Fin Configurations
Authors: Todorov Georgi , Kamberov Konstantin , Zlatev Blagovest
Published: August 2024

Presented in the paper is a CFD finite element analysis of a submersible vehicle used for the imaging of plankton for fisheries research. Researched are different fluid flow conditions – different orientations of the flow relative to the submersible vehicle and different configuration of the elevator fin and the rudder fin with the goal to calculate the different pressure center positions in order to form curves and compare the specified initial buoyancy and gravity centers. After determining of the metacentric lines in different rudder and fin configuration the conclusion is made that the submersible device will maintain stable equilibrium while changing direction for the analyzed fluid flows.
CFD virtual prototyping of a high temperature energy storage system
Authors: Tsekov R.P.
Published: August 2024

This paper presents a literature review of existing technological solutions for thermal energy storage in solid- or liquid-storage batteries. The lack of a comprehensive approach for the analysis of high-temperature single-chamber accumulators with solid heat storage media is defined. A concept for modeling and studying such a thermal accumulator is presented. A physical and numerical virtual model of a single-chamber thermal accumulator for high-temperature energy storage and dissipation, including for domestic purposes and heating, is built. Initial simulations show very good agreement of the numerical model with practice.
Quasi-three-dimensional modeling as an effective tool for studying flows in turbomachines
Authors: Terziev Angel , Potashev Andrey , Potasheva Elena , Khisameev Ibragim , Valeeva Yulia , Beloev Hristo , Iliev Iliya
Published: August 2024

The development of software tools for calculating the flow of liquid and gas (the so-called computational fluid dynamics (CFD)) makes it possible to calculate the characteristics of the gas flow in areas with an increasingly complex configuration. In particular, the use of CFD tools is increasingly used to determine the flow parameters in the flow parts of turbomachines, such as fans, pumps, turbines, axial and centrifugal compressors. Despite the wide possibilities of these methods, they have the disadvantage of being very time consuming when creating a new flow path of turbomachines and selecting the blade geometry due to the need for numerous intermediate calculations. From this point of view, the use of faster programs based on approximate flow models in the flow parts of turbomachines is quite justified. It is their use that allows you to choose the geometry of the flow path and blades, as close as possible to the desired aerodynamic requirements. In this paper, using the example of calculating the gas flow through the flow path of a Ts4-70 centrifugal fan, the possibilities of such a model are demonstrated.
Opportunities and challenges of converting coal-fired power plants to nuclear power plants
Authors: Petrov Petar , Boycheva Silviya
Published: August 2024

The constant increasing of world’s energy needs and meanwhile the adopted environmental protection policies in the last decade, have led to a reassessment of the sources and technologies used for production of thermal energy and electricity. The policy of carbon neutrality imposes the shut down and replacement of the most environmentally polluting power plants by 2050 which usually are Coal-Fired Power Plants (CPP). They could be replaced by Renewable Power Plants (RPP) or Nuclear Power Plants (NPP). The most promising is the conversion of CPP to NPP (C2N) using nuclear technologies and especially Small modular reactors (SMR) which are the most suitable for the task. This paper provides an overall assessment of the possibilities for C2N transformation with SMR, taking into account the aspects of site selection requirements, available water resources, the possibilities of using existing equipment, systems and infrastructure, the available nuclear technology, as well as non-technical factors. The different options for C2N are examined, focusing on retrofitting and repowering because both options could be the most beneficial ones according to the initial evaluations. However, they face many challenges to overcome due to the combination of different types of equipment that will have to operate with vastly different parameters than originally designed in the case of repowering. The available solutions are discussed here reading the level of development of SMR technologies and the possibilities for their industrialization in a short time, but also the most significant challenges and obstacles to the transformation of CPPs into NPPs.
Study of the efficiency of the joint operation of a cogeneration steam turbine with a heat pump installation
Authors: Hristov Kaloyan
Published: August 2024

In the source of heat energy for centralized heat supply systems, the joint production (cogeneration) of heat and electricity in one energy conversion unit is most often implemented. In most cases, the cogeneration technologies are based on steam turbine installations. Combined heat and power (CHP) generation is undoubtedly a method where the energy of the fuel input for both products is used more efficiently, in contrast to the production of the same amounts of energy by the split production method. To increase the efficiency of cogeneration plants a low potential heat source can be used. For this purpose, in this paper, based on simulation modelling, a comparative analysis of the operation of a combined heat and power steam turbine plant with a heat pump plant with a low-potential heat source will be carried out. In the study, the mains water that is fed for preheating is used as the low-potential heat source.
Implementing microfluidic flow device model in utilizing dural substitutes as pulp capping materials for vital pulp therapy
Authors: Lee Min-Yong , Yoon Hi-Won , Kim Sun-Il , Kwon Jae-Sung , Shin Su-Jung
Published: August 2024

Vital pulp therapy (VPT) has gained prominence with the increasing trends towards conservative dental treatment with specific indications for preserving tooth vitality by selectively removing the inflamed tissue instead of the entire dental pulp. Although VPT has shown high success rates in long-term follow-up, adverse effects have been reported due to the calcification of tooth canals by mineral trioxide aggregates (MTAs), which are commonly used in VPT. Canal calcification poses challenges for accessing instruments during retreatment procedures. To address this issue, this study evaluated the mechanical properties of dural substitute intended to alleviate intra-pulp pressure caused by inflammation, along with assessing the biological responses of human dental pulp stem cells (hDPSCs) and human umbilical vein endothelial cells (HUVECs), both of which play crucial roles in dental pulp. The study examined the application of dural substitutes as pulp capping materials, replacing MTA. This assessment was conducted using a microfluidic flow device model that replicated the blood flow environment within the dental pulp. Computational fluid dynamics simulations were employed to ensure that the fluid flow velocity within the microfluidic flow device matched the actual blood flow velocity within the dental pulp. Furthermore, the dural substitutes (Biodesign; BD and Neuro-Patch; NP) exhibited resistance to penetration by 2-hydroxypropyl methacrylate (HEMA) released from the upper restorative materials and bonding agents. Finally, while MTA increased the expression of angiogenesis-related and hard tissue-related genes in HUVEC and hDPSCS, respectively, BD and NP did not alter gene expression and preserved the original characteristics of both cell types. Hence, dural substitutes have emerged as promising alternatives for VPT owing to their resistance to HEMA penetration and the maintenance of stemness. Moreover, the microfluidic flow device model closely replicated the cellular responses observed in live pulp chambers, thereby indicating its potential use as anin vivotesting platform.
Computational modeling and statistical analysis of buckling characteristics of polysilicon reinforced fiber
Authors: Laftah Waham Ashaier , Wan Abdul Rahman Wan Aizan
Published: August 2024

The purpose of this study is to evaluate the effect of volume fraction of continuous carbon fiber and sample length on buckling characteristics of polysilicon. A statistical design of 12 samples were formulated with constant cross-section area of 2500 mm2 using Design of Experiment software (DOE). The samples were sketched using ABAQUS 2019 software, and the total buckling force each sample was estimated. The estimated buckling forces were statically evaluated as a response using DOE. The estimated forces of 3.48776e07, 4.00652e07 and 5.78142e07 newton for the simulated samples of 100 mm in length and 0,15, and 25% volume fraction respectively, is an indication of positive effect of fiber volume fraction on the necessary force for buckling. In addition, similar tendency was found in other samples (the higher fiber volume fractions the higher buckling force). However, the estimated buckling force for each sample was negatively affected with length of the sample. The result indicated a value of 4.00652E+07, 5.00447E+06 and 1.80390E+06 newton at a constant fiber volume fraction and different length of 100, 300 and 500 mm respectively. The statistical analysis of the simulated buckling force showed a signification design, and the date of one factor effect is highly supported by the simulated buckling forces. The equation of a significant design can be used to estimate the buckling force at any fiber volume fraction and sample length.