bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Effect of Reference Time of Chloride Diffusion Coefficient in Numerical Modelling of Durability of Concrete
Authors: Lehner Petr , Koubová Lenka , Rosmanit Miroslav
Published: September 2022

The results of numerical calculations on the resistance of the reinforced concrete bridge deck to chlorides are compared with a different approach to the diffusion coefficient of the input parameter, and presented. The aim is to point out the necessity of a correct model adjustment in the case of using diffusion parameters obtained differently at different measurement times. The diffusion parameter, as a typical concrete material constant, was derived from electrical resistivity measurements and using the least-squares method from a direct chloride test. Due to the different times of obtaining the concrete parameters, a control calculation was performed, which showed that the numerical model for calculating the initiation of reinforcement corrosion in chloride-exposed reinforced concrete requires the application of not only a suitable diffusion parameter but also an adequate reference time. The article points out the need to use an adequate reference time introduced in the numerical calculation of the durability of reinforced concrete with respect to aggressive substances. The results show that the most appropriate reference time value is derived from the average measurement time related to the lifetime of the concrete.
Optimization of Plasmonic Copper Content at Copper-Modified Strontium Titanate (Cu-SrTiO3): Synthesis, Characterization, Photocatalytic Activity
Authors: Ágoston Áron , Balog Ádám , Narbutas Šarūnas , Dékány Imre , Janovák László
Published: September 2022

Catalyst development still has a major impact on science today, as we can use catalysts to break down certain pollutants in an energy-efficient way. There is no comprehensive literature on the development of SrTiO3-based photocatalysts, so study in this area is justified. Related to this topic, here we report the facile preparation of surface-modified SrTiO3 photocatalyst, performed by plasmonic copper deposition. In the case of the copper-modified samples (0.25–3 wt.% Cu content), the photooxidation of phenol, as model contaminant, was almost 4–5 times higher than the bare SrTiO3. However, the photocatalytic activity was not linearly related to copper content, since the highest photoactivity was achieved at 1 wt.% copper content. The reason for the better activity was the plasmonic effect of copper, which increases the recombination time of charge separation on the catalyst surface. During slower recombination, more water is oxidized to hydroxyl radicals, which can lead to faster degradation of phenol.
A Novel Muscle Atrophy Mechanism: Myocyte Degeneration Due to Intracellular Iron Deprivation
Authors: Suh Dae Keun , Lee Won-Young , Yeo Woo Jin , Kyung Bong Soo , Jung Koo Whang , Seo Hye Kyung , Lee Yong-Soo , Suh Dong Won
Published: September 2022

Muscle atrophy is defined as the progressive degeneration or shrinkage of myocytes and is triggered by factors such as aging, cancer, injury, inflammation, and immobilization. Considering the total amount of body iron stores and its crucial role in skeletal muscle, myocytes may have their own iron regulation mechanism. Although the detrimental effects of iron overload or iron deficiency on muscle function have been studied, the molecular mechanism of iron-dependent muscle atrophy has not been elucidated. Using human muscle tissues and in the mouse rotator cuff tear model, we confirmed an association between injury-induced iron depletion in myocytes and muscle atrophy. In differentiated C2C12 myotubes, the effects of iron deficiency on myocytes and the molecular mechanism of muscle atrophy by iron deficiency were evaluated. Our study revealed that the lower iron concentration in injured muscle was associated with the upregulation of ferroportin, an iron exporter that transports iron out of cells. Ferroportin expression was increased by hypoxia-inducible factor 1α (HIF1α), which is activated by muscle injury, and its expression is controlled by HIF1 inhibitor treatment. Iron deprivation caused myocyte loss and a marked depletion of mitochondrial membrane potential leading to muscle atrophy, together with increased levels of myostatin, the upstream regulator of atrogin1 and muscle RING-finger protein-1 (MuRF1). Myostatin expression under iron deficiency was mediated by an orphan nuclear receptor, dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome (DAX1).
Human Allogeneic Liver-Derived Progenitor Cells Significantly Improve NAFLD Activity Score and Fibrosis in Late-Stage NASH Animal Model
Authors: Najimi Mustapha , Michel Sébastien , Binda Maria M. , Gellynck Kris , Belmonte Nathalie , Mazza Giuseppe , Gordillo Noelia , Vainilovich Yelena , Sokal Etienne
Published: September 2022

Accumulated experimental and clinical evidence supports the development of human allogeneic liver-derived progenitor cells (HALPCs) to treat fibro-inflammatory liver diseases. The aim of the present study was to evaluate their therapeutic effect in a non-alcoholic steatohepatitis (NASH)-STAM mouse model. The immune signaling characteristics of HALPCs were first assessed in vitro. Upon inflammation treatment, HALPCs secreted large amounts of potent bioactive prostaglandin E2 and indoleamine 2,3-dioxygenase, which significantly reduced CD4+ T-lymphocyte proliferation and secretion of proinflammatory cytokines. In vivo, HALPCs were intravenously administered as single or triple shots (of a dose of 12.5 × 106 cells/kg BW) in STAM mice. Transplantation of HALPCs was associated with a significant decrease in the NAFLD activity score at an early stage and in both inflammation and hepatocyte ballooning scores in late-stage NASH. Sirius red staining analyses revealed decreased collagen deposition in the pericentral region at both stages of NASH. Altogether, these findings showed the anti-inflammatory and anti-fibrotic features of HALPCs in an in vivo NASH model, which suggests their potential to reverse the progression of this chronic fibro-inflammatory disease.
MYH9 Facilitates Cell Invasion and Radioresistance in Head and Neck Cancer via Modulation of Cellular ROS Levels by Activating the MAPK-Nrf2-GCLC Pathway
Authors: You Guo-Rung , Chang Joseph T. , Li Yan-Liang , Huang Chi-Wei , Tsai Yu-Liang , Fan Kang-Hsing , Kang Chung-Jan , Huang Shiang-Fu , Chang Po-Hung , Cheng Ann-Joy
Published: September 2022

The MYH9 (Myosin heavy chain 9), an architecture component of the actomyosin cytoskeleton, has been reported to be dysregulated in several types of cancers. However, how this molecule contributes to cancer development is still obscure. This study deciphered the molecular function of MYH9 in head and neck cancer (HNC). Cellular methods included clonogenic survival, wound-healing migration, and Matrigel invasion assays. Molecular techniques included RT-qPCR, western blot, luciferase reporter assays, and flow cytometry. Clinical association studies were undertaken by TCGA data mining, Spearman correlation, and Kaplan-Meier survival analysis. We found that MYH9 was overexpressed in tumors and associated with poor prognosis in HNC patients. MYH9 promoted cell motility along with the modulation of the extracellular matrix (fibronectin, ITGA6, fascin, vimentin, MMPs). Also, MYH9 contributed to radioresistance and was related to the expression of anti-apoptotic and DNA repairing molecules (XIAP, MCL1, BCL2L1, ATM, RAD50, and NBN). Mechanically, MYH9 suppressed cellular ROS levels, which were achieved by activating the pan-MAPK signaling molecules (Erk, p38, and JNK), the induction of Nrf2 transcriptional activity, and the up-regulation of antioxidant enzymes (GCLC, GCLM, GPX2). The antioxidant enzyme GCLC was further demonstrated to facilitate cell invasion and radioresistance in HNC cells. Thus, MYH9 exerts malignant functions in HNC by regulating cellular ROS levels via activating the MAPK-Nrf2-GCLC signaling pathway. As MYH9 contributes to radioresistance and metastasis, this molecule may serve as a prognostic biomarker for clinical application. Furthermore, an in vivo study is emergent to support the therapeutic potential of targeting MYH9 to better manage refractory cancers.
The Plasmodesmata-Located β-1,3-Glucanase Enzyme PdBG4 Regulates Trichomes Growth in Arabidopsis thaliana
Authors: Fan Yijie , Lin Shuangshuang , Li Tongtong , Shi Fengjuan , Shan Guangyao , Zeng Fanchang
Published: September 2022

Intercellular material transport and information transmission in plants are carried out through the plasmodesmata (PD). The amount of callose around the PD controls channel permeability. In plants, β-1,3-glucanase can degrade callose and affect plant growth and development. In this study, the gene producing PD-localized β-1,3-glucanase and regulating the leaf trichomes is identified and named PdBG4. Based on functional analysis through a series of genetic manipulation assays, we found that the high expression of PdBG4 was associated with strong PD permeability and short Arabidopsis thaliana leaf trichomes. Conversely, the low expression of PdBG4 correlated with weak PD permeability and long Arabidopsis thaliana leaf trichomes. This study revealed that the PdBG4 gene negatively modulates leaf trichome growth and development by regulating PD permeability.
The Role of the Pediatric Yorkhill Malnutrition Score (PYMS), Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratios in Malnutrition Prediction of Hospitalized Children
Authors: Gysi Spyridoula , Doulberis Michael , Légeret Corinne , Köhler Henrik
Published: September 2022

Malnutrition in hospitalized children represents a significant burden with occasionally detrimental consequences. In this retrospective analysis of pediatric patients aged one to 16 years old, who were hospitalized in the children’s cantonal hospital of Aarau, Switzerland, we investigated the utilization of PYMS (Pediatric Yorkhill Malnutrition Score) as a routine screening tool for malnutrition in pediatric inpatients. Additionally, we explored the correlation between PYMS and NLR (neutrophil–lymphocyte ratio) and PLR (platelet–lymphocyte ratio), which are two novel biomarkers. Various parameters were analyzed from the medical records of the patients. Most of the sample (n = 211, 77.3%) was characterized by a low PYMS of 0–1 point. Greater NLR and PLR values were significantly associated with greater PYMS (p = 0.030 and p = 0.004, respectively). ROC (receiver operating characteristic curves) analysis revealed that PLR had a significant predictive ability for having PYMS > 1 (AUC = 0.59; 95% CI: 0.51–0.68; p = 0.024). The optimal cut-off was 151 with sensitivity of 51.6% (95% CI: 38.6–64.5%) and specificity of 67.3% (95% CI: 60.5–73.6%). Furthermore, 37% of the children (n = 101) yielded a PLR over 151. Our results support a promising value of PLR as a predictive marker for moderate to severe malnutrition in hospitalized children.
Non-Flammable Dual-Salt Deep Eutectic Electrolyte for High-Voltage Lithium Metal Battery
Authors: Wu Wanbao , Li Qing , Cao Miaomiao , Li Deping , Lu Jingyu , Li Mingyu , Zhang Jiaheng
Published: September 2022

The application of high voltage cathode electrode materials is an effective way to increase the energy density of batteries. However, the development and design of a stable electrolyte at high voltages needs to be further addressed. Herein, we developed a non-flammable dual-salt deep eutectic solvent (DES) as a safe electrolyte containing LiTFSI, LiDFOB, and succinonitrile in different molar ratios. This non-flammable DES provides high ionic conductivity (4.23 mS cm−1) at 25 °C, high Li+ transference number (0.75), and wide electrochemical stability (>5.5 V). When using the designed DES electrolytes in high voltage LiCoO2||Li cells, superior electrochemical performance was achieved at cut-off voltages of 3.0–4.45 V and 3.0–4.6 V, even at a high current density of 2 C. This work offers an in-depth understanding of the critical role of dual-salts in DES and provides an approach to designing safe electrolytes for high voltage LiCoO2||Li cells.
Different Uptake of 68Ga-FAPI and 18F-FDG in Lymphadenopathy Caused by Angioimmunoblastic T-Cell Lymphoma in a Patient with Colon Cancer
Authors: Wu Meiqi , Pan Qingqing , Luo Yaping
Published: September 2022

An 82-year-old man with a history of colon cancer was found with multiple lymphadenopathies and a pulmonary mass. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) detected generalized hypermetabolic lymph nodes and an FDG-avid pulmonary mass. PET/CT with 68Ga-labeled fibroblast activation protein inhibitor (FAPI) revealed intense uptake in the lung mass, consistent with metastatic disease from colon cancer. However, the lymphadenopathies were not avid for 68Ga-FAPI, suggesting a different etiology. The biopsy of a cervical node confirmed angioimmunoblastic T-cell lymphoma. The case showcased the potential of 68Ga-FAPI in differentiation of solid tumor and hematological disease due to different histopathologic nature of stromal fibrosis.
Distribution of Presepsin, Krebs von den Lungen 6, and Surfactant Protein A in Umbilical Cord Blood
Authors: Nam Minjeong , Hur Mina , Kim Hanah , Lee Gun-Hyuk , Park Mikyoung , Kwon Han-Sung , Hwang Han-Sung , Sohn In-Sook
Published: September 2022

Presepsin is an early indicator of infection, and Krebs von den Lungen 6 (KL-6) and Surfactant Protein A (SP-A) are related to the pathogenesis of pulmonary infection and fibrosis. This study aimed to establish reference intervals (RIs) of presepsin, KL-6, and SP-A levels and to evaluate the possible influence of neonatal and maternal factors on presepsin, KL-6, and SP-A levels in umbilical cord blood (UCB). Among a total of 613 UCB samples, the outliers were removed. The RIs for presepsin, KL-6, and SP-A levels were defined using non-parametric percentile methods according to the Clinical and Laboratory Standards Institute guidelines (EP28-A3C). These levels were analyzed according to neonatal and maternal factors: neonatal sex, gestational age (GA), birth weight (BW), Apgar score, delivery mode, the presence of premature rupture of membranes (PROM), gestational diabetes mellitus (GDM), and pre-eclampsia. Presepsin, KL-6, and SP-A levels showed non-parametric distributions and left-skewed histograms. The RIs of presepsin, KL-6, and SP-A levels were 64.9–428.3 pg/mL, 43.0–172.0 U/mL, and 2.1–36.1 ng/mL, respectively. Presepsin, KL-6, and SP-A levels did not show significant differences according to sex, GA, BW, Apgar score, delivery mode, PROM, GDM, and pre-eclampsia. The median level and 97.5th centile RI of KL-6 showed a slight increase with increased GA. We established RIs for presepsin, KL-6, and SP-A levels in large-scaled UCB samples. Further investigation would be needed to determine the clinical significance.
Analysis of the Causes of Solitary Pulmonary Nodule Misdiagnosed as Lung Cancer by Using Artificial Intelligence: A Retrospective Study at a Single Center
Authors: Wu Xiong-Ying , Ding Fan , Li Kun , Huang Wen-Cai , Zhang Yong , Zhu Jian
Published: September 2022

Artificial intelligence (AI) adopting deep learning technology has been widely used in the med-ical imaging domain in recent years. It realized the automatic judgment of benign and malig-nant solitary pulmonary nodules (SPNs) and even replaced the work of doctors to some extent. However, misdiagnoses can occur in certain cases. Only by determining the causes can AI play a larger role. A total of 21 Coronavirus disease 2019 (COVID-19) patients were diagnosed with SPN by CT imaging. Their Clinical data, including general condition, imaging features, AI re-ports, and outcomes were included in this retrospective study. Although they were confirmed COVID-19 by testing reverse transcription-polymerase chain reaction (RT-PCR) with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), their CT imaging data were misjudged by AI to be high-risk nodules for lung cancer. Imaging characteristics included burr sign (76.2%), lobulated sign (61.9%), pleural indentation (42.9%), smooth edges (23.8%), and cavity (14.3%). The accuracy of AI was different from that of radiologists in judging the nature of be-nign SPNs (p < 0.001, κ = 0.036 < 0.4, means the two diagnosis methods poor fit). COVID-19 patients with SPN might have been misdiagnosed using the AI system, suggesting that the AI system needs to be further optimized, especially in the event of a new disease outbreak.
Kindergarten Proximity and the Housing Market Price in Italy
Authors: Bergantino Angela Stefania , Biscione Antonella , de Felice Annunziata , Porcelli Francesco , Zagaria Riccardo
Published: September 2022

This paper investigates the impact of kindergarten proximity on housing market prices in the eleven major Italian Municipalities over the period 2004–2017. For this purpose, we employ a hedonic property price model. We also differentiate the impact of kindergarten proximity on houses’ market price between state and non-state premises. The findings highlight that (i) the level of housing price depends on kindergarten proximity; (ii) some quality school characteristics played a crucial role and (iii) the distinction between public and non-state kindergartens shows that the vicinity of the latter generates a more significant capitalization effect. Finally, the empirical evidence could be useful to several actors involved in urban planning when developing plans for the construction of new kindergartens in order to create a more homogeneous city.
The Impact of Technostress on Teacher Educators’ Work–Family Conflict and Life Satisfaction While Working Remotely during COVID-19 in Pakistan
Authors: Shaukat Sadia , Bendixen Lisa D. , Ayub Nadia
Published: September 2022

This study aims to examine the relationship between teacher educators’ technostress, work–family conflict, and life satisfaction while working from home during the COVID-19 pandemic in Pakistan. The sample consists of 292 respondents, 151 (51.7%) male and 141 (48.3%) female teacher educators, who participated in this study. Three scales, the Technostress Scale (TS), Work–Family Conflict Scale (WFCS), and the Life-Satisfaction Scale (LS), were administered to determine the impact of demographic variables (i.e., gender, age, qualification) on teachers’ technostress, work–family conflict, and life satisfaction. The findings of the study suggest a positive correlation of technostress with work–family conflict (r = 381) and life satisfaction (r = 0.449). Moreover, gender differences were found in the variables of technostress (t = −3.506, df = 290, p ≤ 0.05), work–family conflict (t = −2.834, df = 290, p ≤ 0.05), and life satisfaction (t = −2.916, df = 290, p ≤ 0.05). The present research is a baseline study within the context of Pakistan to report the findings in terms of educators’ technostress, keeping balance between work and life, and status of life satisfaction as a result of teaching virtually while working from home during the pandemic.
A Study on Learner Types in Online Classes by Q-Methodology
Authors: Ahn Byoung-Wook , Song Won-Ick
Published: September 2022

The aim of this research was to analyze the characteristics of each type of learner among university students in online classes. The P sample was composed of 28 students who had participated in online classes. We prepared a Q sample for advanced research, special publication, an open questionnaire, and an interview. Through this process, we suggested different learner types and applied the types through Q methodology, which is well-known for its use in subjective research. We then distributed the P sample amongst Q cards and generated the following results through principal component factor analysis. University students were categorized into four learning types: ‘self-directed’, ‘content’, ‘online’, and ‘team project’. We judged that the class attitude and class satisfaction of students change as the class types are diversified due to the coronavirus. By analyzing the types of learners created by non-face-to-face classes at universities, this study is meaningful in providing teachers with an outline of various classes that are suitable for various types of learners.
Factors Influencing Students’ Achievements in the Content and Cognitive Domains in TIMSS 4th Grade Science and Mathematics in the United Arab Emirates
Authors: Balfaqeeh Asma , Mansour Nasser , Forawi Sufian
Published: September 2022

Trends in International Mathematics and Science Study (TIMSS) is a comparative international assessment study conducted by the International Association for the Evaluation of Educational Achievement (IEA). TIMSS aims to study how educational opportunities are provided for students and what factors are associated with these opportunities. The purpose of this study was to examine the student factors in the United Arab Emirates that have an association with grade 4 students’ TIMSS 2015 results in the content and cognitive domains in the subjects of mathematics and science. The study adopted the quantitative research approach through the data analysis of TIMSS 2015 for grade 4 students in these subjects. The study sample consisted of 21,177 students enrolled in 372 UAE private schools and 186 public schools. The percentage of grade 4 girls who participated in the study was 48%, while the percentage of boys was 52%. A multiple linear regression analysis was conducted to examine the most influential student factors that impact on science and maths achievement. Structural equation modeling (SEM) was implemented to examine the relationships between student factors and the content and cognitive domains of mathematics and science in the TIMSS 2015 results. The findings showed that the student factors with a positive association with student achievement were having breakfast on school days, engaging teaching in mathematics lessons, liking learning science, and confidence in mathematics and science. There was a non-significant correlation between gender and mathematics and science achievement. A surprising finding was that “liking learning mathematics” had a negative association with student performance in that subject. There was a positive association between student engagement and mathematics achievement, while the association between the engagement in science lessons and student performance was found to be insignificant.
An Efficient Hyperspectral Image Classification Method: Inter-Class Difference Correction and Spatial Spectral Redundancy Removal
Authors: Zhao Lei , Pan Qiang , Yuan Shurong , Shi Lei
Published: September 2022

Existing remote sensing images of ground objects are difficult to annotate, and building a hyperspectral dataset requires huge resources. To tackle these problems, this paper proposes a new method with low requirements for the scale of the dataset that involves correcting the inter-class differences of hyperspectral images and eliminating the redundant information of spatial–spectral features. Firstly, the algorithm introduces the spatial information of hyperspectral images into the classification task through the superpixel definition based on the entropy rate, which not only reduces the spatial redundancy information of hyperspectral images but also uses the similarity of spatial neighbors to increase the differences between classes and alleviate the differences within classes. Secondly, under the theoretical guidance of similar spectral fluctuation trends of similar objects, a feature extraction method based on fast Fourier transform is proposed to alleviate spectral feature redundancy and further eliminate the inter-class differences of the algorithm. Finally, to verify the improvement effect of the proposed idea on the traditional classification method, the idea was applied to the traditional SVM algorithm, and experiments were carried out based on the PaviaU and Indian Pines hyperspectral datasets. The simulation results show that the proposed (ERS–FFT–SVM) algorithm shows a significant improvement in classification accuracy when compared with the traditional classification algorithm and is able to perform the small sample classification of hyperspectral images.
Energy-Spectrum Efficiency Trade-Off in UAV-Enabled Mobile Relaying System with Bisection-PSO Algorithm
Authors: An Qi , Huang Yangchao , Hu Hang , Pan Yu , Han Huizhu
Published: September 2022

Unmanned aerial vehicle (UAV)-enabled mobile relaying is regarded as an important wireless connectivity component in areas without infrastructure coverage due to its rapid response, strong mobility, and low cost. This paper studies a delay tolerant UAV-enabled mobile relaying system and adopts the load-carry-and-deliver paradigm. The UAV is employed to assist in the information transmission from a ground transmitter to a ground receiver with their direct link blocked. Two kinds of UAV flight trajectories are proposed in this system, i.e., a straight line and circular trajectory. Suppose that the UAV employs time-division duplexing (TDD)-based decode-and-forward (DF) relaying. This paper then aims to maximize the spectrum efficiency (SE) and energy efficiency (EE) in of the UAV-enabled relaying system by jointly optimizing the time allocation, flight speed, and the flying radius of the circular trajectory. Then, we develop an efficient algorithm by leveraging the bisection method and particle swarm optimization (PSO) algorithm. Simulation results show the superiority of the proposed algorithm as compared to other benchmark schemes. In addition, numerical results show that, when the communication distance is 1000 m, the SE and EE performance of the circular trajectory is better than the SLF trajectory when the obstacle height is greater than 300 m. Thus, the height of the obstacle between the communication nodes and the trade-off between the SE and EE should be taken into account when we design the optimal trajectory of the UAV-enabled mobile relaying system.
LTE and NB-IoT Performance Estimation Based on Indicators Measured by the Radio Module
Authors: Burczyk Robert , Czapiewska Agnieszka , Gajewska Malgorzata , Gajewski Slawomir
Published: September 2022

Monitoring the operating parameters of power grids is extremely important for their proper functioning as well as for ensuring the security of the entire infrastructure. As the idea of the Internet of Things becomes more ubiquitous, there are tools for monitoring the state of the complex electrical grid and means to control it. There are also developed new measuring devices and transmission technologies allowing for the transfer of performed measurements from many places to the network management center. However, there are still no devices that act as data concentrators, which would integrate many transmission technologies and protocols in one device, supporting the communication between those different transmission technologies and which would realize edge computing to assist the management center by prioritizing and combining transmitted data. In this article, the authors present a device that meets the above-mentioned requirements. There are presented research results leading to the development of a decision algorithm, called Multilink—ML, dedicated to the presented device. This algorithm enables the selection between LTE and NB-IoT interfaces for packet transmission without the need to burden the communication system with additional transmissions.
Novel Channel/QoS Aware Downlink Scheduler for Next-Generation Cellular Networks
Authors: Taha Dalia H. Y. , Haci Huseyin , Serener Ali
Published: September 2022

Downlink schedulers play a vital part in the current and next-generation wireless networks. The next generation downlink scheduler should satisfy the demand for different requirements, such as dealing with ultra-dense networks and the need to run real-time (RT) and non-real-time (nRT) applications, with a high quality of service (QoS). Many researchers have developed various schedulers for these, but none have introduced one scheduler to target them all. This paper introduces a novel channel/QoS aware downlink scheduler algorithm, called Advanced Fair Throughput Optimized Scheduler (AFTOS), for ultra-dense networks. AFTOS is a multi-QoS scheduler that aims to maximize system spectrum efficiency and user throughput with enhanced fairness, delay, and packet loss ratio (PLR). It is capable of handling RT and nRT traffic. We developed two new policies, called Adjusted Largest Weighted Delay First (ALWDF) and Fair Throughput Optimized Scheduler (FTOS), for RT and nRT traffic. Then, we joint them to introduce our novel downlink scheduler Advanced Fair Throughput Optimized Scheduler (AFTOS). For evaluating the suggested algorithm, we undertook experiments to decide the ideal parameter value for the proposed approaches and compared the proposed solution to current best practices. The findings prove that the AFTOS algorithm can achieve its objectives, outperforming the alternative techniques.
A New Non-Isolated High-Gain Single-Switch DC–DC Converter Topology with a Continuous Input Current
Authors: Gholizadeh Hossein , Ben-Brahim Lazhar
Published: September 2022

An ultra-high step-up, non-isolated DC–DC converter with a continuous input current was developed as a result of this research. This converter’s architecture consists of a voltage multiplier cell (VMC), a positive output super lift Luo converter (POSLLC), and a quadratic boost converter (QBS) (also referred to as a cascaded boost topology (CBT)). Thus, the bold points of the topologies mentioned earlier enhance the voltage gain of the proposed topology. It is important to note that when the duty cycle is at 50%, the converter attains a voltage gain of ten. Additionally, the constant input current of the topology reduces the current stress on the input filter capacitor. This converter’s topology was investigated and studied under various operating conditions: ideal and non-ideal modes, as well as continuous and discontinuous current modes (CCM/DCM). The converter’s efficiency and voltage gain were also compared to those of newly proposed converters. PLECS and MATLAB software tools were used in the investigation of the proposed topology. A 200 V/200 W prototype was constructed. The experimental results validated the theoretical study and the simulation results. The extracted efficiency was 91%.
Modelling and Performance Analysis of Cyclic Hydro-Pneumatic Energy Storage System Considering the Thermodynamic Characteristics
Authors: Gao Lulu , Wang Dongyue , Jin Chun , Yi Tong
Published: September 2022

The energy storage system of electric-drive heavy mining trucks takes on a critical significance in the characteristics including excellent load capacity, economy, and high efficiency. However, the existing battery-based system does not apply to harsh cold environments, which is the common working condition for the above trucks. A type of cycle hydro-pneumatic energy storage system for the trucks was proposed in this study. The dynamic model of the system, including the dynamic and thermodynamic models of hydraulic and pneumatic parts, was built to analyze the performance of the system. Subsequently, the thermodynamic characteristics were clarified during the energy storage and released through the real test condition-based simulation. The power and energy performances of the system were studied in practice based on the above characteristics. The analysis of the results showed that the system reduced 22.03% driving power at the optimal braking energy recovery rate, the energy density was nearly 12.6 MJ/m3, the maximum input power was higher than 230 kW, and the cycle efficiency was about 40.6%. The results of this study will be conducive to the application of the hydro-pneumatic energy storage system for the electric-drive mining trucks and reducing the resulting carbon emission.
The Use of a Roadheader Simulator in Research of Dynamics and Energy-Consumption of Excavating Underground Roadways and Tunnels
Authors: Cheluszka Piotr , Remiorz Eryk , Rostami Jamal
Published: September 2022

Boom-type roadheaders are commonly used for excavation of roadways in underground mines, tunnels, and other architectural structures using trenchless techniques, as well as sinking shafts and occasionally excavating the harder soil and softer formations in cut and cover construction. The main research and development of these machines is to offer solutions for automatic control. This refers to automation or robotization of the operation, and raises the possibility of their eventual unmanned operation. This article presents a roadheader research simulator which implements experimentally verified mathematical models describing the dynamics of a roadheader in operation and the rock cutting process. Due to very high computational requirements, a distributed system comprising several workstations connected via TCP/IP was used. Both the visualization of the roadheader in the heading face of the excavation and the graphic simulation of the course of the rock-cutting process were carried out using the Autodesk Inventor Professional 2022 graphics engine. It provided the simulator with a virtual scene environment and enabled the control of the roadheader model’s movement during the simulated cutting process, including the generation of breakout graphics in the heading face while drilling a roadway or tunnel. The presented roadheader simulator enables the determination of various time characteristics, for example, dynamic loads, power demand, efficiency, energy consumption, and others. It is still under development.
Optimization Design of the Organic Rankine Cycle for an Ocean Thermal Energy Conversion System
Authors: Yang Xiaowei , Liu Yanjun , Chen Yun , Zhang Li
Published: September 2022

This study selects five parameters as decision variables for the optimization design of an ocean thermal energy conversion system, including the evaporating temperature, the condensing temperature, the pinch-point temperature difference between the evaporator and condenser, and the working fluid flow rate. The optimization goal is to maximize the net output power per unit area and the exergy efficiency. The final scheme is comprehensively screened out from the Pareto solution set through some evaluation indexes. Finally, this study also analyzes the effects of four decision variables on the optimization objectives and the evaluation indexes. This study finds that evaporating temperature and condensing temperature have similar effects on the two objective functions. However, the pinch-point temperature difference has different effects on them. The back work ratio is obviously affected by the condensing temperature. A small pinch-point temperature difference is beneficial and improves the performance of an ocean thermal energy conversion system. The effects of evaporating temperature and condensing temperature on the investment cost per unit net output power are roughly similar to those on the net output power per unit heat exchange area. However, the effects of the pinch-point temperature difference on the two performance aspects are inconsistent.
Passivity-Based Control of Dual Active Bridge Converter in Constant Power Load Condition
Authors: Li Jianguo , Zhao Yuming , Wu Xuezhi , Zhang Yajing , Wang Jiuhe
Published: September 2022

This paper presents a passivity-based control (PBC) based on the Euler–Lagrange (EL) model for dual active bridge (DAB) converters in the constant power load (CPL) condition. The EL model, which is derived from Kirchhoff’s current equations at the input and output nodes, is first presented in the DAB application, and the bidirectional CPL is considered in the theoretical analysis, simulation, and physical verification. The PBC has strong robustness to large-signal disturbance and negative incremental resistance load, and it is suitable for DAB converters in the CPL condition. In this paper, the DAB’s EL model, passivity analysis, stability analysis, and controller design are described in detail. The simulation results based on SIMULINK are also given in this paper. Finally, a DAB converter prototype is built to demonstrate the validity and feasibility of the proposed approach.
A Pipe Ultrasonic Guided Wave Signal Generation Network Suitable for Data Enhancement in Deep Learning: US-WGAN
Authors: Peng Lisha , Li Shisong , Sun Hongyu , Huang Songling
Published: September 2022

A network ultrasonic Wasserstein generative adversarial network (US-WGAN), which can generate ultrasonic guided wave signals, is proposed herein to solve the problem of insufficient datasets for pipe ultrasonic nondestructive testing based on deep neural networks. This network was trained with pre-enhanced and US-WGAN-enhanced datasets with 3000 epochs; the ultrasound signals generated by the US-WGAN were proved to be of high quality (peak signal-to-noise ratio scores in the range of 30–50 dB) and belong to the same population distribution as the original dataset. To verify the effectiveness of the US-WGAN, a fully connected neural network with seven layers was established, and the performances of the network after data enhancement using the US-WGAN and popular virtual defects were verified for the same network parameters and structures. The results show that adoption of the US-WGAN effectively suppresses the overfitting phenomenon while training the network and increases the dataset size, thereby improving the training and testing accuracies (>97%). Additionally, we noted that a simple, fully connected shallow neural network was sufficient for achieving high-accuracy defect classification using the US-WGAN data enhancement method.
Electrical Generators for Large Wind Turbine: Trends and Challenges
Authors: Bensalah Amina , Barakat Georges , Amara Yacine
Published: September 2022

This paper presents an overview of the emerging trends in the development of electrical generators for large wind turbines. To describe the developments in the design of electrical generators, it is necessary to look at the conversion system as a whole, and then, the structural and mechanical performances of the drive train need to be considered. Many drive train configurations have been proposed for large wind turbines; they should ensure high reliability, long availability and reduced maintainability. Although most installed wind turbines are geared, directly driven wind turbines with permanent magnet generators have attracted growing interest in the last few years, which has been in parallel to the continuous increase of the per unit turbine power. The aim of this work is to present the recent commercial designs of electrical generators in large wind turbines. Both the strengths and weaknesses of the existing systems are discussed. The most emerging technologies in high-power, low-speed electrical generators are investigated. Furthermore, a comparative analysis of different electrical generator concepts is performed, and the generators are assessed upon a list of criteria such as the mass, cost, and mass-to-torque ratio. Within the framework of these criteria, it may help to determine whether the electrical generator is technically feasible and economically viable for high-power wind turbines. Finally, this review could help to determine suitable generators for use in large and ultra-large wind energy systems.
Energy Transition: Renewable Energy-Based Combined Heat and Power Optimization Model for Distributed Communities
Authors: Gul Eid , Baldinelli Giorgio , Bartocci Pietro
Published: September 2022

New energy technologies are gaining rising importance because of climate change and increasing energy demand, and they show an enormous potential to mitigate environmental issues. With the purpose of maximizing the renewable energy utilization, combined heat and power systems are considered more effective, economical, and ecological. However, renewable energy-based combined heat and power systems are still in the development phase. Hence, this study presents a new methodology to produce combined electricity and heat from wind and solar PV systems to meet the energy demand of small, distributed communities. For this scope, an optimization model is developed to exploit rationally the power generation from renewables and meet the electricity and heating demand of two selected communities. The curtailed energy of solar and wind systems is used to produce heat by a thermal load controller combined with a natural gas boiler. The developed model is also integrated with the grid station for energy exchange. This study contributes also to evaluate the economic and environmental feasibility of combined heat and power systems, and determine the best optimal operational strategies to extend the renewable energy utilization and minimize energy costs. The obtained results show that a significant amount of clean energy can be produced, covering the 79% of the energy demand of the selected communities, at the lowest levelized cost of energy of 0.013 €/kWh; meanwhile, the proposed system reduces 4129 tons of CO2 emissions annually.
Experimental and Analytical Investigation of an Immiscible Displacement Process in Real Structure Micromodels
Authors: Lüddeke Christian Truitt , Gaol Calvin Lumban , Strobel Gion Joel , Ganzer Leonhard
Published: September 2022

The recovery of oil from a reservoir can be accomplished with various methods, one of the most commonly applied types being waterflooding. A common theory used to describe immiscible displacement is the Buckley–Leverett theory. A brand new type of micromodel, generated and fabricated by using a micro-computer tomography (μCT) image stack of a real sandstone core, was used to conduct immiscible displacement experiments. Critical logging data were recorded, and a high-resolution camera took pictures of the displacement process. In an image processing tool (MATLAB), an algorithm was developed to evaluate the pictures of the experiment and to examine the changes in the saturations of the displacing and the displaced fluid. The main objective of the displacement experiment was to validate the new microchip in two-phase displacement experiments and to assess the feasibility of the image processing algorithm. This was performed by comparing the results of the experimental to the analytical solutions, which were derived from the Buckley–Leverett theory. The comparison of the results showed a good match between the two types of solutions. The applicability of the analytical results to the experimental procedures was observed. Additionally, the usage of the newly fabricated micromodel and its potential to visualize the fluid flow behavior in porous media were assessed.
Optimal Coordination of Time Delay Overcurrent Relays for Power Systems with Integrated Renewable Energy Sources
Authors: Al Talaq Muntathir , Al-Muhaini Mohammad
Published: September 2022

With the gradual increase in load demand due to population and economic growth, integrating renewable energy sources (RES) into the grid represents a solution for meeting load demand. However, integrating RES might change the power system type from radial to non-radial, where the current can flow forward and backward. Consequently, power system analysis methods must be updated. The impact on power systems includes changes in the load flow affecting the voltage level, equipment sizing, operating modes, and power system protection. Conventional power system protection methods must be updated, as RES integration will change the power flow results and the short circuit levels in the power system. With an RES contribution to short circuit, existing settings might experience missed coordination which will result in unnecessary tripping. This paper considers the impact of integrating renewable energy sources into power system protection on overcurrent time delay settings. A new method to upgrade/adjust time delay settings is developed utilizing genetic algorithm (GA) optimization. The proposed optimization method can be used to evaluate the impact of integrating RES on the exiting overcurrent setting, and can provide new settings without the need to replace existing protection devices when the short circuit is within equipment thermal limits.
Gasification Characteristics of High Moisture Content Lignite under CO2 and Auto-Generated Steam Atmosphere in a Moving Bed Tubular Reactor
Authors: Gao Haojie , Wen Zhisong , Jin Lizhu , Xiong Xin , Zhu Yuezhao
Published: September 2022

An external thermal high-temperature continuous feed moving bed tubular reactor was used for the gasification of high moisture content lignite (30.41 wt.%) under CO2 and an auto-generated steam atmosphere. The objectives of this study are to illustrate the synergistic gasification characteristics of high moisture content lignite and CO2 in the tubular reactor; CO2 and auto-generated steam (steam released from the lignite) were used as gasification agents for lignite gasification. The effects of temperature and CO2 flow rate were also investigated. Experimental results showed that when the gasification temperature increased from 800 °C to 1000 °C, the H2 yield also increased from 8.45 mol kg−1 to 17.86 mol kg−1. This may indicate that the H2O-CO2 gasification of semi-coke was enhanced with the rise in temperature. At 900 °C, the gas yield increased with the increase in CO2 flow rate, while the yield of char and liquid product showed an opposite trend. The lower heating value of the H2-rich syngas varied from 11.73 MJ m−3 to 12.77 MJ Nm−3. The experimental results proved that the high moisture content lignite in-situ CO2 gasification process is an effective methodology for the clean and efficient utilization of lignite.
Swirl-Bypass Nozzle for CO2 Two-Phase Ejectors: Numerical Design Exploration
Authors: Ringstad Knut Emil , Banasiak Krzysztof , Ervik Åsmund , Hafner Armin
Published: September 2022

In this work, a novel ejector design concept of a swirl-bypass nozzle is proposed to improve off-design performance of CO2 two-phase ejectors. The swirl-bypass nozzle allows part of the flow to bypass into the ejector mixing chamber to generate swirl. The design of such a device is investigated using a 3D multiphase CFD model. An extensive experimental test campaign is conducted to validate the baseline homogeneous equilibrium CFD model. The model’s prediction motive mass flow rate within 2–12% error and suction mass flow rate was predicted with 3–50% error. Based on the tested ejector geometry, simulations of different ejector swirl-bypass inlets are conducted. The results show that, for the current design, total entrainment of the ejector is reduced by 2–20% with the swirl-bypass inlet. The axial position of the bypass inlet plays a primary role in the bypass inlet flow rate, and, consequently, in suction flow reduction. This is found to be due to the bypass flow blocking off the suction mass flow rate, which has a net negative impact on performance. Finally, several design improvements to improve future designs are proposed.
The Nexus of Energy, Green Economy, Blue Economy, and Carbon Neutrality Targets
Authors: Sarwar Suleman , Waheed Rida , Aziz Ghazala , Apostu Simona Andreea
Published: September 2022

The aim of current study is to investigate the significance of green and blue economic activities to mitigate the carbon emission in Saudi Arabia. We use the time series data which covers the period from 1990 to 2019. For empirical estimations, we use nonlinear ARDL approach which confirms that energy indicators and blue economic indicators are not mature enough to achieve carbon neutrality objectives. However, after Vision 2030 empirics, positive shocks in green indicators are turning down the carbon level. The findings of energy and blue indicators are useful for policy recommendations which help to achieve the sustainable environmental goals of Vision 2030.