bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Organic and Inorganic Fertilizers on Soil Nutrient Conditions in Rice Fields with Varying Soil Fertility
Authors: Ma Guozhu , Cheng Shenghai , He Wenli , Dong Yixuan , Qi Shaowu , Tu Naimei , Tao Weixu
Published: May 2023

The majority of crop-growing areas in China have low or medium fertility levels, which limits the yield of crops grown in those areas. Fertilizer application can improve soil quality, but the effects of such treatments vary depending on the base soil fertility. However, the specific differences associated with the application of different fertilizer types to soils of varying fertility levels have yet to be clearly delineated. Here, the influences of several fertilizer types on physical, chemical, and biological soil indicators were assessed in rice fields in the red soil area of Hunan Province with varying base fertility levels: Hehua (low fertility), Dahu (medium fertility), and Longfu (high fertility). Four treatments were applied to these fields: no fertilizer, standard fertilizer, 60% chemical fertilizer + 40% organic fertilizer, and 100% chemical fertilizer. Across the three sites and treatment groups, the largest increases in total nitrogen and phosphorus contents were in Hehua and Longfu, respectively. Soil organic matter content increased most significantly in Hehua. Application of any type of fertilizer increased the total and fast-acting nutrient content in the low-yielding fields, whereas organic fertilizers increased the nutrient content and soil biological indicators more than chemical fertilizer alone did; the effect of organic fertilizer application on the combined enzyme activity of the soil was also higher than that of chemical fertilizers alone. Overall, these experiments provide a theoretical basis and technical support for rational fertilizer application and improvement of Hunan’s red soil quality based on the natural soil fertility levels.
A Review of Research on Urban Playability from a Social Justice Perspective
Authors: Ye Yang , Yang Yuhan
Published: May 2023

Playability is an attribute that refers to the ability to stimulate individual responses or collective action in an immersive activity in an exploratory way. Playability is an important component of the enjoyment and well-being of urban dwellers, has the potential to stimulate urban vitality and is an important expression of the inclusiveness and equity of urban space. The pursuit of economic development and efficiency-oriented urban construction has led to the domination of urban space by overcrowded traffic, economy-oriented commerce and densely populated housing. Moreover, the existence of playable space has become a scarce resource and is seen as a site for the materialisation of social rights. As the haze of the COVID-19 pandemic fades and cities are again exposed to wider and more participatory use, determining how to adapt urban spaces to the playability needs of users of different ages, cultural backgrounds and social classes, and provide them with appropriate site use and experience, is becoming a hot issue of concern for building equitable and high-quality urban spaces. The study of the playability of urban spaces is highly complex, and the related research on social justice is cryptic. In order to better investigate the social equity aspects of urban playability, this paper integrates scientometric and manual methods to review the relevant research. This paper takes 2664 related papers from the Web of Science (WOS) core dataset from 1998 to 2022 as the research object and employs CiteSpace to organise the existing research results of playful urban spaces. Quantitative analysis is used to clarify the theoretical foundations, developments and research hotspots of urban spatial playability, while the manual collation and generalisation of the studies uncover the hidden issues of social justice research. Based on the proposed research method, we summarize the key three research stages related to urban spatial playability and social equity. We also discuss the development of urban spatial playability in the perspective of social justice from three aspects: micro, meso and macro. The results can help readers better understand the current status and development process of research on playful urban space. In particular, we clarify the issues related to social justice under the theme of the playability of urban spaces and provide directions for future research on building playful cities and promoting the development of urban socio-spatial equity.
Characteristics, Drivers, and Development Modes of Rural Space Commercialization under Different Altitude Gradients: The Case of the Mountain City of Chongqing
Authors: Lv Zhenyi , Yang Aoxi , Wang Yahui
Published: May 2023

The spatial commercialization of rural areas is essential to achieve rural reconstruction and promote overall rural rejuvenation. Through the use of a land use transfer matrix and kernel density, this study uncovers the pattern characteristics, driving forces, and development patterns of rural spatial commodification at various altitudes, providing a scientific reference for rural spatial usage at various altitudes. The main conclusions of this study are as follows: (1) rural spatial commercialization is the result of land use transformation, and the differences in rural spatial commercialization development patterns lead to different characteristics in the local land use changes; (2) the implementation of urbanization, industrialization, and rural revitalization strategies has promoted the development of rural spatial commercialization to some extent; (3) There are significant differences in the characteristics of the land use change and the development pattern of rural space commercialization at various altitudes. The areas below 500 m are mainly for recreational projects that have a repeatable consumption and that are distributed in a concentrated and continuous manner. For such areas, the agglomeration effect should be taken full advantage of, and thus they should be developed in groups. The areas between 500 and 1000 m serve mainly the surrounding residents; the mode is based on the leisure and recreational projects with a block-shaped spatial distribution. In such areas, branded rural spaces with special features should be created. The areas above 1000 m are used primarily to construct tourist attractions and are dispersed in a point pattern. In such areas, the transportation conditions should be improved and the rural resources revitalized by designing reasonable travel routes.
Spatial Distribution Characteristics and Driving Factors of Tourism Resources in China
Authors: Zhang Xiaodong , Han Haoying , Tang Yongjun , Chen Zhilu
Published: May 2023

The spatial distribution characteristics and influencing factors of tourist attractions in China are analyzed by GIS and SPSS. The spatial distribution characteristics and main influencing factors of urban landscape tourism resources in China are deeply explored in order to provide a reference for the construction of a national park system and for the optimal allocation of tourism resources in the future. The results show the following: (1) the spatial pattern of tourism resources in China is strong in the southeast and weak in the northwest. It shows the spatial structure of a global concentrated contiguous distribution, A-level zonal distribution, and national point distribution. The distribution pattern of concentrated contiguous areas is consistent with the spatial distribution of major urban agglomerations in China. (2) There is a serious imbalance in the allocation of A-level tourist attractions in Central, Southwest, Northwest, and Northeast China. The allocation of A-level tourist attractions in East China is in an absolute dominant position, whereas that in South China and North China is at a medium level. National tourism resources show obvious characteristics of being strong in the east and weak in the west. We mainly take the provincial capital city as the core point of agglomeration, showing the obvious “administrative district” distribution characteristics. (3) The level of urban management, the scale of urban construction, the development of the real estate industry, the employment population of tertiary industry, and the level of urban economic development are all factors that have a significant correlation with the spatial distribution of urban tourism resources.
Comparative Proteomic Analysis of the Venoms from the Most Dangerous Scorpions in Morocco: Androctonus mauritanicus and Buthus occitanus
Authors: Hilal Ines , Khourcha Soukaina , Safi Amal , Hmyene Abdelaziz , Asnawi Syafiq , Othman Iekhsan , Stöcklin Reto , Oukkache Naoual
Published: May 2023

Morocco is known to harbor two of the world’s most dangerous scorpion species: the black Androctonus mauritanicus (Am) and the yellow Buthus occitanus (Bo), responsible for 83% and 14% of severe envenomation cases, respectively. Scorpion venom is a mixture of biological molecules of variable structures and activities, most of which are proteins of low molecular weights referred to as toxins. In addition to toxins, scorpion venoms also contain biogenic amines, polyamines, and enzymes. With the aim of investigating the composition of the Am and Bo venoms, we conducted an analysis of the venoms by mass spectrometry (ESI-MS) after separation by reversed-phase HPLC chromatography. Results from a total of 19 fractions obtained for the Am venom versus 22 fractions for the Bo venom allowed the identification of approximately 410 and 252 molecular masses, respectively. In both venoms, the most abundant toxins were found to range between 2–5 kDa and 6–8 kDa. This proteomic analysis not only allowed the drawing of an extensive mass fingerprint of the Androctonus mauritanicus and Buthus occitanus venoms but also provided a better insight into the nature of their toxins.
Classical Borrelia Serology Does Not Aid in the Diagnosis of Persistent Symptoms Attributed to Lyme Borreliosis: A Retrospective Cohort Study
Authors: Stelma Foekje F. , Berende Anneleen , Ter Hofstede Hadewych , Vrijmoeth Hedwig D. , Vos Fidel , Kullberg Bart-Jan
Published: May 2023

Objective: The diagnosis of Lyme borreliosis is based on two-tier testing using an ELISA and Western blot. About 5–10% of patients report persistent symptoms of unknown etiology after treatment, resulting in substantial difficulties in further diagnostic workup. This paper presents a study aimed at determining whether serology can differentiate between patients with persistent symptoms attributed to Lyme and other patients with Lyme borreliosis. Methods: A retrospective cohort study included 162 samples from four subgroups: patients with persistent symptoms of Lyme (PSL), early Lyme borreliosis with erythema migrans (EM), patients tested in a general practitioner setting (GP), and healthy controls (HC). ELISA, Western blots, and multiplex assays from different manufacturers were used to determine inter-test variations in PSL and to compare reactivity against Borrelia-specific antigens among the groups. Results: In comparing the IgG and IgM reactivity by Western blot, IgG was more often positive in the PSL group than in the GP group. The individual antigen reactivity was similar between the PSL and EM or GP groups. Inter-test agreement among the manufacturers was variable, and agreement was higher for IgG testing compared to IgM. Conclusions: Serological testing is unable to define the subgroup of patients with persistent symptoms attributed to Lyme borreliosis. Additionally, the current two-tier testing protocol shows a large variance among different manufacturers in these patients.
Tribological Response of δ-Bi2O3 Coatings Deposited by RF Magnetron Sputtering
Authors: Rodil Sandra E. , Depablos-Rivera Osmary , Sánchez-López Juan Carlos
Published: May 2023

Bismuth oxide (Bi2O3) coatings and composite coatings containing this oxide have been studied due to their potential applications in gas sensing, optoelectronics, photocatalysis, and even tribology. Two parametric models based on chemical features have been proposed with the aim of predicting the lubricity response of oxides. However, such models predict contradictory values of the coefficient of friction (COF) for Bi2O3. In this study, we deposited Bi2O3 coatings, via magnetron sputtering, on AISI D2 steel substrates to evaluate the tribological responses of the coatings and determine which parametric model describes them better. Experimentally, only coatings presenting the cubic defective fluorite-like δ-Bi2O3 phase could be evaluated. We performed pin-on-disk tests at room temperature and progressively increasing temperatures up to 300 °C using alumina and steel counter-bodies. Low wear and COFs (0.05 to 0.15) indicated that the δ-phase behaves as a lubricious solid, favoring the validity of one of the models. An alternative explanation is proposed for the low COF of the defective fluorite-like structure since it is well known that it contains 25% of anionic vacancies that can be ordered to form low shear-strength planes, similar to the Magnéli phases. Two challenges for future potential applications were observed: one was the low adhesion strength to the substrate, and the other was the thermal stability of this phase.
Effect of CH4 Flow Rate on the Tribological Behaviors of TiCN Films against Si3N4 Ceramic and Steel Ball
Authors: Lyu Yanhong , Zheng Jianyun , Sun Huilian , Deng Xinrong , Liu Yang , Zhang Qiaoyu
Published: May 2023

Control of the structural, mechanical and tribological properties of TiCN films play an important role in its numerous applications, including the cutting tools, mechanical components, aeronautical and biomedical engineering industries. Direct-current magnetron sputtering (DCMS) system was applied to deposit TiCN films onto n-type silicon (100) at room temperature. The Ti-TiN interlayer was used to enhance the adhesive strength between the coating and the substrate. The composition and microstructure of the TiCN films were studied using X-ray photoelectron spectroscopy (XPS) and field-emitted scanning electron microscopy (FESEM). The mechanical properties of the films as a function of methane (CH4) flow ratio were then characterized using nano-indentation measurements. The tribological behavior of TiCN films was investigated by UMT-2MT tribometer against a Si3N4 ceramic and AISI52100 steel ball. After the tribological tests, the wear rate of the films was obtained by the 3D surface profiler and the component content of wear debris was evaluated by energy dispersive X-ray spectroscopy (EDS). The results show that the tribological properties of TiCN films are a function of CH4 flow rates. The film obtained at a 10 sccm CH4 flow rate possesses a minimum average COF value of 0.1964 and reaches 72,000 cycles against a Si3N4 ball over the test duration. Furthermore, the wear rate was only 2.076 × 10−6 mm3/N·m. Furthermore, the TiCN films exhibited longer lifespan against the Si3N4 ball than against the steel ball under the normal load of 1 N, indicating that the TiCN films present better lubricative properties when against low-hardness counterparts than high-hardness counterparts.
Potential Lubricating Mechanism of Hyaluronic Acid for a Reduction of Albumin-Mediated Friction in the Artificial Joint System
Authors: Su Chen-Ying , Lu Yi-Fang , Lu Yung-Chang , Huang Chang-Hung , Fang Hsu-Wei
Published: May 2023

The average lifespan of artificial joints is 15–25 years, but it is still too short for young and active patients. Human synovial albumin is easily adsorbed on the surfaces of artificial joint materials and has increased friction when subjected to conformational changes. Most studies have focused on the interaction between synovial fluid components and artificial joints when protein conformation has not been modified, but not on how to reduce friction and wear caused by denatured proteins. This study aimed to investigate whether hyaluronic acid could provide lubrication for albumin-mediated friction when high friction was caused by the disrupted secondary structure of albumin. Thermally processed human synovial albumin was used as denatured protein while friction testing, measurement of conformation, adsorption, and viscosity analysis were investigated. The results demonstrated that adding fresh hyaluronic acid to thermally processed albumin solution could reduce 50% of the friction coefficient caused by totally disrupted albumin. The viscosity of thermally processed albumin with fresh hyaluronic acid increased 40 times more than denatured albumin alone, and the adsorbed albumin area with fresh hyaluronic acid increased twice. The results showed hyaluronic acid provided lubrication by increasing the viscosity for friction mediated by denatured albumin, and it may provide a potential solution for prolonging the lifespan of artificial joints.
Dynamic of a Flexible Rotor-Bearing System Supported by Worn Tilting Journal Bearings Experiencing Rub-Impact
Authors: Tofighi-Niaki Ebrahim , Safizadeh Mir Saeed
Published: May 2023

Wear usually occurs in the loaded part of hydrodynamic bearings and leads to bearing geometry imperfections. This paper investigates the effects of wear-induced geometric imperfections of tilting pad journal bearings (TPJBs) on the dynamic behavior of the system. Furthermore, the effect of wear on the journal-bearing rub-induced contact pressure severity is investigated. A novel tribo-dynamic model is proposed for a flexible rotor-worn TPJB which integrates a mixed elastohydrodynamic model with a rotor-worn TPJB thermal and dynamic model to assess the effects of the bearing wear progression on rotor-TPJB behavior. Based on the results, wear changes the temperature distribution of the pads and oil film as well as the dynamic behavior of the system. Dynamic simulations reveal a higher vibration level and contact pressure for the worn TPJBs near the system’s critical speed and service speed. Finally, thermal and dynamic condition indicators are suggested to detect TPJB wear severity at its early stages.
(4Z,4′Z)-2,2′-(Ethane-1,2-diylbis(sulfanediyl))bis(1-phenyl)-4-(pyridin-2-ylmethylene)-1H-imidazol-5(4H)-one)dicopper(II) Tetrabromide
Authors: Al-Khazraji Ahmed S. H. , Berezina Anna V. , Bai Xiumei , Tafeenko Victor A. , Borisov Roman S. , Ofitserov Evgeny N. , Bian Jinlei , Shtil Alexander A. , Finko Alexander V.
Published: May 2023

The title compound was characterized for the first time by a full range of physical methods including UV, FTIR, mass spectrometry and X-ray structure determination. The copper atoms have a distorted tetrahedral structure close to a trigonal pyramid.
Relevant Aspects of Titanium Topography for Osteoblastic Adhesion and Inhibition of Bacterial Colonization
Authors: Rodriguez-González Raquel , Monsalve-Guil Loreto , Jimenez-Guerra Alvaro , Velasco-Ortega Eugenio , Moreno-Muñoz Jesus , Nuñez-Marquez Enrique , Pérez Roman A. , Gil Javier , Ortiz-Garcia Ivan
Published: May 2023

The influence of the surface topography of dental implants has been studied to optimize titanium surfaces in order to improve osseointegration. Different techniques can be used to obtain rough titanium, however, their effect on wettability, surface energy, as well as bacterial and cell adhesion and differentiation has not been studied deeply. Two-hundred disks made of grade 4 titanium were subjected to different treatments: machined titanium (MACH), acid-attacked titanium (AE), titanium sprayed with abrasive alumina particles under pressure (GBLAST), and titanium that has been treated with GBLAST and then subjected to AE (GBLAST + AE). The roughness of the different treatments was determined by confocal microscopy, and the wettability was determined by the sessile drop technique; then, the surface energy of each treatment was calculated. Osteoblast-like cells (SaOs-2) were cultured, and alkaline phosphatase was determined using a colorimetric test. Likewise, bacterial strains S. gordonii, S. oralis, A. viscosus, and E. faecalis were cultured, and proliferation on the different surfaces was determined. It could be observed that the roughness of the GBLAST and GBLAS + AE was higher, at 1.99 and 2.13 μm of Ra, with respect to the AE and MACH samples, which were 0.35 and 0.20 μm, respectively. The abrasive treated surfaces showed lower hydrophilicity but lower surface energy. Significant differences could be seen at 21 days between SaOS-2 osteoblastic cell adhesion for the blasted ones and higher osteocalcin levels. However, no significant differences in terms of bacterial proliferation were observed between the four surfaces studied, demonstrating the insensitivity of bacteria to topography. These results may help in the search for the best topographies for osteoblast behavior and for the inhibition of bacterial colonization.
Determination of the Strength of Consolidated Powder Materials with a Pull-Based Tester
Authors: Wajs Justyna , Wiącek Joanna , Horabik Józef , Stasiak Mateusz
Published: May 2023

In recent years, there has been increasing interest in the agglomeration of bulk materials. New methods are being sought to improve the measurement of bulkiness in food powders. This study aimed to design a new measuring device to assess the phenomenon of caking as well as the degree of strength of free-flowing powders. Wheat flour and potato starch have been used in the experiment and loaded into a perforated container. A steel or polypropylene measuring rod has been placed in the middle, and 5 kPa and 10 kPa were loaded, respectively. The new method is based on measuring the force through a sensor when pulling out measuring rods from the powder sample. It was shown that higher strength values have been obtained for powders loaded with 10 kPa and that groove depth has not been significant for wheat flour. Additionally, a significant difference in the evolution of the pulling force with time has been observed for wheat flour and starch, revealing a slip-stick phenomenon in the latter one. The pull-based tester is characterized by fast measurement and easy analysis of the results. The tests performed for potato starch and wheat flour have provided significantly different temporal evolutions of the pulling force.
Simulation of Work Hardening in Machining Inconel 718 with Multiscale Grain Size
Authors: Zhuang Kejia , Wang Zhuo , Zou Linli , Fu Changni , Weng Jian
Published: May 2023

Machining nickel-based alloys always exhibits significant work-hardening behavior, which may help to improve the part quality by building a hardened layer on the surface, while also causing severe tool wear during machining. Hence, modeling the work-hardening phenomenon plays a critical role in the evaluation of tool wear and part quality. This paper aims to propose a numerical model to estimate the work-hardening layer for a deeper understanding of this behavior, employing both recrystallization-based and dislocation-based models to cover workpieces with multiscale grain sizes. Different user routines are implemented in the finite element method to simulate the increase in hardness in the deformed area due to recrystallization or changes in the dislocation density. The validation of the proposed model is performed with both literature and experimental data for Inconel 718 with small or large grain sizes. It is found that the recrystallization-based model is more suitable for predicting the work-hardening behavior of small-grain-size Inconel 718 and the dislocation-based model is better for that of large-grain-size Inconel 718. Further, as an important type of cutting tool in machining Inconel 718, the chamfered tools with different edge geometries are employed in the simulations of machining-induced work hardening. The results illustrate that the uncut chip thickness and chamfer angle have a significant influence on the work-hardening behavior.
Advanced Mass Spectrometric Techniques for the Comprehensive Study of Synthesized Silicon-Based Silyl Organic Compounds: Identifying Fragmentation Pathways and Characterization
Authors: Rogowska Agnieszka , Szultka-Młyńska Małgorzata , Kanawati Basem , Pomastowski Paweł , Arendowski Adrian , Gołębiowski Adrian , Schmitt-Kopplin Phillipe , Fordymacka Marta , Sukiennik Jarosław , Krzywik Julia , Buszewski Bogusław
Published: May 2023

The primary objective of this study was to synthesize and characterize novel silicon-based silyl organic compounds in order to gain a deeper understanding of their potential applications and interactions with other compounds. Four new artificial silyl organic compounds were successfully synthesized: 1-O-(Trimethylsilyl)-2,3,4,6-tetra-O-acetyl-β-d-glucopyranose (compound 1), 1-[(1,1-dimethylehtyl)diphenylsilyl]-1H-indole (compound 2), O-tert-butyldiphenylsilyl-(3-hydroxypropyl)oleate (compound 3), and 1-O-tert-Butyldiphenylsilyl-myo-inositol (compound 4). To thoroughly characterize these synthesized compounds, a combination of advanced mass spectrometric techniques was employed, including nanoparticle-assisted laser desorption/ionization mass spectrometry (NALDI-MS), Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), and triple quadrupole electrospray tandem mass spectrometry (QqQ ESI-MS/MS). These analytical methods enabled the accurate identification and characterization of the synthesized silyl organic compounds, providing valuable insights into their properties and potential applications. Furthermore, the electrospray ionization–Fourier transform ion cyclotron resonance–tandem mass spectrometry (ESI-FT-ICR-MS/MS) technique facilitated the proposal of fragmentation pathways for the ionized silyl organic compounds, contributing to a more comprehensive understanding of their behavior during mass spectrometric analysis. These findings suggest that mass spectrometric techniques offer a highly effective means of investigating and characterizing naturally occurring silicon-based silyl organic compounds, with potential implications for advancing research in various fields and applications in different industries.
The Microstructure Evolution and Mechanical Properties of Rotary Friction Welded Duplex Stainless Steel Pipe
Authors: Zhang Shuxin , Xie Faqin , Wu Xiangqing , Luo Jinheng , Li Weiwei , Yan Xi
Published: May 2023

The use of duplex stainless steel (DSS) in various fields is promising due to its excellent anti-corrosion properties, but traditional welding can lead to the formation of unfavorable phases that deteriorate its quality. This study aimed to use the rotary friction weld (RFW) technique to prevent the formation of harmful phases in the welding of an S32205 alloy pipe. The welding parameters used included a rotating speed of 20 m/s, a friction pressure of 10 MPa, a friction time of 30 s, and a forging pressure of 30 MPa. The microstructure and mechanical properties of the resulting RFWed joint were investigated. The results revealed that the weld zone exhibited a microstructure consisting of ferrite and austenite phases, with no deleterious phase detected. The ferrite content was measured to be 53.3%, 54.5%, and 68.7% in the base metal, thermomechanical affected zone (TMAZ), and weld, respectively, owing to the rapid cooling rate in the RFW process, which prevented any harmful phase formation in the weld zone. Furthermore, the RFW process successfully produced an ultrafine grain with a ferrite/austenite grain size of 0.40 μm and 0.41 μm, respectively. The weld zone and TMAZ contained more low-angle grain boundaries (LAGBs) compared to the base metal, which was attributed to the dynamic recovery (DRV) within a grain. The high heating and cooling rates and short welding time of the RFW process did not allow sufficient time for the dynamic recrystallization of the microstructure in the weld zone. However, a slight increase in the ferrite content in the weld zone resulted in grain refinement and an increase in the dislocation density, resulting in a slight increase in the 358 HV0.2 hardness and 823 MPa tensile strength of the weld zone. This study offers a novel approach for obtaining ultrafine grain duplex stainless steel pipes with exceptional mechanical properties through the application of RFW.
Sound Quality Performance of Orthogonal Antisymmetric Composite Laminates Embedded with SMA Wires
Authors: Huang Yizhe , Hu Jiangbo , Wang Jun , Sun Jinfeng , You Ying , Huang Qibai , Xu Enyong
Published: May 2023

Orthogonal antisymmetric composite laminates embedded with shape memory alloys (SMAs) wires have the potential to improve the sound quality of vibro-acoustics by taking advantage of the special superelasticity, temperature phase transition, and pre-strain characteristics of SMAs. In this research, space discretion and mode decoupling were employed to establish a vibro-acoustic sound quality model of SMA composite laminates. The association between the structural material parameters of SMA composite laminates and the sound quality index is then approached through methodologies. Numerical analysis was implemented to discuss the effects of SMA tensile pre-strain, SMA volume fraction, and the ratio of resin-to-graphite in the matrix on the vibro-acoustic sound quality of SMA composite laminates within a temperature environment. Subsequently, the sound quality test for SMA composite laminates is thus completed. The theoretically predicted value appears to agree well with the experimental outcomes, which validates the accuracy and applicability of the dynamic modeling theory and method for the sound quality of SMA composite laminates. The results indicate that attempting to alter the SMA tensile pre-strain, SMA volume fraction, and matrix material ratio can be used to modify loudness, sharpness, and roughness, which provides new ideas and a theoretical foundation for the design of composite laminates with decent sound quality.
Recent Advances in Alkali-Activated Materials with Seawater and Sea Sand
Authors: Sun Zengqing , Li Xiaoyu , Liu Qingsong , Tang Qingyu , Lin Xiaochen , Fan Xiaohui , Huang Xiaoxian , Gan Min , Chen Xuling , Ji Zhiyun
Published: May 2023

The development of sustainable cementitious materials is essential and urgent for the construction industry. Benefiting from excellent engineering properties and a reduced greenhouse gas footprint, alkali-activated materials (AAM) are among the robust alternatives to Portland cement for civil infrastructure. Meanwhile, concrete production also accounts for around 20% of all industrial water consumption, and the global freshwater shortage is increasing. This review discusses recent investigations on seawater-mixed AAMs, including the effects of seawater on workability, reaction mechanism, shrinkage, short and long-term strength, binding of chloride and corrosion of steel reinforcement. Attention is also paid to the utilization of sea sand as aggregate, as well as discussions on the challenges and further research perspectives on the field application of AAMs with seawater and sea sand.
Stochastic Vibrations of a System of Plates Immersed in Fluid Using a Coupled Boundary Element, Finite Element, and Finite Difference Methods Approach
Authors: Guminiak Michał , Kamiński Marcin , Lenartowicz Agnieszka , Przychodzki Maciej
Published: May 2023

The main objective of this work is to investigate the natural vibrations of a system of two thin (Kirchhoff–Love) plates surrounded by liquid in terms of the coupled Stochastic Boundary Element Method (SBEM), Stochastic Finite Element Method (SFEM), and Stochastic Finite Difference Method (SFDM) implemented using three different probabilistic approaches. The BEM, FEM, and FDM were used equally to describe plate deformation, and the BEM was applied to describe the dynamic interaction of water on a plate surface. The plate’s inertial forces were expressed using a diagonal or consistent mass matrix. The inertial forces of water were described using the mass matrix, which was fully populated and derived using the theory of double-layer potential. The main aspect of this work is the simultaneous application of the BEM, FEM, and FDM to describe and model the problem of natural vibrations in a coupled problem in solid–liquid mechanics. The second very important novelty of this work is the application of the Bhattacharyya relative entropy apparatus to test the safety of such a system in terms of potential resonance. The presented concept is part of a solution to engineering problems in the field of structure and fluid dynamics and can also be successfully applied to the analysis of the dynamics of the control surfaces of ships or aircraft.
Corrosion Resistance of Al0.5CoCrFeNiCuxAgy (x = 0.25, 0.5; y = 0, 0.1) High-Entropy Alloys in 0.5M H2SO4 Solution
Authors: Samoilova Olga , Pratskova Svetlana , Shaburova Nataliya , Ostovari Moghaddam Ahmad , Trofimov Evgeny
Published: May 2023

The electrochemical behavior of the as-cast Al0.5CoCrFeNiCuxAgy (x = 0.25, 0.5; y = 0, 0.1) high-entropy alloys (HEAs) in a 0.5M H2SO4 solution was studied. Polarization measurements were carried out in a standard three-electrode electrochemical cell at room temperature using a platinum counter electrode and a saturated silver chloride reference electrode. For Al0.5CoCrFeNiCu0.5 and Al0.5CoCrFeNiCu0.5Ag0.1, copper segregation along the grain boundaries was observed, which highly dissolved in the sulfuric acid solution and resulted in low corrosion resistance of the samples. Introducing Ag into Al0.5CoCrFeNiCu0.25 HEA led to the precipitation of a copper–silver eutectic structure, in which the copper regions were selectively dissolved in the sulfuric acid solution. Al0.5CoCrFeNiCu0.25 exhibited the best corrosion resistance with the corrosion current density of Icorr = 3.52 ± 0.02 μA/cm2, significantly superior to that of the Al0.5CoCrFeNi sample without copper and silver (Icorr = 6.05 ± 0.05 μA/cm2). Finally, the results indicated that suppressing elemental segregation by annealing or tailoring chemical composition is essential to improve the corrosion resistance of Al0.5CoCrFeNiCuxAgy HEAs.
Effects of Waste Glass Powder on Rheological and Mechanical Properties of Calcium Carbide Residue Alkali-Activated Composite Cementitious Materials System
Authors: Chen Youzhi , Wu Xiuqi , Yin Weisong , Tang Shichang , Yan Ge
Published: May 2023

As a municipal solid waste, waste glass undergoes pozzolanic activity when ground to a certain fineness. In this paper, calcium carbide residue (CCR) and Na2CO3 were used as composite alkali activators for a glass powder-based composite cementitious system. A total of 60% fly ash (FA) and 40% ground granulated blast furnace slag (GGBS) were used as the reference group of the composite cementitious material system, and the effects of 5%, 10%, 15%, and 20% glass powder (GP) replacing FA on the rheological behavior, mechanical properties, and microstructure of alkali-activated composite cementitious systems were investigated. The results showed that with the increase in GP replacing FA, the fluidity of the alkali-activated materials gradually decreased, the shear stress and the equivalent plastic viscosity both showed an increasing trend, and the paste gradually changed from shear thinning to shear thickening. Compared with the reference sample, the fluidity of the alkali-activated material paste with a 20% GP replacement of FA was reduced by 15.3%, the yield shear stress was increased by 49.6%, and the equivalent plastic viscosity was elevated by 32.1%. For the 28d alkali-activated material pastes, the compressive strength and flexural strength were increased by 13% and 20.3%, respectively. The microstructure analysis showed the substitution of FA by GP promoted the alkali-activated reaction to a certain extent, and more C-A-S-H gel was formed.
Ex Situ Study on the Co-Preparation of Pitch and Carbon Black from Petroleum Residue to Improve the Cost-Efficiency of the Pitch Synthesis Plant
Authors: Kim Ji-Hong
Published: May 2023

This study aims to improve the economic efficiency of the pitch synthesis reaction on the pilot plant by optimizing the pitch synthesis reaction and utilization of the byproduct. The pitch was synthesized using a 150 L pilot plant with pyrolyzed fuel oil as a precursor. The pitch synthesis reaction is carried out through volatilization and polycondensation, which occur at 300 and 400 °C. Volatilization is terminated during heating; thus, additional soaking time is meaningless and reduces the process efficiency. Soaking time is a major variable when the synthesis temperature exceeds 400 °C. The byproduct is generated through volatilization; thus, its chemical characteristics are only influenced by the reaction temperature. The byproduct consists of various polycyclic aromatic hydrocarbons. The average molecular weight and yield of the byproduct increase with the reaction temperature. Carbon black was synthesized using chemical vapor deposition from the byproduct. The particle size of carbon black was controlled by the used precursor (byproduct), and the electrical conductivity of prepared carbon black has a maximum of 58.0 S/cm. Therefore, carbon black, which is synthesized from the byproduct of pitch synthesis, is expected to be used as a precursor for conductive material used in lithium-ion batteries or supercapacitors.
Clarithromycin-Loaded Submicron-Sized Carriers: Pharmacokinetics and Pharmacodynamic Evaluation
Authors: Rawat Reetika , Chouhan Raghuraj Singh , Sadhu Veera , Sharma Manu
Published: May 2023

The current study aims to improve clarithromycin bioavailability and effectiveness in complicated intra-abdominal infection management. Therefore, clarithromycin-loaded submicron dual lipid carriers (CLA-DLCs) were developed via hot high shear homogenization technique and evaluated for colloidal parameters, release behavior, stability study, and in-vitro antibiofilm activity. Bioavailability and therapeutic efficacy of optimized formulation on hampering cytokines storm induction was determined in E. coli-induced peritonitis. The developed CLA-DLCs (particle size 326.19 ± 24.14 nm, zeta potential −31.34 ± 2.81 mV, and entrapment efficiency 85.78 ± 4.01%) exhibited smooth spherical shapes and sustained in vitro release profiles. Long-term stability study of optimized CLA-DLCs ensured maintenance of colloidal parameters for 1 year at room temperature. In vitro antimicrobial studies revealed 3.43-fold higher anti-biofilm activity of CLA-DLCs compared with clarithromycin. In addition, the relative bioavailability of CLA-DLCs was enhanced 5.89-fold compared to pure drug in rats. The remarkable decrease in microbial burden in blood as well as tissues, along with oxidative stress markers (lipid peroxidation, myeloperoxidase activity, and carbonylated protein level) and immunological markers (total leukocyte count, neutrophil migration, NO, TNF-, and IL-6) on treatment with CLA-DLCs enhanced the survival in a rat model of peritonitis compared with the pure drug and untreated groups. In conclusion, CLA-DLCs hold promising potential in management of intra-abdominal infections and prevention of associated complications.
A 3D Reduced Common Mode Voltage PWM Algorithm for a Five-Phase Six-Leg Inverter
Authors: Fernandez Markel , Robles Endika , Aretxabaleta Iker , Kortabarria Iñigo , Andreu Jon , Martín José Luis
Published: May 2023

Neutral point voltage control converters (NPVCC) are being considered for AC drive applications, where their additional degree of freedom can be used for different purposes, such as fault tolerance or common mode voltage (CMV) reduction. For every PWM-driven converter, the CMV is an issue that must be considered since it can lead to shaft voltages between rotor and stator windings, generating bearing currents that accelerate bearing degradation, and can also produce a high level of electromagnetic interference (EMI). In light of these considerations, in this paper a three-dimensional reduced common mode voltage PWM (3D RCMV-PWM) technique is proposed which effectively reduces CMV in five-phase six-leg NPVCCs. The mathematical description of both the converter and the modulation technique, in space-vector and carrier-based approaches, is included. Furthermore, the simulation and experimental analysis validate the CMV reduction capability in addition to the good behaviour in terms of the efficiency and harmonic distortion of the proposed RCMV-PWM algorithm.
A Cu12 Metallacycle Assembled from Four C3-Symmetric Spin Frustrated Triangular Units
Authors: Ali Basharat , David Grégoire , Gendron Frédéric , Li Xiao-Lei , Cador Olivier , Plass Winfried , Le Guennic Boris , Tang Jinkui
Published: May 2023

Assembling metallacycles with interesting topological arrangements is a critical task for chemists. We report here a novel dodecanuclear CuII compound, [{Cu3L(µ-N3)}4(Py)14]·2Py (Cu12) (where Py = pyridine and [H6L]Cl = tris(2-hydroxybenzylidine)triaminoguanidinium chloride, respectively), with the topology of a cycle accomplished by four two-connecting approximately flat C3-symmetric guanidine-based ligands. Each ligand affords three tridentate metal-binding cavities and the four node-to-node connections through single azido bridges are provided by pairs of metal centers. A theoretical investigation using CASSCF in addition to DFT calculations showed strong antiferromagnetic coupling within the Cu3-triangles, resulting in spin-frustrated systems. However, these calculations were not able to properly reproduce the very weak antiferromagnetic couplings between the triangle units, highlighting the challenge of describing the magnetic behavior of this compound.
Dirichlet and Neumann Boundary Value Problems for Dunkl Polyharmonic Equations
Authors: Yuan Hongfen , Karachik Valery
Published: May 2023

Dunkl operators are a family of commuting differential–difference operators associated with a finite reflection group. These operators play a key role in the area of harmonic analysis and theory of spherical functions. We study the solution of the inhomogeneous Dunkl polyharmonic equation based on the solutions of Dunkl–Possion equations. Furthermore, we construct the solutions of Dirichlet and Neumann boundary value problems for Dunkl polyharmonic equations without invoking the Green’s function.
Efficient Decision Making for Sustainable Energy Using Single-Valued Neutrosophic Prioritized Interactive Aggregation Operators
Authors: Riaz Muhammad , Farid Hafiz Muhammad Athar , Antucheviciene Jurgita , Demir Gülay
Published: May 2023

To reduce greenhouse gas emissions, conserve the environment, and reduce dependency on fossil fuels, the transition from fossil energy to renewable energy is deemed essential. Several companies around the globe, especially big conglomerates, were pioneers in the use of renewable energy. For sustainable growth, Pakistani businesses are growing increasingly interested in the use of green sources in manufacturing and economic activities. In recent years, there has been a growth in the number of companies that are eager to use renewable energies to produce products that correspond to green standards, therefore boosting their competitiveness. Yet, the selection of an appropriate energy source for any industrially complex project is not a simple task, as numerous qualitative and quantitative characteristics must be considered. To arrive at a feasible conclusion, this research provides a multi-criteria paradigm for sustainable energy selection in a single-valued neutrosophic environment. This work developed an innovative aggregation operators approach that interprets the input evaluation using single-valued neutrosophic numbers. For this, a “single-valued neutrosophic prioritized interactive weighted averaging operator and single-valued neutrosophic prioritized interactive weighted geometric operator” has been introduced. Several additional appealing features of these aggregation operators are also discussed. The application of the recommended operators for sustainable energy related to the industrial complex is discussed. A comparison analysis proves the empirical existence of the suggested methodology’s consistency and superiority.
From Cell–Cell Interaction to Stochastic and Deterministic Descriptions of a Cancer–Immune System Competition Model
Authors: Morgado Gabriel , Lemarchand Annie , Bianca Carlo
Published: May 2023

We consider a cell–cell interaction model of competition between cancer cells and immune system cells, first introduced in the framework of the thermostatted kinetic theory, and derive a master equation for the probability of the number of cancer cells and immune system cells for a given activity. Macroscopic deterministic equations for the concentrations and mean activities of cancer cells and immune system cells are deduced from the kinetic equations. The conditions for which the 3Es of immunotherapy (elimination, equilibrium, and escape) are reproduced are discussed. Apparent elimination of cancer followed by a long pseudo-equilibrium phase and the eventual escape of cancer from the control of the immune system are observed in the three descriptions. The macroscopic equations provide an analytical approach to the transition observed in the simulations of both the kinetic equations and the master equation. For efficient control of activity fluctuations, the steady states associated with the elimination of either cancer or immune system disappear and are replaced by a steady state in which cancer is controlled by the immune system.
Global Stability of Traveling Waves for the Lotka–Volterra Competition System with Three Species
Authors: Hu Shulin , Pan Chaohong , Wang Lin
Published: May 2023

The stability of traveling waves for the Lotka–Volterra competition system with three species is investigated in this paper. Specifically, we first show the asymptotic behavior of traveling wave solutions and then establish the local stability and the global stability under the weighted functional space. For local stability, the spectrum approach is used, while for global stability, the comparison principle and squeezing theorem are combined.
Optimal Strategy of the Dynamic Mean-Variance Problem for Pairs Trading under a Fast Mean-Reverting Stochastic Volatility Model
Authors: Zhang Yaoyuan , Xiong Dewen
Published: May 2023

We discuss the dynamic mean-variance (MV) problem for pairs trading with the assumptions that one of the security prices satisfies a stochastic volatility model (SVM) and the corresponding price spread follows an Ornstein–Uhlenbeck (OU) process. We provide a semi-closed-form of the optimal strategy based on the solution of a PDE, which is difficult to solve explicitly. Thus, we assume that one of the security prices satisfies the Scott model, a fast-mean-reverting volatility model, and give a closed-form approximation for the optimal strategy. Empirical studies, by using historical data from Chinese security markets, show that the Scott model produces a more stable strategy by better capturing mean-reverting volatility.
The Gibbons, Ross, and Shanken Test for Portfolio Efficiency: A Note Based on Its Trigonometric Properties
Authors: Agrrawal Pankaj
Published: May 2023

This study is intended as a note and provides an extension to a much-used and established test for portfolio efficiency, the Gibbons, Ross, and Shanken GRS-Wald test. Tests devised to measure portfolio efficiency are crucial to the theoretical issues related to CAPM (Capital Asset Pricing Model) testing and have applications for the fund manager who seeks to rank portfolio performance. This study looks at the GRS-Wald test for portfolio efficiency and extends it to make it visually more interpretive without any loss of generality in its structure. The geometrically recast statistic draws upon the trigonometric properties of a portfolio in the mean-variance space and a mathematical proof of the equivalence of the two statistics is provided. The GRS-Wald test is a widely used statistic in studies addressing the issue of portfolio efficiency and CAPM deviations. A simulation demonstrates the use of the recast GRS-Wald test in testing for the mean-variance efficiency of a test portfolio. The study also provides a table of the GRS-Wald test, based on a range of mean-variance locations (cosine of portfolio angles) at which the test portfolio and the efficient market portfolio can be placed.