bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Characterization of a Planar Micro-Conveyor Device Based on Cooperative Legged Piezoelectric MEMS Resonators
Authors: Ruiz-Díez Víctor , Ababneh Abdallah , Seidel Helmut , Sánchez-Rojas José Luis
Published: July 2022

This paper reports the design, fabrication, and performance of a hybrid piezoelectric planar micro-conveyor based on Micro-Electromechanical Systems (MEMS) bridge resonators and featuring 3D-printed vertical legs. The device includes two cooperating silicon plate resonators with an area of 5 × 1 mm2, actuated by an integrated aluminum-nitride (AlN) piezoelectric thin film. An optimally designed array of 3D-printed projection legs was attached to the plates, to convert the standing-wave (SW) vertical vibrations into horizontal rotations or translations of the supported slider. An open-loop control strategy based on burst-type driving signals, with different numbers of sinusoidal cycles applied on each of the resonators, allowed the cooperation of the two bridges to set up prescribed trajectories of small flat objects, up to 100 mg, with positional accuracy below 100 nm and speeds up to 20 mm/s, by differential drive actuation. The effect of the leg tip and sliders’ surface finish on the conveyor performance was investigated, suggesting that further optimizations may be possible by modifying the tribological properties. Finally, the application of the micro-conveyor as a reconfigurable electronic system, driven by a preprogrammed sequence of signals, was demonstrated by delivering some surface-mount technology (SMD) parts lying on a 65 mg glass slider.
Metasurface-Based Quantum Searcher on a Silicon-On-Insulator Chip
Authors: Wei Zeyong , Li Haoyu , Dou Linyuan , Xie Lingyun , Wang Zhanshan , Cheng Xinbin
Published: July 2022

Optical analog computing has natural advantages of parallel computation, high speed and low energy consumption over traditional digital computing. To date, research in the field of on-chip optical analog computing has mainly focused on classical mathematical operations. Despite the advantages of quantum computing, on-chip quantum analog devices based on metasurfaces have not been demonstrated so far. In this work, based on a silicon-on-insulator (SOI) platform, we illustrated an on-chip quantum searcher with a characteristic size of 60 × 20 μm2. We applied classical waves to simulate the quantum search algorithm based on the superposition principle and interference effect, while combining it with an on-chip metasurface to realize modulation capability. The marked items are found when the incident waves are focused on the marked positions, which is precisely the same as the efficiency of the quantum search algorithm. The proposed on-chip quantum searcher facilitates the miniaturization and integration of wave-based signal processing systems.
On the Isomorphism of Sodium at the M(2) Site in Eudialyte-Group Minerals: The Crystal Structure of Mn-Deficient Manganoeudialyte and the Problem of the Existence of the M(2)Na-Dominant Analogue of Eudialyte
Authors: Aksenov Sergey M. , Chukanov Nikita V. , Pekov Igor V. , Nelyubina Yulia V. , Varlamov Dmitry A. , Kogarko Lia N.
Published: July 2022

Sodium plays an important role in the crystal structures of eudialyte-group minerals given that it can occupy different crystallographic sites. Predominantly, it distributes between the N(1–5) sites situated in the large cavities of the heteropolyhedral framework. Rarely, Na occupies split sites of the M(2) microregion where it can predominate over other elements (predominantly Mn, Fe2+, and Fe3+). The crystal structure of the Mn-deficient manganoeudialyte from the Lovozero alkaline complex (Kola Peninsula, Russia) has been refined. The trigonal unit–cell parameters are: a = 14.1848(2) Å, c = 30.4726(3) Å, V = 5309.90(11) Å3. The sample is a rare example of a high-sodium and high-calcium representative of the eudialyte group with Fe + Mn < 2 apfu. The idealized formula is Na14Ca6[(Mn,Fe)2Na]Zr3Si2[Si24O72]O(OH)·2H2O with bivalent components, Mn2+ and Fe2+, dominating at the M(2) site. The regularities of isomorphism involving M(2)Na in EGMs and the problem of the existence of the M(2)Na-dominant analogue of eudialyte are discussed. The new data obtained in this work confirm the previous conclusion that the complete isomorphism between Ca-deficient and Ca-rich members of the eudialyte group cannot be realized in frames of a single-space group (R3m, R-3m or R3). Thus, the existence of the M(2)Na analogue of eudialyte remains questionable.
Allanite in Variscan Post-Collisional Lamprophyre Dykes from Les Guilleries (NE Iberia) as a Part of Rare Earth Elements Recycling in Collisional Orogens
Authors: Mellado Esteban , Corbella Mercè , Kylander-Clark Andrew
Published: July 2022

Recent studies of Late Permian calc-alkaline lamprophyre dykes located in the Les Guilleries Paleozoic massif of the Catalan Coastal Range have revealed that allanite is present as the main REE-bearing accessory phase, which is the object of this study. The lamprophyre dykes are amphibole–plagioclase-dominated spessartites with a wide variety of accessory phases, including titanite, ilmenite, allanite, fluorapatite, spinel, zircon, and sulfides, and show complex alteration textures related to secondary albite, chlorite, epidote, titanite and calcite. The allanite crystal composition, analyzed by SEM-EPMA and LA-ICP-MS, evidences the solid solution between epidote and allanite with a ferriallanite component, similar to what is found in Variscan post-collisional granitoids from western Europe. However, heterogeneity in crystal shapes, sizes, type of zoning, dissolution embayment textures, growth of epidote coronas, mineral paragenesis, and the unique geochemical characteristics of allanite crystals suggest multiple crystallization events. At least two types of allanite–epidote composite grains have been identified: allanite Type I, with regular allanite–epidote core-to-rim zoning and a secondary allanite rim; and allanite Type II, with anhedral allanite cores surrounded by epidote coronas. Additionally, irregular zoning, complex dissolution textures and REE redistribution suggest the occurrence of deuteric and/or post-magmatic processes, which are also common in Variscan post-collisional plutons from the Catalan Coastal Range and nearby Paleozoic massifs. Multivariate statistical analyses of major elements in allanite–epidote composite grains show a relationship between major textural and geochemical variations for three out of ten principal components, mainly related to cationic substitutions between ferriallanite-(Ce) and epidote, but also involving Mn and Ti(REE3+ + Fe2+ + Ti4+ + Mg2+ + Mn2+ = Al3+ + Ca2+ + Fe3+). The allanite U-Pb-Th- weighted mean age of 265 ± 15 Ma (MSWD = 0.57) is roughly similar to the age of emplacement of the lamprophyres in the upper crust in the mid–late Permian, and coincides with the period following the main tectonometamorphic and magmatic events of the post-collisional evolution in the Catalan Coastal Range. Th/U and La/Sm ratios suggest a metamorphic origin for most allanite grains, but a combination of metamorphic processes prior to partial melting, early–late magmatic crystallization, and/or post-magmatic hydrothermal processes is the most plausible explanation to account for the diversity of allanite grains in Les Guilleries lamprophyres.
The Heavy Mineral Map of Australia: Vision and Pilot Project
Authors: Caritat Patrice , McInnes Brent , Walker Alexander , Bastrakov Evgeniy , Rowins Stephen , Prent Alexander
Published: July 2022

We describe a vision for a national-scale heavy mineral (HM) map generated through automated mineralogical identification and quantification of HMs contained in floodplain sediments from large catchments covering most of Australia. The composition of the sediments reflects the dominant rock types in each catchment, with the generally resistant HMs largely preserving the mineralogical fingerprint of their host protoliths through the weathering-transport-deposition cycle. Heavy mineral presence/absence, absolute and relative abundance, and co-occurrence are metrics useful to map, discover and interpret catchment lithotype(s), geodynamic setting, magmatism, metamorphic grade, alteration and/or mineralization. Underpinning this vision is a pilot project, focusing on a subset from the national sediment sample archive, which is used to demonstrate the feasibility of the larger, national-scale project. We preview a bespoke, cloud-based mineral network analysis (MNA) tool to visualize, explore and discover relationships between HMs as well as between them and geological settings or mineral deposits. We envisage that the Heavy Mineral Map of Australia and MNA tool will contribute significantly to mineral prospectivity analysis and modeling, particularly for technology critical elements and their host minerals, which are central to the global economy transitioning to a more sustainable, lower carbon energy model.
Aliskiren Hemifumarate Proliposomes for Improved Oral Drug Delivery: Formulation Development, In Vitro and In Vivo Permeability Testing
Authors: Kunamaneni Priyanka , Kovvasu Surya , Yeung Steven , Wang Jeffrey , Shah Salim , Betageri Guru
Published: July 2022

The objective of this study was to develop proliposomal formulations for a poorly bioavailable drug, aliskiren hemifumarate (AKH). A solvent evaporation method was used to prepare proliposomes using different lipids. The lipids of selection were soy phosphatidylcholine (SPC), dimyristoylphosphatidylcholine (DMPC), and dimyristoylphosphatidylglycerol sodium (DMPG Na), stearylamine, and cholesterol in various ratios. Proliposomes were evaluated for particle size, zeta potential, in vitro drug release, in vitro permeability, and in vivo pharmacokinetics upon hydration with aqueous phase. In vitro drug release studies were conducted in 0.01 N hydrochloric acid using USP type II dissolution apparatus. Parallel artificial membrane permeation assay (PAMPA) and Caco-2 cell line models were used to study the in vitro drug permeation. Male Sprague-Dawley (SD) rats were used to conduct in vivo pharmacokinetic studies. Among different formulations, proliposomes with drug/DMPC/cholesterol/stearylamine in the ratio of 1:5:0.025:0.050 (w/w/w/w) demonstrated the desired particle size, higher zeta potential, and higher encapsulation efficiency. The PAMPA and Caco-2 cell line experiments showed a significantly higher permeability of AKH with proliposomes as compared to pure AKH. In animal studies, the optimized formulation of proliposomes showed significant improvement in the rate and extent of absorption of AKH. Specifically, following a single oral administration, the relative bioavailability of AKH proliposome formulation was 230% when compared to pure AKH suspension.
Phytophenol Dimerization Reaction: From Basic Rules to Diastereoselectivity and Beyond
Authors: Liu Shuqin , Li Xican , Chen Ban , Ouyang Xiaojian , Xie Yulu , Chen Dongfeng
Published: July 2022

Phytophenol dimerization, which is a radical-mediated coupling reaction, plays a critical role in many fields, including lignin biosynthesis. To understand the reaction, 2,2-diphenyl-1-picrylhydrazyl radical was used to initiate a series of phytophenol dimerization reactions in methanol. The products were identified using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-Q-TOF-MS/MS) analysis in situ. The identified products mainly included biphenols, magnolol, honokiol, gingerol 6,6′-dimers, 3,6-dimethoxylcatechol β,β′ dimer, euphorbetin, bis-eugenol, dehydrodiisoeugenol, trans-ε-viniferin, (+) pinoresinol, and (−) pinoresinol. Structure–function relationship analysis allowed four basic rules to be defined: meta-excluded, C–C bonding domination, ortho-diOH co-activation, and exocyclic C=C involvement. The exocyclic C=C involvement, however, required conjugation with the phenolic core and the para-site of the -OH group, to yield a furan-fused dimer with two chiral centers. Computational chemistry indicated that the entire process was completed via a radical coupling reaction and an intramolecular conjugate addition reaction. Similar results were also found for the horseradish peroxidase (HRP)-catalyzed coniferyl alcohol dimerization, which produced (+) and (−) pinoresinols (but no (−) epipinoresinol), suggesting that the HRP-catalyzed process was essentially an exocyclic C=C-involved phytophenol dimerization reaction. The reaction was highly diastereoselective. This was attributed to the intramolecular reaction, which prohibited Re-attack. The four basic rules and diastereoselectivity can explain and even predict the main products in various chemical and biological events, especially oxidase-catalyzed lignin cyclization.
Challenges and Opportunities of Implementing Data Fusion in Process Analytical Technology—A Review
Authors: Casian Tibor , Nagy Brigitta , Kovács Béla , Galata Dorián László , Hirsch Edit , Farkas Attila
Published: July 2022

The release of the FDA’s guidance on Process Analytical Technology has motivated and supported the pharmaceutical industry to deliver consistent quality medicine by acquiring a deeper understanding of the product performance and process interplay. The technical opportunities to reach this high-level control have considerably evolved since 2004 due to the development of advanced analytical sensors and chemometric tools. However, their transfer to the highly regulated pharmaceutical sector has been limited. To this respect, data fusion strategies have been extensively applied in different sectors, such as food or chemical, to provide a more robust performance of the analytical platforms. This survey evaluates the challenges and opportunities of implementing data fusion within the PAT concept by identifying transfer opportunities from other sectors. Special attention is given to the data types available from pharmaceutical manufacturing and their compatibility with data fusion strategies. Furthermore, the integration into Pharma 4.0 is discussed.
The Dispersion and Coagulation of Negatively Charged Ca2Nb3O10 Perovskite Nanosheets in Sodium Alginate Dispersion
Authors: Fu Si , Zhang Binbin , Miao Zhiying , Li Zhenyang , Tu Rong , Zhang Song , Li Bao-Wen
Published: July 2022

Chemically exfoliated nanosheets have been extensively employed as functional nanofillers for the fabrication of polymer nanocomposites due to their remarkable electrical, magnetic and optical properties. However, achieving a good dispersion of charged nanosheets in polymer matrix, which will determine the performance of polymer nanocomposites, remains a challenge. Herein, we investigated the dispersion and aggregation behavior of negatively charged Ca2Nb3O10 (CNO) perovskite nanosheets in negatively charged sodium alginate (SA) aqueous dispersion using dynamic light scattering (DLS). When CNO nanosheets meet with SA, aggregation and coagulation inevitably occurred owing to the absorption of SA on nanosheets. By controlling the electrostatic attraction between positively charged poly(ethylene imine) (PEI) and negatively charged SA, the charge density and hydrodynamic size of SA can be tuned to enable the good dispersion of CNO nanosheets in SA. This result may provide a new strategy to achieve the good dispersion of charged nanosheets in charged polymers for the rational design of multifunctional nanocomposites.
Biocompatible Casein Electrolyte-Based Electric-Double-Layer for Artificial Synaptic Transistors
Authors: Kim Hwi-Su , Park Hamin , Cho Won-Ju
Published: July 2022

In this study, we proposed a synaptic transistor using an emerging biocompatible organic material, namely, the casein electrolyte as an electric-double-layer (EDL) in the transistor. The frequency-dependent capacitance of the indium-tin-oxide (ITO)/casein electrolyte-based EDL/ITO capacitor was assessed. As a result, the casein electrolyte was identified to exhibit a large capacitance of ~1.74 μF/cm2 at 10 Hz and operate as an EDL owing to the internal proton charge. Subsequently, the implementation of synaptic functions was verified by fabricating the synaptic transistors using biocompatible casein electrolyte-based EDL. The excitatory post-synaptic current, paired-pulse facilitation, and signal-filtering functions of the transistors demonstrated significant synaptic behavior. Additionally, the spike-timing-dependent plasticity was emulated by applying the pre- and post-synaptic spikes to the gate and drain, respectively. Furthermore, the potentiation and depression characteristics modulating the synaptic weight operated stably in repeated cycle tests. Finally, the learning simulation was conducted using the Modified National Institute of Standards and Technology datasets to verify the neuromorphic computing capability; the results indicate a high recognition rate of 90%. Therefore, our results indicate that the casein electrolyte is a promising new EDL material that implements artificial synapses for building environmental and biologically friendly neuromorphic systems.
Ultra-Thin, Short-Focus, and High-Aperture Metalens for Generating and Detecting Laser Optical Vortices
Authors: Nalimov Anton , Kotlyar Victor
Published: July 2022

A combined high-aperture metalens in a thin silicon nitride film that consists of two tilted sectored metalenses is considered. Each sector of the metalens consists of a set of binary subwavelength gratings. The diameter of the metalens is 14 μm. Using a time-domain finite difference method, we show that the metalens can simultaneously detect optical vortices with two topological charges −1 and −2, almost over the entire spectrum of visible wavelengths. The metalens can distinguish several wavelengths that are focused at different points in the focal plane due to a 1-nm change in wavelength resulting in a focal spot shift of about 4 nm. When the metalens is illuminated by a Gaussian beam with left-handed circular polarization, two optical vortices with topological charges 1 and 2 are simultaneously formed 6-μm apart at the focal distance of 6 μm.
Vegetarian and Vegan Diets: Beliefs and Attitudes of General Practitioners and Pediatricians in France
Authors: Villette Cécile , Vasseur Pauline , Lapidus Nathanael , Debin Marion , Hanslik Thomas , Blanchon Thierry , Steichen Olivier , Rossignol Louise
Published: July 2022

Studies suggest a decreasing trend in the consumption of meat products and a growing interest in vegetarian diets. Medical support may be relevant, especially when switching to a vegan diet. Our objective was to describe the beliefs and attitudes of primary care physicians toward vegetarian diets. A cross-sectional survey was conducted among general practitioners and pediatricians thorough a questionnaire including socio-demographic characteristics, specific care to vegetarians, and the risks and benefits of vegetarian diets according to physicians. Out of the 177 participating physicians, 104 (59%) have seen at least one vegetarian patient in consultation in the last three months. Half of the physicians declared that they would dissuade their patients from switching to a vegan diet (n = 88, 51%) and 14% (n = 24) from switching to an ovo-lacto-vegetarian (OLV) diet. Most physicians (n = 141, 88%) did not feel informed enough about these diets. Physicians thought that the most frequent deficiencies for OLV and vegan diets were iron (76% and 84%, respectively) and protein (45% and 79%, respectively). These results highlight the fact that French primary care physicians feel concerned by this subject and need more information on these diets. Specific recommendations would be useful to support their practice and relationship with vegetarians.
Methods Used for Enhancing the Bioavailability of Oral Curcumin in Randomized Controlled Trials: A Meta-Research Study
Authors: Mimica Bruna , Bučević Popović Viljemka , Banjari Ines , Jeličić Kadić Antonia , Puljak Livia
Published: July 2022

It is unknown how randomized controlled trials (RCTs) approach the problem related to curcumin bioavailability. We analyzed methods and reporting regarding the bioavailability of systemic oral curcumin used in RCTs. We searched PubMed on 12 September 2020, to find articles reporting RCTs that used curcumin as an intervention. We extracted data about trial characteristics, curcumin products used, methods for improving curcumin bioavailability, and mentions of curcumin bioavailability. We included 165 RCTs. The most common category of intervention was simply described as “curcumin” or “curcuminoids” without a commercial name. There were 107 (64%) manuscripts that reported that they used methods to enhance the oral bioavailability of curcuminoids used in their intervention; 25 different methods were reported. The most common method was the addition of piperine (23%). Phospholipidated curcumin, a combination of curcumin and turmeric oils, nanomicellar curcumin, and colloidal dispersion of curcumin were the next most common methods. Fourteen trials (8.4%) compared more than one different curcumin product; nine (7.9%) trials compared the bioavailability/pharmacokinetics of curcumin products. In conclusion, a high number of diverse methods were used, and very few trials compared different curcumin products. More studies are needed to explore the comparative bioavailability and efficacy of different curcumin products.
Central Composite Optimization of Glycerosomes for the Enhanced Oral Bioavailability and Brain Delivery of Quetiapine Fumarate
Authors: Zaki Randa Mohammed , Alfadhel Munerah M. , Alossaimi Manal A. , Elsawaf Lara Ayman , Devanathadesikan Seshadri Vidya , Almurshedi Alanood S. , Yusif Rehab Mohammad , Said Mayada
Published: July 2022

This study aimed to formulate and statistically optimize glycerosomal formulations of Quetiapine fumarate (QTF) to increase its oral bioavailability and enhance its brain delivery. The study was designed using a Central composite rotatable design using Design-Expert® software. The independent variables in the study were glycerol % w/v and cholesterol % w/v, while the dependent variables were vesicle size (VS), zeta potential (ZP), and entrapment efficiency percent (EE%). The numerical optimization process resulted in an optimum formula composed of 29.645 (w/v%) glycerol, 0.8 (w/v%) cholesterol, and 5 (w/v%) lecithin. It showed a vesicle size of 290.4 nm, zeta potential of −34.58, and entrapment efficiency of 80.85%. The optimum formula was further characterized for DSC, XRD, TEM, in-vitro release, the effect of aging, and pharmacokinetic study. DSC thermogram confirmed the compatibility of the drug with the ingredients. XRD revealed the encapsulation of the drug in the glycerosomal nanovesicles. TEM image revealed spherical vesicles with no aggregates. Additionally, it showed enhanced drug release when compared to a drug suspension and also exhibited good stability for one month. Moreover, it showed higher brain Cmax, AUC0–24, and AUC0–∞ and plasma AUC0–24 and AUC0–∞ in comparison to drug suspension. It showed brain and plasma bioavailability enhancement of 153.15 and 179.85%, respectively, compared to the drug suspension. So, the optimum glycerosomal formula may be regarded as a promising carrier to enhance the oral bioavailability and brain delivery of Quetiapine fumarate.
Japan’s Forgotten God: Jūzenji in Medieval Texts and the Visual Arts
Authors: Porath Or
Published: July 2022

This study examines Jūzenji 十禅師, a medieval god worshiped within the Sannō cult at Hie Shrine during the twelfth to sixteenth centuries. The article demonstrates that Tendai thinkers promoted Jūzenji to a supreme ontological status since his liminal and ambivalent character afforded him the unique role of redirecting the sinful desires of the flesh into awakening. Three different figures promoted Jūzenji. First, the Tendai abbot Jien 慈円 (1155–1255) constructed ritual programs that raised Jūzenji to the apogee of the Sannō Shintō pantheon, which combined with engi literature concerning Jien’s sexuality, permitted the re-envisioning of Jūzenji as a libidinal god. Second, the preceptors of Mt. Hiei (kaike 戒家) transformed Jūzenji into an embodiment of the precepts, which enabled Jūzenji to encapsulate morality and thereby render sexual sins null. Third, Tendai Sannō Shintō theologians (kike 記家) interweaved Jūzenji with the doctrine of the threefold truth (santai 三諦), which became the basis of the Taimitsu sexual initiation known as Chigo Kanjō 児灌頂. As such, this article offers an important case study whereby a subsidiary god outshines its own godhead for the purpose of legitimating sexuality.
Improvement and Assessment of Ocean Color Algorithms in the Northwest Pacific Fishing Ground Using Himawari-8, MODIS-Aqua, and VIIRS-SNPP
Authors: Huang Chuanyang , Liu Yang , Luo Yanping , Wang Yuntao , Liu Xudong , Zhang Yong , Zhuang Yunyun , Tian Yongjun
Published: July 2022

Chlorophyll-a (Chl-a) is an important marine indicator, and the improvement in Chl-a concentration retrieval for ocean color remote sensing is always a major challenge. This study focuses on the northwest Pacific fishing ground (NPFG) to evaluate and improve the Chl-a products of three mainstream remote sensing satellites, Himawari-8, MODIS-Aqua, and VIIRS-SNPP. We analyzed in situ data and found that an in situ Chl-a concentration of 0.3 mg m−3 could be used as a threshold to distinguish the systematic deviation of remote sensing Chl-a data in the NPFG. Based on this threshold, we optimized the Chl-a algorithms of the three satellites by data grouping, and integrated multisource satellite Chl-a data by weighted averaging to acquire high-coverage merged data. The merged data were thoroughly verified by Argo Chl-a data. The Chl-a front of merged Chl-a data could be represented accurately and completely and had a good correlation with the distribution of the NPFG. The most important marine factors for Chl-a are nutrients and temperature, which are affected by mesoscale eddies and variations in the Kuroshio extension. The variation trend of merged Chl-a data is consistent with mesoscale eddies and Kuroshio extension and has more sensitive responses to the marine climatic conditions of ENSO.
Experimental Study of Maritime Moving Target Detection Using Hitchhiking Bistatic Radar
Authors: Song Jie , Xiong Wei , Chen Xiaolong , Lu Yuan
Published: July 2022

Hitchhiking bistatic radar system takes the direct wave signal that is transmitted by the non-cooperative radar emitter as the reference to detect and analyze the target echo signal, so as to realize the positioning and tracking of the target. This radar system has the advantages of low cost and strong survivability. Aiming at the problem of passive radar to covert the detection of maritime targets, this paper develops a hitchhiking bistatic radar system for maritime target detection, which uses the shore-based radar as the non-cooperative radar emitter. By continuously collecting the direct wave and target echo data of the non-cooperative radar, the direct wave reference signal reconstruction, pulse compression, interference suppression and synchronization processing, non-coherent integration, MTI (moving target indication), clutter map processing, and adaptive CFAR (constant false alarm rate) detection are completed to obtain the azimuth, bistatic range, and Doppler frequency of the target, and finally realize the positioning of non-cooperative maritime targets. This paper first introduces and demonstrates the composition principle of the system, introduces the signal processing implementation method of the system in detail, and tests and analyzes the key algorithms. The experimental results show that the system can realize the passive coherent detection of maritime moving targets and locate multiple targets at the same time. The experiment obtains a very clear PPI (plane position indicator) display picture of the hitchhiking bistatic radar system, and the radar detection data of the experimental system is in good agreement with the AIS (automatic identification system) data.
Near-Surface NO2 Concentration Estimation by Random Forest Modeling and Sentinel-5P and Ancillary Data
Authors: Li Meixin , Wu Ying , Bao Yansong , Liu Bofan , Petropoulos George P.
Published: July 2022

In the present study, a daily model is proposed for estimating the near-surface NO2 concentration in China, combining for the first time the Random Forest (RF) machine learning algorithm with the tropospheric NO2 columns from the TROPOspheric Monitoring Instrument (TropOMI) satellite and meteorological and NO2 data of surface sites in China for the year 2019. Furthermore, near-surface NO2 concentration data of ground sites during the COVID-19 outbreak from 1–5 February 2020 were used to verify the developed model. The daily model was verified by the ten-fold cross-validation method, revealing a coefficient of determination (R2) of 0.78 and root-mean-square error (RMSE) of 7.04 μg/m3, which are reasonable and also comparable to other published studies. In addition, our model showed that near-surface NO2 in China during the COVID-19 pandemic was significantly reduced compared with 2019, and these predictions were in good agreement with reference ground data. Our proposed model can also provide NO2 estimates for areas in western China where there are few ground monitoring sites. Therefore, all in all, our study findings suggest that the model established herein is suitable for estimating the daily NO2 concentration near the surface in China and, as such, can be used if there is a lack of surface sites and/or missing observations in some areas.
Experimental Parametric Study of a Functional-Magnetic Material Designed for the Monitoring of Corrosion in Reinforced Concrete Structures
Authors: Souriou David , Kadkhodazadeh Sima , Dérobert Xavier , Guilbert David , Ihamouten Amine
Published: July 2022

The presence of aggressive agents (such as chloride ions brought by seawater) in reinforced concrete structures is responsible for the corrosion of the steel rebars. A Structural Health Monitoring technology is developed as a new passive preventive method that would allow for the detection of and for the ability to follow the presence of chloride ions in the cover concrete of reinforced concrete. This technology, referenced as Functional Magnetic Material (FMM), consists on the measurement with an external interrogator of a Magnetic Observable (MO), partially shielded by a patch and corrodible by chloride ions. This paper presents the results of a parametric experimental study, allowing the validation of the concept of this technology, by highlighting the variation of the MO while considering the geometry and the corrosion level of the patch (based on its Relative Mass Loss—RML), as well as the distance between the samples and the interrogator. The results show that the MO of the FMM significantly varies with the increase in the RML of the patch. A 10%-RML for the patch is sufficient for detecting a variation of the MO of the FMM, and the relative variations of the MO are strongly dependent on the distance between the FMM and the magnetometer, as well as the patch’s thickness.
Estimation of Grazing Activity of Dairy Goats Using Accelerometers and Global Positioning System
Authors: Chebli Youssef , El Otmani Samira , Hornick Jean-Luc , Bindelle Jérôme , Cabaraux Jean-François , Chentouf Mouad
Published: July 2022

The recent development of advanced electronic sensors to monitor and record animal grazing activity provides a real opportunity to facilitate understanding of their behavioral responses. This study aimed to characterize the grazing activity and protein–energy requirements of grazing dairy goats in a Mediterranean woodland in northern Morocco by combining two sensors, the Global Positioning System (GPS) and three axis accelerometers. An experiment was conducted in a representative woodland with eight dairy goats. Measurements were undertaken during the three main grazing seasons (spring, summer, and autumn) for two consecutive and contrasting years. Grazing activity parameters were assessed using GPS collars and leg position sensors. The results showed that grazing time was higher in spring (57% and 59%) than in summer (39% and 36%) and autumn (41% and 45%), respectively, for the dry and wet years (p < 0.001). During the two studied years, the daily horizontal distance traveled by the goats increased from spring (about 4.5 km) to summer (about 6.5 km) and autumn (about 7.4 km), while greater daily vertical distances were recorded over similar distances during summer–autumn. Several protein–energy intakes that were insufficient to cover the requirements of the grazing goats were recorded, especially in summer. The combination of GPS collars and accelerometers contributed to a better understanding of the grazing activities of dairy goats in the studied Mediterranean woodland. These findings provide useful data on the protein–energy balances of dairy goats and offer additional information that could be useful for herders and managers to enhance goat-feeding strategies and guarantee high-performance in the semi-extensive traditional goat farming system.
A High-Detection-Efficiency Optoelectronic Device for Trace Cadmium Detection
Authors: Gu Huangling , Wang Long
Published: July 2022

Cadmium (Cd) pollution in soil is a serious threat to food security and human health, while, currently, the most widely used detection methods cannot accurately reflect the content of heavy metals in soil. Soil heavy metal detection combined with microelectronic sensors has become an important means of environmental heavy metal pollution prevention and control. X-ray Fluorescence spectrometry (XRF) can capture the excitation spectrum of metal elements, which is often used to detect Cd (II). However, due to the lack of high-performance optoelectronic devices, the analysis accuracy of the system cannot meet the requirements. Therefore, this study proposes a high-detection-efficiency photodiode (HDEPD) which can effectively improve the detection accuracy of the analyzer. The HDEPD is manufactured based on a 0.18 μm standard complementary metal-oxide-semiconductor (CMOS) process. The volt-ampere curve, spectral response and noise characteristics of the device are obtained by constructing a test circuit combined with a spectral detection system. The test results show that the threshold voltage of HDEPD is 12.15 V. When the excess bias voltage increases from 1 V to 3 V, the spectral response peak of the device appears at 500 nm, and the photon detection probability (PDP) increases from 41.7% to 52.8%. The dark count rate (DCR) is 31.9 Hz/μm2 at a 3 V excess bias voltage. Since the excitation spectrum peak of Cd (II) is between 500 nm and 600 nm, the wavelength response range of HDEPD fully meets the detection requirements of Cd (II).
Dual-Band CPW Graphene Antenna for Smart Cities and IoT Applications
Authors: Morales-Centla Nathaniel , Torrealba-Melendez Richard , Tamariz-Flores Edna Iliana , López-López Mario , Arriaga-Arriaga Cesar Augusto , Munoz-Pacheco Jesus M. , Gonzalez-Diaz Victor R.
Published: July 2022

In this paper, a dual-band graphene coplanar waveguide antenna is designed for smart cities and internet of things applications. A graphene film is chosen as the conductive material for the radiation patches and ground plane with a thickness of 240 μm and an electric conductivity of 3.5 × 105 S/m. The dielectric is glass with a dielectric permittivity of 6 and a thickness of 2 mm. The implementation of the antenna on glass permits the integration of the antenna in smart cities and IoT applications. This antenna is based on two trapezoidal patches that generate the dual-band behavior. The overall dimensions of the antenna are 30 mm × 30 mm × 2 mm. The reflection coefficient, gain, and radiation patterns were measured and compared with the simulations. The antenna covers two frequency bands; the lower band covers the 2.45 GHz ISM band, and the upper band range covers from 4 to 7 GHz.
Dual Band MEMS Directional Acoustic Sensor for Near Resonance Operation
Authors: Alves Fabio , Rabelo Renato , Karunasiri Gamani
Published: July 2022

In this paper, we report on the design and characterization of a microelectromechanical systems (MEMS) directional sensor inspired by the tympana configuration of the parasitic fly Ormia ochracea. The sensor is meant to be operated at resonance and act as a natural filter for the undesirable frequency bands. By means of breaking the symmetry of a pair of coupled bridged membranes, two independent bending vibrational modes can be excited. The electronic output, obtained by the transduction of the vibration to differential capacitance and then voltage through charge amplifiers, can be manipulated to tailor the frequency response of the sensor. Four different frequency characteristics were demonstrated. The sensor exhibits, at resonance, mechanical sensitivity around 6 μm/Pa and electrical sensitivity around 13 V/Pa. The noise was thoroughly characterized, and it was found that the sensor die, rather than the fundamental vibration, induces the predominant part of the noise. The computed average signal-to-noise (SNR) ratio in the pass band is about 91 dB. This result, in combination with an accurate dipole-like directional response, indicates that this type of directional sensor can be designed to exhibit high SNR and selectable frequency responses demanded by different applications.
An Algorithm for Task Allocation and Planning for a Heterogeneous Multi-Robot System to Minimize the Last Task Completion Time
Authors: Patil Abhishek , Bae Jungyun , Park Myoungkuk
Published: July 2022

This paper proposes an algorithm that provides operational strategies for multiple heterogeneous mobile robot systems utilized in many real-world applications, such as deliveries, surveillance, search and rescue, monitoring, and transportation. Specifically, the authors focus on developing an algorithm that solves a min–max multiple depot heterogeneous asymmetric traveling salesperson problem (MDHATSP). The algorithm is designed based on a primal–dual technique to operate given multiple heterogeneous robots located at distinctive depots by finding a tour for each robot such that all the given targets are visited by at least one robot while minimizing the last task completion time. Building on existing work, the newly developed algorithm can solve more generalized problems, including asymmetric cost problems with a min–max objective. Though producing optimal solutions requires high computational loads, the authors aim to find reasonable sub-optimal solutions within a short computation time. The algorithm was repeatedly tested in a simulation with varying problem sizes to verify its effectiveness. The computational results show that the algorithm can produce reliable solutions to apply in real-time operations within a reasonable time.
Self-Sovereign Identity: A Systematic Review, Mapping and Taxonomy
Authors: Schardong Frederico , Custódio Ricardo
Published: July 2022

Self-Sovereign Identity (SSI) is an identity model centered on the user. The user maintains and controls their data in this model. When a service provider requests data from the user, the user sends it directly to the service provider, bypassing third-party intermediaries. Thus, SSI reduces identity providers’ involvement in the identification, authentication, and authorization, thereby increasing user privacy. Additionally, users can share portions of their personal information with service providers, significantly improving user privacy. This identity model has drawn the attention of researchers and organizations worldwide, resulting in an increase in both scientific and non-scientific literature on the subject. This study conducts a comprehensive and rigorous systematic review of the literature and a systematic mapping of theoretical and practical advances in SSI. We identified and analyzed evidence from reviewed materials to address four research questions, resulting in a novel SSI taxonomy used to categorize and review publications. Additionally, open challenges are discussed along with recommendations for future work.
High-Speed Path Probing Method for Large-Scale Network
Authors: Luo Zhihao , Liu Jingju , Yang Guozheng , Zhang Yongheng , Hang Zijun
Published: July 2022

In large-scale network topology discovery, due to the complex network structure and dynamic change characteristics, it is always the focus of network topology measurement to obtain as many network paths as possible in a short time. In this paper, we propose a large-scale network path probing approach in order to solve the problems of low probing efficiency and high probing redundancy commonly found in current research. By improving the packet delivery order and the update strategy of time-to-live field values, we redesigned and implemented an efficient large-scale network path probing tool. The experimental results show that the method-derived tool can complete path probing for a sample of 12 million/24 network address segments worldwide within 1 hour, which greatly improves the efficiency of network path probing. Meanwhile, compared to existing methods, the proposed method can reduce the number of packets sent by about 10% with the same number of network addresses found, which effectively reduces probing redundancy and alleviates the network load.
A Rolling Bearing Fault Diagnosis Based on Conditional Depth Convolution Countermeasure Generation Networks under Small Samples
Authors: Peng Cheng , Zhang Shuting , Li Changyun
Published: July 2022

Aiming at the problems of low fault diagnosis accuracy caused by insufficient samples and unbalanced data sample distribution in bearing fault diagnosis, this paper proposes a fault diagnosis method for rolling bearings referencing conditional deep convolution adversarial generative networks (C−DCGAN) for efficient data augmentation. Firstly, the concept of conditional constraints is used to guide and improve the sample generation process of the original generative adversarial network, and specific constraints are added to the data generation model to perform a balanced expansion of muti-category fault data for small sample data sets. Secondly, aiming at the phenomena of training instability, gradient disappearance and gradient explosion in the imbalanced sample set, it is proposed to optimize the structure of the generative network by using the structure of self-defined skip connections and spectral normalization, while using the Wasserstein distance with penalty term instead of cross entropy. The function is used as the loss function of the generative adversarial network to improve the stable feature extraction ability of the generative network and the effect of the training process; in this way, simulation sample data with only a small variation from the real data distribution can be generated. Finally, the complete fault data set (after mixing the original data with sufficient fault category and sample number) and the generated data are input into the one-dimensional convolution neural network for fault diagnosis of rolling bearing. The experiment’s results show that the diagnosis method in this paper can improve the fault classification effect of rolling bearings by generating balanced and sufficient sample data.
IoT and Satellite Sensor Data Integration for Assessment of Environmental Variables: A Case Study on NO2
Authors: Cukjati Jernej , Mongus Domen , Žalik Krista Rizman , Žalik Borut
Published: July 2022

This paper introduces a novel approach to increase the spatiotemporal resolution of an arbitrary environmental variable. This is achieved by utilizing machine learning algorithms to construct a satellite-like image at any given time moment, based on the measurements from IoT sensors. The target variables are calculated by an ensemble of regression models. The observed area is gridded, and partitioned into Voronoi cells based on the IoT sensors, whose measurements are available at the considered time. The pixels in each cell have a separate regression model, and take into account the measurements of the central and neighboring IoT sensors. The proposed approach was used to assess NO2 data, which were obtained from the Sentinel-5 Precursor satellite and IoT ground sensors. The approach was tested with three different machine learning algorithms: 1-nearest neighbor, linear regression and a feed-forward neural network. The highest accuracy yield was from the prediction models built with the feed-forward neural network, with an RMSE of 15.49 ×10−6 mol/m2.
Millimeter-Wave Radar Localization Using Indoor Multipath Effect
Authors: Hao Zhanjun , Yan Hao , Dang Xiaochao , Ma Zhongyu , Jin Peng , Ke Wenze
Published: July 2022

The positioning of indoor electronic devices is an essential part of human–computer interaction, and the accuracy of positioning affects the level of user experience. Most existing methods for RF-based device localization choose to ignore or remove the impact of multipath effects. However, exploiting the multipath effect caused by the complex indoor environment helps to improve the model’s localization accuracy. In response to this question, this paper proposes a multipath-assisted localization (MAL) model based on millimeter-wave radar to achieve the localization of indoor electronic devices. The model fully considers the help of the multipath effect when describing the characteristics of the reflected signal and precisely locates the target position by using the MAL area formed by the reflected signal. At the same time, for the situation where the radar in the traditional Single-Input Single-Output (SISO) mode cannot obtain the 3D spatial position information of the target, the advantage of the MAL model is that the 3D information of the target can be obtained after the mining process of the multipath effect. Furthermore, based on the original hardware, it can achieve a breakthrough in angular resolution. Experiments show that our proposed MAL model enables the millimeter-wave multipath positioning model to achieve a 3D positioning error within 15 cm.
Women Entrepreneurship and Sustainable Development: Bibliometric Analysis and Emerging Research Trends
Authors: Raman Raghu , Subramaniam Nava , Nair Vinith Kumar , Shivdas Avinash , Achuthan Krishnashree , Nedungadi Prema
Published: July 2022

Women entrepreneurship has attracted the attention of academics and practitioners with a large body of research studies in recent years. Past literature reviews on women entrepreneurship have been criticized for their limited scope, lack of interdisciplinary perspective, and the need for more objective, technology-facilitated analytical methods. Our study provides insights into the development of women entrepreneurship research, including a new analysis through the lens of sustainable development and the impact of the COVID-19 pandemic. Bibliometric indicators and a systematic literature review approach are used to analyze literature published between 1991 and 2021 to better map the development of research and related opportunities for enhancing studies on women entrepreneurship. In addition to traditional bibliometric indicators such as publications, citations, etc., we used altmetrics, a new metric to assess the engagement and impact of publications based on social media presence. The Dimensions database has been used to assemble and arrange 3157 publications on women entrepreneurship, of which 843 publications are directly aligned with the Sustainable Development Goals (SDG) and 80 publications related to COVID-19. Our findings indicate that the top three SDG of interest to researchers are: SDG 8, decent work and economic growth; SDG 10, reducing inequalities; and SDG 5, gender equality. Within each SDG, we find concentrated studies on themes relating to the socio-political and small-medium enterprises, including family business management and gender biases, and their implications for sustainable development. Further, studies on the impact of COVID-19 reveal a significant bias towards women’s empowerment in ICT, digitization, and e-commerce while exposing the need for gender-moderated policies and governmental interventions. We offer suggestions for future studies on enabling and measuring the contributions of women’s entrepreneurship to sustainable development, including capital investments and the long-term impacts of the pandemic on women-led enterprises.