bluuebunny/crossref_metadata_2025 huggingface dataset:
Water Exchange Due to Wind and Waves in a Monsoon Prevailing Tropical Atoll
Authors: Chen Shi-Ming
Published: January 2023

Physical forcings affect water exchange in coral reef atolls. Characteristics of the consequent water exchange depend on the atoll morphology and the local atmospheric and hydrographic conditions. The pattern of water exchange at the Dongsha atoll under the influences of tides, wind, and waves was investigated by conducting realistic modeling and numerical experiments. The analyses suggest that the southwestern wind could enhance the inflow transports at the southern reef flat and the outflow transports at the northern reef flat/north channel. The northeastern wind induces an inversed pattern. Unlike the wind, the waves always strengthen the inflow transports at the reef flat, and the locations of strengthened transports depend on the incident directions of the waves. Wind and waves induce shorter hydrodynamic time scales than tides, suggesting more vigorous water exchange during high wind and waves. The directions of wind and waves significantly affect the spatial distributions of the residence time and the age. This implies that the hydrodynamic processes in the Dongsha Atoll would have significant seasonal variability. This study presents different circulation patterns in an atoll system influenced by calm weather and strong wind/waves.
SNARE Protein AoSec22 Orchestrates Mycelial Growth, Vacuole Assembly, Trap Formation, Stress Response, and Secondary Metabolism in Arthrobotrys oligospora
Authors: Zhu Yingmei , Zhou Duanxu , Bai Na , Liu Qianqian , Zhao Na , Yang Jinkui
Published: January 2023

Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) facilitate intracellular vesicle trafficking and membrane fusion in eukaryotes and play a vital role in fungal growth, development, and pathogenicity. However, the functions of SNAREs are still largely unknown in nematode-trapping fungi. Arthrobotrys oligospora is a representative species of nematode-trapping fungi that can produce adhesive networks (traps) for nematode predation. In this study, we characterized AoSec22 in A. oligospora, a homolog of the yeast SNARE protein Sec22. Deletion of Aosec22 resulted in remarkable reductions in mycelial growth, the number of nuclei, conidia yield, and trap formation, especially for traps that failed to develop mature three-dimensional networks. Further, absence of Aosec22 impaired fatty acid utilization, autophagy, and stress tolerance; in addition, the vacuoles became small and fragmented in the hyphal cells of the ∆Aosec22 mutant, and large vacuoles failed to form. The reduced sporulation capacity correlated with the transcriptional repression of several sporulation-related genes, and the impaired accumulation of lipid droplets is in line with the transcriptional repression of several genes involved in fatty acid oxidation. Moreover, absence of Aosec22 remarkably impaired secondary metabolism, resulting in 4717 and 1230 compounds upregulated and downregulated in the ∆Aosec22 mutant, respectively. Collectively, our data highlighted that the SNARE protein AoSec22 plays a pleiotropic role in mycelial growth and development, vacuole assembly, lipid metabolism, stress response, and secondary metabolism; in particular, it is required for the proper development of traps in A. oligospora.
Stroke Risk in Young Women with Primary Dysmenorrhea: A Propensity-Score-Matched Retrospective Cohort Study
Authors: Yeh Chung-Hsin , Sung Fung-Chang , Muo Chih-Hsin , Yen Pao-Sheng , Hsu Chung Y.
Published: January 2023

Background: Studies on strokes associated with dysmenorrhea are limited. We conducted a propensity-score-matched retrospective cohort study to assess the risk of stroke in women with primary dysmenorrhea (PD). Methods: From the claims data of one million people in Taiwan’s insurance program, we identified 18,783 women aged 15–40 years, newly diagnosed with PD in 2000–2010, without a history of stroke. We randomly selected a comparison cohort without stroke history and dysmenorrhea, with the same sample size matched by age, index date, and propensity score. We began a follow-up with individuals one year after cohort entry to the end of 2013 to capture stroke events. Results: The two study cohorts were well-matched for age and comorbidities, with 54% of women aged 15–24. Stroke incidence was 1.5-fold higher in the PD cohort than in the comparison cohort (6.05 vs. 4.01 per 10,000 person-years, or 99 vs. 65 cases), with an adjusted hazard ratio (aHR) of 1.51 (95%CI 1.11–2.06) after adjustment for matched pairs. Nearly 70% of strokes were ischemic strokes, which occurred 1.6 times more frequently in the PD cohort than in the comparison cohort (4.40 vs. 2.71 per 10,000 person-years, or 72 vs. 44 cases), aHR = 1.61 (95% CI 1.11–2.33), after adjustment for matched pairs. The incidence of hemorrhagic stroke was also higher in the PD cohort than in the comparison cohort (1.65 vs. 1.29 per 10,000 person-years, or 27 versus 21 cases), but the difference was not significant. Conclusion: Women of reproductive age with PD are at increased risk for ischemic stroke.
Paradoxes and Tensions in Interorganizational Relationships: A Systematic Literature Review
Authors: Fortes Marcos Vinícius Bitencourt , Agostini Lara , Wegner Douglas , Nosella Anna
Published: January 2023

This paper examines the literature on paradoxes and tensions in interorganizational relationships (IORs) and identifies how such tensions are managed in interorganizational settings. In a systematic literature review, we analyzed 95 papers published between 1997 and 2021 on the subject of paradoxes in IORs. The sample showed a variety of paradoxes occurring in different interorganizational contexts, such as knowledge sharing and protection, short- and long-term orientation, and exploration and exploitation. The diversity of such paradoxes has led to crescent interest in cooperation. Our main results show that contextual factors and management practices influence the balance between paradoxes. Although the particular context of each IOR may be unique in terms of balancing paradoxical elements, we identified a set of “pre-tension practices” and “post-tension practices” which may help avoid the emergence of tensions or reduce their adverse effects. The findings of our systematic literature review have also enabled us to propose future research avenues concerning managing tensions in IORs, for instance, the link between paradoxes and IOR performance.
Multi-Window Identification of Landslide Hazards Based on InSAR Technology and Factors Predisposing to Disasters
Authors: Niu Chong , Yin Wenping , Xue Wei , Sui Yujing , Xun Xingqing , Zhou Xiran , Zhang Sheng , Xue Yong
Published: January 2023

Identification of potential landslide hazards is of great significance for disaster prevention and control. CNN (Convolutional Neural Networks), RNN (Recurrent Neural Networks) and many other deep learning methods have been used to identify landslide hazards. However, most samples are made with a fixed window size, which affects recognition accuracy to some extent. This paper presents a multi-window hidden danger identification CNN method according to the scale of the landslide in the experimental area. Firstly, the hidden danger area is preliminarily screened by InSAR deformation processing technology. Secondly, based on topography, geology, hydrology and human activities, a total of 15 disaster-prone factors are used to create factor datasets for in-depth learning. According to the general scale of the landslide, models with four window sizes of 48 × 48, 32 × 32, 16 × 16 and 8 × 8 are trained, respectively, and several window models with better recognition effect and suitable for the scale of landslide in the experimental area are selected for the accurate identification of landslide hazards. The results show that, among the four windows, 16 × 16 and 8 × 8 windows have the best model recognition effect. Then, according to the scale of the landslide, these optimal windows are pertinently selected, and the precision, recall rate and F-measure of the multi-window deep learning model are improved (82.86%, 78.75%, 80.75%). The research results prove that the multi-window identification method of landslide hazards combining InSAR technology and factors predisposing to disasters is effective, which can play an important role in regional disaster identification and enhance the scientific and technological support ability of geological disaster prevention and mitigation.
Spatial Dynamics of the Shore Coverage within the Zone of Influence of the Chambo River, Central Ecuador
Authors: Echeverría-Puertas Julie , Echeverría Magdy , Cargua Franklin , Toulkeridis Theofilos
Published: January 2023

The predominant aim of the current study was to evaluate the spatial dynamics of the riparian coverage of the area of influence of the Chambo River in the area of the river’s source (middle-high basin), between 2500 and 3000 m.a.s.l. For its execution, Landsat 7 images from the year 2000, RapidEye from the year 2009, and Spot 6 from the year 2019 were used in the time range of 2000–2009 and 2009–2019. These were subjected to supervised classification by applying the maximum likelihood algorithm, identifying five classes of soil cover, being pasture, crops, soil-remnants of paramo, forest, and anthropic. The classification results were validated by calculating the precision measures and the kappa index. With the use of cross-tabulation matrices, the gains, losses, and persistence in the two periods studied were identified. There, it was determined that, in the first study period, the soil cover-paramo remnants presented the highest percentage of loss (26.70%), the crop cover the highest percentage of gain (28.91%), and in the second period, the crop class presented the highest percentages of losses (18.94%) and gains (17.29%). The cartographic projection of the area for the year 2030 predicts that the areas anthropic category will increase by 1.27%, that of forest will decrease by 1.19%, that of soil-remnants of paramo will gain 0.79%, and crop and pasture cover will decrease by 0.45% and 0.43%, respectively. The results obtained allow for the transitions between coverages to be attributed to population growth, afforestation, reforestation, deforestation and agricultural activities, volcanic eruptions, land colonization, and expansion of agricultural activity. Complementary studies are recommended that involve livelihoods and water quality, which facilitate the identification of vulnerable areas to propose adaptation, prevention, and/or restoration measures.
Biofilm Lifestyle in Recurrent Urinary Tract Infections
Authors: Lila Amr S. Abu , Rajab Azza A. H. , Abdallah Marwa H. , Rizvi Syed Mohd Danish , Moin Afrasim , Khafagy El-Sayed , Tabrez Shams , Hegazy Wael A. H.
Published: January 2023

Urinary tract infections (UTIs) represent one of the most common infections that are frequently encountered in health care facilities. One of the main mechanisms used by bacteria that allows them to survive hostile environments is biofilm formation. Biofilms are closed bacterial communities that offer protection and safe hiding, allowing bacteria to evade host defenses and hide from the reach of antibiotics. Inside biofilm communities, bacteria show an increased rate of horizontal gene transfer and exchange of resistance and virulence genes. Additionally, bacterial communication within the biofilm allows them to orchestrate the expression of virulence genes, which further cements the infestation and increases the invasiveness of the infection. These facts stress the necessity of continuously updating our information and understanding of the etiology, pathogenesis, and eradication methods of this growing public health concern. This review seeks to understand the role of biofilm formation in recurrent urinary tact infections by outlining the mechanisms underlying biofilm formation in different uropathogens, in addition to shedding light on some biofilm eradication strategies.
Parasitism Shifts the Effects of Native Soil Microbes on the Growth of the Invasive Plant Alternanthera philoxeroides
Authors: Cai Chaonan , Zhao Yingying , Yuan Yongge , Li Junmin
Published: January 2023

Soil microbes play an important role in plant invasion, and parasitic plants regulate the growth of invasive plants. However, the mechanisms by which parasitic plants regulate the effects of soil microbes on invasive plants have not been investigated. Here, we used the invasive plant Alternanthera philoxeroides and the holoparasitic plant Cuscuta grovonii to test whether and how C. grovonii parasitism shifts the effect of native soil microbes on the growth of A. philoxeroides. In a factorial setup, A. philoxeroides was grown in pots with the presence versus absence of parasitism and the presence versus absence of native soil microbes. The findings showed that native soil microbes increased the biomass and clonal growth of A. philoxeroides only in the absence of a parasite, whereas parasitism decreased the biomass and clonal growth of A. philoxeroides only in the presence of soil microbes. In addition, the presence of soil microbes increased the deleterious effects of the parasite on A. philoxeroides. These results indicate that parasitism can shift the effects of native soil microbes on the growth of the invasive plant A. philoxeroides. Our results enrich the understanding of the mechanisms underlying the success of plant invasion.
Gut Microbiome Composition in Patients with Chronic Urticaria: A Review of Current Evidence and Data
Authors: Krišto Mirela , Lugović-Mihić Liborija , Muñoz Melba , Rupnik Maja , Mahnic Aleksander , Ozretić Petar , Jaganjac Morana , Ćesić Diana , Kuna Matea
Published: January 2023

Recent studies have linked gut microorganism composition and chronic urticaria (CU); however, the underlying mechanisms responsible for this connection are unknown. Since the human immune system is in homeostasis with microbiota, and the composition of the microbiome regulates the development and function of the immune system, it is likely that an alteration of microbiota components (a dysbiosis) could influence the course of chronic spontaneous urticaria (CSU), including disease severity, patient quality of life and treatment outcome. To date, several studies have identified changes in the gut microbiota composition of patients with CSU, though only a few have exhibited metabolic abnormalities associated with gut dysbiosis. The studies on CSU patients predominantly showed that the relative abundance of beneficial bacteria was decreased (Firmicutes and Bacteroides), while that of opportunistic bacteria was increased (Enterobacteria and Proteobacteria). In addition, serum metabolome analysis revealed that gut microbiota-associated alterations in unsaturated fatty acids and the butanoate metabolism pathway may play a role in CSU. These findings are potentially associated with inflammation mediated by the imbalance of Th1/Th2/Th17 cytokines, which might contribute to CSU pathogenesis. Further research in this field could improve clinical, diagnostic, and therapeutic approaches to patients with CSU. By applying new knowledge on gut microbial communities and metabolomics, future CSU therapies could modify the microbiota composition using agents such as probiotics or other similar agents, which, in combination with current standard therapies, could hopefully lead to a reduction in symptoms and an improved quality of life for CSU patients.
Abundance and Dynamics of Small Mammals in New Zealand: Sequential Invasions into an Island Ecosystem Like No Other
Authors: King Carolyn
Published: January 2023

New Zealand had no people or four-footed mammals of any size until it was colonised by Polynesian voyagers and Pacific rats in c. 1280 AD. Between 1769 and 1920 AD, Europeans brought three more species of commensal rats and mice, and three predatory mustelids, plus rabbits, house cats hedgehogs and Australian brushtail possums. All have in turn invaded the whole country and many offshore islands in huge abundance, at least initially. Three species are now reduced to remnant populations, but the other eight remain widely distributed. They comprise an artificial but interacting and fully functional bottom-up predator-prey system, responding at all levels to interspecific competition, habitat quality and periodic resource pulsing.
Effects of Clinical Use on the Mechanical Properties of Bio-Active® (BA) and TriTanium® (TR) Multiforce Nickel-Titanium Orthodontic Archwires
Authors: Stoyanova-Ivanova Angelina , Georgieva Mirela , Petrov Valeri , Andreeva Laura , Petkov Alexander , Georgiev Velizar
Published: January 2023

Multiforce orthodontic archwires are thermodynamic wires made of nickel-titanium alloy (Ni-Ti). They release biologically tolerable forces along their length, progressively increasing from front to back. The frontal archwires’ segments distribute the weakest force: the premolar, the greater, and the molar, the greatest. The aim of the present study was to determine the influence of clinical use on the mechanical properties of two types of multi-force orthodontic archwires (TriTanium®, American orthodontics; Bio-Active®, GC) with dimensions of 0.016 × 0.022 inches for periods of up to 8 weeks and over 8 weeks of in-vivo use. A three-point bending test was used, and the data gained is statistically analyzed through a multi-variance comparison Mann-Whitney test. We found that after uses of up to 8 weeks and over 8 weeks, the shape memory effect and superelasticity are preserved, as well as the tendency for differential force release along the length of the archwires is kept.
A Bi-Modulus Material Model for Bending Test on NHL3.5 Lime Mortar
Authors: Grazzini Rebecca , Misseri Giulia , Rovero Luisa
Published: January 2023

The research provides an innovative contribution to the interpretation of three-point and four-point bending tests on mortars by employing a bi-modulus material model, which assumes an asymmetric constitutive law, i.e., different elastic moduli in tension and in compression. To this aim, Euler–Bernoulli and Timoshenko bi-modulus beam models are defined, and the related displacement fields are reported for three-point loading, and provided for the first time for the four-point bending layout. A wide experimental campaign, including uni-axial tensile and compressive tests, three-point and four-point bending tests, and on notched specimens three-point tests for mode-I fracture energy, has been carried out on lime mortar specimens exploiting traditional contact (CE-DT) and contactless (DIC) measurement systems. Experimental results provided the values of tensile and compressive mechanical characteristics, which are employed to validate estimations of the analytical model. The tension-to-compression moduli ratio experimentally observed is on average 0.52. Experimental outcomes of the DIC analysis proved the bi-modulus behaviour during the four-point bending tests showing visible shifting of the neutral axis. The bi-modulus analytical model provides closer results to the experimental ones for the slender specimens subjected to four-point bending.
Preparation of CaCO3/Al(OH)3 Composites via Heterogeneous Nucleation
Authors: Xu Yan , Bao Weijun , Ding Hao , Qu Jingkui
Published: January 2023

As one of the most widely used inorganic fine powder fillers, calcium carbonate is cheap. However, considering its poor light transmittance, it is not suitable to be added to resin matrix composites that require high light transmittance. Aluminum hydroxide has good light transmission and flame retardancy, but it is more expensive than calcium carbonate. CaCO3/Al(OH)3 composites with a core-shell structure that showed a trend toward the performance of aluminum hydroxide not only improved the surface properties of CaCO3, but also increased the added value of CaCO3. In the present paper, CaCO3/Al(OH)3 composites were successfully prepared in sodium aluminate solution via heterogeneous nucleation. Four types of calcium sources, including calcite-type precipitated calcium carbonate, vaterite-type precipitated calcium carbonate, ground calcium carbonate with two different particle sizes as the precursors and supersaturated sodium aluminate solution as the substrate, have been deeply investigated in terms of their influence on the preparation of CaCO3/Al(OH)3 composites. Results showed that the calcium carbonate precursor greatly affected the formation of CaCO3/Al(OH)3 composites. Both the precipitated calcium carbonate and the small particle ground calcium carbonate are likely to undergo anti-causticization and a complexation reaction with it to generate 3CaO·Al2O3·6H2O and 3CaO·Al2O3·CaCO3·11H2O, which go against the coating of calcium carbonate with aluminum hydroxide. Within the experimental range, the use of ground calcium carbonate with a particle size of 400–500 mesh is more suitable as a precursor for the preparation of core-shell CaCO3/Al(OH)3 composites.
Deformation and Cracking Resistance of MgO-Incorporated Cementitious Material: A Review
Authors: Lu Jinyuan , Feng Pan , Li Hua , Tian Qian
Published: January 2023

In China, MgO-based expansive agent (MEA) has been used for concrete shrinkage compensation and cracking control for over 40 years. The expansive behavior of MEA in cementitious materials could be manipulated to some extent by adjusting the calcination process of MEA and influenced by the restraint condition of the matrix. It is key to investigate the factors related to deformation and cracking resistance so that the desired performance of MEA in certain concrete structures could be achieved. This paper reviews the influence of key parameters such as hydration reactivity, dosage, and calcination conditions of MEA, the water-to-binder ratio, supplementary cementitious material, aggregates, and curing conditions on the deformation and cracking resistivity of cement paste, mortar, and concrete with an MEA addition. The numerical simulation methods and deformation prediction models are then summarized and analyzed for more reasonable estimations.
Producing Soft Magnetic Composites by Spark Plasma Sintering of Pseudo Core–Shell Ni–Fe Alloy@Mn0.5Zn0.5Fe2O4 Powders
Authors: Cotojman Loredana , Marinca Traian Florin , Popa Florin , Neamțu Bogdan Viorel , Prică Virgiliu Călin , Chicinaș Ionel
Published: January 2023

Soft magnetic composite (SMC) cores have been obtained by Spark Plasma Sintering (SPS) using pseudo core–shell powders. Pseudo core–shell powders are formed by a core of soft magnetic particle (nanocrystalline permalloy or supermalloy) surrounded by a thin layer (shell) of nanosized soft ferrite (Mn0.5Zn0.5Fe2O4). Three compositions of pseudo core–shell powders were prepared, with 1, 2 and 3 wt.% of manganese–zinc mixt ferrite. The pseudo core–shell powders were compacted by SPS at temperatures between 500 and 700 °C, with a holding time ranging from 0 to 10 min. Several techniques have been used for characterization of the samples, both, powders and compacts X-ray diffraction (XRD, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), magnetic hysteresis measurements (DC and AC) and electrical resistivity. The electrical resistivity is in the order of 1 × 10−2 Ωm, 3–4 orders of magnitude higher than supermalloy electrical resistivity. The SPS at lower temperatures (500 °C) conserves the initial phases of the composite, but increasing the sintering temperature and/or sintering time produces a solid-state reaction between the alloy and ferrite phases, with negative consequence on the magnetic properties of the compacts. The initial relative permeability is around 40 and remains constant until to 2000 Hz. The power losses are lower than 2 W/kg until to 2000 Hz.
Nondestructive Examination of Carbon Fiber-Reinforced Composites Using the Eddy Current Method
Authors: Łukaszuk Ryszard , Chady Tomasz
Published: January 2023

This paper presents the results of experiments using the eddy current system designated for nondestructive inspection of carbon fiber-reinforced composites. For this purpose, the eddy current testing system with a differential transducer with two pairs of excitation coils oriented perpendicularly and a central pick-up coil was utilized. The transducer measures the magnetic flux difference flowing through the pick-up coil. The transducer of this design has already been successfully utilized to inspect isotropic metal structures. However, the anisotropy of the composites and their lower conductivity compared to metal components made the transducer parameters adjustment essential. Thus, various excitation frequencies were considered and investigated. The system was evaluated using a sample made of orthogonally woven carbon fiber-reinforced composites with two artificial flaws (the notches with a maximum relative depth of 30% and 70%, respectively, thickness of 0.4 mm, and a length of 5 mm). The main goal was to find a configuration suitable for detecting hidden flaws in such materials.
Influence of Bonding Area on Dynamic Failure Behavior of Notched Reinforced Concrete Beams
Authors: Song Min , Wang Zhiyong , Zhang Jie , Wang Zhihua
Published: January 2023

To study the effect of the bonding area on the dynamic failure process of a reinforced concrete beam with the same reinforcement ratio, the experimental and numerical researches on the impact response of notched reinforced concrete beams in the low-velocity regime (≤2.5 m/s) are presented. The tests are carried out with a drop hammer impact testing machine and then the structural responses under different impact velocities are analyzed. Additionally, the dynamic three-point bending simulation for specimens with different bonding areas, but the same reinforcement ratio is conducted. In this numerical model, the parameters of a cohesive model verified from a steel bar pullout test are applied to the bonding layer to simulate the bond-slip behavior of steel bars. Then, the energy dissipation for each component (e.g., concrete, a steel bar, and the bonding layer) are compared and discussed. The dynamic experimental results suggest that the energy absorbed during the impact process increases with the growth of the impact velocity, while the effect of the impact velocity on the reaction force can be ignored. The numerical results indicate that the failure pattern changes from a bending failure to shear failure with the increase in the bonding area and impact velocity. With the growth of the bonding area, the steel bars reach the plastic stage easily and the internal energy dissipation of the bonding layer decreases, which protects the bonding effect between the steel bar and concrete effectively.
Recycling and Processing of Waste Materials
Authors: Wiśniewska Paulina , Hejna Aleksander , Saeb Mohammad Reza
Published: January 2023

Just a few days ago, the world population, as expected, surpassed 8 billion [...]
Residual Compressive Strength Prediction Model for Concrete Subject to High Temperatures Using Ultrasonic Pulse Velocity
Authors: Kim Wonchang , Choi Hyeonggil , Lee Taegyu
Published: January 2023

This study measured and analyzed the mechanical properties of normal aggregate concrete (NC) and lightweight aggregate concrete (LC) subjected to high temperatures. The target temperature was set to 100, 200, 300, 500, and 700 °C, and W/C was set to 0.41, 0.33 and 0.28 to evaluate high temperature properties at various intensities. Measurement parameters included mass loss, compressive strength, ultrasonic pulse velocity (UPV), and elastic modulus. We compared the residual mechanical properties between the target and preheating temperatures (20 °C) and then analyzed the correlation between UPV and compressive strength. According to the research findings, after exposure to high temperatures, LC demonstrated a higher mass reduction rate than NC at all levels and exhibited higher residual mechanical properties. The results of analyzing the correlation between compressive strength and UPV for concrete subjected high temperatures were very different from the compressive strength prediction equation previous proposed at room temperature, and the error range of the residual strength prediction equation considering W/C was reduced.
Numerical Study on Effect of Contact and Interfacial Resistance on Thermal Conductivity of Dispersed Composites
Authors: Kondo Atsushi , Matsuura Hiroshi , Ito Yoshiharu
Published: January 2023

A series of finite element analyses were conducted to clarify the effect of contact and interfacial resistance between constituents on effective thermal conductivities of dispersed composites. Equally dispersed fillers in FCC (face-centered cubic) and BCC (body-centered cubic) material systems were extracted from cyclic microstructures as unit cell models. In addition to spherical fillers, a polyhedron called the Wigner–Seitz cell that can realize a fully packed microstructure was chosen as the shape of the filler to investigate the effect of contact between the high volumetric fraction of fillers. The effective thermal conductivities of the resulting composites were calculated based on the FEA results and compared to the theoretical results for various volume fractions of the fillers including the maximum packing fraction. The following conclusions were obtained from the present study: 1. The effect of the contact depending on the shape and configuration of the fillers has more of a significant influence on the effective thermal conductivity than the influence of the increase in the volume fraction of the fillers. 2. When the contact occurred, the effective thermal conductivity became more than double that without contact. 3. Interfacial thermal resistance must be less than the order of 10−4 m2 K/W to obtain improvement in the effective thermal conductivity by compounding the fillers.
A Nitrogen-Rich DOPO-Based Derivate for Increasing Fire Resistance of Epoxy Resin with Comparable Transparency
Authors: Lu Jiayi , Cai Boyu , Xu Wendi , Wang Luze , Luo Zhonglin , Wang Biaobing
Published: January 2023

To endow synergistically epoxy resin (EP) with excellent fire resistance and high optical transparency, a nitrogen-rich DOPO-based derivate (named as FATP) was synthesized and incorporated into EP. It showed that the incorporation of the FATP reduced the fire hazard of the EP, as demonstrated by the fact that the EP/4% FATP blends gained a UL-94 V-0 rating and an LOI value of 35%, with the lowest values of the THR (86.7 MJ/m2), the PHRR (1059.3 kW/m2), and the TSP (89.6 MJ/m2). The presence of the FATP also reduced the thermal stability and the crosslinking density whilst improving the curing reaction and the storage modulus of the EP/FATP blends. The TG-FTIR spectra showed that •HPO/•PO free radicals and some nonflammable gases (HN3 and NH3) were produced during the pyrolysis, and the characterization (SEM, Raman spectroscopy, and XPS) of char residues confirmed that the FATP facilitated the formation of continuous and compact carbon layers of greater graphitization degree. It was thus concluded that the FATP played the flame-retardant roles in both the gas and condensed phases. Furthermore, the FREPs kept almost identical transparency as the pristine EP, and mechanical properties were also slightly enhanced. The FREPs presented in this work show promising applications in the fields of advanced optical technology.
Experimental Analysis of Channel Steel Member under Tension Load with Damage in the Unconnected Legs
Authors: Sayed Ahmed M. , Alanazi Hani , Abadel Aref A. , Alharbi Yousef R. , Shamsudin Mohd F.
Published: January 2023

Damage occurring to steel element structures is highly possible due to tearing ruptures, corrosion, or the adoption of sudden loads. The damage has a great effect on their capacity to bear load and the corresponding elongation, as well as the distribution of the stresses in the cross-section of the element. Therefore, in the present research, experimental tests were carried out on 15 specimens of channel steel elements with different damage ratios in the unconnected legs and at different locations along the element’s length. Through the test, the load and the corresponding elongation values were obtained for the control and damaged specimens. From the study of the different variables, it was demonstrated that the damage location does not significantly affect the load capacity, with a maximum difference of 1.9%. With the presence of the damage in only one leg at a ratio of less than or equal to 40%, the prediction of the value of the loss in the load is within the safe limit. However, if this ratio increases, there is a defect in calculating the loss in the load as it is greater than the effect of the damage. If there is any damage in the two legs of the channel together, the prediction of the loss of load is within the safe limit, where the loss is less than the effect of the damage ratio. We propose a model that can predict the capacitance of the axial load of steel channel elements through identifying the ratio of damage in the unconnected leg.
Tensile Deformation Behaviors of Pure Ti with Different Grain Sizes under Wide-Range of Strain Rate
Authors: Deguchi Misaki , Yamasaki Shigeto , Mitsuhara Masatoshi , Nakashima Hideharu , Tsukamoto Genki , Kunieda Tomonori
Published: January 2023

In this study, pure titanium equivalent to Grade 1 was subjected to tensile tests at strain rates ranging from 10−6 to 100 s−1 to investigate the relationship between its mechanical properties and its twinning and slip. Deformation properties and microstructures of samples having average grain sizes of 210 μm (Ti-210), 30 μm (Ti-30), and 5 μm (Ti-5) were evaluated. With increasing strain rates, the 0.2% proof stress and ultimate tensile strength increased for all samples; the fracture strain increased for Ti-210, decreased for Ti-5, and changed negligibly for Ti-30. Comparing high (100 s−1) and low (10−6 s−1) strain rates, twinning occurred more frequently in Ti-30 and Ti-210 at high strain rates, but the frequency did not change in Ti-5. The frequency of 1st order pyramidal slip tended to be higher in Ti-30 and Ti-5 at low strain rates. The higher ductility exhibited by Ti-210 at high strain rates was attributed to the high frequency of twinning. In contrast, the higher ductility of Ti-5 at low strain rates was attributed to the activity of the 1st order pyramidal slip.
A Fault Tolerance Method for Multiple Current Sensor Offset Faults in Grid-Connected Inverters
Authors: Zhang Fan , Jin Guangfeng , Geng Junchao , Wang Tianzhen , Han Jingang , Razik Hubert , Wang Yide
Published: January 2023

Three-phase grid-connected inverters have been widely used in the distributed generation system, and the current sensor has been applied in closed-loop control in inverters. When the current sensor offset faults occurs, partial fault features of multiple current sensors disappear from the closed-loop control grid-connected system, which leads to difficulties for fault diagnostics and fault-tolerant control. This paper proposes a fault tolerance method based on average current compensation mode to eliminate these adverse effects of fault features. The average current compensation mode compensates the average of the three-phase current to the αβ axis current to realize the fault feature reconstruction of the current sensor. The mode does not affect the normal condition of the system. Then, the data-driven method is used for fault diagnosis, and the corresponding fault tolerant control model is selected according to the diagnosis results. Finally, the experimental results show that the proposed strategy has a good fault tolerance control performance and can improve the fault feature discrimination and diagnostic accuracy.
A Blockchain Approach of Model Architecture for Crowdsourcing Design Services under the Context of Social Manufacturing
Authors: Liu Dianting , Liang Dong
Published: January 2023

Crowdsourcing design is generally monitored by the platform. However, the traditional crowdsourcing platforms face problems such as centralization, lack of credibility and vulnerability to single point of failure. Under the context of social manufacturing, how to address these potential issues has both research and substantial value. In this paper, we introduce decentralized blockchain technology for crowdsourcing service systems and propose a method to manage and control the process of crowdsourcing design services. We depict complex crowdsourcing logic by smart contract. The process of crowdsourcing design is not dependent on any third party. It is decentralized, tamper-proof, traceable and protects the privacy of users to a certain extent. We implement this crowdsourcing design system on a specific blockchain test network to experiment and test its functionalities. Experiment results show the feasibility and usability of our crowdsourcing design system. In the future, we will further improve the algorithmic logic of smart contracts so that they can run stably and securely in a complex node network environment.
Detecting Arabic Cyberbullying Tweets Using Machine Learning
Authors: Alduailaj Alanoud Mohammed , Belghith Aymen
Published: January 2023

The advancement of technology has paved the way for a new type of bullying, which often leads to negative stigma in the social setting. Cyberbullying is a cybercrime wherein one individual becomes the target of harassment and hatred. It has recently become more prevalent due to a rise in the usage of social media platforms, and, in some severe situations, it has even led to victims’ suicides. In the literature, several cyberbullying detection methods are proposed, but they are mainly focused on word-based data and user account attributes. Furthermore, most of them are related to the English language. Meanwhile, only a few papers have studied cyberbullying detection in Arabic social media platforms. This paper, therefore, aims to use machine learning in the Arabic language for automatic cyberbullying detection. The proposed mechanism identifies cyberbullying using the Support Vector Machine (SVM) classifier algorithm by using a real dataset obtained from YouTube and Twitter to train and test the classifier. Moreover, we include the Farasa tool to overcome text limitations and improve the detection of bullying attacks.
The Buckling Operator: Inverse Boundary Value Problem
Authors: Ma Yanjun
Published: January 2023

In this paper, we consider a zeroth-order perturbation q(x) of the buckling operator Δ2−κΔ, which can be uniquely determined by measuring the Dirichlet-to-Neumann data on the boundary. We extend the conclusion of the biharmonic operator to the buckling operator, but the Dirichlet-to-Neumann map given in this study is more meaningful and general.
Dispatch for a Continuous-Time Microgrid Based on a Modified Differential Evolution Algorithm
Authors: Zhang Lei , Tang Rui
Published: January 2023

The carbon trading mechanism is proposed to remit global warming and it can be considered in a microgrid. There is a lack of continuous-time methods in a microgrid, so a continuous-time model is proposed and solved by differential evolution (DE) in this work. This research aims to create effective methods to obtain some useful results in a microgrid. Batteries, microturbines, and the exchange with the main grid are considered. Considering carbon trading, the objective function is the sum of a quadratic function and an absolute value function. In addition, a composite electricity price model has been put forward to conclude the common kinds of electricity prices. DE is utilized to solve the constrained optimization problems (COPs) proposed in this paper. A modified DE is raised in this work, which uses multiple mutation and selection strategies. In the case study, the proposed algorithm is compared with the other seven algorithms and the outperforming one is selected to compare two different types of electricity prices. The results show the proposed algorithm performs best. The Wilcoxon Signed Rank Test is also used to verify its significant superiority. The other result is that time-of-use pricing (ToUP) is economic in the off-peak period while inclining block rates (IBRs) are economic in the peak and shoulder periods. The composite electricity price model can be applied in social production and life. In addition, the proposed algorithm puts forward a new variety of DE and enriches the theory of DE.
Numerical Simulation and Structure Optimization of Multilayer Metamaterial Plus-Shaped Solar Absorber Design Based on Graphene and SiO2 Substrate for Renewable Energy Generation
Authors: Alsaif Haitham , Patel Shobhit K. , Ali Naim Ben , Armghan Ammar , Aliqab Khaled
Published: January 2023

Renewable energy is the energy for future generations as it is clean and widely available. The solar absorber is a sustainable energy source that converts solar energy into heat energy. The structural optimization is analyzed to enhance the absorption of the multilayer design. The proposed efficient solar absorber is made of a multilayer plus-shaped resonator supported by a SiO2 substrate with a graphene spacer. The multilayer approach is utilized to enhance the absorption of the overall structure. The absorption of the multilayer solar absorber design is presented with AM 1.5 response observing the amount of energy absorbed from solar radiation. The different structural parameters are optimized to obtain the efficiency plus-shaped absorber design. The results of a different angle of incidence clearly show that the absorber is giving high absorption over a wide-angle range. The design results are also being analyzed with other similar works to show the improvement. The proposed absorber with high efficiency will be a good choice for solar thermal energy conversion applications.
Fetal Growth Restriction and Clinical Parameters of Newborns from HIV-Infected Romanian Women
Authors: Cambrea Simona Claudia , Dumea Elena , Petcu Lucian Cristian , Mihai Cristina Maria , Ghita Constantin , Pazara Loredana , Badiu Diana , Ionescu Costin , Cambrea Mara Andreea , Botnariu Eosefina Gina , Dumitrescu Florentina
Published: January 2023

Background and Objectives: The present study assessed the fetal growth restriction and clinical parameters of both human immunodeficiency virus (HIV)-negative and HIV-positive newborns from HIV-infected mothers in two HIV-acquired immunodeficiency syndrome regional centers (RCs) in Constanta and Craiova, Romania, in order to evaluate the adverse birth-related outcomes. Materials and Methods: These represent a retrospective study conducted between 2008 and 2019, in which 408 pregnant HIV-positive women, 244 from Constanta RC and 164 from Craiova RC, were eligible to participate in the study. Consecutive singleton pregnancies delivered beyond 24 weeks of pregnancy were included. Growth restriction in newborns was defined as the birth weight (BW) being less than the third percentile, or three out of the following: BW < 10th percentile; head circumference (HC) < 10th percentile; birth length (BL) < 10th percentile; prenatal diagnosis of fetal growth restriction; and maternal pregnancy information. Of the 244 newborns delivered in Constanta, RC, 17 were HIV-positive, while in Craiova, RC, of the 164 newborns, 9 were HIV-positive. All HIV-positive women were on combined antiretroviral therapy (cART) during pregnancy, similar to all HIV-positive newborns who received ARTs for the first six weeks. We search for the influence of anthropometrical parameters (i.e., HC, BL, and BW), as well as clinical parameters (i.e., newborn sex and Apgar score) for both HIV-negative and HIV-positive newborns, along with the survival rate of HIV-positive newborns. Results: There were no differences in the sex of the newborns within either group, with more than 50% being boys. Similarly, the Apgar score did not show any statistically significant values between the two groups (i.e., p = 0.544 for HIV-positive newborns vs. p = 0.108 for HIV-negative newborns). Interestingly, our results showed that in Craiova, RC, there was a chance of 2.16 to find an HIV-negative newborn with an HC < 10th percentile and a 2.54 chance to find an HIV-negative newborn with a BL < 10th percentile compared to Constanta, RC, without any significant differences. On the contrary, Constanta, RC, represented a higher risk of death (i.e., 3.049 times, p = 0.0470) for HIV-positive newborns compared to Craiova, RC. Conclusions: Our results support the idea that follow-up of fetal growth restriction should be part of postnatal care in this high-risk population to improve adverse birth-related outcomes.
Disseminated MAI in an HIV Patient-An Unusual Presentation
Authors: Simon Joshni , Lambert Joella , Mosco-Guzman Jose , Dittmer Kaitlyn , Stern-Harbutte Alison , Connelly Weston
Published: January 2023

Patients with Human Immunodeficiency Virus (HIV), and especially Acquired Immunodeficiency Syndrome (AIDS), can present in a multitude of ways with a variety of possible pathologies. This can prove to be a challenge to a clinician. The patient, in this case, was found to have disseminated Mycobacterium-avium-intracellulare (MAI), despite compliance with antiretroviral therapy (ART), who presented with right upper quadrant pain, isolated elevated alkaline phosphatase, and sepsis. Imaging revealed multiple splenic lesions, bilateral psoas abscesses, abdominal lymphadenopathy, and a large right pleural effusion with a mediastinal shift to the left. Psoas abscesses were drained and the cultures grew acid-fast bacilli. The patient was treated with azithromycin, ethambutol and rifabutin. Classically, MAI infections of patients compliant with ART therapy present with localized disease. This case offers a different presentation of MAI despite compliance with ART therapy.
Application of Ferromagnetic Microwires as Temperature Sensors in Measurements of Thermal Conductivity
Authors: Churyukanova Margarita , Stepashkin Andrey , Sarakueva Aida , Mashera Vadim , Grebenshchikov Yury , Odintsov Vladimir , Petrov Valery , Gudoshnikov Sergey
Published: January 2023

A method for the determination of the thermal conductivity of polymer composite materials by using Co-based ferromagnetic microwires is proposed. Microwire segments were integrated into the samples of studied materials during their manufacture and used as current microheaters and resistance thermometers. As a representative material, we used a material based on nitrile butadiene rubber filled with hexagonal boron nitride after its low-temperature carbonization and a significant increase in thermal conductivity. The thermal conductivity values of composite samples determined during experiments varied from 1.0 W/(m·K) to 1.8 W/(m·K) depending on the percentage of boron nitride. The thermal conductivity values obtained are in good agreement with the estimates obtained by the standard laser flash method.