bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of High-Speed Powder Feeding on Microstructure and Tribological Properties of Fe-Based Coatings by Laser Cladding
Authors: Wang Qiang , Qian Runling , Yang Ju , Niu Wenjuan , Zhou Liucheng , Pan Xinlei , Su Chengming
Published: November 2021

In order to improve the wear resistance of 27SiMn steel substrate, Fe-based alloy coatings were prepared by laser cladding technology in the present study. In comparison to the conventional gravity powder feeding (GF) process, high-speed powder feeding (HF) process was used to prepare Fe-based alloy coating on 27SiMn steel substrate. The effect of diversified energy composition of powder materials on the microstructure and properties of coatings were systematically studied. X-ray diffractometer (XRD), optical microscope (OM) and scanning electron microscope (SEM) were used to analyze the phase structure and microstructure of Fe-based alloy coatings, and the hardness and tribological properties were measured by the microhardness tester and ball on disc wear tester, respectively. The results show that the microstructure of conventional gravity feeding (GF) coatings was composed of coarse columnar crystals. In comparison, owing to the diversification of energy composition, the microstructure of the high-speed powder feeding (HF) coatings consists of uniform and small grains. The total energy of the HF process was 75.5% of that of the GF process, proving that high-efficiency cladding can be achieved at lower laser energy. The refinement of the microstructure is beneficial to improve the hardness and wear resistance of the coating, and the hardness of the HF coating increased by 9.4% and the wear loss decreased to 80.5%, compared with the GF coating. The wear surface of the HF coating suffered less damage, and the wear mechanism was slightly adhesive wear. In contrast, wear was more serious in the GF coating, and the wear mechanism was transformed into severe adhesive wear.
Study on Wear Resistance and Corrosion Resistance of HVOF Surface Coating Refabricate for Hydraulic Support Column
Authors: Wu Mian , Pan Lin , Duan Haitao , Wan Changxin , Yang Tian , Gao Mingchuan , Yu Siliang
Published: November 2021

The hydraulic support column bears loading and makes reciprocating motion ceaselessly for extended periods, so its service life is far shorter than that of the overall hydraulic support. This paper offers a comparative study on the surface coating of hydraulic support columns with hard chrome plating and high-velocity oxygen fuel (HVOF) thermal spraying refabricating to analyze the impact of different refabricating processes on the microstructure, hardness, corrosion resistance, and wear resistance of the coating (plating). The result shows that the structure of the HVOF coating is uniformly compact, and the HVOF WC10Co4Cr coating has better wear resistance, more than four times that of hard chrome plating. In the neutral salt spray test, the HVOF Ni60 coating shows rustiness at 720 h of the test, which suggests its corrosion resistance is nearly five times that of hard chrome plating. Hence, under the harsh corrosive wear environment, the refabricating HVOF Ni60 is a more suitable replacement for the hydraulic support column coating than the hard chrome plating. Thus, the HVOF Ni60 coating could be an effective replacement for hard chrome plating.
Ship Painting Process Design Based on IDBSACN-RF
Authors: Bu Henan , Yuan Xin , Niu Jianmin , Yu Wenjuan , Ji Xingyu , Lyu Hongyu , Zhou Honggen
Published: November 2021

The painting process is an essential part of the shipbuilding process. Its quality is directly related to the service life and maintenance cost of the ship. Currently, the design of the painting process relies on the experience of technologists. It is not conducive to scientific management of the painting process and effective control of painting cost. Therefore, an intelligent design algorithm for the ship painting process is proposed in this paper. Density-Based Spatial Clustering of Applications with Noise (DBSCAN) is used to form categories of painting objects by cluster analysis. The grey wolf optimization (GWO) is introduced to realize the adaptive determination of clustering parameters and avoid the deviation of clustering results. Then, a painting object classification model is constructed based on the random forest (RF). Finally, the recommendation of the painting process is realized based on the multi-objective evaluation function. Effectiveness is verified by taking the outer plate above the waterline of a shipyard H1127/7 as the object. The results show that the performance of DBSCAN is significantly improved. Furthermore, the accurate classification of painting objects by RF is achieved. The experiment proves that the dry film thickness qualification rate obtained by the painting process designed by IDBSCAN-RF is 92.3%, which meets the requirements of the performance standard of protective coatings (PSPC).
Experimental Study and Mathematical Modeling of the Processes Occurring in ZrN Coating/Silumin Substrate Systems under Pulsed Electron Beam Irradiation
Authors: Koval Nikolay N. , Koval Tamara V. , Krysina Olga V. , Ivanov Yurii F. , Teresov Anton D. , Moskvin Pavel V. , Tran My Kim An , Prokopenko Nikita A. , Petrikova Elizaveta A.
Published: November 2021

This paper presents a study of a combined modification of silumin, which included deposition of a ZrN coating on a silumin substrate and subsequent treatment of the coating/substrate system with a submillisecond pulsed electron beam. The local temperature on the samples in the electron-beam-affected zone and the thickness of the melt zone were measured experimentally and calculated using a theoretical model. The Stefan problem was solved numerically for the fast heating of bare and ZrN-coated silumin under intense electron beam irradiation. Time variations of the temperature field, the position of the crystallization front, and the speed of the front movement have been calculated. It was found that when the coating thickness was increased from 0.5 to 2 μm, the surface temperature of the samples increased from 760 to 1070 °C, the rise rate of the surface temperature increased from 6 × 107 to 9 × 107 K/s, and the melt depth was no more than 57 μm. The speed of the melt front during the pulse was 3 × 105 µm/s. Good agreement was observed between the experimental and theoretical values of the temperature characteristics and melt zone thickness.
RETRACTED: Advanced Binder-Free Electrode Based on CuCo2O4 Nanowires Coated with Polypyrrole Layer as a High-Performance Nonenzymatic Glucose Sensing Platform
Authors: Hatshan Mohammad , Aslam Sadia , Bokov Dmitry , Ibrahim Ahmed , Mustafa Yasser , Davarpanah Afshin , Elveny Marischa , Ali Shafaqat
Published: November 2021

In this work, the CuCo2O4 nanowires (CuCo2O4 NWs) were grown on carbon cloth electrode (CCE) and then coated with polypyrrole (pPy) layer (CuCo2O4 NWs-pPy@CCE). The morphology and structure characterization of as-prepared CuCo2O4 NWs-pPy@CCE were carried out using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field-emission scanning electron microscope (FESEM), thermogravimetric analysis (TGA), and transmission electron microscope (TEM). The CuCo2O4 NWs-pPy@CCE was applied directly as an electrocatalyst toward nonenzymatic glucose oxidation. Due to the advantages of this 3D structure, it offer high availability to the analyte/electrolyte, abundant electrochemical-active sites, and high stability and conductivity. As a glucose sensor, the CuCo2O4 NWs-pPy@CCE shows wide linear range (0.01 to 21.3 mM), excellent sensitivity (4.41 μA μM−1 cm−2), good selectivity, low detection limit (0.2 μM), and rapid response time (<1 s) toward glucose detection. Furthermore, the designed sensor shows a great ability in detection of glucose in biological real samples.
The Application of Deep Learning Algorithms for PPG Signal Processing and Classification
Authors: Esgalhado Filipa , Fernandes Beatriz , Vassilenko Valentina , Batista Arnaldo , Russo Sara
Published: November 2021

Photoplethysmography (PPG) is widely used in wearable devices due to its conveniency and cost-effective nature. From this signal, several biomarkers can be collected, such as heart and respiration rate. For the usual acquisition scenarios, PPG is an artefact-ridden signal, which mandates the need for the designated classification algorithms to be able to reduce the noise component effect on the classification. Within the selected classification algorithm, the hyperparameters’ adjustment is of utmost importance. This study aimed to develop a deep learning model for robust PPG wave detection, which includes finding each beat’s temporal limits, from which the peak can be determined. A study database consisting of 1100 records was created from experimental PPG measurements performed in 47 participants. Different deep learning models were implemented to classify the PPG: Long Short-Term Memory (LSTM), Bidirectional LSTM, and Convolutional Neural Network (CNN). The Bidirectional LSTM and the CNN-LSTM were investigated, using the PPG Synchrosqueezed Fourier Transform (SSFT) as the models’ input. Accuracy, precision, recall, and F1-score were evaluated for all models. The CNN-LSTM algorithm, with an SSFT input, was the best performing model with accuracy, precision, and recall of 0.894, 0.923, and 0.914, respectively. This model has shown to be competent in PPG detection and delineation tasks, under noise-corrupted signals, which justifies the use of this innovative approach.
Reinforcing SLA Consensus on Blockchain
Authors: Kapsoulis Nikolaos , Psychas Alexandros , Litke Antonios , Varvarigou Theodora
Published: November 2021

Cloud Infrastructure as a Service (IaaS) Service Level Agreements (SLAs) assessment constitutes the de facto area of interest and applications in the public cloud infrastructure. However, the domination of colossal corporations tends to monopolize the way metrics and Key Performance Indicators (KPIs) are measured and determined, leading to governed environments where the clientele is unable to obtain accurate and unbiased assessment of SLAs. Leaning toward SLA self-assessment, this paper provides a fair SLA consensus approach with innate transparency and privacy by leveraging permissioned blockchains that are equipped with Trusted Execution Environments (TEEs). The SLA assessment intelligence is performed inside enclaved smart contracts isolated from the on-chain entities views. The result constitutes a permissioned blockchain ecosystem where the IaaS and their clientele commonly agree on all the respective SLA monitoring and computation rules beforehand, as defined in any SLA assessment process, while the SLA consensus scheme constantly audits the SLA metrics based on these pre-approved regulations.
Physical Properties Investigations of Ternary-Layered Carbides M2PbC (M = Ti, Zr and Hf): First-Principles Calculations
Authors: Alrebdi Tahani A. , Kanoun Mohammed Benali , Goumri-Said Souraya
Published: November 2021

We investigated structure optimization, mechanical stability, electronic and bonding properties of the nanolaminate compounds Ti2PbC, Zr2PbC, and Hf2PbC using the first-principles calculations. These structures display nanolaminated edifices where MC layers are interleaved with Pb. The calculation of formation energies, elastic moduli and phonons reveal that all MAX phase systems are exothermic, and are intrinsically and dynamically stable at zero and under pressure. The mechanical and thermal properties are reported with fundamental insights. Results of bulk modulus and shear modulus show that the investigated compounds display a remarkable hardness. The elastic constants C11 and C33 rise more quickly with an increase in pressure than that of other elastic constants. Electronic and bonding properties are investigated through the calculation of electronic band structure, density of states, and charge densities.
Foam Glass Crystalline Granular Material from a Polymineral Raw Mix
Authors: Miryuk Olga , Fediuk Roman , Amran Mugahed
Published: November 2021

The article is devoted to the development of resource-saving technology of porous granular materials for energy-efficient construction. The relevance of the work for international research is to emphasize expanding the raw material base of porous lightweight concrete aggregates at the expense of technogenic and substandard materials. The work aims to study the processes of porization of glass crystalline granules from polymineral raw materials mixtures. The novelty of the work lies in the establishment of regularities of thermal foaming of glass crystalline granules when using waste of magnetic separation of skarn-magnetite (WMS) ores and lignite clay. Studies of liquid glass mixtures with various mineral fillers revealed the possibility of the formation of a porous structure with the participation of opoka, WMS and lignite clay. This is due to the presence in the materials of substances that exhibit thermal activity with the release of a gas phase. The foaming efficiency of the investigated materials increases when combined with glass breakage. The addition of WMS and lignite clay to the glass mixture increases the pore size in comparison with foam glass. The influence of the composition of raw mixtures on the molding and stability of granules is determined. The addition of sodium carbonate helps to strengthen the raw granules and reduce the softening temperature of the mass. The composition of the molding mixture of glass breakage, liquid glass and a multicomponent additive is developed, which provides an improvement in the molding properties of the glass mass, foaming of granules at a temperature of 750 °C. Foam glass crystalline granules have polymodal porosity, characterized by a density of 330–350 kg/m3, a compressive strength of 3.2–3.7 MPa, and a thermal conductivity of 0.057–0.061 W/(m·°C). Accordingly, the developed granules have a high potential use in structural and heat-insulating concretes.
Perspective/Discussion on “Quantum Mechanical Metric for Internal Cohesion in Cement Crystals” by C. C. Dharmawardhana, A. Misra and Wai-Yim Ching
Authors: Makul Natt
Published: November 2021

The single most important structural material, and the major Portland cement binding phase in application globally, is calcium silicate hydrate (C-S-H). The concentration has increasingly changed due to its atomic level comprehension because of the chemistry and complex structures of internal C-S-H cohesion in cement crystals at different lengths. This perspective aimed at describing on calcium-silicate-hydrates (C-S-H) structures with differing contents of Ca/Si ratio based on the report entitled “Quantum mechanical metric for internal cohesion in cement crystals” published by C. C. Dharmawardhana, A. Misra and Wai-Yim Ching. Crystal structural and bond behaviors in synthesized C-S-H were also discussed. The investigator studied large subset electronic structures and bonding of the common C-S-H minerals. From each bonding type, the results and findings show a wide variety of contributions, particularly hydrogen bonding, that allow critical analyses of spectroscopic measurement and constructions of practical C-S-H models. The investigator found that the perfect overall measurement for examining crystal cohesions of the complex substances is the total bond density (TBOD), which needs to be substituted for traditional metrics such as calcium to silicon ratios. In comparison to Tobermorite and Jennite, hardly known orthorhombic phased Suolunites were revealed to have greater cohesion and total order distribution density than those of the hydrated Portland cement backbone. The findings of the perspective showed that utilizing quantum mechanical metrics, the total bond orders and total bond order distributions are the most vital criteria for assessing the crystalline cohesions in C-S-H crystals. These metrics encompass effects of both interatomic interactions and geometric elements. Thus, the total bond order distribution and bond order offer comprehensive and in-depth measures for the overall behaviors of these diverse groups of substances. The total bond order distributions must clearly be substituted for the conventional and longstanding Ca/Si ratios applied in categorizing the cement substances. The inconspicuous Suolunite crystals were found to have the greatest total bond order distributions and the perfect bonding characteristics, compositions, and structures for cement hydrates.
Design of MFI Type Aluminum- and Titanium-Containing Zeolites
Authors: Kuz’micheva Galina M. , Domoroshchina Elena N. , Kravchenko Galina V.
Published: November 2021

HZSM-5 (MFI type) of composition (Hx)[Al3+xSi12−xO24] × wH2O and nanocomposites NA/HZSM-5, NA:M/HZSM-5 (NA—nanoscale anatase; M = V, Ni, Ag) with Si/Al = 12, 25, 40, 300 (sp.gr. Pnma or P21/n; z = 8), as well as zeolites [(Ti4+xSi12−xO24] × wH2O (TS) with Si/Ti = 47, 53, 73.5 (sp.gr. Pnma) were studied by XRPD, XAS, FTIR-spectroscopy, BET, XPS, SEM, EDX, TPD, UV–VIS-spectroscopy, UV–DRS, and chemiluminescence methods. The results obtained together with photocatalytic, adsorption, antimicrobial, catalytic properties were analyzed using crystallochemical concepts and literature data. It was shown that NA or NA:M introduction into HZSM-5 leads, respectively, to the photodegradation of MeO dye in the UV region or difenoconazole in the visible range, and contributes to the appearance in the dark of adsorption (almost complete extraction of P(V), As(V), and Se(V) from aquatic environment) and bacteriostatic properties in respect to Staphylococcus epidermidis, Bacillus antracoides, and Escherichia coli for NA:Ag/HZSM-5(40, 300). The presence of titanium ions in NA nanoparticles on the HZSM-5 surface improves the catalytic activity in ethanol and propane (the best performance for NA/HZSM-5(25) and NA/HZSM-5(40), respectively) conversion. Determination of the composition (surface and bulk) and structure (statistical and local) of TS zeolites together with the found correlations made it possible to propose new catalysts in the reactions of propane, ethanol, and allyl chloride conversion.
Two-Dimensional Composite Acoustic Metamaterials of Rectangular Unit Cell from Pentamode to Band Gap
Authors: Li Qi , Wu Ke , Zhang Mingquan
Published: November 2021

Pentamode metamaterials have been receiving an increasing amount of interest due to their water-like properties. In this paper, a two-dimensional composite pentamode metamaterial of rectangular unit cell is proposed. The unit cells can be classified into two groups, one with uniform arms and the other with non-uniform arms. Phononic band structures of the unit cells were calculated to derive their properties. The unit cells can be pentamode metamaterials that permit acoustic wave travelling or have a total band gap that impedes acoustic wave propagation by varying the structures. The influences of geometric parameters and materials of the composed elements on the effective velocities and anisotropy were analyzed. The metamaterials can be used for acoustic wave control under water. Simulations of materials with different unit cells were conducted to verify the calculated properties of the unit cells. The research provides theoretical support for applications of the pentamode metamaterials.
Effect of Overheating Temperature on Thermal Cycling Creep Properties of K465 Superalloy
Authors: Guo Xiaotong , Liang Zeshan , Nan Xiaobin , Jiang Chunxu , Li Yong , Li Li , He Liang , Yang Shizheng
Published: November 2021

Turbine blades in aircraft engines may encounter overheating and suffer serious creep property degradation. In this study, the thermal cycling creep experiments were conducted on K465 superalloy under (900 °C/30 min–1100 °C/3 min)/50 MPa, (900 °C/30 min–1150 °C/3 min)/50 MPa and (1000 °C/30 min–1150 °C/3 min)/50 MPa. The investigated thermal cycling creep properties were dramatically degraded, and increasing the overheating temperatures significantly decreased the thermal cycling creep life. The secondary γ′ precipitates obviously dissolved and the area fraction decreased to around 35.2% under (900 °C/30 min–1150 °C/3 min)/50 MPa and (1000 °C/30 min–1150 °C/3 min)/50 MPa, which was almost half that after the standard solution treatment. The decline of the thermal cycling creep properties was mainly due to the significant dissolution of γ′ precipitates. The creep holes/cracks were mainly distributed at the M6C carbides and γ/γ′ eutectics interfaces, M6C carbides and γ′ film interfaces in the grain boundaries, and resulted in the final intergranular fracture.
Study of the Effect of Y2O3 Doping on the Resistance to Radiation Damage of CeO2 Microparticles under Irradiation with Heavy Xe22+ Ions
Authors: Ivanov Igor , Rspayev Ruslan , Sapar Aset , Mustafin Daulet , Zdorovets Maxim , Kozlovskiy Artem
Published: November 2021

This paper presents the results of a study on the influence of Y2O3 doping on the resistance to radiation damage and an assessment of structural changes associated with the accumulation of radiation defects in CeO2 microparticles under irradiation with heavy Xe22+ ions. The relevance of this study consists of the prospects for the use of CeO2 microparticles as materials and candidates of inert matrices of nuclear fuel. A method of solid-phase synthesis was applied to obtain microparticles with different concentrations of dopant. It included grinding of CeO2 and Y2O3 microparticles followed by thermal sintering at 1100 °C in an oxygen-containing medium to produce highly ordered microparticles. During the study of the structural characteristics of the synthesized microparticles, it was found that increasing the dopant concentration from 0.05 mol.% to 0.15 mol.% leads to an increase in the crystallinity degree as well as a decrease in dislocation density. According to the results of the assessment of the resistance of microparticles to radiation damage, it was found that an increase in the dopant concentration leads to a decrease in swelling and structural distortion by more than 2.5–3 times, which indicates an increase in the radiation resistance.
Acoustic Focusing with Intensity Modulation Based on Sub-Wavelength Waveguide Array
Authors: Zhang Mingran , Gu Guangrui
Published: November 2021

Acoustic focusing with intensity modulation plays an important role in biomedical and life sciences. In this work, we propose a new approach for simultaneous phase and amplitude manipulation in sub-wavelength coupled resonant units, which has not been reported so far. Based on the equivalent impedance and refractive index modulation induced by the change of geometry, arbitrary amplitude response from 0 to 1 and phase shift from 0 to 2π is realized. Thus, the acoustic focusing with intensity modulation can be achieved via waveguide array. Herein, the focal length can be adjusted by alternating the length of supercell, and the whole system can work in a broadband of 0.872f0–1.075f0. By introducing the coding method, the thermal viscosity loss is reduced, and the wavefront modulation can be more accurate. Compared with previous works, our approach has the advantages of simple design and broadband response, which may have promising applications in acoustic communication, non-destructive testing, and acoustic holography.
Study on the Evolution of the γ′ Phase and Grain Boundaries in Nickel-Based Superalloy during Interrupted Continuous Cooling
Authors: Wang Haiping , Liu Dong , Wang Jianguo , Yang Yanhui , Rao Haodong , Wang Hai , Nan Jungang , Wang Longxiang
Published: November 2021

The formation of the irregular γ′ precipitates in the nickel-based superalloy Waspaloy was investigated during the continuous cooling, which is relevant to the cooling rates and interrupted temperature. The morphology of the γ′ precipitates was observed to change from a dispersed sphere to the flower-like one with the decreasing of the cooling rates. It was found that there are three modes of transportation of the solute atoms involved in relation to the γ′ precipitates: dissolution from the small γ′ precipitates to the γ matrix, diffusion to the large γ′ precipitates from the matrix, and the short distance among γ′ precipitates close to each other. Meanwhile, the slower cooling rates tend to result in the serrated grain boundaries, and the wavelength between successive peaks (λ) and the maximum amplitude (A) are larger with the decreasing of the cooling rates. The content of the low ΣCSL boundaries increases with the decreasing of the cooling rates, which is of great benefit in improving the creep property of the Waspaloy.
Flow Map for Hydrodynamics and Suspension Behavior in a Continuous Archimedes Tube Crystallizer
Authors: Sonnenschein Jana , Friedrich Pascal , Aghayarzadeh Moloud , Mierka Otto , Turek Stefan , Wohlgemuth Kerstin
Published: November 2021

The Archimedes Tube Crystallizer (ATC) is a small-scale coiled tubular crystallizer operated with air-segmented flow. As individual liquid segments are moved through the apparatus by rotation, the ATC operates as a pump. Thus, the ATC overcomes pressure drop limitations of other continuous crystallizers, allowing for longer residence times and crystal growth phases. Understanding continuous crystallizer phenomena is the basis for a well-designed crystallization process, especially for small-scale applications in the pharmaceutical and fine chemical industry. Hydrodynamics and suspension behavior, for example, affect agglomeration, breakage, attrition, and ultimately crystallizer blockage. In practice, however, it is time-consuming to investigate these phenomena experimentally for each new material system. In this contribution, a flow map is developed in five steps through a combination of experiments, CFD simulations, and dimensionless numbers. Accordingly, operating parameters can be specified depending on ATC design and material system used, where suspension behavior is suitable for high-quality crystalline products.
Raman Response of Quantum Critical Ferroelectric Pb-Doped SrTiO3
Authors: Linnik Ekaterina D. , Mikheykin Alexey S. , Rubi Diego , Shirokov Vladimir B. , Mezzane Daoud , Kondovych Svitlana V. , Lukyanchuk Igor A. , Razumnaya Anna G.
Published: November 2021

A quantum paraelectric SrTiO3 is a material situated in close proximity to a quantum critical point (QCP) of ferroelectric transition in which the critical temperature to the ferroelectric state is suppressed down to 0 K. However, the understanding of the behavior of the phase transition in the vicinity of this point remains challenging. Using the concentration x of Pb in solid solution Sr1−xPbxTiO3 (PSTx) as a tuning parameter and applying the combination of Raman and dielectric spectroscopy methods, we approach the QCP in PSTx and study the interplay of classical and quantum phenomena in the region of criticality. We obtain the critical temperature of PSTx and the evolution of the temperature-dependent dynamical properties of the system as a function of x to reveal the mechanism of the transition. We show that the ferroelectric transition occurs gradually through the emergence of the polar nanoregions inside the non-polar tetragonal phase with their further expansion on cooling. We also study the ferroelastic cubic-to-tetragonal structural transition, occurring at higher temperatures, and show that its properties are almost concentration-independent and not affected by the quantum criticality.
Effects of Fluorogypsum and Flue-Gas Desulfurization Gypsum on the Hydration and Hardened Properties of Alkali Slag Cement
Authors: Wang Cheng , He Hang , Wang Yuli , Xue Wenyue
Published: November 2021

In order to explore the influence of the types of waste gypsum on the properties of alkali slag cement, fluorogypsum (FG) and flue-gas desulfurization (FGD) gypsum were comparatively investigated. Moreover, the action mechanisms of FG and FGD gypsum on the properties of alkali slag cement were analyzed. The results show that both the FG and FGD gypsum prolonged the setting time of the alkali slag cement paste. However, the prolongation effect of FG was more pronounced than the FGD gypsum. When the compressive strength was maximum, the contents of FG and FGD gypsum were 5 and 6 wt.%, respectively. At 3 and 28 days, compared to the control sample, the compressive strengths increased by 59.3% and 24.3%, and 66.9% and 33.9%, respectively. Furthermore, the XRD, TG-DTA and SEM-EDS results showed that, with the increase in the contents of FG and FGD gypsum, ettringite was more easily produced and the hydration products were more abundant in the system. The greater the gypsum content of the paste, the less accumulated was the heat of hydration. The change of micro-structure caused by the formation of ettringite was the main reason for the difference in the properties of cement.
Prediction of Pore Volume Dispersion and Microstructural Characteristics of Concrete Using Image Processing Technique
Authors: K Dhanalakshmi , J Maheswaran. , Avudaiappan Siva , Amran Mugahed , Aepuru Radhamanohar , Fediuk Roman , Vatin Nikolai
Published: November 2021

Concrete has served an essential role in many infrastructural projects. Factors including pore percentage, pore distribution, and cracking affect concrete durability. This research aims to better understand pore size distribution in cement-based materials. Micro-computed tomography (micro-CT) pictures were utilised to characterise the interior structure of specimens without destroying them. The pore dispersion of the specimens was displayed in 3D, utilising the data and imaging techniques collected, and the pore volume dispersion was examined using a volume-based approach. Another way to describe heterogeneous pore features is the chord-length distribution, which was calculated from three-dimensional micro-CT scans and correlated with the traditional method. The collected specimens were subjected to physical and mechanical testing. In addition, image processing techniques were used to conduct the studies. The results showed that the chord-length distribution-based pore size distribution is very successful than the traditional volume-based technique. The acquired data could be used for research and to forecast the characteristics of the materials.
Chitosan/Selenium Nanoparticles Attenuate Diclofenac Sodium-Induced Testicular Toxicity in Male Rats
Authors: El-Megharbel Samy M. , Al-Salmi Fawziah A. , Al-Harthi Sarah , Alsolami Khadeejah , Hamza Reham Z.
Published: November 2021

The detrimental effect of diclofenac sodium (Diclo-Na) on male reproductive organs is reported upon in this paper. Chitosan is a polysaccharide composed of various amounts of glucosamine. Chitosan nanoparticles (CH-NPs) have attracted much attention owing to their biomedical activity. Selenium (Se) has a vital role in nutrition, plays an important role in enhancing male reproduction, and has a wide range of free radical scavenging activities. However, the study of the impact of chitosan nanoparticles in combination with Se (IV) (CH-NPs/Se) on male reproductive toxicity associated with Diclo-Na administration is lacking in recent literature. The current study assessed the ameliorative effects of complexes of CH-NPs/Se (IV) on Diclo-Na and the ways in which they alter reproductive toxicity in male rats. Male rats were treated for 30 days successively, either with Diclo-Na (10 mg/kg) or co-treated with a CH-NPs/Se complex (280 mg/kg). Sperm characteristics, marker enzymes of testicular function, LH, FSH, and testosterone were evaluated in addition to oxidative stress markers and histological alterations. CH-NPs/Se significantly alleviated Diclo-Na-induced decline in sperm count and motility, testicular function enzymes, and levels of LH and testosterone in serum. Additionally, CH-NPs/Se co-administration at 280 mg/Kg, inhibited the Diclo-Na-induced decline of antioxidant enzyme activities and elevated oxidative stress indices and reactive free radicals in testicular homogenates of male rats. CH-NPs/Se (280 mg/kg) alone improved Diclo-Na and ameliorated histological damages in exposed rats. In conclusion, chitosan improved testicular function in Diclo-Na-treated rats by enhancing the testosterone hormone levels, ameliorating testicular tissue, and inhibiting markers of oxidative stress in male rats.
Effect of Slab Reheating Temperature on Cold Rolling Texture Evolution of Nb-Containing Grain-Oriented Silicon Steel
Authors: Wang Liguang , Wang Shuhuan , Li Jie , Liang Jinyu , Feng Yunli
Published: November 2021

Texture control of grain-oriented silicon steel is the key factor to ensure the magnetic properties of the finished product. Nb-containing grain-oriented silicon steel with different slab reheating temperatures was hot rolled followed by single-stage or two-stage cold rolling, and the textures were also analyzed. In the single-stage cold rolling process, as the slab reheating temperature is reduced, the intensity of the rotating cube texture {100}<011> and Goss texture {011}<100> drops, and that of the {111}<112> texture increases. In the two-stage cold rolling process, with the decrease in the slab reheating temperature, the intensity of the {111}<112> texture increases from 4.958 to 6.809. At the same slab reheating temperature, the intensity of the rotating cube texture declines more significantly in the two-stage cold rolling process. Finally, two-stage cold rolling with the slab reheating temperature of 1220 °C is found to be more beneficial for the formation of a sharp Goss texture during the second recrystallization. The magnetic induction intensity B800 of the final product is 1.87 T, and the iron loss P1.7/50 is 1.36 W/kg.
Association between Ureteral Clamping Time and Acute Kidney Injury during Robot-Assisted Radical Cystectomy
Authors: Ishiyama Yudai , Kondo Tsunenori , Ishihara Hiroki , Yoshida Kazuhiko , Iizuka Junpei , Tanabe Kazunari , Takagi Toshio
Published: November 2021

Robot-assisted radical cystectomy (RARC) is replacing open radical cystectomy (ORC) and requires clamping of the ureters, resulting in a predisposition to postrenal acute kidney injury (AKI). We investigated the association between ureteral clamping or its duration and acute/chronic postoperative kidney function. Patients who underwent radical cystectomy (robotic or open) at two tertiary institutions during 2002–2021 were retrospectively enrolled. In those who underwent RARC, the maximum postoperative percentage serum creatinine level (%sCre) change was plotted against ureteral clamping duration. They were divided into two groups using the median clamping time (210 min), and the maximum %sCre change and percentage estimated glomerular filtration rate (%eGFR) change at 3–6 months (chronic) were compared between the ORC (no clamp), RARC < 210, and RARC ≥ 210 groups. In 44 RARC patients, a weak correlation was observed between the duration of ureteral clamping and %Cre change (R2 = 0.22, p = 0.001). Baseline serum creatinine levels were comparable between the groups. However, %sCre change was significantly larger in the RARC ≥ 210 group (N = 17, +32.1%) than those in the RARC < 210 (N = 27, +6.1%) and ORC (N = 76, +9.5%) groups (both, p < 0.001). Chronic %eGFR change was comparable between the groups. Longer clamping of the ureter during RARC may precipitate AKI; therefore, the clamping duration should be minimized.
Anthropogenic Food Utilization and Seasonal Difference in Diet of Cercopithecus lowei at a Community Protected Forest in Ghana
Authors: Bempah Godfred , Lu Changhu , Yi Yoonjung
Published: November 2021

In recent times, the diet and foraging behaviors of wild animals are influenced by anthropogenic foods since they often share their natural habitats with humans. We investigated the composition, preferred food item, contribution of anthropogenic food at garbage dump sites, and the seasonal effects on the diet of Lowe’s monkeys (Cercopithecus lowei) in the Duasidan Monkey Sanctuary, Ghana. We found that Lowe’s monkeys fed on 13 plant species, as well as anthropogenic foods and invertebrates. The composition of plant diet changed seasonally: Lowe’s monkeys relied more on buds in the dry season while they consumed more fruits in the wet season. However, anthropogenic food was a major component of the diet for both wet (34.8%) and dry seasons (41.3%), suggesting that the monkeys consistently rely on anthropogenic food throughout the year. Nevertheless, we did not observe any conflict between monkeys and local people. The results suggest that Lowe’s monkeys heavily rely on anthropogenic food at human garbage dumps while they maintain a part of their foraging activities in the wild, indicating a need for the proper management of garbage as well as the protection of the natural habitats of Lowe’s monkeys in the Duasidan Monkey Sanctuary, Ghana.
Do Active and Passive Antipredator Defences in the Toad Epidalea calamita Differ between Males and Females from Natural Habitats and Agrosystems?
Authors: Zamora-Camacho Francisco Javier
Published: November 2021

Due to their assumed costs, simultaneous antipredator strategies are expected to face trade-offs, which, however, could be milder in individuals subjected to a more intense predator pressure. In this work, I studied the relationship between locomotion and parotoid glands in the natterjack toad, Epidalea calamita. Specifically, I predicted that individuals with reduced sprint speed would rely more on their chemical defences, having larger and more aposematically coloured parotoid glands. In addition, I expected this trade-off to be more evident in females and toads from pine grove habitats, because, according to previous work, males and toads from agrosystems are under greater predator pressure. However, sprint speed showed no relationship with coloration, but toads with proportionally greater parotoid glands were also proportionally faster. Thus, the costs of these antipredator traits might not be high enough to make them interfere, or the benefits of simultaneous optimisation of sprint speed and parotoid gland size might outweigh the costs of it in some individuals. In any case, habitat and sex did not affect these relationships, so the trends detected are valid across sexes and the habitats studied.
Seasonal Variation in Fecal Glucocorticoid Levels and Their Relationship to Reproductive Success in Captive Populations of an Endangered Parrot
Authors: Ramos-Güivas Brian , Jawor Jodie M. , Wright Timothy F.
Published: November 2021

Many species are threatened with extinction, and captive breeding programs are becoming more common to avoid this outcome. These programs serve to prevent extinction and produce individuals for eventual reintroduction to natural populations in historical habitat. Captive animals experience different energetic demands than those in the wild, however, and as a result may have different levels of glucocorticoid hormones. Glucocorticoids help with responses to energetically expensive and potentially stressful situations. Elevated glucocorticoid levels can also potentially alter reproduction and other key behaviors, thus complicating successful captive breeding. The Puerto Rican parrot (Amazona vittata) is a critically endangered parrot that currently exists in only two wild and two captive populations. Its recovery program provides a good platform to better understand how glucocorticoid levels may relate to reproductive success under captive conditions. We validated a corticosterone assay in this species and used non-invasive techniques of measuring fecal glucocorticoid metabolites of males and females from two captive populations (Rio Abajo and El Yunque) of Puerto Rican parrots over two consecutive breeding seasons, 2017 and 2018, and the pre-breeding season of 2018, which occurred just after Hurricane Maria struck Puerto Rico. Our results show that levels of fecal glucocorticoid metabolites of males measured during the breeding season of 2018 negatively correlated to the number of total eggs and fertile eggs laid by pairs. In contrast, there was a positive relationship of female fecal glucocorticoid metabolite levels during the pre-breeding season of 2018 with total eggs laid. In males from the Rio Abajo population, we found seasonal differences in fecal glucocorticoid metabolite levels, with higher levels during the pre-breeding season of 2018 compared to both 2017 and 2018 breeding seasons. There was no difference in the mean value of male fecal glucocorticoid metabolites between the 2017 breeding season and 2018 breeding season which started four months after Hurricane Maria struck Puerto Rico. We did find sex differences during the pre-breeding season of 2018 in birds from the Rio Abajo population. Adjustments in the care routine of both populations that could reduce circulating baseline glucocorticoids and avoid frequent, sudden elevations of glucocorticoids should be considered. These results provide a baseline for future comparison with reintroduced populations of this endangered species and other species with captive breeding programs.
Validity of Pampus liuorum Liu & Li, 2013, Revealed by the DNA Barcoding of Pampus Fishes (Perciformes, Stromateidae)
Authors: Wei Jiehong , Wu Renxie , Xiao Yongshuang , Zhang Haoran , Jawad Laith A. , Wang Yajun , Liu Jing , Al-Mukhtar Mustafa A.
Published: November 2021

The genus Pampus contains seven valid species, which are commercially important fishery species in the Indo-Pacific area. Due to their highly similar external morphologies, Pampus liuorum has been proposed as a synonym of Pampus cinereus. In this study, partial sequences of COI (582 bp) and Cytb (1077 bp) were presented as potential DNA barcodes of six valid Pampus species and the controversial species P. liuorum. A species delimitation of the seven Pampus species was performed to verify their validities. Explicit COI barcoding gaps were found in all assessed species, except for P. liuorum and P. cinereus, which resulted from their smaller interspecific K2P distance (0.0034–0.0069). A Cytb barcoding gap (0.0200) of the two species was revealed, with a K2P distance ranging from 0.0237 to 0.0277. The longer Cytb fragment is thus a more suitable DNA barcode for the genus Pampus. In the genetic tree, using concatenated Cytb and COI sequences, the seven species reciprocally formed well-supported clades. Species delimitations with ABGD, GMYC, and bPTP models identified seven operational taxonomic units, which were congruent with the seven morphological species. Therefore, all of the seven analyzed species, including P. liuorum, should be kept as valid species.
Biogeography of Long-Jawed Spiders Reveals Multiple Colonization of the Caribbean
Authors: Čandek Klemen , Agnarsson Ingi , Binford Greta J. , Kuntner Matjaž
Published: November 2021

Dispersal ability can affect levels of gene flow thereby shaping species distributions and richness patterns. The intermediate dispersal model of biogeography (IDM) predicts that in island systems, species diversity of those lineages with an intermediate dispersal potential is the highest. Here, we tested this prediction on long-jawed spiders (Tetragnatha) of the Caribbean archipelago using phylogenies from a total of 318 individuals delineated into 54 putative species. Our results support a Tetragnatha monophyly (within our sampling) but reject the monophyly of the Caribbean lineages, where we found low endemism yet high diversity. The reconstructed biogeographic history detects a potential early overwater colonization of the Caribbean, refuting an ancient vicariant origin of the Caribbean Tetragnatha as well as the GAARlandia land-bridge scenario. Instead, the results imply multiple colonization events to and from the Caribbean from the mid-Eocene to late-Miocene. Among arachnids, Tetragnatha uniquely comprises both excellently and poorly dispersing species. A direct test of the IDM would require consideration of three categories of dispersers; however, long-jawed spiders do not fit one of these three a priori definitions, but rather represent a more complex combination of attributes. A taxon such as Tetragnatha, one that readily undergoes evolutionary changes in dispersal propensity, can be referred to as a ‘dynamic disperser’.
Diversity, Biogeography and Community Ecology of Ants: Introduction to the Special Issue
Authors: Andersen Alan N.
Published: November 2021

Ants are a ubiquitous, highly diverse and ecologically dominant faunal group [...]
Antarctic Special Protected Area 161 as a Reference to Assess the Effects of Anthropogenic and Natural Impacts on Meiobenthic Assemblages
Authors: Semprucci Federica , Appolloni Luca , Grassi Eleonora , Donnarumma Luigia , Cesaroni Lucia , Tirimberio Giuseppina , Chianese Elena , Di Donato Paola , Russo Giovanni , Balsamo Maria , Sandulli Roberto
Published: November 2021

The Antarctic region is usually considered a pristine area. Nevertheless, regional warming effects and increasing human activities, including the presence of several research stations, are inducing considerable environmental changes that may affect the ecosystem’s functions. Therefore, during the XXXIII Antarctic expedition, we carried out an investigation in Terra Nova bay (Ross Sea), close to the Antarctic Specially Protected Area (ASPA) n.161. In particular, we compared the effects of two different types of impacts on the meiobenthic assemblages: anthropogenic impact (AI), associated with the activity of Mario Zucchelli Research Station (MZS), and natural impact (NI) attributable to a large colony of Adélie penguins (Pygoscelis adeliae) in Adelie Cove. For each impacted site, a respective control site and two sampling depths (20 and 50 m) were selected. Several environmental variables (pH, dissolved oxygen, major and minor ions, heavy metals, organic load, and sediment grain size) were measured and analysed, to allow a comprehensive characterization of the sampling areas. According to the criteria defined by Unites States Environmental Protection Agency (US EPA 2009), heavy metal concentrations did not reveal critical conditions. However, both the MZS (AI20) and penguin colony (NI20) sites showed higher heavy metal concentrations, the former due to human activities related to the Italian research station, with the latter caused by the penguins excrements. Meiobenthic richness and abundance values suggested that the worst ecological condition was consistently related to the Adélie penguins colony. Furthermore, the higher contribution of r-strategists corroborates the hypothesis that the chronic impact of the penguin colonies may have stronger effects on the meiobenthos than the human activities at the MZS. Food is not limited in shallow Antarctic bottoms, and microscale differences in primary and secondary production processes can likely explain the greater spatial heterogeneity, highlighted both by the univariate and multivariate attributes of meiobenthic assemblage (i.e., richness, diversity, abundance, whole structure assemblage, and rare taxa) at the deeper stations. As reported in other geographical regions, the assemblage structure of rare meiobenthic taxa is confirmed to be more susceptible to environmental variations, rather than the whole assemblage structure.