bluuebunny/crossref_metadata_2025 huggingface dataset:
Multimodal Assessment of the Prognostic Role of Ectopic Inner Foveal Layers on Epiretinal Membrane Surgery
Authors: Gesualdo Carlo , Rossi Settimio , Iodice Clemente Maria , Rosolia Andrea , Melillo Paolo , Della Corte Michele , Simonelli Francesca
Published: July 2023

Background: To perform a multimodal assessment of the ectopic inner foveal layers’ (EIFL) prognostic role on idiopathic epiretinal membrane (ERM) surgery. Methods: We retrospectively followed-up for 12 months 27 patients who underwent ERM surgery and stratified them based on EIFL presence (group 1) or absence (group 2) at baseline. Central Retinal Thickness (CRT) and best-corrected visual acuity (BCVA) were compared pre- and post-operatively at 1, 4 and 12 months, whereas fixation stability (FS), macular sensitivity (MS) and multifocal electroretinogram (mfERG) responses were confronted at baseline and 12 months. Results: In group 1, BCVA improved at 4 and 12 months (MD = 0.14 (SE = 0.04); MD = 0.13 (SE = 0.05), respectively) as well as in group 2 (MD = 0.31 (SE = 0.07); MD = 0.41 (SE = 0.08), respectively). CRT did not change in group 1, whereas it decreased in group 2 at 4 and 12 months (MD = −73.13; SE = 23.56; MD = −76.20; SE = 23.56). MS showed no changes in both groups after surgery. FS did not change in group 1, whereas group 2 improved FS 2° (+8.91 ± 13.97) and FS 4° (+4.33 ± 3.84). MfERG P1 wave did not change in group 1, while in group 2 αP1-2, αP1-3 and αP1-4 improved postoperatively (27.97 ± 27.62; 12.51 ± 17.36; 10.49 ± 17.19, respectively). Conclusions: Multimodal assessment confirmed that EIFL negatively affected ERM surgery outcomes.
Special Issue: “Latest Advances on Urological Surgery”
Authors: Sacco Emilio
Published: July 2023

Urology has always been at the forefront of surgical innovation which aims to improve patients outcomes and cost-effectiveness [...]
TEM Study of a Layered Composite Structure Produced by Ion-Plasma Treatment of Aluminum Coating on the Ti-6Al-4V Alloy
Authors: Nikolaev Aleksey , Ramazanov Kamil’ , Nazarov Almaz , Mukhamadeev Vener , Zagibalova Elena , Astafurova Elena
Published: July 2023

Using the methods of transmission electron microscopy and energy-dispersive spectroscopy, we study the microstructure and phase composition of the coating and modified intermetallic layers obtained in a Ti-6Al-4V alloy by the deposition of the Al coating and subsequent processing in low-pressure non-self-sustained arc discharge plasma (CIPT—complex ion-plasma treatment). The deposition of the aluminum coating on the Ti-6Al-4V alloy is accompanied by the formation of a layered and a gradient microstructure: nanocrystalline near the “coating/substrate” interface and ultrafine-grained in the outer part of the aluminum coating, with α-stabilized region of ≈5 µm thick in the surface layer in base titanium alloy. After the CIPT, the coating and the surface of the base titanium alloy have a layered morphology: each of the layers possesses different grain structure and composition. In the direction from the outer surface of the specimen to the base material, the following phase sequence has been confirmed by diffraction and elemental analysis: TiAl3 → TiAl3 + nc-(Al(Ti) + α-Ti) → nc-(Al(Ti) + α-Ti) → TiAl3 → TiAl3 + TiAl → TiAl → Ti3Al → α-Ti alloy → (α + β)-Ti alloy. The nanocrystalline aluminum layer, which has been formed during the deposition of the aluminum coating, does not undergo phase transformation and recrystallization under the CIPT. Nanocrystalline structure can favor the interdiffusion of the elements between the coating and base material, and stimulate phase transformation in coarser grains situated under and over it.
Experimental Study on Low-Velocity Impact Performance of GFRP Trapezoidal Corrugated Sandwich Structures
Authors: Deng Yunfei , Deng Yao , Liu Wenquan , Zhang Shitong , Tian Kuo
Published: July 2023

Glass fiber trapezoidal corrugated sandwich structures are composed of trapezoidal cores and glass fiber-reinforced polymer (GFRP) panels. A series of low-velocity impact tests were conducted to investigate the impact resistance performance, considering the effects of impact position, impactor shape, and impactor diameter on the damage mechanism of sandwich structures. When the impactor shape and impact energy remain constant, the maximum impact load at the node impact point is higher than at the base, while the displacement of impact at the base is significantly higher than that at the node. Secondly, when the impactor diameter and energy of the impactor are the same, the hemispherical impactor requires less penetration energy to impact the sandwich structure compared to the flat impactor. Comparing the shape of the impactor, it is found that the smaller the contact surface of the impactor, the more concentrated the stress, and the lower the required penetration energy. Finally, when the impactor shape and impact energy are the same, as the diameter of impactor increases, the damage expansion during impacting on the sandwich structure becomes more sufficient, resulting in decreased impact displacement and smaller impact damage caused to the sandwich structure.
There Are over 60 Ways to Produce Biocompatible Calcium Orthophosphate (CaPO4) Deposits on Various Substrates
Authors: Dorozhkin Sergey V.
Published: July 2023

A The present overview describes various production techniques for biocompatible calcium orthophosphate (abbreviated as CaPO4) deposits (coatings, films and layers) on the surfaces of various types of substrates to impart the biocompatible properties for artificial bone grafts. Since, after being implanted, the grafts always interact with the surrounding biological tissues at the interfaces, their surface properties are considered critical to clinical success. Due to the limited number of materials that can be tolerated in vivo, a new specialty of surface engineering has been developed to desirably modify any unacceptable material surface characteristics while maintaining the useful bulk performance. In 1975, the development of this approach led to the emergence of a special class of artificial bone grafts, in which various mechanically stable (and thus suitable for load-bearing applications) implantable biomaterials and artificial devices were coated with CaPO4. Since then, more than 7500 papers have been published on this subject and more than 500 new publications are added annually. In this review, a comprehensive analysis of the available literature has been performed with the main goal of finding as many deposition techniques as possible and more than 60 methods (double that if all known modifications are counted) for producing CaPO4 deposits on various substrates have been systematically described. Thus, besides the introduction, general knowledge and terminology, this review consists of two unequal parts. The first (bigger) part is a comprehensive summary of the known CaPO4 deposition techniques both currently used and discontinued/underdeveloped ones with brief descriptions of their major physical and chemical principles coupled with the key process parameters (when possible) to inform readers of their existence and remind them of the unused ones. The second (smaller) part includes fleeting essays on the most important properties and current biomedical applications of the CaPO4 deposits with an indication of possible future developments.
Calcium Trimetaphosphate-Loaded Electrospun Poly(Ester Urea) Nanofibers for Periodontal Tissue Engineering
Authors: Toledo Priscila T. A. , Anselmi Caroline , Dal-Fabbro Renan , Mahmoud Abdel H. , Abel Alexandra K. , Becker Matthew L. , Delbem Alberto C. B. , Bottino Marco C.
Published: July 2023

The objective of this research was to create and appraise biodegradable polymer-based nanofibers containing distinct concentrations of calcium trimetaphosphate (Ca-TMP) for periodontal tissue engineering. Poly(ester urea) (PEU) (5% w/v) solutions containing Ca-TMP (15%, 30%, 45% w/w) were electrospun into fibrous scaffolds. The fibers were evaluated using SEM, EDS, TGA, FTIR, XRD, and mechanical tests. Degradation rate, swelling ratio, and calcium release were also evaluated. Cell/Ca-TMP and cell/scaffold interaction were assessed using stem cells from human exfoliated deciduous teeth (SHEDs) for cell viability, adhesion, and alkaline phosphatase (ALP) activity. Analysis of variance (ANOVA) and post-hoc tests were used (α = 0.05). The PEU and PEU/Ca-TMP-based membranes presented fiber diameters at 469 nm and 414–672 nm, respectively. Chemical characterization attested to the Ca-TMP incorporation into the fibers. Adding Ca-TMP led to higher degradation stability and lower dimensional variation than the pure PEU fibers; however, similar mechanical characteristics were observed. Minimal calcium was released after 21 days of incubation in a lipase-enriched solution. Ca-TMP extracts enhanced cell viability and ALP activity, although no differences were found between the scaffold groups. Overall, Ca-TMP was effectively incorporated into the PEU fibers without compromising the morphological properties but did not promote significant cell function.
Robotic Belt Finishing with Process Control for Accurate Surfaces
Authors: Torres Ramón , Mata Sara , Iriarte Xabier , Barrenetxea David
Published: July 2023

The aerospace industry still relies on manual processes for finish applications, which can be a tedious task. In recent years, robotic automation has gained interest due to its flexibility and adaptability to provide solutions to this issue. However, these processes are difficult to automate, as the material removal rate can vary due to changes in the process variables. This work proposes an approach for automatically modeling the material removal process based on experimental data in a robotic belt grinding application. The methodology concerns the measurement of the removed mass of a test part during a finishing process using an automatic precision measurement system. Then, experimental models are used to develop a control algorithm for continuous material removal that maintains a uniform finishing process by regulating the robot’s feed rate. Next, the results for various experimental material removal models under different process conditions are presented, showing the process parameter’s influence on the removal capacity. Finally, the proposed control algorithm is validated, achieving a constant material removal rate.
Wave Transmission over Rubble-Mound Submerged Breakwaters
Authors: Repousis Elpidoforos , Roupas Ioannis , Memos Constantine
Published: July 2023

This study focuses on the prediction of technical efficiency of narrow-crested submerged permeable rubble-mound breakwaters, in terms of wave attenuation. A number of existing formulae for estimating wave transmission coefficient for submerged breakwaters can be found in the literature, whereas in this work further improvement for that estimation has been achieved mainly through physical modelling. A series of 2D experiments under scale were conducted for regular and random waves providing data on wave transmission coefficient and respective wave breaking characteristics. A Boussinesq-type wave model capable of simulating wave propagation for regular waves over porous submerged breakwaters was also used in order to provide additional wave transmission information. Data analysis showed that wave breaking mechanism significantly affects wave energy dissipation and, therefore, wave breaking occurrence and type can be directly linked to wave transmission coefficient for a given structure’s geometry and sea state. The result of this work is the proposal of a set of simple semi-empirical equations for predicting wave transmission coefficient over small profile porous submerged breakwaters in relevance to the parameterization of the expected dominant wave breaking mechanism.
Study on the Dynamic Optimal Control Strategy of an Electric-Hydrogen Hybrid Energy Storage System for a Direct Drive Wave Power Generation System
Authors: Chang Xinyue , Huang Lei , Zhang Xiaoyu , Yang Jianlong , Liu Haitao
Published: July 2023

A direct drive wave power generation system (DDWPGS) has the advantages of a simple structure and easy deployment, and is the first choice to provide electricity for islands and operation platforms in the deep sea. However, due to the off-grid, the source and load cannot be matched, so accommodation is an important issue. Hydrogen storage is the optimal choice for offshore wave energy accommodation. Therefore, aiming at the source-load mismatch problem of the DDWPGS, an electric-hydrogen hybrid energy storage system (HESS) for the DDWPGS is designed in this paper. Based on the characteristics of the devices in the electric-hydrogen HESS, a new dynamic power allocation strategy and its control strategy are proposed. Firstly, empirical mode decomposition (EMD) is utilized to allocate the power fluctuations that need to be stabilized. Secondly, with the state of charge (SOC) of the battery and the operating characteristics of the alkaline electrolyzer being considered, the power assignments of the battery and the electrolyzer are determined using the rule-based method. In addition, model predictive control (MPC) with good tracking performance is used to adjust the output power of the battery and electrolyzer. Finally, the supercapacitor (SC) is controlled to maintain the DC bus voltage while also balancing the system’s power. A simulation was established to verify the feasibility of the designed system. The results show that the electric-hydrogen HESS can stabilize the power fluctuations dynamically when the DDWPGS captures instantaneous power. Moreover, its control strategy can not only reduce the start-stop times of the alkaline electrolyzer but also help the energy storage devices to maintain a good state and extend the service life.
Numerical Study of the Local Scouring Process and Influencing Factors of Semi-Exposed Submarine Cables
Authors: Li Qishun , Hao Yanpeng , Zhang Peng , Tan Haotian , Tian Wanxing , Chen Linhao , Yang Lin
Published: July 2023

Local scouring might result in the spanning of submarine cables, endangering their mechanical and electrical properties. In this contribution, a three-dimensional computational fluid dynamics simulation model is developed using FLOW-3D, and the scouring process of semi-exposed submarine cables is investigated. The effects of the sediment critical Shields number, sediment density, and ocean current velocity on local scouring are discussed, and variation rules for the submarine cables’ spanning time are provided. The results indicate that three scouring holes are formed around the submarine cables. The location of the bottom of the holes corresponds to that of the maximum shear velocity. The continuous development of scouring holes at the wake position leads to the spanning of the submarine cables. The increase in the sediment’s critical Shields number and sediment density, as well as the decrease in the ocean current velocity, will extend the time for maintaining the stability of the upstream scouring hole and retard the development velocity of the wake position and downstream scouring holes. The spanning time has a cubic relationship with the sediment’s critical Shields number, a linear relationship with the sediment density, and an exponential relationship with the ocean current velocity. In this paper, the local scouring process of semi-exposed submarine cables is studied, which provides a theoretical basis for the operation and maintenance of submarine cables.
Delivery Mode and Perinatal Antibiotics Influence the Infant Gut Bacteriome and Mycobiome: A Network Analysis
Authors: Tejesvi Mysore V. , Turunen Jenni , Salmi Sonja , Reunanen Justus , Paalanne Niko , Tapiainen Terhi
Published: July 2023

Both exposure to antibiotics at birth and delivery via Caesarean section influence the gut bacteriome’s development in infants. Using 16S rRNA and internal transcribed spacer sequencing on the Ion Torrent platform, we employed network analysis to investigate the bacterial and fungal interkingdom relationships in the gut microbiome from birth to age 18 months in a prospective cohort study of 140 infants. The gut microbiome at ages six and 18 months revealed distinctive microbial interactions, including both positive and negative associations between bacterial and fungal genera in the gut ecosystem. Perinatal factors, delivery mode and intrapartum antibiotic exposure affected the associations between bacterial and fungal species. In infants exposed and unexposed to perinatal antibiotics, the gut microbiome formed distinct networks for the bacteriome and mycobiome. The fungi Saccharomyces, Trichosporon, Pezoloma, Cystofilobasidium, Rigidoporus and Fomitopsis were strongly associated with exposure to antibiotics at birth. Hyaloscypha, Trichosporon, Fomitopsis and Vishniacozyma were strongly associated with the control group that was not exposed to antibiotics. Five distinct networks were formed according to delivery mode. The present study confirms that bacteria and fungi clearly interact in the infant gut ecosystem. Furthermore, perinatal factors appear to influence the relationships between bacteria and fungi in the developing gut microbiome.
Production of L-Malic Acid by Metabolically Engineered Aspergillus nidulans Based on Efficient CRISPR–Cas9 and Cre-loxP Systems
Authors: Chen Ziqing , Zhang Chi , Pei Lingling , Qian Qi , Lu Ling
Published: July 2023

Aspergillus nidulans has been more extensively characterized than other Aspergillus species considering its morphology, physiology, metabolic pathways, and genetic regulation. As it has a rapid growth rate accompanied by simple nutritional requirements and a high tolerance to extreme cultural conditions, A. nidulans is a promising microbial cell factory to biosynthesize various products in industry. However, it remains unclear for whether it is also a suitable host for synthesizing abundant L-malic acid. In this study, we developed a convenient and efficient double-gene-editing system in A. nidulans strain TN02A7 based on the CRISPR–Cas9 and Cre-loxP systems. Using this gene-editing system, we made a L-malic acid-producing strain, ZQ07, derived from TN02A7, by deleting or overexpressing five genes (encoding Pyc, pyruvate carboxylase; OahA, oxaloacetate acetylhydrolase; MdhC, malate dehydrogenase; DctA, C4-dicarboxylic acid transporter; and CexA, citric acid transporter). The L-malic acid yield in ZQ07 increased to approximately 9.6 times higher (up to 30.7 g/L titer) than that of the original unedited strain TN02A7, in which the production of L-malic acid was originally very low. The findings in this study not only demonstrate that A. nidulans could be used as a potential host for biosynthesizing organic acids, but also provide a highly efficient gene-editing strategy in filamentous fungi.
Development of an Imaging Flow Cytometry Method for Fungal Cytological Profiling and Its Potential Application in Antifungal Drug Development
Authors: McMahon Courtney L. , Esqueda Marisol , Yu Jieh-Juen , Wall Gina , Romo Jesus A. , Vila Taissa , Chaturvedi Ashok , Lopez-Ribot Jose L. , Wormley Floyd , Hung Chiung-Yu
Published: July 2023

Automated imaging techniques have been in increasing demand for the more advanced analysis and efficient characterization of cellular phenotypes. The success of the image-based profiling method hinges on assays that can rapidly and simultaneously capture a wide range of phenotypic features. We have developed an automated image acquisition method for fungal cytological profiling (FCP) using an imaging flow cytometer that can objectively measure over 250 features of a single fungal cell. Fungal cells were labeled with calcofluor white and FM4-64FX, which bind to the cell wall and lipophilic membrane, respectively. Images of single cells were analyzed using IDEAS® software. We first acquired FCPs of fungal cells treated with fluconazole, amphotericin B, and caspofungin, each with a distinct mode of action, to establish FCP databases of profiles associated with specific antifungal treatment. Once fully established, we investigated the potential application of this technique as a screening methodology to identify compounds with novel antifungal activity against Candida albicans and Cryptococcus neoformans. Altogether, we have developed a rapid, powerful, and novel image-profiling method for the phenotypic characterization of fungal cells, also with potential applications in antifungal drug development.
Spatiotemporal Transfer of Source-Sink Landscape Ecological Risk in a Karst Lake Watershed Based on Sub-Watersheds
Authors: Zhou Zhongfa , Zhao Weiquan , Lv Sisi , Huang Denghong , Zhao Zulun , Sun Yaopeng
Published: July 2023

Non-point source pollution is an important source of ecological risk in karst lakes. The process of source–sink landscapes is the main pathway of pollution migration and plays an important role in water quality. In this study, the ecological risk evolution in the past 30 years was studied in a karst lake watershed with 495 sub-basins as the basic evaluation unit, and the risk assessment model of non-point source pollution was improved by using rainfall and fertilizer application. The results show that (1) the area of cultivated land shrank significantly, with forest land and construction land showing an upward trend in general; (2) the layout of the sink landscape continuously shrank, while the source landscape gradually expanded, and the space of high load values further increased and shifted from a flower-like layout distribution to concentrated contiguity, with some values exceeding 0.5; (3) the 252 sub-watersheds of the sink landscape migrated from very low risk to low risk, while the risk of the source landscape changed from medium risk to high and very high risk in 48 sub-watersheds; and (4) in terms of the overall trend of ecological risk transformation of the source–sink landscape, the transformation of sink landscapes to source landscapes was greater than that of source landscapes to sink landscapes, and the overall ecological risk showed an increasing trend.
Will Transcranial Magnetic Stimulation Improve the Treatment of Obsessive–Compulsive Disorder? A Systematic Review and Meta-Analysis of Current Targets and Clinical Evidence
Authors: Grassi Giacomo , Moradei Corinna , Cecchelli Chiara
Published: July 2023

Background: Although in 2017 a repetitive transcranial magnetic stimulation (rTMS) protocol received Food and Drug Administration approval for the first time for the treatment of obsessive–compulsive disorder (OCD), which neural target and which protocol should be used for OCD are still debated. The aim of the present study was to perform a systematic review and meta-analysis of the available open and sham-controlled trials. Methods: The primary analysis included a pairwise meta-analysis (over 31 trials), and then subgroup analyses were performed for each targeted brain area. Meta-regression analyses explored the possible moderators of effect size. Results: The pairwise meta-analysis showed a significant reduction in OCD symptoms following active rTMS (g = −0.45 [95%CI: −0.62, −0.29]) with moderate heterogeneity (I2 = 34.9%). Subgroup analyses showed a significant effect of rTMS over the bilateral pre-SMA (supplementary motor area), the DLPFC (dorsolateral prefrontal cortex), the ACC/mPFC (anterior cingulate cortex and medial prefrontal cortex), and the OFC (orbitofrontal cortex). No moderators of the effect size emerged. Conclusions: TMS of several brain targets represents a safe and effective treatment option for OCD patients. Further studies are needed to help clinicians to individualize TMS protocols and targets for each patient.
Current Treatment Approach, Emerging Therapies and New Horizons in Systemic Lupus Erythematosus
Authors: Athanassiou Panagiotis , Athanassiou Lambros
Published: July 2023

Systemic lupus erythematosus (SLE), the prototype of systemic autoimmune diseases is characterized by extreme heterogeneity with a variable clinical course. Renal involvement may be observed and affects the outcome. Hydroxychloroquine should be administered to every lupus patient irrespective of organ involvement. Conventional immunosuppressive therapy includes corticosteroids, methotrexate, cyclophosphamide, mycophenolate mofetil, azathioprine, cyclosporine and tacrolimus. However, despite conventional immunosuppressive treatment, flares occur and broad immunosuppression is accompanied by multiple side effects. Flare occurrence, target organ involvement, side effects of broad immunosuppression and increased knowledge of the pathogenetic mechanisms involved in SLE pathogenesis as well as the availability of biologic agents has led to the application of biologic agents in SLE management. Biologic agents targeting various pathogenetic paths have been applied. B cell targeting agents have been used successfully. Belimumab, a B cell targeting agent, has been approved for the treatment of SLE. Rituximab, an anti-CD20 targeting agent is also used in SLE. Anifrolumab, an interferon I receptor-targeting agent has beneficial effects on SLE. In conclusion, biologic treatment is applied in SLE and should be further evaluated with the aim of a good treatment response and a significant improvement in quality of life.
(±)-N-(1,2-Bis(3,4-dimethoxyphenyl)ethyl)-2-(2-fluoro-[1,1′-biphenyl]-4-yl)propanamide
Authors: Manolov Stanimir , Bojilov Dimitar , Ivanov Iliyan , Nedialkov Paraskev
Published: July 2023

The title compound, (±)-N-(1,2-bis(3,4-dimethoxyphenyl)ethyl)-2-(2-fluoro-[1,1′-biphenyl]-4-yl)propanamide, was obtained for the first time from 1,2-bis(3,4-dimethoxyphenyl) ethan-1-amine and (±)-flurbiprofen in one step. The newly synthesized bio-functional hybrid compound was fully characterized using 1H, 13C-NMR, UV, and mass spectral data.
(2R, 4S, 5S) 1-(4-(4-(((7-Chloroquinolin-4-yl)amino)methyl)-1H-1,2,3-triazol-1-yl)-5-(hydroxymethyl)tetrahydrofuran-2-yl)-5-methylpyrimidine-2,4(1H,3H)-dione
Authors: Kuan Houin , Xie Yuhan , Guo Yuzhu , Gianoncelli Alessandra , Ribaudo Giovanni , Coghi Paolo
Published: July 2023

1,2,3-triazole pharmacophore is a widely recognized motif used for a variety of applications, including drug discovery, chemical biology, and materials science. We herein report the synthesis of a derivative of azidothymidine (AZT), which was combined with the 7-chloro quinoline scaffold through a 1,4-disubstituted 1,2,3-triazole. The chemical structure of the new molecule was fully characterized by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H-NMR), carbon-13 nuclear magnetic resonance (13C-NMR), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond correlation (HMBC) distortionless enhancement by polarization transfer (DEPT), correlation spectroscopy (1H-1H-COSY), ultraviolet (UV) spectroscopy, and high-resolution mass spectrometry (HRMS). Computational studies were used to predict the interaction of the synthesized compound with HIV reverse transcriptase, a target of relevance for developing new therapeutics against AIDS. The drug-likeness of the compound was also investigated by computing the physico-chemical properties that are important for the pharmacokinetic profile.
Benzo[1,2-d:4,5-d′]bis([1,2,3]thiadiazole)-4-carbonitrile
Authors: Chmovzh Timofey N. , Kudryashev Timofey A. , Gaisin Karim S. , Rakitin Oleg A.
Published: July 2023

Electron-withdrawing heterocyclic units are found in most organic optoelectronic materials. Benzo[1,2-d:4,5-d′]bis([1,2,3]thiadiazole) is an interesting new heterocyclic system, the chemical properties of which are much less studied than other fused thiadiazoles. Cyano derivatives of electron-accepting heterocycles are known as potential components of photoluminescent materials. In this communication, benzo[1,2-d:4,5-d′]bis([1,2,3]thiadiazole)-4-carbonitrile was successfully obtained via the cyanation of 4-bromobenzo[1,2-d:4,5-d′]bis([1,2,3]thiadiazole) with copper(I) cyanide in DMF. The structure of the newly synthesized compound was established by means of elemental analysis, high-resolution mass spectrometry, 1H and 13C NMR, and IR spectroscopy.
Fiber Laser Alloying of Additively Manufactured 18Ni-300 Maraging Steel Part Surface: Effect of Processing Parameters on the Formation of Alloyed Surface Layer and Its Properties
Authors: Škamat Jelena , Bučelis Kęstutis , Černašėjus Olegas , Indrišiūnas Simonas
Published: July 2023

The development of new efficient, economical, and safe methods for strengthening the working surfaces of parts is an important task in the field of improving the reliability and resourcefulness of critical equipment and structures. In the present paper, laser boronizing is investigated as an alternative method for improving the wear resistance of maraging steel parts manufactured by laser powder bed fusion (LPBF). After LPBF, the specimens’ surface was covered with an amorphous boron paste (0.03–0.6 mm) and laser processed with a continuous-wave fiber laser in melting mode (λ—1070 nm; power—300 W; spot Ø—1.0 mm) at 500–1500 mm/min laser beam scanning speeds. Scanning electron microscopy, X-ray microanalysis, Knoop hardness, and dry sliding wear tests were applied to investigate the geometry, microstructure, hardness and its distribution, heat-affected zones, wear resistance, and wear mechanism of the alloyed layers. The boronized layers of thickness ~280–520 µm with microstructure from hypoeutectic to borides’ mixture were obtained, whose hardness varied from ~490 to ~2200 HK0.2. With laser boronizing, the wear resistance was improved up to ~7.5 times as compared with aged LPBF samples. In further method development, the problem of thermal cracking and softening of the heat-affected zone should be solved.
Creep Monitoring of Submersible Observation Windows Using Mueller Matrix Imaging
Authors: Tu Haibo , Bu Xingying , Liao Ran , Zhang Hailong , Ma Guoliang , Li Hening , Wan Jiachen , Ma Hui
Published: July 2023

Safety of the observation window is one of the core concerns for manned submersibles. When subjected to underwater static pressure, extrusion and creep deformation always occur in the observation window, which can pose a threat to both safety and optical performance. To assess the deformation, real-time and non-contact monitoring methods are necessary. In this study, a conceptual setup based on the waveplate rotation and dual-DoFP (division of focal-plane polarimeter) polarization camera is built for the observation window’s creep monitoring by measuring the Mueller matrix images of the samples under different pressures and durations. Then, a series of characteristic parameters, such as t1, R, r, R′, are extracted from the Muller matrix images by Mueller matrix transformation (MMT), Mueller matrix polar decomposition (MMPD), correlation analysis and phase unwrapping method. The results demonstrate that these parameters can effectively describe the observation window’s creep at different pressure levels which are simulated by finite element analysis. Additionally, more characterization parameters, such as ψ, A and D, are given from the Mueller matrix images and discussed to illustrate the method’s potential for further applications and investigations. Ultimately, future devices based on this method could serve as a valuable tool for real-time and non-contact creep monitoring of the submersible observation windows.
Effects of Defects on Masonry Confinement with Inorganic Matrix Composites
Authors: Lignola Gian Piero , Manfredi Gaetano , Prota Andrea
Published: July 2023

Fabric-reinforced cementitious matrix (FRCM) composites are currently considered a suitable solution for strengthening existing structures. Confinement applications are still being investigated, since experimental programs showed significant scatter in the results and theoretical models are struggling to become established as a consequence. The main aim of this study is the identification of potential sources of scatter in the confinement efficiency of FRCM wrappings, in defects such as fiber slip within the matrix or imperfect straightening of fibers, or premature failure of fibers once exposed after complete matrix cracking. A theoretical incremental approach is proposed to simulate such effects. The approach is incremental, but not iterative, so that no convergence is required and the incremental step size has an impact only on the smoothness of the nonlinear theoretical stress vs. strain curves of the FRCM confined material, among other simulation results. Theoretical results are compared to experimental outcomes of previous tests. The main source of variability can be identified in the cited defects, and the approach can be considered satisfactory to simulate the effects of defects and the high scatter found in experimental results; however, further uncertainties in the behavior of materials can be included in future refinements of this study.
FEM-GAN: A Physics-Supervised Deep Learning Generative Model for Elastic Porous Materials
Authors: Argilaga Albert
Published: July 2023

X-ray μCT imaging is a common technique that is used to gain access to the full-field characterization of materials. Nevertheless, the process can be expensive and time-consuming, thus limiting image availability. A number of existing generative models can assist in mitigating this limitation, but they often lack a sound physical basis. This work presents a physics-supervised generative adversarial networks (GANs) model and applies it to the generation of X-ray μCT images. FEM simulations provide physical information in the form of elastic coefficients. Negative X-ray μCT images of a Hostun sand were used as the target material. During training, image batches were evaluated with nonparametric statistics to provide posterior metrics. A variety of loss functions and FEM evaluation frequencies were tested in a parametric study. The results show, that in several test scenarios, FEM-GANs-generated images proved to be better than the reference images for most of the elasticity coefficients. Although the model failed at perfectly reproducing the three out-of-axis coefficients in most cases, the model showed a net improvement with respect to the GANs reference. The generated images can be used in data augmentation, the calibration of image analysis tools, filling incomplete X-ray μCT images, and generating microscale variability in multiscale applications.
Effects of Bi–Sn–Pb Alloy and Ball-Milling Duration on the Reactivity of Magnesium–Aluminum Waste-Based Materials for Hydrogen Production
Authors: Buryakovskaya Olesya A. , Ambaryan Grayr N. , Tarasenko Alexey B. , Suleimanov Musi Zh. , Vlaskin Mikhail S.
Published: July 2023

In the present study, composite materials were elaborated of mixed scrap of Mg-based casting alloys and low melting point Bi–Sn–Pb alloy by high energy ball milling, and their reactivity in NaCl solution with hydrogen release was tested. The impacts of the additive content and ball milling duration on their microstructure and hydrogen generation performance were investigated. Scanning electron microscopy (SEM) analysis revealed significant microstructural transformations of the particles during milling, and X-ray diffraction analysis (XRD) proved the formation of new intermetallic phases Mg3Bi2, Mg2Sn, and Mg2Pb. The said intermetallic phases were anticipated to act as ‘microcathodes’ enhancing galvanic corrosion of the base metal. The dependency of the samples’ reactivity on the additive content and milling duration was determined to be nonmonotonic. For the samples with 0, 2.5, and 5 wt.% Rose alloy, ball-milling during 1 h provided the highest hydrogen generation rates and yields (as compared to 0.5 and 2 h), while in the case of the maximum 10 wt.%, the optimal time shifted to 0.5 h. The sample activated with 10 wt.% Rose alloy for 0.5 h provided the highest ‘metal-to-hydrogen’ yield and rapid reaction, thus overperforming those with lower additive contents and that without additives.
Investigation of Asphalt Self-Healing Capability Using Microvasculars Containing Rejuvenator: Effects of Microvascular Content, Self-Healing Time and Temperature
Authors: Sun Qian , Wang Xin-Yu , Wang Sai , Shao Rong-Yue , Su Jun-Feng
Published: July 2023

The oily rejuvenator acted as the healing agent in microvasculars. A tensile test was designed to evaluate the self-healing efficiency of asphalt affected by microvascular number, self-healing time and temperature. It was found that the healing agent was slowly released through the microporous channels on the inner shell of the microvascular. The release modes of the agent can work together to improve the self-healing efficiency. The self-healing values of the three samples (asphalt, asphalt/microvasculars without rejuvenator and asphalt/microvasculars with rejuvenator) are 51%, 53%, and 71%. The self-healing capability of the asphalt samples with a healing agent is much greater than that of the other two without a healing agent at the same time. More microvascular rupture at the asphalt sample interface led to a higher self-healing efficiency. The self-healing efficiency values of the three samples (asphalt samples with one, two, and three microvasculars) are 52%, 67%, and 73%, respectively. The self-healing efficiency of the same sample increased during 1–3 days from 26% to 88% in one self-healing cycle. The self-healing efficiency value indicated that increasing the temperature improved each sample’s self-healing efficiency. The above trend of change also applies to the second self-healing process. A higher temperature reduces the resistance to molecular motion and accelerates the molecular action of bitumen and the healing agent. The time–temperature equivalence principle can be fully applied to comprehend asphalt self-healing.
Novel Insight into the Photophysical Properties and 2D Supramolecular Organization of Poly(3,4-ethylenedioxythiophene)/Permodified Cyclodextrins Polyrotaxanes at the Air–Water Interface
Authors: El Haitami Alae , Resmerita Ana-Maria , Ursu Laura Elena , Asandulesa Mihai , Cantin Sophie , Farcas Aurica
Published: July 2023

Two poly(3,4-ethylenedioxythiophene) polyrotaxanes (PEDOT∙TMe-βCD and PEDOT∙TMe-γCD) end-capped by pyrene (Py) were synthesized by oxidative polymerization of EDOT encapsulated into TMe-βCD or TMe-γCD cavities with iron (III) chloride (FeCl3) in water and chemically characterized. The effect of TMe-βCD or TMe-γCD encapsulation of PEDOT backbones on the molecular weight, thermal stability, and solubility were investigated in depth. UV–vis absorption, fluorescence (FL), phosphorescence (PH), quantum efficiencies, and lifetimes in water and acetonitrile were also explored, together with their surface morphology and electrical properties. Furthermore, dynamic light scattering was used to study the hydrodynamic diameter (DH) and z-potential (ZP-ζ) of the water soluble fractions of PEDOT∙TMe-βCD and PEDOT∙TMe-γCD. PEDOT∙TMe-βCD and PEDOT∙TMe-γCD exhibited a sharp monodisperse peak with a DH of 55 ± 15 nm and 122 ± 32 nm, respectively. The ZP-ζ value decreased from −31.23 mV for PEDOT∙TMe-βCD to −20.38 mV for PEDOT∙TMe-γCD, indicating that a negatively charged layer covers their surfaces. Surface pressure–area isotherms and Brewster angle microscopy (BAM) studies revealed the capability of the investigated compounds to organize into sizeable and homogeneous 2D supramolecular assemblies at the air–water interface. The control of the 2D monolayer organization through the thermodynamic parameters of PEDOT∙TMe-βCD and PEDOT∙TMe-γCD suggests potential for a wide range of optoelectronic applications.
Strength and Electrical Properties of Cementitious Composite with Integrated Carbon Nanotubes
Authors: Lushnikova Anna , Plé Olivier , De Souza Gomes Yago , Jia Xiaohui , Yang Wei
Published: July 2023

The main objective of this work was to study the effects of carbon nanotubes (CNTs) on the strength and electrical properties of cement mortar. Molecular dynamic simulations (MDSs) were carried out to determine the mechanical and electrical properties of a cementitious composite and its associated mechanisms. To model the atomic structure of a calcium silicate hydrate (C-S-H) gel, tobermorite 11Å was chosen. Single-walled carbon nanotubes (SWCNTs) embedded in a tobermorite structure were tested numerically. In particular, it was concluded that a piezoelectric effect can be effectively simulated by varying the concentration levels of carbon nanotubes. The deformation characteristics were analyzed by subjecting a sample to an electrical field of 250 MV/m in the z-direction in a simulation box. The results indicated a progressively stronger converse piezoelectric response with an increasing proportion of carbon nanotubes. Additionally, it was observed that the piezoelectric constant in the z-direction, denoted by d33, also increased correspondingly, thereby validating the potential for generating an electrical current during sample deformation. An innovative experiment was developed for the electrical characterization of a cementitious composite of carbon nanotubes. The results showed that the electrostatic current measurements exhibited a higher electric sensitivity for samples with a higher concentration of CNTs.
Study of the Macro and Micro Characteristics of and Their Relationships in Cemented Backfill Based on SEM
Authors: Zhao Fengwen , Hu Jianhua , Liu Taoying , Zhou Tan , Ren Qifan
Published: July 2023

Nuclear magnetic resonance can only quantitatively obtain porosity and pore size distribution, but as a conventional microstructure observation technology, scanning electron microscope (SEM) can select different magnifications to observe the microstructure of backfill materials. However, the processing of SEM images is not deep enough. In this paper, Image-Pro Plus 6.0 software was used to extract the data from SEM images, and the parameters of the area, and the perimeter, aspect ratio and roundness of the pores in the SEM images were obtained. The fractal characteristics of the pores in the SEM image were obtained by using the slit island method fractal theory. The concretization and quantification analysis of the pores’ complexity were achieved. A functional relationship model for the strength and pore parameters was constructed; thus, the influence law of pore characteristics on strength was quantitatively analyzed. The conclusions included: (1) Pore parameters indicate that most pores in backfill are irregular, and only a few pores are regular—however, the whole structure has good fractal characteristics (R2 > 0.96). (2) The fractal dimension of pores is directly proportional to the roundness, the aspect ratio, and the pore content of pores—which indicates that the complexity of pores is related to both pore shape and pore content. (3) The strength had a linear inverse relationship with the roundness, aspect ratio, pore content, and fractal dimension—which indicates that all characteristics of pores have a certain influence on the strength.
Compact and Polarization Insensitive Satellite Band Perfect Metamaterial Absorber for Effective Electromagnetic Communication System
Authors: Afsar Md. Salah Uddin , Faruque Mohammad Rashed Iqbal , Abdullah Sabirin , Al-Mugren K. S.
Published: July 2023

A commercially viable metal–dielectric–metal configured triple-band metamaterial absorber is offered in this paper. It is an aggregation of four compact symmetric circles, with a swastika-shaped metal structure, which are bonded by two split-ring resonators (SRRs). Copper (annealed) of electrical conductivity 5.8 × 107 Sm−1 is used for the ground plate and resonator portion of the top layer and an FR 4 dielectric of permittivity 4.3 is used as a substrate. The structural parameters of the unit cell were determined by a trial and error method. FIT-based 3D simulation software (CST microwave studio, 2019 version was used to characterize the proposed perfect metamaterial absorber (PMA). Three resonance peaks were observed at frequencies 3.03, 5.83 and 7.23 GHz with an absorbance of 99.84%, 99.03% and 98.26%, respectively. The numerical result has been validated by some authentic validation methods. Finally, a microwave network analyzer (PNA) of Agilent N5227 with waveguide ports were deployed for measurement. The simulation and experimental results show better harmony. The proposed PMA has a unique design and a small dimension with higher absorption compared to other contemporary studies. This special type of polarization, insensitive S- and C-band PMA, is designed for a telecommunication system via full-time raw satellite and radar feeds.
Application of Odd Harmonic Resonances of a Single Crystal to Generation and Reception of Superharmonic Waves for Sensitive Monitoring of Heat-Treated Materials
Authors: Jeong Hyunjo
Published: July 2023

In nonlinear ultrasonic testing, the quadratic and more recently cubic nonlinearity parameters are frequently measured as a quantitative indicator of damaged material state. Application of higher-order harmonics can improve the sensitivity of detection and monitoring for damages and microstructures due to their higher values of nonlinearity parameters. The excitation and reception of higher-order harmonics, so-called superharmonics, which use the third to fifth harmonics arising from nonlinear wave propagation, is not sufficiently investigated and applied. The purpose of this communication is to develop a highly sensitive superharmonic nondestructive technique that efficiently generates and receives third- and fifth-order harmonics using the odd harmonic resonances of a single piezoelectric crystal. The method focuses on the measurement of fifth harmonic generation and reception, and the calculation of the relative quintic nonlinearity parameter (δ’). The method also addresses the issue of source nonlinearity that may be contained in the measured fifth harmonic amplitude. The measurement results of δ’ for a series of precipitation heat-treated samples clearly show a much better sensitivity than the results of the cubic nonlinearity parameter (γ’). The proposed method enables a highly sensitive and true pulse-echo mode nonlinear ultrasound testing.
Anti-Inertia Disturbance Control of Permanent Magnet Synchronous Motor Based on Integral Time-Varying Fast Terminal Sliding Mode
Authors: Xie Fang , Ni Shilin , Wang Houying , Xu Jinghu , Zheng Ziang
Published: July 2023

To improve the speed control performance of a permanent magnet synchronous motor (PMSM) when the moment of inertia changes during operation, this paper studies an anti-inertia disturbance method based on integral time-varying fast terminal sliding mode control (ITFTSMC). First, the mechanical motion equation of the permanent magnet synchronous motor is established to obtain the inverse relationship between the moment of inertia and the rate of speed change. Second, the extended state observer is designed to identify the moment of inertia online and improve real-time tracking accuracy. Third, to solve the motor speed fluctuation caused by the sudden inertia change, an integral time-varying fast terminal sliding mode control method is proposed, which improves both speed stability through integral time-varying and rapidity through the fast terminal. The identified moment of inertia is then updated to the integral time-varying fast terminal sliding mode controller in real time to meet the dynamic performance of the permanent magnet synchronous motor when said inertia changes. Finally, simulation and comparative experiments were used to verify the feasibility and effectiveness of the abovementioned proposed methods.