bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving Mechanical and Tribological Behaviors of GLC Films on NBR under Water Lubrication by Doping Ti and N
Authors: Zhou Zhen , Han Yanfeng , Qian Jin
Published: July 2022

Water lubrication has been widely used in marine equipment, where rubber bearings and seals suffer intense friction and severe wear under mixed and boundary conditions. It has good research prospects and practical value to study the composite of amorphous carbon on water lubrication rubber to improve lubrication and reduce wear. In this work, modified graphite-like carbon films incorporated with titanium and nitrogen ((Ti:N)-GLC) were integrated on nitrile butadiene rubber (NBR) with multi-target magnetron sputtering. Direct current (DC) sputtering of graphite target was used as the carbon source. The incorporation of Ti and N elements was accomplished by using radio frequency (RF) magnetron sputtering of three different targets: Ti, TiC and TiN, to optimize the mechanical and tribological performance. This work is aimed to clarify the modification mechanism of Ti and N incorporation and obtain the optimum scheme. The influence of RF power on surface topography, chemical composition, mechanical properties and tribological properties was investigated by SEM, XPS, Raman spectra, nanoindentor and tribometer. The consequences revealed that the characteristics of films depend on RF target types and power. For the Ti-C and TiC-C series, when RF power is 100 W and below, with low content of Ti (6 at.%~13 at.%) and N (around 10 at.%), the incorporation of Ti and N optimizes the surface topology, improves the mechanical properties and maintains excellent adhesion to NBR substrate. The tribological and wear behaviors of (Ti:N)-GLC films are better than GLC films under mixed and boundary lubrication. When RF power grows to 200 W, the dopants result in the deterioration of surface and mechanical properties, followed by worse lubrication and wear behaviors. For TiN-C series, the incorporation of TiN takes no advantage over GLC films, even worse in the case of high RF power. Overall, the incorporation of Ti or TiC by magnetron sputtering in Ar/N2 atmosphere is an effective modification method for GLC films on NBR to improve mechanical and tribological behaviors.
Improvement of Monitoring Technology for Corrosive Pollution of Marine Environment under Cloud Computing Platform
Authors: Jiang Yongzeng , Dong Jing , Qi Xiaoyu , Wang Fazhi
Published: July 2022

In view of the increasingly serious problem of marine ecological environmental pollution, the traditional marine environmental corrosive pollution monitoring technology has poor monitoring accuracy and poor monitoring timeliness, and the improvement of the marine environmental corrosive pollution monitoring technology under the cloud computing platform is proposed. The research significance and corrosion influence factors of steel corrosion in the marine environment are described, and the research progress of corrosion mechanism in five different zones of the marine environment is reviewed. Cloud computing parallelizes the processing of corrosive pollution data in the marine environment through virtualization and distributed technology, which greatly improves the efficiency of the algorithm. This paper studies the existing cloud computing platform and ocean monitoring system architecture, uses the distributed architecture to design a cloud computing-oriented ocean monitoring system and meets the design requirements in data collection and data processing. The experimental results show that the precision of marine environmental corrosion pollution monitoring technology proposed in this paper is 96% on average, and the completion rate of monitoring images is 82% on average, which can effectively realize marine environmental corrosion pollution monitoring.
Initial Microstructure Effects on Hot Tensile Deformation and Fracture Mechanisms of Ti-5Al-5Mo-5V-1Cr-1Fe Alloy Using In Situ Observation
Authors: Fu Mingzhu , Pan Suping , Liu Huiqun , Chen Yuqiang
Published: July 2022

The hot tensile deformation and fracture mechanisms of a Ti-5Al-5Mo-5V-1Cr-1Fe alloy with bimodal and lamellar microstructures were investigated by in situ tensile tests under scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The results show that the main slip deformation modes are prismatic slip ({11¯00}<112¯0>) and pyramidal slip ({11¯01}<112¯0>) under tension at 350 °C. In the bimodal microstructure, several parallel slip bands (SBs) first form within the primary α (αP) phase. As the strain increases, the number of SBs in the αP phase increases significantly and multislip systems are activated to help further coordinate the increasing deformation. Consequently, the microcracks nucleate and generally propagate along the SBs in the αP phase. The direction of propagation of the cracks deflects significantly when it crosses the αP/β interface, resulting in a tortuous crack path. In the lamellar microstructure, many dislocations pile up at the coarse-lath α (αL) phase near the grain boundaries (GBs) due to the strong fencing effect thereof. As a result, SBs develop first; then, microcracks nucleate at the αL phase boundary. During propagation, the cracks tend to propagate along the GB and thus lead to the intergranular fracture of the lamellar microstructure.
The Hydrolyzation and Hydrolysis Rates of Chlorodifluoromethane during Catalytic Hydrolysis over Solid Acid (Base) MoO3(MgO)/ZrO2 Catalyst
Authors: Tan Xiaofang , Mao Junhao , Ren Guoqing , Chang Yu , Jia Lijuan , Liu Tiancheng
Published: July 2022

Chlorodifluoromethane (HCFC-22) is one of the air pollutants that destroy the ozone layer and warm the earth. In order to degrade HCFC-22, the catalytic hydrolysis method is currently the most effective environmental technology. Herein, we prepare solid acid MoO3/ZrO2 and solid base MgO/ZrO2 catalysts for the degradation of HCFC-22, with a particular focus on revealing the effects of the catalyst preparation methods, calcination temperatures, and hydrolysis temperatures on the hydrolyzation and hydrolysis rates of HCFC-22. The catalysts are characterized by XRD, N2 isothermal adsorption–desorption, and NH3-TPD. The results show that the solid acid (base) MoO3(MgO)/ZrO2 catalysts have strong catalytic activity for the degradation of HCFC-22, while the catalytic activity of the solid acid MoZr is better than that of the solid base MgZr catalyst and the hydrolysis rate can reach more than 90%. The water vapor generates B-acid centers on the MoO3(MgO)/ZrO2 framework and promotes the hydrolysis of HCFC-22 to HF and HCl.
Optical Terahertz Sources Based on Difference Frequency Generation in Nonlinear Crystals
Authors: Liu Yang , Zhong Kai , Wang Aiqiang , Zhou Mengchen , Li Shanchuang , Gao Lu , Zhang Ze
Published: July 2022

Terahertz (THz) sources, ranging from 0.1 THz to 10 THz, between microwaves and infrared waves, have important applications in spectral detection, medical imaging, communication, etc. Difference frequency generation (DFG) is an effective method for generating terahertz with the characteristics of low cost, simple structure, widely tunable range, no threshold, and room-temperature operation. This paper reviews various optical terahertz sources of difference frequency generation based on nonlinear crystals, including DFG with inorganic crystals, DFG with organic crystals, DFG with quasi-phase-matching (QPM) crystals, DFG in waveguides, cavity-enhanced DFG, and cascaded DFG. Their recent advances, as well as their advantages and disadvantages, are fully present and discussed. This review is expected to provide a comprehensive reference for researchers in this field and a quick understanding of optical THz sources of difference frequency generation with nonlinear crystals.
Bifurcated Halogen Bond-Driven Supramolecular Double Helices from 1,2-Dihalotetrafluorobenzene and 2,2′-Bi(1,8-naphthyridine)
Authors: Wang Ziyu
Published: July 2022

The unique enantiomeric pairs of double helices have been found in the structure of the cocrystal between 1,2-diiodotetrafluorobenzene and 2,2′-bi(1,8-naphthyridine). The formation of the supramolecular double helices is driven by the strong bifurcated iodine bonds which can force the herringbone packing arrangement of the molecules 2,2′-bi(1,8-naphthyridine) into a face-to-face π···π stacking pattern. In contrast, the cocrystal between 1,2-dibromotetrafluorobenzene (or 1,2-dichlorotetrafluorobenzene) and 2,2′-bi(1,8-naphthyridine) was not obtained under the same conditions. The interaction energies of the bifurcated halogen bonds and π···π stacking interactions were computed with the reliable dispersion-corrected density functional theory. The computational results show that the bifurcated iodine bond is much stronger than the bifurcated bromine bond and bifurcated chlorine bond, and it is the much stronger bifurcated iodine bond that makes the cocrystal of 1,2-diiodotetrafluorobenzene and 2,2′-bi(1,8-naphthyridine) much easier to be synthesized.
Locoregional Management of Breast Cancer: A Chronological Review
Authors: Al-Rashdan Abdulla , Deban Melina , Quan May Lynn , Cao Jeffrey Q.
Published: July 2022

Locoregional management of breast cancer is founded on evidence generated over a vast time period, much longer than the career span of many practicing physicians. Oncologists rely on specific patient and tumour characteristics to recommend modern-day treatments. However, some of this information may not have been available during prior periods in which the evidence was generated. For example, the comprehensive Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) meta-analyses published in the 2000s typically included older trials accruing patients between the 1960s and 1980s. This raises some uncertainty about whether conclusions from studies conducted in prior eras are as relevant or applicable to modern-day patients and treatments. Reviewing the chronological order and details of the evidence can be beneficial to understanding these nuances. This review discusses the evolution of locoregional management through some key clinical trials. We aim to highlight the time period in which the evidence was generated and emphasize the 10-year outcomes for the comparability of results. Evidence supporting surgical management of the breast and axilla, as well as details of radiotherapy are discussed briefly for all stages of breast cancer.
Diabetic Retinopathy Detection from Fundus Images of the Eye Using Hybrid Deep Learning Features
Authors: Butt Muhammad Mohsin , Iskandar D. N. F. Awang , Abdelhamid Sherif E. , Latif Ghazanfar , Alghazo Runna
Published: July 2022

Diabetic Retinopathy (DR) is a medical condition present in patients suffering from long-term diabetes. If a diagnosis is not carried out at an early stage, it can lead to vision impairment. High blood sugar in diabetic patients is the main source of DR. This affects the blood vessels within the retina. Manual detection of DR is a difficult task since it can affect the retina, causing structural changes such as Microaneurysms (MAs), Exudates (EXs), Hemorrhages (HMs), and extra blood vessel growth. In this work, a hybrid technique for the detection and classification of Diabetic Retinopathy in fundus images of the eye is proposed. Transfer learning (TL) is used on pre-trained Convolutional Neural Network (CNN) models to extract features that are combined to generate a hybrid feature vector. This feature vector is passed on to various classifiers for binary and multiclass classification of fundus images. System performance is measured using various metrics and results are compared with recent approaches for DR detection. The proposed method provides significant performance improvement in DR detection for fundus images. For binary classification, the proposed modified method achieved the highest accuracy of 97.8% and 89.29% for multiclass classification.
AI-Based Chest CT Analysis for Rapid COVID-19 Diagnosis and Prognosis: A Practical Tool to Flag High-Risk Patients and Lower Healthcare Costs
Authors: Esposito Giovanni , Ernst Benoit , Henket Monique , Winandy Marie , Chatterjee Avishek , Van Eyndhoven Simon , Praet Jelle , Smeets Dirk , Meunier Paul , Louis Renaud , Kolh Philippe , Guiot Julien
Published: July 2022

Early diagnosis of COVID-19 is required to provide the best treatment to our patients, to prevent the epidemic from spreading in the community, and to reduce costs associated with the aggravation of the disease. We developed a decision tree model to evaluate the impact of using an artificial intelligence-based chest computed tomography (CT) analysis software (icolung, icometrix) to analyze CT scans for the detection and prognosis of COVID-19 cases. The model compared routine practice where patients receiving a chest CT scan were not screened for COVID-19, with a scenario where icolung was introduced to enable COVID-19 diagnosis. The primary outcome was to evaluate the impact of icolung on the transmission of COVID-19 infection, and the secondary outcome was the in-hospital length of stay. Using EUR 20000 as a willingness-to-pay threshold, icolung is cost-effective in reducing the risk of transmission, with a low prevalence of COVID-19 infections. Concerning the hospitalization cost, icolung is cost-effective at a higher value of COVID-19 prevalence and risk of hospitalization. This model provides a framework for the evaluation of AI-based tools for the early detection of COVID-19 cases. It allows for making decisions regarding their implementation in routine practice, considering both costs and effects.
Liquid Biopsy with Detection of NRASQ61K Mutation in Cerebrospinal Fluid: An Alternative Tool for the Diagnosis of Primary Pediatric Leptomeningeal Melanoma
Authors: Mastronuzzi Angela , Fabozzi Francesco , Rinelli Martina , De Vito Rita , Agolini Emanuele , Colafati Giovanna Stefania , Cacchione Antonella , Carai Andrea , De Ioris Maria Antonietta
Published: July 2022

Primary leptomeningeal melanoma (PLMM) is a very rare disease in childhood with a poor prognosis. NRASQ16K mutation frequently drives malignant transformation in this population, so its evaluation should be considered in childhood PLMM diagnosis. In the presented case, the mutation was detected by Sanger sequencing performed on DNA extracted from cerebrospinal fluid neoplastic cells. Liquid biopsy has been shown to be a safe and reliable technique for the diagnosis of PLMM. Its use can potentially be extended to other neoplasms of the central nervous system bearing well-defined molecular mutations, sparing the patient invasive surgery and finally allowing a more rapid diagnosis and early initiation of targeted therapies.
MiRNAs in Lung Cancer: Diagnostic, Prognostic, and Therapeutic Potential
Authors: Wani Javaid Ahmad , Majid Sabhiya , Imtiyaz Zuha , Rehman Muneeb U. , Alsaffar Rana M. , Shah Naveed Nazir , Alshehri Sultan , Ghoneim Mohammed M. , Imam Syed Sarim
Published: July 2022

Lung cancer is the dominant emerging factor in cancer-related mortality around the globe. Therapeutic interventions for lung cancer are not up to par, mainly due to reoccurrence/relapse, chemoresistance, and late diagnosis. People are currently interested in miRNAs, which are small double-stranded (20–24 ribonucleotides) structures that regulate molecular targets (tumor suppressors, oncogenes) involved in tumorigeneses such as cell proliferation, apoptosis, metastasis, and angiogenesis via post-transcriptional regulation of mRNA. Many studies suggest the emerging role of miRNAs in lung cancer diagnostics, prognostics, and therapeutics. Therefore, it is necessary to intensely explore the miRNOME expression of lung tumors and the development of anti-cancer strategies. The current review focuses on the therapeutic, diagnostic, and prognostic potential of numerous miRNAs in lung cancer.
Methods of Anterior Torque Control during Retraction: A Systematic Review
Authors: Kuc Anna Ewa , Kotuła Jacek , Nahajowski Marek , Warnecki Maciej , Lis Joanna , Amm Ellie , Kawala Beata , Sarul Michał
Published: July 2022

Background: There are various methods of controlling the inclination of the incisors during retraction, but there is no evidence as to the advantages of some methods over others. The purpose of this systematic review and meta-analysis was to determine the effectiveness of the methods used to control torque during anterior teeth retraction. Methods: In accordance with the PRISMA guidelines, the main research question was defined in the PICO format [P: patients with complete permanent dentition; I: the maxillary incisor torque after (I) and before I retraction with straight-wire appliance and different modes of torque control; O: statistically significant differences in torque values of the upper incisors after orthodontic treatment]. The MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases were searched for keywords combining: retraction orthodontics, torque control orthodontics, torque orthodontics, inclination orthodontics, torque control retraction. The articles were subjected to risk of bias and quality analyses with the ROBINS-I protocol and the modified Newcastle–Ottawa QAS, respectively. Meta-analyses were performed with both fixed- and random-effects models. Results: 13 articles were selected in which total number of 580 subjects took part. In all studies, incisors were retroclined during retraction by 2.46° (mean difference), which was statistically significant. Considering the articles separately, the differences in torque between the study group and the control group were statistically significant in six articles. The Q statistic was 36.25 with p = 0.0003 and I2 = 66.9%, which indicated a high level of study heterogeneity. Conclusion: Both properly performed corticotomy and en-masse retraction using orthodontic microimplants seem to be the most effective and scientifically validated methods of torque control. Further high-quality research is needed to perform better quality analyses and draw more reliable conclusions.
C1-C2 Rotatory Subluxation in Adults “A Narrative Review”
Authors: González David C. Noriega , Ardura Aragón Francisco , Sanjuan Jesús Crespo , Maniega Silvia Santiago , Andrino Alejandro León , García Fraile Rubén , Labrador Hernández Gregorio , Calabia-Campo Juan , Caballero-García Alberto , Córdova-Martínez Alfredo
Published: July 2022

The atlantoaxial joint C2 (axis) with the anterior arch of C1 (atlas) allows 50% of cervical lateral rotation. It is responsible for precise and important movements that allow us to perform precise actions, both in normal and working life. Due to low incidence in adults, this condition often goes undiagnosed, or the diagnosis is delayed and the outcome is worse. An early diagnosis and treatment are essential to ensure satisfactory neurological and functional outcomes. The aim of this review is to analyze C1-C2 rotatory subluxation in adults, given its rarity. The time between injury and reduction is key, as it is directly related to prognosis and the severity of the treatment options. Due to low incidence in adults, this condition often goes undiagnosed, or the diagnosis is delayed as a lot of cases are not related to a clear trauma, with a poor prognosis just because of the late diagnosis and the outcome is worse. The correct approach and treatment of atlantoaxial dislocation requires a careful study of the radiological findings to decide the direction and plane of the dislocation, and the search for associated skeletal anomalies.
The Use of Confocal Laser Endomicroscopy in Diagnosing Barrett’s Esophagus and Esophageal Adenocarcinoma
Authors: Vaculová Jitka , Kroupa Radek , Kala Zdeněk , Dolina Jiří , Grolich Tomáš , Vlažný Jakub , Said David , Izakovičová Hollá Lydie , Bořilová Linhartová Petra , Procházka Vladimír , Joukal Marek , Jabandžiev Petr , Slabý Ondřej , Kunovský Lumír
Published: July 2022

Confocal laser endomicroscopy (CLE) is a diagnostic technique that enables real-time microscopic imaging during microscopic examination and evaluation of epithelial structures with 1000-fold magnification. CLE can be used in the diagnosis of various pathologies, in pneumology, and in urology, and it is very widely utilized in gastroenterology, most importantly in the diagnosis of Barrett’s esophagus (BE), esophageal adenocarcinoma (EAC), biliary strictures, and cystic pancreatic lesions. A literature search was made in MEDLINE/PubMed and Google Scholar databases while focusing on diagnostics using CLE of BE and EAC. We then examined randomized and observational studies, systematic reviews, and meta-analyses relating to the utilization of CLE in BE and EAC diagnostics. Here, we discuss whether CLE can be a suitable diagnostic method for surveillance of BE. Even though many studies have proven that CLE increases diagnostic accuracy in detecting neoplastic transformation of BE, CLE is still not used as a standard diagnostic tool in BE surveillance due to a deficiency of scientific evidence. More studies and data are needed if CLE is to find a place as a new technique in BE surveillance.
Optimized Selection of Water Resource Allocation Schemes Based on Improved Connection Entropy in Beijing’s Southern Plain
Authors: Li Chen , Men Baohui , Yin Shiyang
Published: July 2022

Increased urbanization has caused problems such as increasing water consumption and the continuous deterioration of the groundwater environment. It is necessary to consider the groundwater quality in the water resource optimization system and increase the rate of reclaimed water development to reduce the amount of groundwater exploitation and achieve sustainable development of water resources. This study used the Daxing District, a region of Beijing’s southern plain, as an example to evaluate water quality by analyzing water quality data of surface and groundwater from 2012 to 2016 and actual water-use schemes from 2006 to 2016. Three groundwater extraction modes were set up based on NO3–N concentrations, water resources were optimized under three extraction modes, and water resource optimization schemes were determined based on the improved connection entropy. The results show that (1) the surface water quality was poor, and the proportion of V4 type water in the indexes of NH3–N and chemical oxygen demand (COD) was the largest. The surface water can only be used for agricultural irrigation. The pollution sources contributing most to NH3–N and COD were domestic and agricultural pollution sources. (2) The groundwater quality was good. The NO3–N index was primarily type I–III water, accounting for 95.20% of the total samples. Severe NH3–N pollution areas were mainly in the northern region, and most regional groundwater can be used for various purposes. (3) Taking 2016 as an example, three groundwater exploitation modes were set to optimize water resource allocation, and the results showed that the rate of groundwater development and NO3–N pollution decreased significantly after optimization. (4) Connection entropy is an evaluation method that combines connection numbers and entropy, including identify, difference, and opposition entropy. As connection entropy being a kind of complete entropy, which can reflect the difference of the system in different states, based on the improved connection entropy, the connection entropies of optimal water resource allocation and actual water-use schemes were calculated. The connection entropy of groundwater exploitation mode 3 was less than that of groundwater exploitation modes 1 and 2 and actual water-use schemes from 2006 to 2016. Therefore, exploitation mode 3’s water resource optimization scheme was recommended. In the paper, satisfactory results have been obtained. As a kind of complete entropy, connection entropy has great research value in dealing with complex hydrological problems. This study’s research methods and outcomes can provide methodological and theoretical lessons for water management in freshwater-deficient areas.
Challenges and Opportunities of Mathematics in Digital Times: Preschool Teachers’ Views
Authors: Lavidas Konstantinos , Apostolou Zoi , Papadakis Stamatios
Published: July 2022

The COVID-19 pandemic has caused an unprecedented crisis. Worldwide, preschool teachers were invited to develop the students’ learning experience in a new digital environment for mathematics. This research investigates preschool teachers’ mathematics practices during remote teaching and the use of digital tools in teaching mathematics after their return to actual classes. Views from sixteen Greek preschool teachers were collected with semi-structured interviews and analyzed using thematic analysis. The results showed that mathematical activities such as Numbers and Operations, Geometry, and Measurement occurred during distance learning in digital preschool classrooms. They made little reference to activities related to Algebra, while they did not refer to Data Analysis and Probability. They also seemed to prefer mathematical activities based on Connections and Representation processes in their digital classrooms. Preschool teachers reported that parents supported this process by their presence, and digital learning communities supported learning activities by providing guidelines and innovative approaches to them in digital times. However, after returning to face-to-face schooling, preschool teachers seemed to use digital tools to a lesser degree. They also mention that in face-to-face schooling, they prefer to utilize the authentic communication frameworks emphasizing problem-solving activities to enhance all mathematical processes. Implications for preschool teacher professional development are discussed.
Design and Evaluation among Young Adults of a Financial Literacy Scale Focused on Key Financial Decisions
Authors: Méndez Prado Silvia Mariela , Chiluiza Katherine , Everaert Patricia , Valcke Martin
Published: July 2022

The present study underpins the design and validation of a Financial Literacy (FL) scale in the Latin American and the Caribbean (LAC) context. Though scales are available, they do not meet contextual characteristics and seem to miss out on a focus on Key Financial Decisions (KFD). Scale design was consistent with an extensive literature review (2010–2021). Forty-four items scale covering the dimensions of Financial Attitude, Financial Behavior, and Financial Knowledge were presented to 478 young adults aged 18–30, and women 58% of them. The results reflect a robust FL scale by applying Confirmatory Factor Analysis (CFA). The data about young adults’ FL can be used as a benchmark in future studies fostering the development of FL in the Latin American and Caribbean contexts.
Identity Making as a Colonization Process, and the Power of Disability Justice to Cultivate Intersectional Disobedience
Authors: Boda Phillip Andrew
Published: July 2022

Intersectionality has been used to describe the products of difference but scholars who work intersectionally in the tradition of Disability Justice have argued that attention should focus on the process of identity making—those processes by which some Lives–Hopes–Dreams are positioned as more valuable and Whole because of our societies’ commitments to racial capitalist coloniality. This work uses intersectionality as critical social theory, combined with broader cultural analyses of colonization as a process that did not stop within the creation of the Modern Western world, to visibilize identities often explicitly erased: students labeled with disabilities. Through excavating group-made artifacts from a larger research study, I show how intersectionally-disobedient grammars can serve to illuminate complex identity making beyond juxtaposed colonialities of power, and, therein, I situate this bricolage approach as an embodiment toward Disability Justice.
Factors Influencing Students’ Continuance Intention to Learn in Blended Environments at University
Authors: Baranova Tatiana , Kobicheva Aleksandra , Tokareva Elena
Published: July 2022

(1) Background: The main goal of this study was to determine the factors that have an influence on the continuance intention to learn in blended environments. (2) Methods: For our study, we created a research model based on the Expectation–Confirmation Model (ECM) and Theory of Planned Behavior (TPB), which involves a total of seven latent constructs and contains a total of eight hypotheses. A total of 301 undergraduate and postgraduate students studying at Humanity Institute of Peter the Great Polytechnic University voluntarily participated in the study. The online survey consisted of 22 items that determined the seven indicators studied and was conducted in the spring semester of 2021. For our analysis and hypothesis testing, we used PSS 24.0 and SmartPLS 3.0 programs. (3) Results: According to the results of this study, all the proposed hypotheses were confirmed, which confirmed the influencing power of research model indicators. Also, it was revealed that such indicators as confirmation and attitude are the key factors that affect the continuance intention to learn in a blended environment. (4) Conclusions: As the COVID-19 pandemic is an ever-changing situation, it is important to understand student perceptions of blended learning and manage their continuance intention to learn in such environments. This study contributes to such knowledge and provides insightful implications for academia.
Fully Differential Current-Mode Configuration for the Realization of First-Order Filters with Ease of Cascadability
Authors: Kumar Atul , Kumar Sumit , Elkamchouchi Dalia H. , Urooj Shabana
Published: July 2022

It is well known that fully differential signal processing is more advantageous than single-ended signal processing in a noisy environment, and is widely used in audio, video and other signal processing applications. This paper introduces a new fully differential configuration that contains a first-order low-pass (LP) filter, high-pass (HP) filter, and all-pass (AP) filter, all present within the same circuit design. The proposed fully differential configuration is simple and employs only one multiple-output current differencing transconductance amplifier and one grounded capacitor. The circuit has a wide operating frequency range (up to 73 MHz). The additional features offered by the proposed circuit include use of the lowest number of active and passive components, suitability of the integrated circuit chip, support of cascadability, electronic tunability, no passive component-matching restrictions, availability of all first-order responses, i.e., LP, HP, and AP, and low-level operating supply voltages. Non-ideal and parasitic analyses are investigated for the proposed circuit, and PSPICE simulation results are presented to verify the proposed theory. Additionally, the proposed fully differential LP filter circuit is experimentally verified using off-the-shelf ICs. Moreover, the cascading feasibility is demonstrated by realizing a fully differential nth-order LP filter.
Power-Efficient Trainable Neural Networks towards Accurate Measurement of Irregular Cavity Volume
Authors: Zhang Xin , Jiang Yueqiu , Gao Hongwei , Yang Wei , Liang Zhihong , Liu Bo
Published: July 2022

Irregular cavity volume measurement is a critical step in industrial production. This technology is used in a wide variety of applications. Traditional studies, such as waterflooding-based methods, have suffered from the following shortcomings, i.e., significant measurement error, low efficiency, complicated operation, and corrosion of devices. Recently, neural networks based on the air compression principle have been proposed to achieve irregular cavity volume measurement. However, the balance between data quality, network computation speed, convergence, and measurement accuracy is still underexplored. In this paper, we propose novel neural networks to achieve accurate measurement of irregular cavity volume. First, we propose a measurement method based on the air compression principle to analyze seven key parameters comprehensively. Moreover, we integrate the Hilbert–Schmidt independence criterion (HSIC) into fully connected neural networks (FCNNs) to build a trainable framework. This enables the proposed method to achieve power-efficient training. We evaluate the proposed neural network in the real world and compare it with typical procedures. The results show that the proposed method achieves the top performance for measurement accuracy and efficiency.
Simple Learning-Based Robust Trajectory Tracking Control of a 2-DOF Helicopter System
Authors: Reyhanoglu Mahmut , Jafari Mohammad , Rehan Muhammad
Published: July 2022

Stabilization and tracking control of Unmanned Aircraft Systems (UASs) such as helicopters in a complex environment with system uncertainties, unknown disturbances, and noise is a challenging task; therefore, to compensate for system uncertainties and unknown disturbances, this paper presents a trajectory tracking control strategy for a 2-DOF (degree of freedom) helicopter system testbed by employing a gradient descent-based simple learning control law that minimizes the cost function corresponding to desired closed-loop error dynamics of the nonlinear system under control. In addition, to ensure the stability of the closed-loop nonlinear system, further analysis is provided. The learning capability of the designed controller makes it suitable to take system uncertainties and unknown disturbances into account. The results of computer simulations and real-time experiment using the Quanser AERO helicopter are included to demonstrate the effectiveness of the designed control strategy.
Electron-Irradiation-Induced Degradation of Transfer Characteristics in Super-Junction VDMOSFET
Authors: Jiang Jing , Wang Shaogang , Liu Xu , Liu Jianhui , Li Jun , Zhou Dexiang , Zhang Guoqi , Ye Huaiyu , Tan Chunjian
Published: July 2022

High electric-field stress is an effective solution to the recovery of irradiated devices. In this paper, the dependence of the recovery level on the magnitude of gate voltage and duration is investigated. Compared with the scheme of high gate-bias voltage with a short stress time, the transfer characteristics are significantly recovered by applying a low electric field with a long duration. When the electric field and stress time are up to a certain value, the threshold voltage almost approaches the limitation, which is less than that before irradiation. Meanwhile, the effect of temperature on the recovery of the irradiated devices is also demonstrated. The result indicates that a high temperature of 175 °C used for the irradiated devices’ annealing does not play a role in promoting the recovery of transfer characteristics. In addition, to obtain a deep-level understanding of threshold degradation, the first-principles calculations of three Si/SiO2 interfaces are performed. It is found that new electronic states can be clearly observed in the conduction bans and valence bands after the Si-H/-OH bonds are broken by electron irradiation. However, their distribution depends on the selection of the passivation scheme. Ultimately, it can be observed that the threshold voltage linearly decreases with the increase in interface charge density. These results can provide helpful guidance in the deep interpretation of threshold degradation and the recovery of the irradiated super-junction devices.
Towards Self-Powered WSN: The Design of Ultra-Low-Power Wireless Sensor Transmission Unit Based on Indoor Solar Energy Harvester
Authors: Mahdi Elsiddig Haroun Fathi , Mohamad Deros Siti Noratiqah , Ahmed Alkahtani Ammar , Md Din Norashidah
Published: July 2022

The current revolution in communication and information technology is facilitating the Internet of Things (IoT) infrastructure. Wireless Sensor Networks (WSN) are a broad category of IoT applications. However, power management in WSN poses a significant challenge when the WSN is required to operate for a long duration without the presence of a consistent power source. In this paper, we develop a batteryless, ultra-low-power Wireless Sensor Transmission Unit (WSTx) depending on the solar-energy harvester and LoRa technology. We investigate the feasibility of harvesting ambient indoor light using polycrystalline photovoltaic (PV) cells with a maximum power of 1.4 mW. The study provides comprehensive power management design details and a description of the anticipated challenges. The measured power consumption of the developed WSTx was 0.02109 mW during the sleep mode and 11.1 mW during the operation mode. The harvesting system can harvest energy up to 1.2 mW per second, where the harvested energy can power the WSTx for six hours with a maximum power efficiency of 85.714%.
Multi-Hop Routing Protocols for Oil Pipeline Leak Detection Systems
Authors: Alhomyani Haneen , Fadel Mai , Dimitriou Nikos , Bakhsh Helen , Aldabbagh Ghadah , Alkhuraiji Samar
Published: July 2022

In recent years, various applications have emerged requiring linear topologies of wireless sensor networks (WSN). Such topologies are used in pipeline (water/oil/gas) monitoring systems. The linear structure has a significant impact on network performance in terms of delay, throughput, and power consumption. Regarding communication efficiency, routing protocols play a critical role, considering the special requirements of linear topology and energy resources. Therefore, the challenge is to design effective routing protocols that can address the diverse requirements of the monitoring system. In this paper, we present various wireless communication technologies and existing leak detection systems. We review different routing protocols focusing on multi-hop hierarchical protocols, highlighting the limitations and design issues related to packet routing in linear pipeline leak detection networks. Additionally, we present a LoRa multi-hop model for monitoring aboveground oil pipelines. A set of model parameters are identified such as the distance between sensors. In addition, the paper determines some calculations to estimate traffic congestion and energy consumption. Several alternative model designs are investigated. The model is evaluated using different multi-hop communication scenarios, and we compare the data rate and energy to provide an energy-efficient and low-cost leak detection system.
Design of a Slotted Waveguide Antenna Based on TE20 Mode in Ku-Band Suitable for Direct Metal Laser Sintering
Authors: Chairi Youssef , Abedrrabba Sarra , Allanic Rozenn , Amiaud Anne-Charlotte , El Oualkadi Ahmed , Quendo Cédric , Merlet Thomas , Reklaoui Kamal , Le Gouguec Thierry
Published: July 2022

This paper describes the design of a novel Ku-band slotted waveguide antenna (SWA), taking into consideration the advantages and drawbacks of using a 3D direct metal laser sintering (DMLS) process. Indeed, the DMLS process makes it possible to produce a SWA with 64 radiating slots and its feeding network in a single and monolithic process. However, considering the lack of accuracy of the process, the whole design must be completely thought out and planned to avoid sensitive dimensions. Coupling irises inside such structures are elements of major sensitivity in this regard, so the radiating waveguides in the present work were designed to be TE20 ones, avoiding this kind of iris. Thus, a TE10 to TE20 converter was designed to be implemented in the overall power supply structure of an antenna array made up of four linear SWAs with 16 slots each. Both the elementary 16-slot SWA and the complete SWA with the feeding network were manufactured using DMLS. At a resonant frequency of 15 GHz, the measured realized gain is 22.26 dB with sidelobe levels below 10.1 dB. The measured reflection coefficient is lower than −12.6 dB at the center frequency. These measured performances confirm the proof of concept.
Dracon: An Open-Hardware Based Platform for Single-Chip Low-Cost Reconfigurable IoT Devices
Authors: Parrilla Luis , García Antonio , Castillo Encarnación , Álvarez-Bermejo José Antonio , López-Villanueva Juan Antonio , Meyer-Baese Uwe
Published: July 2022

The development of devices for the Internet of Things (IoT) requires the rapid prototyping of different hardware configurations. In this paper, a modular hardware platform allowing to prototype, test and even implement IoT appliances on low-cost reconfigurable devices is presented. The proposed platform, named Dracon, includes a Z80-clone microprocessor, up to 64 KB of RAM, and 256 inputs/outputs (I/Os). These I/Os can be used to connect additional co-processors within the same FPGA, external co-processors, communications modules, sensors and actuators. Dracon also includes as default peripherals a UART for programming and accessing the microprocessor, a Real Time Clock, and an Interrupt Timer. The use of an 8-bit microprocessor allows the use of the internal memory of the reconfigurable device as program memory, thereby, enabling the implementation of a complete IoT device within a single low-cost chip. Indeed, results using a Spartan 7 FPGA show that it is possible to implement Dracon with only 1515 6-input LUTs while operating at a maximum frequency of 80 MHz, which results in a better trade-off in terms of area and performance than other less powerful and less versatile alternatives in the literature. Moreover, the presented platform allows the development of embedded software applications independently of the selected FPGA device, enabling rapid prototyping and implementations on devices from different manufacturers.
Inhibiting Oil Splitting and Backflow in Electrowetting Displays by Designing a Power Function Driving Waveform
Authors: Tian Lixia , Zhang Hu , Yi Zichuan , Zhang Bingsong , Zhou Rui , Zhou Guofu , Gong Jianlong
Published: July 2022

Electrowetting display (EWD) is one of the latest and most promising reflective displays. However, some defects are easily caused in a driving process. For example, the aperture ratio of pixels can be reduced due to oil splitting, and the grayscale cannot be stabilized due to charge trapping. These defects can be effectively solved by designing driving waveforms for EWDs. So, a power function driving waveform was proposed in this paper, which consisted of an oil splitting suppression stage, a direct current (DC) driving stage and an oil stabilization stage. Firstly, the relationships among luminance values, power constants and driving time were measured. An optimal oil splitting suppression stage was obtained, which could effectively inhibit oil splitting. Then, the response time could be reduced by a DC voltage in the DC driving stage. Finally, a voltage slope was tested during the oil stabilization stage, which was used to counteract voltage created by the charge trapping. The experimental results showed that compared with a linear function waveform, the response time could be shortened by 16.1%, and the luminance value could be increased by 3.8%. The aperture ratio and oil stability of EWD can be effectively improved by these findings, thereby increasing its potential application in the display field.
Human-Centered Efficient Explanation on Intrusion Detection Prediction
Authors: Lee Yongsoo , Lee Eungyu , Lee Taejin
Published: July 2022

The methodology for constructing intrusion detection systems and improving existing systems is being actively studied in order to detect harmful data within large-capacity network data. The most common approach is to use AI systems to adapt to unanticipated threats and improve system performance. However, most studies aim to improve performance, and performance-oriented systems tend to be composed of black box models, whose internal working is complex. In the field of security control, analysts strive for interpretation and response based on information from given data, system prediction results, and knowledge. Consequently, performance-oriented systems suffer from a lack of interpretability owing to the lack of system prediction results and internal process information. The recent social climate also demands a responsible system rather than a performance-focused one. This research aims to ensure understanding and interpretation by providing interpretability for AI systems in multiple classification environments that can detect various attacks. In particular, the better the performance, the more complex and less transparent the model and the more limited the area that the analyst can understand, the lower the processing efficiency accordingly. The approach provided in this research is an intrusion detection methodology that uses FOS based on SHAP values to evaluate if the prediction result is suspicious and selects the optimal rule from the transparent model to improve the explanation.
Forward-Looking Imaging Based on the Linear Wavefront of the Modulated Field
Authors: Zhong Yiming , Zhang Yi , Yu Yiwen , Sun Houjun , Zhang Xiangdong
Published: July 2022

The vortex electromagnetic wave improves the range-azimuth forward-looking imaging performance with its spiral spatial phase distribution. However, the beam of the vortex electromagnetic wave is divergent, which makes it difficult to detect the targets near the center of the beam. In addition, the vortex electromagnetic wave only has the phase change in the azimuth direction and can hardly estimate the elevation position of the targets. In this paper, a linear wavefront control method based on the amplitude weighting of the array antenna is proposed. The modulated field has a phase gradient in both azimuth and elevation directions and has a maximum radiation intensity in the center of the beam. The imaging model based on the modulated field is theoretically derived and simulations are conducted to demonstrate the imaging performance. The modulated field constructed by the linear array can realize range-azimuth two-dimensional imaging with azimuth resolution of 1/5 beam width. The modulated field constructed by the circular array can realize range-azimuth-elevation three-dimensional imaging, and the resolution of the azimuth and elevation directions is 1/3 of the beam width.
Improving Delivery Probability in Mobile Opportunistic Networks with Social-Based Routing
Authors: Jesús-Azabal Manuel , García-Alonso José , Soares Vasco N. G. J. , Galán-Jiménez Jaime
Published: July 2022

There are contexts where TCP/IP is not suitable for performing data transmission due to long delays, timeouts, network partitioning, and interruptions. In these scenarios, mobile opportunistic networks (MONs) are a valid option, providing asynchronous transmissions in dynamic topologies. These architectures exploit physical encounters and persistent storage to communicate nodes that lack a continuous end-to-end path. In recent years, many routing algorithms have been based on social interactions. Smartphones and wearables are in vogue, applying social information to optimize paths between nodes. This work proposes Refine Social Broadcast (RSB), a social routing algorithm. RSB uses social behavior and node interests to refine the message broadcast in the network, improving the delivery probability while reducing redundant data duplication. The proposal combines the identification of the most influential nodes to carry the information toward the destination with interest-based routing. To evaluate the performance, RSB is applied to a simulated case of use based on a realistic loneliness detection methodology in elderly adults. The obtained delivery probability, latency, overhead, and hops are compared with the most popular social-based routers, namely, EpSoc, SimBet, and BubbleRap. RSB manifests a successful delivery probability, exceeding the second-best result (SimBet) by 17% and reducing the highest overhead (EpSoc) by 97%.