bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculation of the Three Partition Coefficients logPow, logKoa and logKaw of Organic Molecules at Standard Conditions at Once by Means of a Generally Applicable Group-Additivity Method
Authors: Naef Rudolf , Acree William E.
Published: March 2024

Assessment of the environmental impact of organic chemicals has become an important subject in chemical science. Efficient quantitative descriptors of their impact are their partition coefficients logPow, logKoa and logKaw. We present a group-additivity method that has proven its versatility for the reliable prediction of many other molecular descriptors for the calculation of the first two partition coefficients and indirectly of the third with high dependability. Based on the experimental logPow data of 3332 molecules and the experimental logKoa data of 1900 molecules at 298.15 K, the respective partition coefficients have been calculated with a cross-validated standard deviation S of only 0.42 and 0.48 log units and a goodness of fit Q2 of 0.9599 and 0.9717, respectively, in a range of ca. 17 log units for both descriptors. The third partition coefficient logKaw has been derived from the calculated values of the former two descriptors and compared with the experimentally determined logKaw value of 1937 molecules, yielding a standard deviation σ of 0.67 log units and a correlation coefficient R2 of 0.9467. This approach enabled the quick calculation of 29,462 logPow, 27,069 logKoa and 26,220 logKaw values for the more than 37,100 molecules of ChemBrain’s database available to the public.
3-(2-Chloroethoxy)-1-(4-methoxyphenyl)-1H-pyrazole-4-carbaldehyde
Authors: Varvuolytė Gabrielė , Bieliauskas Aurimas , Kleizienė Neringa , Žukauskaitė Asta , Šačkus Algirdas
Published: March 2024

Herein, we describe the synthesis of 3-(2-chloroethoxy)-1-(4-methoxyphenyl)-1H-pyrazole-4-carbaldehyde via the Vilsmeier-Haack reaction. The structure of this previously unreported compound is thoroughly elucidated through NMR, FT-IR spectroscopy and HRMS spectrometry.
Image-Based Tool Characterization and DEM Simulation of Abrasive Brushing Processes
Authors: Hoyer Anton , Uhlmann Eckart
Published: March 2024

Brushing with bonded abrasives is a finishing process used for deburring, edge rounding, and roughness reduction. However, due to the complex motion, chipping, and wear behavior of abrasive filaments, industrial brushing processes have historically relied on empirical knowledge. To gain a better understanding of filament interactions, a physical model based on the discrete element method was developed to simulate process forces and contact areas. Filament patterns of round brushes were determined through the use of laser line triangulation and image processing. These filament patterns showed interlocked filaments and yielded more accurate results when used in brushing simulations than the oversimplified square patterns, which were used in previous research. Simulation confirms the occurrence of filament interactions, distinguishes between sweeping and striking filament motions, and reveals dynamic behavior at high brushing velocities that may increase undesirable tool wear.
Multi-Objective Green Closed-Loop Supply Chain Management with Bundling Strategy, Perishable Products, and Quality Deterioration
Authors: Pakdel Golnaz Hooshmand , He Yong , Pakdel Sina Hooshmand
Published: March 2024

This study presents a four-objective mathematical model to improve closed-loop supply chain (CLSC) management. The aim of this research is to reduce the costs of the entire chain, risk, emission of pollutants, and time to deliver the product to the customer in uncertain demand condition. In this paper, the NSGAII algorithm is used to solve the model. In this algorithm, among the answers of each generation, a number of them are selected using the two-run tournament selection method. In the binary selection method, the answers are randomly selected from the population, and then a comparison is made between these two answers, and whichever is better is finally selected. The selection criteria in NSGA-II are, firstly, the rank, and secondly, the crowding distance related to the answer. Also, the performance of the NSGA-II algorithm on the same model and data has been compared with the MOPSO algorithm. In the proposed algorithm, if it encounters an impossible solution, it exits the local mode and solves the problem in global conditions. The results show that the proposed method strikes a better balance between discovery and efficiency criteria and avoids falling into local optima. Therefore, in addition to its effectiveness in discovering optimal answers, the genetic-based method has high speed and subsequently, high convergence and diversity rates compared to the particle swarm method. Also, compared to previous methods in the green closed-loop supply chain, the proposed method is better than the modified genetic algorithm, reducing the costs of the chain by about 2.38%.
Design and Real-Time Implementation of a Cascaded Model Predictive Control Architecture for Unmanned Aerial Vehicles
Authors: Borbolla-Burillo Patricio , Sotelo David , Frye Michael , Garza-Castañón Luis E. , Juárez-Moreno Luis , Sotelo Carlos
Published: March 2024

Modeling and control are challenging in unmanned aerial vehicles, especially in quadrotors where there exists high coupling between the position and the orientation dynamics. In simulations, conventional control strategies such as the use of a proportional–integral–derivative (PID) controller under different configurations are typically employed due to their simplicity and ease of design. However, linear assumptions have to be made, which turns into poor performance for practical applications on unmanned aerial vehicles (UAVs). This paper designs and implements a hierarchical cascaded model predictive control (MPC) for three-dimensional trajectory tracking using a quadrotor platform. The overall system consists of two stages: the mission server and the commander stabilizer. Different from existing works, the heavy computational burden is managed by decomposing the overall MPC strategy into two different schemes. The first scheme controls the translational displacements while the second scheme regulates the rotational movements of the quadrotor. For validation, the performance of the proposed controller is compared against that of a proportional–integral–velocity (PIV) controller taken from the literature. Here, real-world experiments for tracking helicoidal and lemniscate trajectories are implemented, while for regulation, an extreme wind disturbance is applied. The experimental results show that the proposed controller outperforms the PIV controller, presenting less signal effort fluctuations, especially in terms of rejecting external wind disturbances.
Reduced Biquaternion Windowed Linear Canonical Transform: Properties and Applications
Authors: Yang Hehe , Feng Qiang , Wang Xiaoxia , Urynbassarova Didar , Teali Aajaz A.
Published: March 2024

The quaternion windowed linear canonical transform is a tool for processing multidimensional data and enhancing the quality and efficiency of signal and image processing; however, it has disadvantages due to the noncommutativity of quaternion multiplication. In contrast, reduced biquaternions, as a special case of four-dimensional algebra, possess unique advantages in computation because they satisfy the multiplicative exchange rule. This paper proposes the reduced biquaternion windowed linear canonical transform (RBWLCT) by combining the reduced biquaternion signal and the windowed linear canonical transform that has computational efficiency thanks to the commutative property. Firstly, we introduce the concept of a RBWLCT, which can extract the time local features of an image and has the advantages of both time-frequency analysis and feature extraction; moreover, we also provide some fundamental properties. Secondly, we propose convolution and correlation operations for RBWLCT along with their corresponding generalized convolution, correlation, and product theorems. Thirdly, we present a fast algorithm for RBWLCT and analyze its computational complexity based on two dimensional Fourier transform (2D FTs). Finally, simulations and examples are provided to demonstrate that the proposed transform effectively captures the local RBWLCT-frequency components with enhanced degrees of freedom and exhibits significant concentrations.
Modeling Wave Packet Dynamics and Exploring Applications: A Comprehensive Guide to the Nonlinear Schrödinger Equation
Authors: Karjanto Natanael
Published: March 2024

The nonlinear Schrödinger (NLS) equation stands as a cornerstone model for exploring the intricate behavior of weakly nonlinear, quasi-monochromatic wave packets in dispersive media. Its reach extends across diverse physical domains, from surface gravity waves to the captivating realm of Bose–Einstein condensates. This article delves into the dual facets of the NLS equation: its capacity for modeling wave packet dynamics and its remarkable breadth of applications. We illuminate the derivation of the NLS equation through both heuristic and multiple-scale approaches, underscoring how distinct interpretations of physical variables and governing equations give rise to varied wave packet dynamics and tailored values for dispersive and nonlinear coefficients. To showcase its versatility, we present an overview of the NLS equation’s compelling applications in four research frontiers: nonlinear optics, surface gravity waves, superconductivity, and Bose–Einstein condensates. This exploration reveals the NLS equation as a powerful tool for unifying and understanding a vast spectrum of physical phenomena.
Research and Implementation of Denoising Algorithm for Brain MRIs via Morphological Component Analysis and Adaptive Threshold Estimation
Authors: Awudong Buhailiqiemu , Yakupu Paerhati , Yan Jingwen , Li Qi
Published: March 2024

The inevitable noise generated in the acquisition and transmission process of MRIs seriously affects the reliability and accuracy of medical research and diagnosis. The denoising effect for Rician noise, whose distribution is related to MR image signal, is not good enough. Furthermore, the brain has a complex texture structure and a small density difference between different parts, which leads to higher quality requirements for brain MR images. To upgrade the reliability and accuracy of brain MRIs application and analysis, we designed a new and dedicated denoising algorithm (named VST–MCAATE), based on their inherent characteristics. Comparative experiments were performed on the same simulated and real brain MR datasets. The peak signal-to-noise ratio (PSNR), and mean structural similarity index measure (MSSIM) were used as objective image quality evaluation. The one-way ANOVA was used to compare the effects of denoising between different approaches. p < 0.01 was considered statistically significant. The experimental results show that the PSNR and MSSIM values of VST–MCAATE are significantly higher than state-of-the-art methods (p < 0.01), and also that residual images have no anatomical structure. The proposed denoising method has advantages in improving the quality of brain MRIs, while effectively removing the noise with a wide range of unknown noise levels without damaging texture details, and has potential clinical promise.
Exploring the Mediating Role of Sleep Deficit-Related Functional Status in Subacute Stroke Survivors
Authors: Kumar Sunil , Parveen Sarah , Manzar Md Dilshad , Alghadir Ahmad H. , Khan Masood , Al-Quliti Khalid Wasel , Spence David Warren , Pandi-Perumal Seithikurippu R. , Bahammam Ahmed S. , Noohu Majumi M.
Published: March 2024

Background: Understanding post-stroke fatigue (PSF) and its associated factors is crucial for effective therapy and rehabilitation. This study aimed to assess the mediating role of the excessive daytime sleepiness-related functional status (SFS) on the relationship between sleep and the severity of fatigue in subacute stroke survivors. Methods: Subacute stroke survivors (n = 50; male = 38; female = 12), completed a cross-sectional study involving the Pittsburgh sleep quality index (PSQI), the Epworth sleepiness scale (ESS), the insomnia severity index (ISI), the functional outcome of the sleep questionnaire (FOSQ), and the fatigue severity scale (FSS). Results: The SFS mediated the association between the severity of fatigue and sleep problems. The PSQI and FOSQ (b = −0.37, p < 0.001), and the FOSQ and FSS were correlated (b = −0.18, p < 0.05), with a significant indirect effect of the PSQI on the FSS. The ISI correlated with the FOSQ (b = −0.20, p < 0.001), with significant direct (b = 0.15, p < 0.001), as well as indirect, effects of the ISI on the FSS. The ESS correlated with the FOSQ (b = −0.23, p < 0.001), with a significant indirect effect of the ESS on the FSS. Conclusions: In subacute stroke survivors, fatigue and sleep are linked. Increased understanding of sleep-PSF may help in exploring new targets for supplement therapy.
Transcriptomic Profiling of Pleural Effusions: Differences in Malignant and Infectious Fluids
Authors: Zamora-Molina Lucía , García-Pachón Eduardo , Amorós Marta , Gijón-Martínez Julia , Sánchez-Almendro Judith , Baeza-Martínez Carlos , Hernández-Blasco Luis , Galiana Antonio
Published: March 2024

Background and Objectives: Different cellular and molecular processes are involved in the production of malignant and infectious pleural effusions. However, the underlying mechanisms responsible for these differences or their consequences remain incompletely understood. The objective of this study was to identify differences in gene expression in pleural exudates of malignant and infectious aetiology and establish the possible different biological processes involved in both situations. Materials and Methods: RNA transcriptomic analysis was performed on 46 pleural fluid samples obtained during diagnostic thoracocenteses from 46 patients. There were 35 exudates (19 malignant and 16 infectious effusions) and 11 transudates that were used as a reference control group. Differential gene expression analysis for both exudative groups was identified. An enrichment score using the Human Kegg Orthology database was used for establishing the biological processes associated with malignant and infectious pleural effusions. Results: When comparing malignant exudates with infectious effusions, 27 differentially expressed genes with statistical significance were identified. Network analysis showed ten different biological processes for malignant and for infectious pleural effusions. In malignant fluids, processes related to protein synthesis and processing predominate. In infectious exudates, biological processes in connection with ATP production prevail. Conclusions: This study demonstrates differentially expressed genes in malignant and infectious pleural effusions, which could have important implications in the search for diagnostic or prognostic biomarkers. In addition, for the first time, biological processes involved in these two causes of pleural exudates have been described.
Variation of Soil Bacterial Communities in Forest Soil Contaminated with Chainsaw Lubricants
Authors: Kim Ikhyun , Nguyen Manh Ha , Lee Sanggon , Choi Byoungkoo , Shin Keumchul
Published: March 2024

Pollutants can exist in the soil for a long time and alter the bacterial community. Using lubricants to prevent the wear of chainsaw blades is necessary for thinning activities and wood harvesting. We investigated the influences of soil contamination with chainsaw lubricants on soil bacterial communities. Bio-oil, mineral oil, and recycled oil were scattered on each treatment to investigate variations in soil bacterial structure during treated periods using the Illumina MiSeq sequencing platform. The results obtained were 5943 ASVs, 5112 ASVs, and 6136 ASVs after treatment at one month, six months, and twelve months, respectively. There was a significant difference in Shannon and Simpson indices between treatments and controls. A total of 46 bacterial genera with an average relative abundance of more than 1.0% were detected in all soil samples. Massilia was the most common genus detected in control at one month, with an average relative abundance of 14.99%, while Chthoniobacter was the most abundant genus detected in bio-oil, mineral oil, and recycled oil treatments at one month, with an average relative abundance of 13.39%, 14.32%, and 10.47%, respectively. Among the three chainsaw lubricants, bio-oil and mineral oil had fewer impacts than recycled oil. The abundances of several functional bacteria groups in the bio-oil treatment were higher than in other treatments and controls. Our results indicated that different chainsaw lubricants and their time of application affected the soil bacterial community composition.
Isolation and Culture of Primary Human Dental Pulp Cells—A Description of Technical and Methodological Steps to Maximise Predictability and Yield
Authors: Kearney Michaela , McReynolds David E. , Duncan Henry F.
Published: March 2024

The dental pulp has critical functions in tooth development as well as an ongoing role in promoting and maintaining the vitality of teeth. In particular, its regenerative ability allows dental tissues to be restored following damage caused by traumatic injury or caries. Regenerative endodontic procedures aim to utilise these processes to stimulate dental pulp repair in a minimally invasive manner and reduce the need for more invasive procedures such as root canal treatment. Dental pulp is a source of dental pulp cells (DPCs), which has a subpopulation of dental pulp stem cells (DPSCs), which are attractive for use in regenerative medicine due to their high proliferation rate, ability to differentiate into multiple cell types, and their preserved vitality following cryopreservation. The development of next-generation clinical therapeutics that maximise the potential of dental pulp relies on strong empirical evidence arising from in vitro experimentation. Here, we describe a modified method for the efficient isolation of primary human DPCs from sound third molar teeth for culture using an explant outgrowth method on basement membrane-coated flasks, as well as using high-resolution macro-photography to illustrate the methods. Critically, steps are taken to minimise potential physical and mechanical trauma to the cells and maximise yield. Human DPCs cultured using this method can be further expanded in cell culture flasks to facilitate their use in various in vitro experimental procedures.
Enhancing Calculus Learning through Interactive VR and AR Technologies: A Study on Immersive Educational Tools
Authors: Pinter Logan , Siddiqui Mohammad Faridul Haque
Published: March 2024

In the realm of collegiate education, calculus can be quite challenging for students. Many students struggle to visualize abstract concepts, as mathematics often moves into strict arithmetic rather than geometric understanding. Our study presents an innovative solution to this problem: an immersive, interactive VR graphing tool capable of standard 2D graphs, solids of revolution, and a series of visualizations deemed potentially useful to struggling students. This tool was developed within the Unity 3D engine, and while interaction and expression parsing rely on existing libraries, core functionalities were developed independently. As a pilot study, it includes qualitative information from a survey of students currently or previously enrolled in Calculus II/III courses, revealing its potential effectiveness. This survey primarily aims to determine the tool’s viability in future endeavors. The positive response suggests the tool’s immediate usefulness and its promising future in educational settings, prompting further exploration and consideration for adaptation into an Augmented Reality (AR) environment.
Social Prescribing Competence among Community Pharmacists and Pharmacy Students in Norway
Authors: Gabeyre Riyaan Mahamud , Hussein Misbah , Salih Siedra , Amir Salia , Gazerani Parisa
Published: March 2024

Background and aim: Social prescribing, which links patients to non-clinical services and involves general physicians, has been gaining traction. Community pharmacists, who are integral to primary healthcare, have untapped potential in social prescribing. This study explores social prescribing competence among Norwegian community pharmacists and pharmacy students. Method: A cross-sectional study utilizing an anonymous online questionnaire to collect quantitative data was conducted. Inspired by the limited relevant literature, the questionnaire was constructed, pilot-tested, and distributed in a one-week window within a Facebook group for Norwegian pharmacists. The questionnaire comprised 23 questions categorized into demographic details and competence assessment, covering general knowledge, attitude, and barriers/facilitators related to social prescribing. Statistical analyses were employed to determine the competence of the participants. Results: The online questionnaire collected data from 96 participants, primarily females (79.2%), aged 25–34 (40.6%), who were identified as community pharmacists (49.0%). Most (91.7%) worked in community pharmacies, with 31.3% having over 10 years of experience. Despite positive client relationships (93.8%), statistical analysis revealed no significant associations between competence and variables such as work experience, education, or gender. The custom scoring system yielded an average competence score of 1.98 on a 5-point scale, with attitudes and perceptions of participants scoring 3.82. Overall competence was calculated at 3.4, indicating a moderate level. Conclusions: The findings of this study reveal that the participants had limited knowledge regarding social prescribing, emphasizing the need for education. However, the participants showed strong enthusiasm for competence development. This groundwork paves the way for future investigations centered on pilot-testing strategies to boost social prescribing knowledge and engagement among Norwegian community pharmacists and pharmacy students.
Web Survey of Turkish Pharmacy Students Comparing First and Fifth Years’ Antidepressant Awareness and Stigmatizing Attitudes Regarding Depression and Anxiety
Authors: Yalçın Nadir , Özkan Gökçe Gül , Allegaert Karel , Ak Sertaç , Demirkan Kutay
Published: March 2024

The prevalence of depression and anxiety has increased day by day. Prejudice, self-stigma, and public stigma, on the other hand, continue to prevent patients from seeking adequate treatment, particularly in traditional communities. In this web-based, cross-sectional study, both the presence of depression and anxiety, and the knowledge, attitude, and awareness of first- and fifth (final)-year pharmacy students were examined via an online survey. The aim was to demonstrate the potential impact of public information and five years of pharmacy school on knowledge, attitude, and awareness. Our study population consisted of first- and fifth-year pharmacy students enrolled in one faculty of pharmacy during the spring semester of 2022–2023. The Beck Depression Inventory and Beck Anxiety Scale were utilized to measure the presence of depression and anxiety, while the Depression and Antidepressant Awareness and Knowledge Scale (DAKAS) was applied to assess their knowledge, attitude, and awareness. Fifth-year participants (n = 101) exhibited noticeably fewer stigmatizing attitudes than first-year participants (n = 104) (p < 0.05). There was no statistically significant difference between the mean Beck Depression Inventory and Beck Anxiety scores in first- and fifth-year pharmacy students. Being in the fifth class (OR: 3.690; p = 0.025), being of female gender (OR: 4.653; p < 0.001), and having a relationship with someone who took a psychotropic (OR: 3.060; p = 0.008) were associated with a lower overall stigma score by multiple linear regression analysis. The students’ awareness of antidepressants and familiarity with mental health issues at the end of their pharmacy education were higher and stigmatization behavior was lower than in first-year students. The positive attitudes at the end of their training towards depression will reduce the likelihood of future pharmacists’ patients from being exposed to stigmatization, prevents the formation of an additional stress factor, and likely will improve pharmacy practices.
A Transformerless Converter with Common-Mode Decoupling in Low-Voltage Hybrid Grids
Authors: Wang Lei , Zhang Xinfang , Han Xiaoqing , Ren Yu , Zhang Baifu , Wang Peng
Published: March 2024

Compared with isolated converters, transformerless converters are a preferred choice in low-voltage grids due to their efficiency and lower cost. However, leakage current and common mode (CM) voltage appear through the converter and ground in hybrid grids, which consist of AC and DC subgrids. The leakage current and CM voltage seriously influence operation and power quality in low-voltage distribution systems. This paper proposes a common-ground-type (CGT) converter equipped with a CM decoupling control strategy to eliminate the leakage current and CM voltage. A CM model is derived, and the leakage current and CM voltage are analyzed in detail. A CGT four-leg converter is constructed to eliminate the high frequency CM voltage. A dual DQ current control loop is developed to suppress the DC double-frequency ripple. Additionally, an active damping method is proposed, based on the neutral current feed-forward plus inductor current feedback, to attenuate the low frequency CM voltage. The proposed converter and control strategy guarantees excellent performance in suppressing leakage current and CM voltage. The DC voltage of the converter connected to the DC grid maintains stability and symmetry. The leakage current is significantly reduced, and the leakage current suppression performance is improved by 83%. The high frequency CM voltage is attenuated from 50%udc to 2%udc, and the low frequency CM voltage is suppressed from approximately 32%udc to 3%udc, which is a significant improvement compared with the traditional method. In addition, the proposed control strategy has good transient performance when the load changes abruptly. Finally, an experimental platform is established to validate the feasibility and performance. The experiment results showed that the proposed control strategy improves the system performance and power quality.
Convective Hot Air Drying of Red Cabbage (Brassica oleracea var. Capitata Rubra): Mathematical Modeling, Energy Consumption and Microstructure
Authors: Vega-Galvez Antonio , Gomez-Perez Luis S. , Ah-Hen Kong Shun , Zepeda Francisca , García-Segovia Purificación , Bilbao-Sainz Cristina , Mejías Nicol , Pasten Alexis
Published: March 2024

This study examined the convective drying of red cabbage at temperatures ranging from 50 to 90 °C. Mathematical modeling was used to describe isotherms, drying kinetics and rehydration process. The effects of drying conditions on energy consumption and microstructure were also evaluated. The Halsey model had the best fit to the isotherm data and the equilibrium moisture was determined to be 0.0672, 0.0490, 0 0.0379, 0.0324 and 0.0279 g water/g d.m. at 50, 60, 70, 80 and 90 °C, respectively. Drying kinetics were described most accurately by the Midilli and Kuçuk model. Also, the diffusion coefficient values increased with drying temperature. Lower energy consumption was found for drying at 90 °C and the rehydration process was best described by the Weibull model. Samples dehydrated at 90 °C showed high water holding capacity and better maintenance of microstructure. These results could be used to foster a sustainable drying process for red cabbage.
Sugarcane Rapadura: Characteristics of the Oldest Historical Energy Food and Its Native Production Method
Authors: Santos Ricardo , Assis Renata , Freitas Raquel , Barbosa Isabele , Ceccatto Vânia
Published: March 2024

Rapadura is a well-recognized sugar-cane-derived product with a sweet, characteristic flavor and hard texture. This product is a cultural Brazilian landmark, particularly in Ceará, Brazil, where it is usually produced by small family businesses and consumed locally. This feature contributes to the difficulties of rapadura production standardization, a requirement for the global market. Against this backdrop, this study focuses on analyzing the centesimal composition and mineral content of rapadura. Six samples from different cities in Ceará were analyzed for moisture, ash, lipids, proteins, carbohydrates, energy value, and minerals. The results ranged from 6.42–11.74% for moisture, 0.23–1.12% for ash, 0.49–0.92% for protein, 85.18–89.12% for lipids, and 352.00–391.19 Kcal for energy value. Significant variations were observed between the samples, showing a lack of standardization in the production process. The analysis of micronutrients revealed low levels, with copper and iron standing out in sample D. It can be concluded that the rapadura analyzed meets the physical-chemical parameters established by national legislation and is a food rich in carbohydrates and energy.
Development of a Time-Gated Epithermal Neutron Spectrometer for Resonance Absorption Measurements Driven by a High-Intensity Laser
Authors: Lan Zechen , Arikawa Yasunobu , Abe Yuki , Mirfayzi Seyed Reza , Morace Alessio , Hayakawa Takehito , Wei Tianyun , Yogo Akifumi
Published: March 2024

The advance of laser-driven neutron sources (LDNSs) has enabled neutron resonance spectroscopy to be performed with a single shot of a laser. In this study, we describe a detection system of epithermal (∼eV) neutrons especially designed for neutron resonance spectroscopy. A time-gated photomultiplier tube (PMT) with a high cut-off ratio was introduced for epithermal neutron detection in a high-power laser experiment at the Institute of Laser Engineering, Osaka University. We successfully reduced the PMT response to the intense hard X-ray generated as a result of the interaction between laser light and the target material. A time-gated circuit was designed to turn off the response of the PMT during the laser pulse and resume recording the signal when neutrons arrive. The time-gated PMT was coupled with a 6Li glass scintillator, serving as a time-of-flight (TOF) detector to measure the neutron resonance absorption values of 182W and 109Ag in a laser-driven epithermal neutron generation experiment. The neutron resonance peaks at 4.15 eV of 182W and 5.19 eV of 109Ag were detected after a single pulse of laser at a distance of 1.07 m.
Effects of Solar Intrusion on the Calibration of the Metop-C Advanced Microwave Sounding Unit-A2 Channels
Authors: Yan Banghua , Cao Changyong , Sun Ninghai
Published: March 2024

This study presents our first discovery about two abnormal problems in the blackbody calibration target associated with the antenna unit A2 in the Metop-C AMSU-A instrument. The problems include the anomalous patterns in both blackbody kinetic temperature Tw and radiative temperature (measured in warm count or Cw), and the time lag between orbital cycles of Tw and Cw. This study further determines solar intrusion as the root cause of the anomalous pattern problem. According to our analysis, solar illumination is constantly observed during each orbit near the satellite terminator, causing anomalous changes in Cw and Tw, characterized by sudden and abnormal increases typically for more than 16 min. The resultant maximum antenna temperature errors due to abnormal increases in Cw are approximately in the range from 0.15 K to 0.25 K, while the maximum errors due to the abnormal increase in Tw are in the range from 0.04 K to 0.07 K, varying with orbit, season, and channel. The time shift feature is characterized with a changeable time lag with the season in the Tw orbital cycle in comparison with the Cw cycle. The longest time lag up to about 18 min occurs in summer through early fall, while the time lag can be decreased down to about 9 min in winter through early spring. Hence, this study underscores the imperative need for future research to rectify radiance errors and reconstruct a more accurate long-term Metop-C AMSU-A radiance data set for channels 1 and 2, crucial for climate studies.
Optical–SAR Data Fusion Based on Simple Layer Stacking and the XGBoost Algorithm to Extract Urban Impervious Surfaces in Global Alpha Cities
Authors: Ahmad Muhammad Nasar , Shao Zhenfeng , Javed Akib , Ahmad Israr , Islam Fakhrul , Skilodimou Hariklia D. , Bathrellos George D.
Published: March 2024

This study proposes a fusion approach to enhancing urban remote sensing applications by integrating SAR (Sentinel-1) and optical (Landsat-8) satellite datasets. The fusion technique combines feature-based fusion and simple layer stacking (SLS) to improve the accuracy of urban impervious surface (UIS) extraction. SAR textures and modified indices are used for feature extraction, and classification is performed using the XGBoost machine learning algorithm in Python and Google Earth Engine. The study focuses on four global cities (New York, Paris, Tokyo, and London) with heterogeneous climatic zones and urban dynamics. The proposed method showed significant results. The accuracy assessment using random validation points shows an overall accuracy of 86% for UIS classification with the SLS method, outperforming single-data classification. The proposed approach achieves higher accuracy (86%) compared to three global products (ESA, ESRI, and Dynamic World). New York exhibits the highest overall accuracy at 88%. This fusion approach with the XGBoost classifier holds potential for new applications and insights into UIS mapping, with implications for environmental factors such as land surface temperature, the urban heat island effect, and urban pluvial flooding.
Lightning Stroke Strength and Its Correlation with Cloud Macro- and Microphysics over the Tibetan Plateau
Authors: Wei Lei , Xu Chen , Sun Zhuling
Published: March 2024

Lightning stroke strength, characterized by energy and peak currents, over the Tibetan Plateau (TP), is investigated by utilizing datasets from the World Wide Lightning Location Network and the Chinese Cloud-to-Ground Lightning Location System during 2016–2019. Focused on the south-central (SC) and southeast (SE) of the TP, it reveals that SE-TP experiences strokes with larger average energy and peak currents. Strong strokes (energy ≥ 100 kJ or peak currents ≥ |100| kA), exhibiting bimodal distribution in winter and summer, are more frequent and have larger average values over the SE-TP than the SC-TP, with diurnal distribution indicating peaks in energy and positive strokes in the middle of the night and negative strokes peaking in the morning. Utilizing the ECMWF/ERA-5 and MERRA-2 reanalysis, we find that stronger strokes correlate with thinner charge zone depths and larger CIWCFs but stable warm cloud depths and zero-degree levels over the SC-TP. Over the SE-TP, stronger strokes are associated with smaller CIWCFs and show turning points for warm cloud depths and zero-degree levels. Thicker charge zone depths correlate with stronger negative strokes but weaker positive strokes. Generating strokes of similar strength over the SC-TP requires larger CIWCFs, thinner warm cloud depths, and lower zero-degree levels than over the SE-TP.
Recent Advances and Current Trends in Transmission Tomographic Diffraction Microscopy
Authors: Verrier Nicolas , Debailleul Matthieu , Haeberlé Olivier
Published: March 2024

Optical microscopy techniques are among the most used methods in biomedical sample characterization. In their more advanced realization, optical microscopes demonstrate resolution down to the nanometric scale. These methods rely on the use of fluorescent sample labeling in order to break the diffraction limit. However, fluorescent molecules’ phototoxicity or photobleaching is not always compatible with the investigated samples. To overcome this limitation, quantitative phase imaging techniques have been proposed. Among these, holographic imaging has demonstrated its ability to image living microscopic samples without staining. However, for a 3D assessment of samples, tomographic acquisitions are needed. Tomographic Diffraction Microscopy (TDM) combines holographic acquisitions with tomographic reconstructions. Relying on a 3D synthetic aperture process, TDM allows for 3D quantitative measurements of the complex refractive index of the investigated sample. Since its initial proposition by Emil Wolf in 1969, the concept of TDM has found a lot of applications and has become one of the hot topics in biomedical imaging. This review focuses on recent achievements in TDM development. Current trends and perspectives of the technique are also discussed.
Transformer Monitoring with Electromagnetic Energy Transmission and Wireless Sensing
Authors: Xu Shuxing , Shang Yurui , Li Zhenming , Lu Yongling , Liu Mingyang , Liu Wei , Wang Zhen , Tang Wei
Published: March 2024

To ensure stable and normal transformer operation, light gas protection of the transformer Buchholz relay is essential. However, false alarms related to light gas protection are common, and troubleshooting them often requires on-site gas sampling by personnel. During this time, the transformer’s operating state may rapidly deteriorate, posing a safety threat to field staff. To tackle these challenges, this work presents the near-field, thin-sliced transformer monitoring system that uses Electromagnetic Energy Transmission and Wireless Sensing Device (ETWSD). The system leverages external wireless energy input to power gas monitoring sensors. Simultaneously, it employs Near-Field Communication to obtain real-time concentrations of light gases, along with the electrified state and temperature. In field testing conducted on transformer relays’ gas collection chambers, the ETWSD effortlessly monitors parameters within warning ranges, encompassing methane gas concentrations around 1000 ppm, leakage voltage ranging from 0–100 V, and relay working temperatures up to 90 °C. Additionally, to facilitate real-time diagnosis for electrical workers, we have developed an Android-based APP software that displays current light gas concentrations, leakage voltage collection values, and temperature, while also enabling threshold judgment, alarms, and data storage. The developed ETWSD is expected to aid on-site personnel in promptly and accurately evaluating transformer light gas protection error alarm faults. It provides a method for simultaneous, contactless, and rapid monitoring of multiple indicators.
Clipping Noise Compensation for Overlapped Time Domain Multiplexing toward Low Peak-to-Average Power Ratio
Authors: Huang Chongda , Zhang Qianzhen , Li Xiaoyuan , Xiao Yue
Published: March 2024

Overlapped Time Domain Multiplexing (OvTDM) is a high-rate transmission technology that employs the idea of superposition coded modulation (SCM) scheme for signal generation, aiming to achieve maximum channel capacity sharing. Meanwhile, it is also widely considered as a promising technique toward physical layer security. As a main drawback of such system, a high peak-to-average power ratio (PAPR) issue in this system, arising from multi-layer superposition, can be addressed through intentional clipping. However, the detection at the receiver side is vulnerable to nonlinear distortion caused by clipping, which can degrade the performance. To mitigate this distortion, this paper proposed an iterative scheme for estimating and partially canceling clipping distortion at the receiver. We managed to mitigate the impact of clipping noise as much as possible and minimize the cost of optimizing PAPR, thereby improving the transmission performance of OvTDM in the context of amplitude clipping.
A 2.4 GHz Wide-Range CMOS Current-Mode Class-D PA with HD2 Suppression for Internet of Things Applications
Authors: Kim Nam-Seog
Published: March 2024

Short-range Internet of Things (IoT) sensor nodes operating at 2.4 GHz must provide ubiquitous wireless sensor networks (WSNs) with energy-efficient, wide-range output power (POUT). They must also be fully integrated on a single chip for wireless body area networks (WBANs) and wireless personal area networks (WPANs) using low-power Bluetooth (BLE) and Zigbee standards. The proposed fully integrated transmitter (TX) utilizes a digitally controllable current-mode class-D (CMCD) power amplifier (PA) with a second harmonic distortion (HD2) suppression to reduce VCO pulling in an integrated system while meeting harmonic limit regulations. The CMCD PA is divided into 7-bit slices that can be reconfigured between differential and single-ended topologies. Duty cycle distortion compensation is performed for HD2 suppression, and an HD2 rejection filter and a modified C-L-C low-pass filter (LPF) reduce HD2 further. Implemented in a 28 nm CMOS process, the TX achieves a wide POUT range of from 12.1 to −31 dBm and provides a maximum efficiency of 39.8% while consuming 41.1 mW at 12.1 dBm POUT. The calibrated HD2 level is −82.2 dBc at 9.93 dBm POUT, resulting in a transmitter figure of merit (TX_FoM) of −97.52 dB. Higher-order harmonic levels remain below −41.2 dBm even at 12.1 dBm POUT, meeting regulatory requirements.
Integrated Automatic Optical Inspection and Image Processing Procedure for Smart Sensing in Production Lines
Authors: Qiu Rong-Qing , Tsai Mu-Lin , Chen Yu-Wen , Singh Shivendra Pratap , Lo Cheng-Yao
Published: March 2024

An integrated automatic optical inspection (iAOI) system with a procedure was proposed for a printed circuit board (PCB) production line, in which pattern distortions and performance deviations appear with process variations. The iAOI system was demonstrated in a module comprising a camera and lens, showing improved supportiveness for commercially available hardware. The iAOI procedure was realized in a serial workflow of image registration, threshold setting, image gradient, marker alignment, and geometric transformation; furthermore, five operations with numerous functions were prepared for image processing. In addition to the system and procedure, a graphical user interface (GUI) that displays sequential image operation results with analyzed characteristics was established for simplicity. To demonstrate its effectiveness, self-complementary Archimedean spiral antenna (SCASA) samples fabricated via standard PCB fabrication and intentional pattern distortions were demonstrated. The results indicated that, compared with other existing methods, the proposed iAOI system and procedure provide unified and standard operations with efficiency, which result in scientific and unambiguous judgments on pattern quality. Furthermore, we showed that when an appropriate artificial intelligence model is ready, the electromagnetic characteristic projection for SCASAs can be simply obtained through the GUI.
LoRa Technology Propagation Models for IoT Network Planning in the Amazon Regions
Authors: Lima Wirlan G. , Lopes Andreia V. R. , Cardoso Caio M. M. , Araújo Jasmine P. L. , Neto Miércio C. A. , Tostes Maria E. L. , Nascimento Andréia A. , Rodriguez Mauricio , Barros Fabrício J. B.
Published: March 2024

Designing and deploying telecommunications and broadcasting networks in the challenging terrain of the Amazon region pose significant obstacles due to its unique morphological characteristics. Within low-power wide-area networks (LPWANs), this research study introduces a comprehensive approach to modeling large-scale propagation loss channels specific to the LoRaWAN protocol operating at 915 MHz. The objective of this study is to facilitate the planning of Internet of Things (IoT) networks in riverside communities while accounting for the mobility of end nodes. We conducted extensive measurement campaigns along the banks of Universidade Federal do Pará, capturing received signal strength indication (RSSI), signal-to-noise ratio (SNR), and geolocated point data across various spreading factors. We fitted the empirical close-in (CI) and floating intercept (FI) propagation models for uplink path loss prediction and compared them with the Okumura–Hata model. We also present a new model for path loss with dense vegetation. Furthermore, we calculated received packet rate statistics between communication links to assess channel quality for the LoRa physical layer (PHY). Remarkably, both CI and FI models exhibited similar behaviors, with the newly proposed model demonstrating enhanced accuracy in estimating radio loss within densely vegetated scenarios, boasting lower root mean square error (RMSE) values than the Okumura–Hata model, particularly for spreading factor 9 (SF9). The radius coverage threshold, accounting for node mobility, was 945 m. This comprehensive analysis contributes valuable insights for the effective deployment and optimization of LoRa-based IoT networks in the intricate environmental conditions of the Amazon region.
Balancing the Efficiency and Sensitivity of Defect Inspection of Non-Patterned Wafers with TDI-Based Dark-Field Scattering Microscopy
Authors: Yu Fei , Xu Min , Wang Junhua , Zhang Xiangchao , Tang Xinlan
Published: March 2024

In semiconductor manufacturing, defect inspection in non-patterned wafer production lines is essential to ensure high-quality integrated circuits. However, in actual production lines, achieving both high efficiency and high sensitivity at the same time is a significant challenge due to their mutual constraints. To achieve a reasonable trade-off between detection efficiency and sensitivity, this paper integrates the time delay integration (TDI) technology into dark-field microscopy. The TDI image sensor is utilized instead of a photomultiplier tube to realize multi-point simultaneous scanning. Experiments illustrate that the increase in the number of TDI stages and reduction in the column fixed pattern noise effectively improve the signal-to-noise ratio of particle defects without sacrificing the detecting efficiency.
Breath Measurement Method for Synchronized Reproduction of Biological Tones in an Augmented Reality Auscultation Training System
Authors: Kono Yukiko , Miura Keiichiro , Kasai Hajime , Ito Shoichi , Asahina Mayumi , Tanabe Masahiro , Nomura Yukihiro , Nakaguchi Toshiya
Published: March 2024

An educational augmented reality auscultation system (EARS) is proposed to enhance the reality of auscultation training using a simulated patient. The conventional EARS cannot accurately reproduce breath sounds according to the breathing of a simulated patient because the system instructs the breathing rhythm. In this study, we propose breath measurement methods that can be integrated into the chest piece of a stethoscope. We investigate methods using the thoracic variations and frequency characteristics of breath sounds. An accelerometer, a magnetic sensor, a gyro sensor, a pressure sensor, and a microphone were selected as the sensors. For measurement with the magnetic sensor, we proposed a method by detecting the breathing waveform in terms of changes in the magnetic field accompanying the surface deformation of the stethoscope based on thoracic variations using a magnet. During breath sound measurement, the frequency spectra of the breath sounds acquired by the built-in microphone were calculated. The breathing waveforms were obtained from the difference in characteristics between the breath sounds during exhalation and inhalation. The result showed the average value of the correlation coefficient with the reference value reached 0.45, indicating the effectiveness of this method as a breath measurement method. And the evaluations suggest more accurate breathing waveforms can be obtained by selecting the measurement method according to breathing method and measurement point.