bluuebunny/crossref_metadata_2025 huggingface dataset:
GC–MS/MS Determination of Synthetic Cathinones: 4-Chloromethcathinone, N-Ethyl Pentedrone, and N-Ethyl Hexedrone in Oral Fluid and Sweat of Consumers under Controlled Administration: Pilot Study
Authors: Nuñez-Montero Melani , Lombroni Claudia , Maida Nunzia , Rotolo Maria , Pichini Simona , Papaseit Esther , Hladun Olga , Ventura Mireia , Poyatos Lourdes , Pérez-Mañá Clara , Farré Magí , Marchei Emilia
Published: May 2023

This study presents a validated GC-MS/MS method for the detection and quantification of 4-chloromethcathinone or clephedrone (4-CMC), N-ethyl Pentedrone (NEP), and N-ethyl Hexedrone (NEH, also named HEXEN) in oral fluid and sweat and verifies its feasibility in determining human oral fluid concentrations and pharmacokinetics following the administration of 100 mg of 4-CMC orally and 30 mg of NEP and NEH intranasally. A total of 48 oral fluid and 12 sweat samples were collected from six consumers. After the addition of 5 μL of methylone-d3 and 200 μL of 0.5 M ammonium hydrogen carbonate, an L/L extraction was carried out using ethyl acetate. The samples, dried under a nitrogen flow, were then derivatized with pentafluoropropionic anhydride and dried again. One microliter of the sample reconstituted in 50 μL of ethyl acetate was injected into GC-MS/MS. The method was fully validated according to international guidelines. Our results showed how, in oral fluid, the two cathinones taken intranasally were absorbed very rapidly, within the first hour, when compared with the 4-CMC which reached its maximum concentration peak in the first three hours. We observed that these cathinones were excreted in sweat in an amount equivalent to approximately 0.3% of the administered dose for 4-CMC and NEP. The total NEH excreted in sweat 4 h after administration was approximately 0.2% of the administered dose. Our results provide, for the first time, preliminary information about the disposition of these synthetic cathinones in the consumers’ oral fluid and sweat after controlled administration.
A Molecular Understanding of the Flame Retardant Mechanism of Zinc Stannate/Polypropylene Composites via ReaxFF Simulations
Authors: Li Jun , Zhu Meilin , Geng Chang , Yuan Yingjie , Fu Zewei , Yan Shu , Feng Rou , Wang Yingwu , Zhou Ying , Meng Liangliang , Zhang Hui , Bai Hongcun
Published: May 2023

As an important new flame retardant, zinc stannate (ZS) shows wide application prospects due to its many advantages. However, the flame retardant mechanism of composites made with polymer combined with ZS is still unclear. In particular, there is a lack of molecular level description of the micro-scale flame retardant mechanism. The combustion mechanism through molecular simulation technology has become an important research paradigm in the field of fire, which can provide new insights for the development of new materials. This work studied the flame retardant mechanism of composites consistent with polypropylene (PP) and ZS using reactive force field molecular dynamics (ReaxFF MD) simulations. A new force field incorporating Sn/Zn/C/H/O components for ZS/PP composites combustion reactions was developed. Twenty different ZS/PP composites were analyzed for their combustion reactions at various temperatures. To investigate the flame retarding mechanism of ZS in composites, the evolutions of reactants, products, and reaction intermediates at the molecular scale were collected. It was revealed that the combustion temperature controlled the degree of oxidation by regulating the consumption of molecular oxygen during PP cracking. An increased combustion temperature reduced the oxygen consumption rate and overall oxygen consumption. As the PP component of composites exceeded 56%, oxygen consumption increased. Evolutions for carbon-containing intermediates and the products in combustions of PP/ZS composites were analyzed. The small carbon-based fragments were more likely to be produced for composites with low PP contents at high temperatures. These results are beneficial to design ZS/PP composites as flame retardant materials.
Safe and Efficient Procedures and Training System for Endoscopic Submucosal Dissection
Authors: Kamitani Yu , Nonaka Kouichi , Misumi Yoshitsugu , Isomoto Hajime
Published: May 2023

Recent improvements in endoscopists’ skills and technological advances have allowed endoscopic submucosal dissection (ESD) to become a standard treatment in general hospitals. As this treatment entails a high risk of accidental perforation or hemorrhage, therapeutic procedures and training methods that enable ESD to be conducted more safely and efficiently are constantly being developed. This article reviews the therapeutic procedures and training methods used to improve the safety and efficiency of ESD and describes the ESD training system used in a Japanese university hospital at which the number of ESD procedures has gradually increased in a newly established Department of Digestive Endoscopy. During the establishment of this department, the ESD perforation rate was zero among all procedures, including those conducted by trainees.
Underwater Image Enhancement via Triple-Branch Dense Block and Generative Adversarial Network
Authors: Yang Peng , He Chunhua , Luo Shaojuan , Wang Tao , Wu Heng
Published: May 2023

The complex underwater environment and light scattering effect lead to severe degradation problems in underwater images, such as color distortion, noise interference, and loss of details. However, the degradation problems of underwater images bring a significant challenge to underwater applications. To address the color distortion, noise interference, and loss of detail problems in underwater images, we propose a triple-branch dense block-based generative adversarial network (TDGAN) for the quality enhancement of underwater images. A residual triple-branch dense block is designed in the generator, which improves performance and feature extraction efficiency and retains more image details. A dual-branch discriminator network is also developed, which helps to capture more high-frequency information and guides the generator to use more global content and detailed features. Experimental results show that TDGAN is more competitive than many advanced methods from the perspective of visual perception and quantitative metrics. Many application tests illustrate that TDGAN can significantly improve the accuracy of underwater target detection, and it is also applicable in image segmentation and saliency detection.
Sports Organizations and Their Defensive Mediatization Strategies: The Sports Journalist’s Perspective
Authors: O’Boyle Neil , Gallagher Aaron
Published: May 2023

This article provides empirical evidence of ‘defensive mediatization strategies’ in the field of sport. These are strategies used by actors individually and collectively to control and sometimes avoid media publicity—for example, by refusing requests for media interviews, or in the case of an organization, by making media literacy training available to its staff. In this article, we use the concept of defensive mediatization strategies to identify and illuminate some of the challenges facing professional sports journalists in the postbroadcast era. The article draws on findings from an ongoing study of the relationships between professional sports organizations, athletes, and journalists, but reports only on interviews conducted with experienced sports journalists in Ireland and Britain (n = 16). Our analysis identifies a number of defensive mediatization strategies used by sports organizations, including increased levels of in-house media, differential treatment of journalists, and an increasingly competitive stance towards journalism generally. We also consider a potentially more pernicious strategy: the hiring of professional sports journalists as internal communications advisers—a switching of role positions that might be termed ‘poacher turned gamekeeper’. The article organizes findings according to the three categories of defensive mediatization strategies identified in the extant literature (persistence, shielding, and immunization) and proposes a fourth category, which we label steering.
REAC Neurobiological Modulation as a Precision Medicine Treatment for Fibromyalgia
Authors: Silva Analízia , Barcessat Ana Rita , Gonçalves Rebeca , Landre Cleuton , Brandão Lethícia , Nunes Lucas , Feitosa Hyan , Costa Leonardo , Silva Raquel , de Lima Emanuel , Monteiro Ester Suane , Rinaldi Arianna , Fontani Vania , Rinaldi Salvatore
Published: May 2023

Fibromyalgia syndrome (FS) is a disorder characterized by widespread musculoskeletal pain and psychopathological symptoms, often associated with central pain modulation failure and dysfunctional adaptive responses to environmental stress. The Radio Electric Asymmetric Conveyer (REAC) technology is a neuromodulation technology. The aim of this study was to evaluate the effects of some REAC treatments on psychomotor responses and quality of life in 37 patients with FS. Tests were conducted before and after a single session of Neuro Postural Optimization and after a cycle of 18 sessions of Neuro Psycho Physical Optimization (NPPO), using evaluation of the functional dysmetria (FD) phenomenon, Sitting and Standing (SS), Time Up and Go (TUG) tests for motor evaluation, Fibromyalgia Impact Questionnaire (FIQ) for quality of life. The data were statistically analyzed, and the results showed a statistically significant improvement in motor response and quality of life parameters, including pain, as well as reduced FD measures in all participants. The study concludes that the neurobiological balance established by the REAC therapeutic protocols NPO and NPPO improved the dysfunctional adaptive state caused by environmental and exposomal stress in FS patients, leading to an improvement in psychomotor responses and quality of life. The findings suggest that REAC treatments could be an effective approach for FS patients, reducing the excessive use of analgesic drugs and improving daily activities.
Ophthalmic Manifestations in Fabry Disease: Updated Review
Authors: Gambini Gloria , Scartozzi Luca , Giannuzzi Federico , Carlà Matteo Mario , Boselli Francesco , Caporossi Tomaso , De Vico Umberto , Baldascino Antonio , Rizzo Stanislao
Published: May 2023

Fabry disease (FD) is an X-linked lysosomal storage disorder, causing Gb-3 (globotriaosylceramide) buildup in cellular lysosomes throughout the body, in particular in blood vessel walls, neuronal cells, and smooth muscle. The gradual accumulation of this glycosphingolipid in numerous eye tissues causes conjunctival vascular abnormalities, corneal epithelial opacities (cornea verticillata), lens opacities, and retinal vascular abnormalities. Although a severe vision impairment is rare, these abnormalities are diagnostic indicators and prognostics for severity. Cornea verticillata is the most common ophthalmic feature in both hemizygous men and heterozygous females. Vessel tortuosity has been linked to a faster disease progression and may be useful in predicting systemic involvement. New technologies such as optical coherence tomography angiography (OCTA) are useful for monitoring retinal microvasculature alterations in FD patients. Along with OCTA, corneal topographic analysis, confocal microscopy, and electro-functional examinations, contributed to the recognition of ocular abnormalities and have been correlated with systemic involvement. We offer an update regarding FD ocular manifestations, focusing on findings derived from the most recent imaging modalities, to optimize the management of this pathology.
Standardization of the Gender Assignment and Agreement Assessment in the Greek Language: Preliminary Evidence from Bilingual Greek—Albanian School Age Children
Authors: Prentza Alexandra , Kaltsa Maria , Tafiadis Dionysios , Tsimpli Ianthi Maria
Published: May 2023

(1) Background: Given the scarcity of data on the psychometric evaluation of measures used with typically developing Greek-speaking bilinguals, this study aims to present preliminary evidence for the standardization and the psychometric evaluation of a gender assignment and agreement assessment designed for the Greek language (henceforth, GAAGL Assessment) employing real and pseudo-words. This is the first study to standardize the GAAGL Assessment and to explore its discriminatory ability with typical populations. (2) Methods: The assessment was designed as part of the BALED project which targeted language skills in bilingual children for whom one language is Greek. For the psychometric evaluation and the exploration of the test’s discriminatory ability we ran a Cronbach’s alpha analysis and a Youden Receiver Operating Characteristics (ROC) analysis across the domains and sub scores of the test. Our sample consisted of 53 typically developing Greek monolingual children and 57 age-matched Greek–Albanian-speaking bilinguals. (3) Results: The results showed: (a) a high internal consistency for the GAAGL Assessment across its four main tasks and (b) excellent discriminatory ability, since statistically significant positive discrimination was detected between monolingual and bilingual children in the tasks and scores of the GAAGL Assessment.
Low Frequency Attenuation Characteristics of Two-Dimensional Hollow Scatterer Locally Resonant Phonon Crystals
Authors: Xu Jingcheng , Chen Changzheng
Published: May 2023

The finite element method (FEM) was applied to study the low frequency band gap characteristics of a designed phonon crystal plate formed by embedding a hollow lead cylinder coated with silicone rubber into four epoxy resin short connecting plates. The energy band structure, transmission loss and displacement field were analyzed. Compared to the band gap characteristics of three traditional phonon crystal plates, namely, the square connecting plate adhesive structure, embedded structure and fine short connecting plate adhesive structure, the phonon crystal plate of the short connecting plate structure with a wrapping layer was more likely to generate low frequency broadband. The vibration mode of the displacement vector field was observed, and the mechanism of band gap formation was explained based on the spring mass model. By discussing the effects of the width of the connecting plate, the inner and outer radii and height of the scatterer on the first complete band gap, it indicated that the narrower the width of the connecting plate, the smaller the thickness; the smaller the inner radius of the scatterer, the larger the outer radius; and the higher the height, the more conducive it is to the expansion of the band gap.
Study on the Effect of PVAc and Styrene on the Properties and Microstructure of MMA-Based Repair Material for Concrete
Authors: Guo Zemeng , Xu Lingling , Lu Shijian , Yan Luchao , Zhu Zhipeng , Wang Yang
Published: May 2023

Methyl methacrylate (MMA) material is considered to be a suitable material for repairing concrete crack, provided that its large volume shrinkage during polymerization is resolved. This study was dedicated to investigating the effect of low shrinkage additives polyvinyl acetate and styrene (PVAc + styrene) on properties of the repair material and further proposes the shrinkage reduction mechanism based on the data of FTIR spectra, DSC testing and SEM micrographs. The results showed that PVAc + styrene delayed the gel point during the polymerization, and the formation of two-phase structure and micropores compensated for the volume shrinkage of the material. When the proportion of PVAc + styrene was 12%, the volume shrinkage could be as low as 4.78%, and the shrinkage stress was reduced by 87.4%. PVAc + styrene improved the bending strength and fracture toughness of most ratios investigated in this study. When 12% PVAc + styrene was added, the 28 d flexural strength and fracture toughness of MMA-based repair material were 28.04 MPa and 92.18%, respectively. After long-term curing, the repair material added with 12% PVAc + styrene showed a good adhesion to the substrate, with a bonding strength greater than 4.1 MPa and the fracture surface appearing at the substrate after the bonding experiment. This work contributes to the obtaining of a MMA-based repair material with low shrinkage, while its viscosity and other properties also can meet the requirements for repairing microcracks.
Influence of Root Post Materials and Aging on Fracture Strength and Marginal Gap Quality of Ceramic Crowns—An In Vitro Study
Authors: Hennig Christoph-Ludwig , Stöcker André , Nitzsche Ann , Marquetand Justus , Jacobs Collin , Jahn Florentine
Published: May 2023

The design of and materials for prosthodontic abutments and posts have significant influences on the fracture resistance of restored teeth. This in vitro study compared the fracture strength and marginal quality of full-ceramic crowns as a function of the inserted root posts via simulation of a five-year period of use. Test specimens were prepared from 60 extracted maxillary incisors using titanium L9 (A), glass-fiber L9 (B), and glass-fiber L6 (C) root posts. The circular marginal gap behavior, linear loading capacity, and material fatigue after artificial aging were investigated. The marginal gap behavior and material fatigue were analyzed using electron microscopy. The linear loading capacity of the specimens was investigated using the Zwick Z005 universal testing machine. None of the tested root post materials showed statistically significant differences in marginal width values (p = 0.921), except in the case of marginal gap location. For Group A, there was a statistically significant difference from the labial to the distal (p = 0.012), mesial (p = 0.000), and palatinal (p = 0.005). Similarly, Group B showed a statistically significant difference from the labial to the distal (p = 0.003), mesial (p = 0.000), and palatinal (p = 0.003). Group C showed a statistically significant difference from the labial to the distal (p = 0.001) and mesial (p = 0.009). Linear load capacity reached mean values of 455.8–537.7 N, and micro-cracks occurred after artificial aging, predominantly in Groups B and C. Through the chosen experimental design, it was shown that the root post material and root post length had no influence on the fracture strength of the test teeth before or after artificial aging. However, the marginal gap location depends on the root post material and its length, which is wider mesially and distally and also tends to be greater palatinally than labially.
Effect of Annealing Temperature on the Microstructure and Mechanical Properties of CoCrFeNiNb0.2Mo0.2 High Entropy Alloy
Authors: Fan Rui , Zhao Sicong , Wang Liping , Wang Lei , Guo Erjun
Published: May 2023

Strengthening the CoCrFeNi high entropy alloy with a face-center cubic structure has become a research prospect in the last decade. Alloying with double elements, Nb and Mo, is an effective method. In this paper, to further enhance the strength of the Nb and Mo contained high entropy alloy, CoCrFeNiNb0.2Mo0.2 was annealing treated at different temperatures for 24 h. As a result, a new kind of Cr2Nb type nano-scale precipitate with a hexagonal close-packed structure was formed, which is semi-coherent with the matrix. Moreover, by adjusting the annealing temperature, the precipitate was tailored with a considerable quantity and fine size. The best overall mechanical properties were achieved in the alloy annealed at 700 °C. The yield strength, ultimate tensile strength, and elongation are 727 MPa, 1.05 GPa, and 8.38%, respectively. The fracture mode of the annealed alloy is a mixture of cleavage and necking-featured ductile fracture. The approach employed in this study offers a theoretical foundation for enhancing the mechanical properties of face-centered cubic high entropy alloys via annealing treatment.
Ballistic Impacts with Bullet Splash—Load History Estimation for .308 Bullets vs. Hard Steel Targets
Authors: Andreotti Riccardo , Casaroli Andrea , Colamartino Ivan , Quercia Mauro , Boniardi Marco Virginio , Berto Filippo
Published: May 2023

The study focuses on testing a simplified way of estimating the resultant force due to ballistic impacts resulting in a full fragmentation of the impactor with no penetration of the target. The method is intended to be useful for the parsimonious structural assessment of military aircrafts with integrated ballistic protection systems by means of large scale explicit finite element simulations. The research investigates the effectiveness of the method in allowing the prediction of the fields of plastic deformation collected by hard steel plates impacted by a wide range of semi-jacketed, monolithic, and full metal jacket .308 Winchester rifle bullets. The outcomes show the effectiveness of the method being strictly related to the full compliance of the considered cases with the bullet-splash hypotheses. The study therefore suggests the application of the load history approach only after careful experimental investigations on the specific impactor–target interactions.
An Experimental Evaluation of Hemp as an Internal Curing Agent in Concrete Materials
Authors: Nazmul Rahnum T. , Sainsbury Bre-Anne , Al-Deen Safat , Garcez Estela O. , Ashraf Mahmud
Published: May 2023

The construction industry is facing increased demand for adopting sustainable ‘green’ building materials to minimise the carbon footprint of the infrastructure sector to meet the United Nations 2030 Sustainability Goals. Natural bio-composite materials such as timber and bamboo have been widely used in construction for centuries. Hemp has also been used in different forms in the construction sector for decades for its thermal and acoustic insulation capability owing to its moisture buffering capacity and thermal conductivity. The current research aims to explore the possible application of hydrophilic hemp shives for assisting the internal curing of concrete materials as a biodegradable alternative to currently used chemical products. The properties of hemp have been assessed based on their water absorption and desorption properties associated with their characteristic sizes. It was observed that, in addition to its excellent moisture absorption capacity, hemp released most of its absorbed moisture into the surroundings under a high relative humidity (>93%); the best outcome was observed for smaller hemp particles (<2.36 mm). Furthermore, when compared to typical internal curing agents such as lightweight aggregates, hemp showed a similar behaviour in releasing its absorbed moisture to the surroundings indicating its potential application as a natural internal curing agent for concrete materials. An estimate of the volume of hemp shives required to provide a similar curing response to traditional internal curing techniques has been proposed.
In Situ Synthesis of NiFeLDH/A–CBp from Pyrolytic Carbon as High-Performance Oxygen Evolution Reaction Catalyst for Water Splitting and Zinc Hydrometallurgy
Authors: Che Kai , Zhao Man , Sun Yanzhi , Pan Junqing
Published: May 2023

Nickel–iron-layered double hydroxide (NiFeLDH) is one of the promising catalysts for the oxygen evolution reaction (OER) in alkaline electrolytes, but its conductivity limits its large-scale application. The focus of current work is to explore low-cost, conductive substrates for large-scale production and combine them with NiFeLDH to improve its conductivity. In this work, purified and activated pyrolytic carbon black (CBp) is combined with NiFeLDH to form an NiFeLDH/A–CBp catalyst for OER. CBp not only improves the conductivity of the catalyst but also greatly reduces the size of NiFeLDH nanosheets to increase the activated surface area. In addition, ascorbic acid (AA) is introduced to enhance the coupling between NiFeLDH and A–CBp, which can be evidenced by the increase of Fe-O-Ni peak intensity in FTIR measurement. Thus, a lower overvoltage of 227 mV and larger active surface area of 43.26 mF·cm−2 are achieved in 1 M KOH solution for NiFeLDH/A–CBp. In addition, NiFeLDH/A–CBp shows good catalytic performance and stability as the anode catalyst for water splitting and Zn electrowinning in alkaline electrolytes. In Zn electrowinning with NiFeLDH/A–CBp, the low cell voltage of 2.08 V at 1000 A·m−2 results in lower energy consumption of 1.78 kW h/KgZn, which is nearly half of the 3.40 kW h/KgZn of industrial electrowinning. This work demonstrates the new application of high-value-added CBp in hydrogen production from electrolytic water and zinc hydrometallurgy to realize the recycling of waste carbon resources and reduce the consumption of fossil resources.
Study of Hybrid Composite Joints with Thin-Ply-Reinforced Adherends
Authors: Ramezani Farin , Carbas Ricardo J. C. , Marques Eduardo A. S. , da Silva Lucas F. M.
Published: May 2023

It has been demonstrated that a possible solution to reducing delamination in a unidirectional composite laminate lies in the replacement of conventional carbon-fibre-reinforced polymer layers with optimized thin-ply layers, thus creating hybrid laminates. This leads to an increase in the transverse tensile strength of the hybrid composite laminate. This study investigates the performance of a hybrid composite laminate reinforced by thin plies used as adherends in bonded single lap joints. Two different composites with the commercial references Texipreg HS 160 T700 and NTPT-TP415 were used as the conventional composite and thin-ply material, respectively. Three configurations were considered in this study: two reference single lap joints with a conventional composite or thin ply used as the adherends and a hybrid single lap. The joints were quasi-statically loaded and recorded with a high-speed camera, allowing for the determination of damage initiation sites. Numerical models of the joints were also created, allowing for a better understanding of the underlying failure mechanisms and the identification of the damage initiation sites. The results show a significant increase in tensile strength for the hybrid joints compared to the conventional ones as a result of changes in the damage initiation sites and the level of delamination present in the joint.
Polyethylene Protective Coating with Anti-Reflective Properties for Silicon Photovoltaic Cells
Authors: Pociask-Bialy Malgorzata
Published: May 2023

The aim of the study was to find the effect of polyethylene (PE) coatings on the short-circuit current of silicon photovoltaic cells covered with glass, in order to improve the short-circuit current of the cells. Various combinations of PE films (thicknesses ranging from 9 to 23 µm, number of layers ranging from two to six) with glasses (greenhouse, float, optiwhite and acrylic glass) were investigated. The best current gain of 4.05% was achieved for the coating combining a 1.5 mm thick acrylic glass with 2 × 12 µm thick PE films. This effect can be related to the formation of an array of micro-wrinkles and micrometer-sized air bubbles with a diameter of 50 to 600 µm in the films, which served as micro-lenses and enhanced light trapping.
Effects of Surface Properties of Fiber on Interface Properties of Carbon Fiber/Epoxy Resin and Its Graphene Oxide Modified Hybrid Composites
Authors: Bai Weihua , Liu Wenjun , Li Weidong , Lin Zewen , Qiu Hong , Hu Xiaolan
Published: May 2023

In the present study, surface properties of three types of carbon fibers (CCF300, CCM40J, and CCF800H) on the interface properties of carbon fiber/epoxy resin (CF/EP) were analyzed. The composites are further modified by graphene oxide (GO) to obtain GO/CF/EP hybrid composites. Meanwhile, the effect of the surface properties of CFs and the additive graphene oxide on the interlaminar shear properties and dynamic thermomechanical properties of GO/CF/EP hybrid composites are also analyzed. The results show that the higher surface oxygen-carbon ratio of carbon fiber (CCF300) has a positive effect on improving the glass transition temperature (Tg) of the CF/EP composites. The Tg of CCF300/EP is 184.4 °C, while the Tg of CCM40J/EP and CCF800/EP are only 177.1 °C and 177.4 °C, respectively. Furthermore, deeper and more dense grooves on the fiber surface (CCF800H and CCM40J) are more conducive to improving the interlaminar shear performance of the CF/EP composites. The interlaminar shear strength (ILSS) of CCF300/EP is 59.7 MPa, and that of CCM40J/EP and CCF800H/EP are 80.1 MPa and 83.5 MPa, respectively. For the GO/CF/EP hybrid composites, graphene oxide with abundant oxygen-containing groups is beneficial to improve the interfacial interaction. Graphene oxide can significantly improve the glass transition temperature and interlamellar shear strength of GO/CCF300/EP composites fabricated by CCF300 with a higher surface oxygen-carbon ratio. For the CCM40J and CCF800H with lower surface oxygen-carbon ratio, graphene oxide has a better modification effect on the glass transition temperature and interlamellar shear strength of GO/CCM40J/EP composites fabricated by CCM40J with deeper and finer surface grooves. Regardless of the type of carbon fiber, the GO/CF/EP hybrid composites with 0.1% graphene oxide have the optimized interlaminar shear strength, and the GO/CF/EP hybrid composites with 0.5% graphene oxide have the maximum glass transition temperature.
Stress Corrosion Cracking of 316L Stainless Steel Additively Manufactured with Sinter-Based Material Extrusion
Authors: Santamaria Ricardo , Wang Ke , Salasi Mobin , Iannuzzi Mariano , Mendoza Michael Y. , Quadir Md Zakaria
Published: May 2023

This study investigates the stress corrosion cracking (SCC) behavior of type 316L stainless steel (SS316L) produced with sinter-based material extrusion additive manufacturing (AM). Sinter-based material extrusion AM produces SS316L with microstructures and mechanical properties comparable to its wrought counterpart in the annealed condition. However, despite extensive research on SCC of SS316L, little is known about the SCC of sinter-based AM SS316L. This study focuses on the influence of sintered microstructures on SCC initiation and crack-branching susceptibility. Custom-made C-rings were exposed to different stress levels in acidic chloride solutions at various temperatures. Solution-annealed (SA) and cold-drawn (CD) wrought SS316L were also tested to understand the SCC behavior of SS316L better. Results showed that sinter-based AM SS316L was more susceptible to SCC initiation than SA wrought SS316L but more resistant than CD wrought SS316L, as determined by the crack initiation time. Sinter-based AM SS316L showed a noticeably lower tendency for crack-branching than both wrought SS316L counterparts. The investigation was supported by comprehensive pre- and post-test microanalysis using light optical microscopy, scanning electron microscopy, electron backscatter diffraction, and micro-computed tomography.
UV-Activated Au Modified TiO2/In2O3 Hollow Nanospheres for Formaldehyde Detection at Room Temperature
Authors: Zhang Su , Huang Baoyu , Jiang Zenghao , Qian Junfan , Cao Jiawei , Feng Qiuxia , Zhang Jianwei , Li Xiaogan
Published: May 2023

Au modified TiO2/In2O3 hollow nanospheres were synthesized by the hydrolysis method using the carbon nanospheres as a sacrificial template. Compared to pure In2O3, pure TiO2, and TiO2/In2O3 based sensors, the Au/TiO2/In2O3 nanosphere-based chemiresistive-type sensor exhibited excellent sensing performances to formaldehyde at room temperature under ultraviolet light (UV-LED) activation. The response of the Au/TiO2/In2O3 nanocomposite-based sensor to 1 ppm formaldehyde was about 5.6, which is higher than that of In2O3 (1.6), TiO2 (2.1), and TiO2/In2O3 (3.8). The response time and recovery time of the Au/TiO2/In2O3 nanocomposite sensor were 18 s and 42 s, respectively. The detectable formaldehyde concentration could go down as low as 60 ppb. In situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) was used to analyze the chemical reactions on the surface of the sensor activated by UV light. The improvement in the sensing properties of the Au/TiO2/In2O3 nanocomposites could be attributed to the nanoheterojunctions and electronic/chemical sensitization of the Au nanoparticles.
Hybrid Plasmas for Materials Processing
Authors: Kusano Reinosuke , Kusano Yukihiro
Published: May 2023

Hybrid plasmas have been reported in various areas of research over the last 40 years. However, a general overview of hybrid plasmas has never been presented or reported. In the present work, a survey of the literature and patents is carried out to provide the reader with a broad view of hybrid plasmas. The term refers to several different configurations of plasmas, including but not limited to: plasmas driven by several power sources simultaneously or sequentially, plasmas that have the properties of both thermal and nonthermal plasmas, plasmas that are enhanced by additional energy, and plasmas that are operated in a unique medium. In addition, a way of evaluating hybrid plasmas in terms of the improvement of processes is discussed, as well as the negative impacts that follow the employment of hybrid plasmas. Regardless of what the hybrid plasma in question is composed of, it often poses a unique advantage to its nonhybrid counterpart, whether it be used for welding, surface treatment, materials synthesis, coating deposition, gas phase reactions, or medicine.
Interfacial Modification and Bending Performance of 3D Orthogonal Woven Composites with Basalt Filament Yarns
Authors: Lyu Lihua , Wen Fangfang , Lyu Tingting , Zhou Xinghai , Gao Yuan
Published: May 2023

To improve their interfacial properties, 3D orthogonal woven fabrics with basalt filament yarns were modified with functionalized carboxylated carbon nanotubes (KH570-MWCNTs) and polydopamine (PDA). Fourier infrared spectroscopy (FT-IR) analysis and scanning electron microscopy (SEM) testing were used. It was demonstrated that both methods could successfully modify basalt fiber (BF) 3D woven fabrics. The 3D orthogonal woven composites (3DOWC) were produced with epoxy resin and 3D orthogonal woven fabrics as raw material by the VARTM molding process. The bending properties of the 3DOWC were tested and analyzed by experimental and finite element analysis methods. The results showed that the bending properties of the 3DOWC modified by KH570-MWCNTs and PDA were significantly improved, and the maximum bending loads were increased by 31.5% and 31.0%. The findings of the finite element simulation and the experiment results were in good agreement, and the simulation error value was 3.37%. The correctness of the finite element simulation results and the model’s validity further reveal the material’s damage situation and damage mechanism in the bending process.
Elemental Substitution at Tl Site of Tl1−xXx(Ba, Sr)CaCu2O7 Superconductor with X = Cr, Bi, Pb, Se, and Te
Authors: Nur-Akasyah Jaafar , Abd-Shukor Roslan , Chong Tet Vui
Published: May 2023

The effects of elemental substitutions at the Tl site of a Tl1−xXx(Ba, Sr)CaCu2O7 superconductor with X = Cr, Bi, Pb, Se, and Te were investigated. This study aimed to determine the elements that enhance and suppress the superconducting transition temperature of the Tl1−xXx(Ba, Sr)CaCu2O7 (Tl-1212) phase. The selected elements belong to the groups of transition metal, post-transition metal, non-metal, and metalloid. The relationship between the transition temperature and ionic radius of the elements was also discussed. The samples were prepared by the solid-state reaction method. The XRD patterns showed a single Tl-1212 phase was formed in the non- and Cr-substituted (x = 0.15) samples. The Cr-substituted samples (x = 0.4) showed a plate-like structure with smaller voids. The highest superconducting transition temperatures (Tc onset, Tcχ′, and Tp) were also achieved by the Cr-substituted samples for x = 0.4 compositions. However, the substitution of Te suppressed the superconductivity of the Tl-1212 phase. Jc inter (Tp) for all samples was calculated to be in the range of 12–17 A/cm2. This work shows that substitution elements with a smaller ionic radius tend to be more favorable in improving the superconducting properties of the Tl-1212 phase.
A Study on the Improvement of Power Density of Axial Flux Motors for Collaborative Robot Joints through Same-Direction Skew
Authors: Hong Min-Ki , Pyo Hyun-Jo , Song Si-Woo , Jung Dong-Hoon , Kim Won-Ho
Published: May 2023

Axial flux motors have a large output density with a large outer diameter of the motor and a short axial length. Since it is advantageous in short axial length, the axial thickness of motor components becomes a very important parameter when designing axial flux motors. Among the components, the back yoke exists to serve as a path for magnetic flux and must have a certain thickness to prevent magnetic saturation. However, as the thickness of the back yoke increases within the axial size limit of the motor, the output of the motor may decrease. In this paper, same-direction skew that increases the cross-sectional area of the magnetic flux path without increasing the thickness of the back yoke is presented. Same-direction skew is a way to increase the cross-sectional area of the back yoke by skewing the rotor and stator in the same direction. The back yoke thickness that can be reduced by same-direction skew was calculated. Performance with same-direction skew designed using the equations was analyzed and compared, and the effectiveness of each type of rotor was verified. The validity of the proposed model was examined using the finite element analysis method.
Magnetoelectric Coupling Effects in Tb-Doped BiFeO3 Nanoparticles
Authors: Apostolova Iliana , Apostolov Angel , Wesselinowa Julia
Published: May 2023

The magnetic, electric, and optical properties in Tb-doped BiFeO3 nanoparticles as functions of size and doping concentrations were investigated using a microscopic model, taking into account both linear and quadratic magnetoelectric (ME) coupling. We observed improved multiferroic properties and band-gap tuning. The magnetization and polarization increased with the decreased nanoparticle size and increased Tb-doping substitution x. The Neel temperature remained nearly unchanged whereas the Curie temperature was reduced with the increased x. There was doping-induced ME coupling. The dielectric constant is discussed as a function of the size, doping, and the magnetic field. The band gap decreased with the decreased size or increased Tb dopants due to competing effects of the compressive strain, oxygen defects on the surface, and Coulomb interactions. Increasing the Tb dopants and decreasing the nanoparticle size improved the ME effect.
Detection of Anomalies in Natural Complicated Data Structures Based on a Hybrid Approach
Authors: Mandrikova Oksana , Mandrikova Bogdana , Esikov Oleg
Published: May 2023

A hybrid approach is proposed to detect anomalies in natural complicated data structures with high noise levels. The approach includes the application of an autoencoder neural network and singular spectrum analysis (SSA) with an adaptive anomaly detection algorithm (AADA) developed by the authors. The autoencoder is the quintessence of the representation learning algorithm, and it projects (selects) data features. Here, under-complete autoencoders are used. They are a product of the development of the principal component method and allow one to approximate complex nonlinear dependencies. Singular spectrum analysis decomposes data through the singular decomposition of matrix trajectories and makes it possible to detect the data structure in the noise. The AADA is based on the combination of wavelet transforms with threshold functions. Combinations of different constructions of wavelet transformation with threshold functions are widely applied to tasks relating to complex data processing. However, when the noise level is high and there is no complete knowledge of a useful signal, anomaly detection is not a trivial problem and requires a complex approach. This paper considers the use of adaptive threshold functions, the parameters of which are estimated on a probabilistic basis. Adaptive thresholds and a moving time window are introduced. The efficiency of the proposed method in detecting anomalies in neutron monitor data is illustrated. Neutron monitor data record cosmic ray intensities. We used neutron monitor data from ground stations. Anomalies in cosmic rays can create serious radiation hazards for people as well as for space and ground facilities. Thus, the diagnostics of anomalies in cosmic ray parameters is quite topical, and research is being carried out by teams from different countries. A comparison of the results for the autoencoder + AADA and SSA + AADA methods showed the higher efficiency of the autoencoder + AADA method. A more flexible NN apparatus provides better detection of short-period anomalies that have complicated structures. However, the combination of SSA and the AADA is efficient in the detection of long-term anomalies in cosmic rays that occur during strong magnetic storms. Thus, cosmic ray data analysis requires a more complex approach, including the use of the autoencoder and SSA with the AADA.
On Two-Point Boundary Value Problems and Fractional Differential Equations via New Quasi-Contractions
Authors: Noorwali Maha , Shagari Mohammed Shehu
Published: May 2023

The aim of this paper is to introduce new forms of quasi-contractions in metric-like spaces and initiate more general conditions for the existence of invariant points for such operators. The proposed notions are then applied to study novel existence criteria for the existence of solutions to two-point boundary value problems in the domains of integer and fractional orders. To attract further research in this direction, important consequences are deduced and discussed to indicate the novelty and generality of our proposed concepts.
Therapeutic Potential of Polyphenols and Other Micronutrients of Marine Origin
Authors: Pereira Leonel , Cotas João
Published: May 2023

Polyphenols are compounds found in various plants and foods, known for their antioxidant and anti-inflammatory properties. Recently, researchers have been exploring the therapeutic potential of marine polyphenols and other minor nutrients that are found in algae, fish and crustaceans. These compounds have unique chemical structures and exhibit diverse biological properties, including anti-inflammatory, antioxidant, antimicrobial and antitumor action. Due to these properties, marine polyphenols are being investigated as possible therapeutic agents for the treatment of a wide variety of conditions, such as cardiovascular disease, diabetes, neurodegenerative diseases and cancer. This review focuses on the therapeutic potential of marine polyphenols and their applications in human health, and also, in marine phenolic classes, the extraction methods, purification techniques and future applications of marine phenolic compounds.
Substitution of D-Arginine at Position 11 of α-RgIA Potently Inhibits α7 Nicotinic Acetylcholine Receptor
Authors: Wu Yong , Zhang Junjie , Ren Jie , Zhu Xiaopeng , Li Rui , Zhangsun Dongting , Luo Sulan
Published: May 2023

Conotoxins are a class of disulfide-rich peptides found in the venom of cone snails, which have attracted considerable attention in recent years due to their potent activity on ion channels and potential for therapeutics. Among them, α-conotoxin RgIA, a 13-residue peptide, has shown great promise as a potent inhibitor of α9α10 nAChRs for pain management. In this study, we investigated the effect of substituting the naturally occurring L-type arginine at position 11 of the RgIA sequence with its D-type amino acid. Our results indicate that this substitution abrogated the ability of RgIA to block α9α10 nAChRs, but instead endowed the peptide with the ability to block α7 nAChR activity. Structural analyses revealed that this substitution induced significant alteration of the secondary structure of RgIA[11r], which consequently affected its activity. Our findings underscore the potential of D-type amino acid substitution as a promising strategy for designing novel conotoxin-based ligands targeting different types of nAChRs.
A Computational Fluid Dynamics Study on Physical Refining of Steel Melts by Filtration
Authors: Akbarnejad Shahin , Sheng Dong-Yuan , Jönsson Pär Göran
Published: May 2023

In this paper, a previous experimental investigation on physical refining of steel melts by filtration was numerically studied. To be specific, the filtration of non-metallic alumina inclusions, in the size range of 1–100 µm, was stimulated from steel melt using a square-celled monolithic alumina filter. Computational fluid dynamics (CFD) studies, including simulations of both fluid flow and particle tracing using the one-way coupling method, were conducted. The CFD predicted results for particles in the size range of ≤5 µm were compared to the published experimental data. The modeled filtration setup could capture 100% of the particles larger than 50 µm. The percentage of the filtered particles decreased from 98% to 0% in the particle size range from 50 µm to 1 µm.
On the Nb5Si3 Silicide in Metallic Ultra-High Temperature Materials
Authors: Tsakiropoulos Panos
Published: May 2023

Refractory metal (RM) M5Si3 silicides are desirable intermetallics in metallic ultra-high temperature materials (UHTMs), owing to their creep properties and high Si content that benefits oxidation resistance. Of particular interest is the alloyed Nb5Si3 that forms in metallic UHTMs with Nb and Si addition. The choice of alloying elements and type of Nb5Si3 that is critical for achieving a balance of properties or meeting a property goal in a metallic UHTM is considered in this paper. Specifically, the different types of alloyed “normal” Nb5Si3 and Ti-rich Nb5Si3, namely “conventional”, “complex concentrated” (CC) or “high entropy” (HE) silicide, in metallic UHTMs with Nb and Si addition were studied. Advanced metallic UHTMs with additions of RMs, transition metals (TMs), Ge, Sn or Ge + Sn and with/without Al and with different Ti, Al, Cr, Si or Sn concentrations were investigated, considering that the motivation of this work was to support the design and development of metallic-UHTMs. The study of the alloyed silicides was based on the Nb/(Ti + Hf) ratio, which is key regarding creep, the parameters VEC and Δχ and relationships between them. The effect of alloying additions on the stability of “conventional”, CC or HE silicide was discussed. The creep and hardness of alloyed Nb5Si3 was considered. Relationships that link “conventional”, CC or HE bcc solid solution and Nb5Si3 in the alloy design methodology NICE (Niobium Intermetallic Composite Elaboration) were presented. For a given temperature and stress, the steady state creep rate of the alloyed silicide, in which TMs substituted Nb, and Al and B substituted Si, depended on its parameters VEC and Δχ and its Nb/(Ti + Hf) ratio, and increased with decreasing parameter and ratio value, compared with the unalloyed Nb5Si3. Types of alloyed Nb5Si3 with VEC and Δχ values closest to those of the unalloyed Nb5Si3 were identified in maps of alloyed Nb5Si3. Good agreement was shown between the calculated hardness and chemical composition of Nb5Si3 and experimental results.