bluuebunny/crossref_metadata_2025 huggingface dataset:
Runoff and Sediment Deposition Characteristics of Gravel-Mulched Land: An Experimental Study
Authors: Wang Shuangtao , Luo Pingping , Li Wangcheng , Lyu Jiqiang , Zhou Meimei
Published: March 2024

The hydrological characteristics of gravel-containing soils are different from those of gravel-free soils, so it is worth further understanding and enriching the theory of soil and water conservation. In this study, adjustable slope (10°, 20°, 30°) test soil boxes with different surface gravel contents (0%, 25%, 50%, 75%, 100%) were prepared to study the runoff erosion characteristics of gravel-covered land slopes under different rainfall conditions (10 mm/h, 20 mm/h, 30 mm/h). Compared with the bare soil, the runoff start time of the three slopes covered with 100% soil surface gravel content is delayed by 38.90, 32.83 and 73.39%, the runoff producing rate of gravel condition under different slopes decreased by 7.20–71.52% and the total amount of sediment yield decreased by 7.94~84.57%. Surface gravel cover can effectively reduce runoff and sediment yield, which is beneficial for better soil and water conservation. The results of this study have a certain reference value for the theory of soil and water conservation and can be used as a basis for guiding efficient agricultural production in gravel-mulched land and construction (like road slope improvement).
Deliberative Democracy and Making Sustainable and Legitimate Development Plans: The Case of the Antalya Kırcami Agrihood
Authors: Erkuş Hilal , Alkan Yavuz Selim , Tırış Gülşah
Published: March 2024

The objective of this study is to examine the process of land-use change through the lens of the preferences of local actors in the Kırcami Agrihood. Our main focus is to investigate whether the decision-making mechanisms used in the Kırcami development plan (i) are carried out in accordance with deliberative democracy and (ii) whether they are true, systematic, and typical tools of deliberative democracy. To do so, in-depth interviews were conducted with local actors, namely residents, investors, and local government, and their preferences and views regarding urban agriculture and the decision-making process were examined through discourses. Our first finding is that very few tools of deliberative democracy are used in the making of the Kırcami development plan, and they are not idealised tools. Our second finding is that less than half of residents and investors participate in these flawed democratic decision-making processes; thus, the transformative power of deliberation does not function in the Kırcami case. Finally, deliberative democratic tools are not incorporated into Turkish legislation at both local and national levels. We conclude that these three issues should be addressed, and genuine tools of deliberative democracy should be used to make the Kırcami development plan more sustainable and legitimate.
An Ecological Overview of Halophytes and Salt-Affected Soils at El Hito Saline Pond (Central Spain): Baseline Study for Future Conservation–Rehabilitation Measures
Authors: Jiménez-Ballesta Raimundo , Cirujano-Bracamonte Santos , Palencia-Mayordomo Eduardo , Álvarez-Soto Mario
Published: March 2024

In an attempt to boost the potential ecological viability of wetlands, this study aimed to discover the relationship between soil salinity and vegetation composition in a quasi-pristine saline pond, “El Hito Lagoon”. This wetland is situated in the largest continuous natural semi-arid steppe land of western Europe (specifically in Castilla La Mancha, Central Spain). Several soil profiles and a series of surface samples (0–10 cm) extracted from a systematic network throughout the saline pond were described, sampled, and analyzed. The most significant results included the detection of elevated levels of soil salinity, with distinctive sub-areas of extreme elevated surface salinity where the pH reading peaked at 9.89 and the electrical conductivity was higher than 40 (dS/m). The very high content of total available P displayed quite an irregular scatter within the soil profile. Specifically, the range oscillated between 8.57 mg/kg and 388.1 mg/kg, several samples having values greater than 100 mg/kg. An aspect that the abundant presence of Salsola soda, a plant frequently found growing in nutrient-rich wetlands, was able to confirm.
Bone Mineral Density in Field Hockey Players: A Systematic Review
Authors: Oteo-Gómez David , Castellar-Otín Carlos , Moreno-Azze Alejandro , Pradas de la Fuente Francisco
Published: March 2024

The aim of this study was to carry out a systematic review to compare and analyse the bone mineral density of field hockey players of both sexes and of different ages, with other sports and with a sedentary population. The search process was carried out using the PubMed, SPORTDiscus, Web of Science and Scopus databases. The search ended on 18 March 2024. We selected articles in which a comparison was made of bone mineral density of the whole body, lumbar spine, femoral neck, arms and legs, among field hockey players, and/or with other sports and/or with a sedentary population. The systematic review followed the guidelines described in the 2020 PRISMA statement. The initial search identified 220 articles. After applying the inclusion and exclusion criteria, the search was narrowed down to seven articles in total. It was observed that the field hockey group had better bone mineral density values than sedentary population and the low-impact sports population. Basketball players had better whole body and leg bone mineral density values than field hockey players. Causality could not be established due to the cross-sectional nature of the included studies. The better bone mineral density values in field hockey players compared to the sedentary population may be because people who participate in impact sports have a better bone mineral density. The differences in bone mineral density between field hockey and low-impact sports could be related to a lower impact during their practice in these disciplines.
Analysis of Dynamic Wear Characteristics of Joint Contact Friction Pair of Excavators Working Device
Authors: Chen Xuehui , Zhang Lei , Li Wei , Wang Zijian , Zhang Zhengbin , Gao Ting , Liu Wei
Published: March 2024

The working device of an excavator in construction machinery is prone to damage and wear under ordinary working conditions. Based on a model of an excavator under typical working conditions, the dynamic load-bearing situation of the three main joint friction subsets of the working device is simulated by using the virtual prototype technology; the location of the functional device with high stress is identified based on finite element analysis, and the correctness of the simulation results is verified by designing strain gauges. Based on this, the dynamic contact stress variation law of the contact surface of the end-face friction subsets was explored, and the end-face wear depth was calculated by combining Archard wear theory and finite element wear simulation technology; the specimens were worn on the end-face wear tester, and the surface wear was observed under the scanning electron microscope to summarize the wear mechanism and analyze the element content changes of the worn surface. The results show that the three main joints of the working device produce large dynamic fluctuations and are prone to wear, and the destructive degree is more prominent; the wear process is accompanied by higher temperatures, fatigue wear, and abrasive wear on the wear surface, and the wear depth value of the right end face is significantly larger than that of the left end face. This method has a significant reference value for reliability analysis and optimization improvement when using construction machinery’s main joint friction pairs.
Forever Chemicals, Per-and Polyfluoroalkyl Substances (PFAS), in Lubrication
Authors: Dias Darrius , Bons Jake , Kumar Abhishek , Kabir M. , Liang Hong
Published: March 2024

Per- and polyfluoroalkyl substances (PFAS), also known as forever chemicals, exhibit exceptional chemical stability and resistance to environmental degradation thanks to their strong C-F bonds and nonpolar nature. However, their widespread use and persistence have a devastating impact on the environment. This review examines the roles of PFAS in tribological applications, specifically in lubricants and lubricating systems. This article focuses on conventional and advanced lubricants, including ionic liquids (ILs) and their use in modern automotive vehicles. The objective of this paper is to provide a comprehensive overview of the adverse impacts of PFAS whilst acknowledging their outstanding performance in surface coatings, composite materials, and as additives in oils and greases. The pathways through which PFAS are introduced into the environment via lubricating systems such as in seals and O-rings are identified, alongside their subsequent dispersion routes and the interfaces across which they interact. Furthermore, we examine the toxicological implications of PFAS exposure on terrestrial and aquatic life forms, including plants, animals, and humans, along with the ecological consequences of bioaccumulation and biomagnification across trophic levels and ecosystems. This article ends with potential remediation strategies for PFAS use, including advanced treatment technologies, biodegradation, recovery and recycling methods, and the search for more environmentally benign alternatives.
Research Progress of Antioxidant Additives for Lubricating Oils
Authors: Xia Deping , Wang Yonggang , Liu Hui , Yan Jincan , Lin Hualin , Han Sheng
Published: March 2024

Lubricating oils play an important role in friction-reducing and anti-wear, as well as enhancing mechanical efficiency. To improve the oxidation stability and service life of lubricating oils, the composition and structure of antioxidants should be strategically designed, and these parameters have significantly affected the performance of antioxidants in lubricating oils. Antioxidants are classified into two types based on the substrates they act on: peroxide decomposers and radical scavengers. In this review, the effects of peroxide decomposers (including sulfur compounds, phosphorus compounds, sulfur–phosphorus compounds, and sulfur–nitrogen compounds) and radical scavengers, such as hindered phenols and aromatic amines, have been discussed as additives in the antioxidant properties of lubricating oils. The results indicate that peroxide decomposers have excellent performances in lubricating oils, but high pollution of S and P is not conducive to their widespread use. On the contrary, radical scavengers also have superior antioxidant properties and no pollution, possessing the potential to replace traditional antioxidants. In addition, molecular structures with (multiple) synergistic antioxidant properties have been extensively designed and reported. This review serves as a reference for researchers to design and develop high-end new antioxidants.
Experimental Study on Water-Plugging Performance of Grouted Concrete Crack
Authors: Zhang Lianzhen , Huang Changxin , Li Zhipeng , Wang Anni , Gao Meng , Gao Yang , Wang Xiaochen
Published: March 2024

In this paper, ordinary Portland cement, ultrafine cement, polyurethane, and epoxy resin were selected as typical grouting materials. Grouting simulation tests were first conducted to prepare the grouted concrete crack sample. The effect of concrete crack parameters (i.e., crack aperture and roughness), grout water–cement ratio, and grouting pressure on the water-plugging performance of different grouting materials was explored through the impermeability test. The microstructure of grouted concrete cracks was analyzed by means of scanning electron microscopy (SEM) and computed tomography (CT), and the difference in water-plugging performance of different grouting materials was explained at the micro level. The results show that the impermeability of the four grouting materials was ranked as follows: Epoxy resin > polyurethane > ultra-fine cement > ordinary Portland cement. The concrete cracks grouted by epoxy resin have the highest plugging failure water pressure and the lowest permeability, which is the optimal grouting material. The effectiveness of crack grouting in water-plugging was directly proportional to the grouting pressure, provided the pressure did not exceed a certain value. When the pressure surpassed the threshold, the increase in pressure did not have a significant impact on the water plugging performance. For the two cement-based materials, the threshold pressure was 1 MPa, while for the other two chemical grouts, it was 2 MPa. The two cement-based grouts with a water–cement ratio of 0.8 showed optimal water-plugging performance. The water-plugging performance of ordinary Portland cement paste, ultra-fine cement pastes, and polyurethane grout was negatively correlated with crack aperture and positively correlated with crack roughness. However, the water-plugging performance of epoxy resin grout was not affected by crack aperture or roughness.
Preparation and Performance Study of n-Undecane Phase Change Cold Storage Material
Authors: Yan Luchao , Wang Yang , Lu Shijian , Zhu Zhipeng , Xu Lingling
Published: March 2024

With the fast development of the cold chain transportation industry, the traditional refrigeration method results in significant energy consumption. To address the national call for energy saving and emission reduction, the search for a new type of energy storage material has already become a future development trend. According to the national standard GB/T28577 for the classification and basic requirements of cold chain logistics, the temperature in frozen logistics is typically below −18 °C. In this study, n-undecane with a phase change temperature of −26 °C is chosen as the core material of microcapsules. Poly(methyl methacrylate) is applied as the shell material, with n-undecane microcapsules being prepared through suspension polymerization for phase change cold storage materials (MEPCM). Using characterization techniques including SEM, DSC, FTIR, and laser particle size analysis, the effects of three types of emulsifiers (SMA, Tween-80, Tween-80/span-80 (70/30)), SMA emulsifier dosage, core–shell ratio, and emulsification rate on the thermal performance and micro-surface morphology of n-undecane/PMMA microcapsules were studied. The results indicate that when comparing SMA, Tween-80, and Tween-80/span-80 (70/30) as emulsifiers, the dodecane/PMMA microcapsules prepared with SMA emulsifier exhibit superior thermal performance and micro-surface morphology, possessing a complete core–shell structure. The optimal microstructure and the highest enthalpy of phase change, measuring 120.3 kJ/kg, are achieved when SMA is used as the emulsifier with a quantity of 7%, a core-to-wall ratio of 2.5:1, and an emulsification speed of 2000 rpm. After 200 hot and cold cycles, the enthalpy of phase change decreased by only 18.6 kJ/kg, indicating the MEPCM thermal performance and cycle life. In addition, these optimized microcapsules exhibit favorable microstructure, uniform particle size, and efficient energy storage, making them an excellent choice for the refrigeration and freezing sectors.
Dynamic Recrystallization Constitutive Model and Texture Evolution of Metastable β Titanium Alloy TB8 during Thermal Deformation
Authors: Zhou Chuankun , Cao Fang , Yang Zhirong , Rao Weifeng
Published: March 2024

The mechanical properties of metastable β-titanium alloys are highly susceptible during the thermal mechanical processing (TMP). In this process, the recrystallization process plays an important role in determining the microstructure and texture evolution. The implementation of dynamic recrystallization (DRX), a process for achieving β-grain refinement, is considered of great significance for the improvement of the properties of metastable β-titanium alloys and their industrial production. Along these lines, in this work, an isothermal compression test of TB8 titanium alloy was carried out by using a Gleeble-3500 thermal simulator. As a result, the rheological stress behavior was analyzed, the thermal processing map was accurately established based on the stress–strain curve, and the optimal processing interval was determined. The DRX kinetic and the DRX grain size models were developed, on the basis of which a new DRX intrinsic model was established to improve the material parameters. Therefore, the actual situation in the working process could be better predicted. The microstructural evolution of TB8 titanium alloy during thermal deformation was comprehensively investigated using the electron backscatter diffraction (EBSD) technique. The obtained results demonstrate a close correlation between the diversity of DRX mechanisms in TB8 alloy and the distribution of dislocation density. Four microstructural textures during thermal deformation were identified, in which the cube texture of (001) <010> and the R-Gorss Nd texture of (110) <110> dominate. Due to the random orientation of the dynamically recrystallized grains, the strength of the R-Gorss Nd texture of (110) <110> increases with the increase in the volume fraction of DRX. On the contrary, it was verified that the dynamic recrystallization behavior has a significant weakening impact on the cube texture of (001) <010>.
The Luminescence of Laser-Produced Carbon Nanodots: The Effect of Aggregation in PEI Solution
Authors: Kaczmarek Agata , Wisniewska Agnieszka , Mościcki Tomasz , Hoffman Jacek
Published: March 2024

Carbon nanodots (CNDs) produced in pure water by the ablation of graphite with a nanosecond laser pulse exhibit weak photoluminescence. A small addition of polyethyleneimine (PEI) to the aqueous suspension of CNDs causes a significant increase in emissions. This paper presents experimental and theoretical studies of the emission properties of CND/PEI systems. The obtained CNDs responded to even trace amounts of PEI in solution (~0.014% v/v), resulting in a significant increase in the initial weak blue emission of CNDs and PEI taken separately. Morphology and size measurements showed that particle aggregation occurred in the presence of the polymer. A decrease in the calculated Stokes shift values was observed with increasing PEI content in the solution. This indicates a reduction in the number of non-radiative transitions, which explains the increase in the emission intensity of the CND/PEI systems. These results therefore confirmed that the increase in the emission of CND/PEI systems is caused by particle aggregation. Kinetic studies proved that the process is controlled mainly by diffusion, the initial stage of which has a dominant influence on determining the optical properties of the system.
Strain Monitoring of Concrete Using Carbon Black-Based Smart Coatings
Authors: Milone Gabriele , Vlachakis Christos , Tulliani Jean-Marc , Al-Tabbaa Abir
Published: March 2024

Given the challenges we face of an ageing infrastructure and insufficient maintenance, there is a critical shift towards preventive and predictive maintenance in construction. Self-sensing cement-based materials have drawn interest in this sector due to their high monitoring performance and durability compared to electronic sensors. While bulk applications have been well-discussed within this field, several challenges exist in their implementation for practical applications, such as poor workability and high manufacturing costs at larger volumes. This paper discusses the development of smart carbon-based cementitious coatings for strain monitoring of concrete substrates under flexural loading. This work presents a physical, electrical, and electromechanical investigation of sensing coatings with varying carbon black (CB) concentrations along with the geometric optimisation of the sensor design. The optimal strain-sensing performance, 55.5 ± 2.7, was obtained for coatings with 2 wt% of conductive filler, 3 mm thickness, and a gauge length of 60 mm. The results demonstrate the potential of applying smart coatings with carbon black addition for concrete strain monitoring.
Thermodynamic Assessment of Molten Bix-Sn1−x (x = 0.1 to 0.9) Alloys and Microstructural Characterization of Some Bi-Sn Solder Alloys
Authors: Niculescu Florentina , Pencea Ion , Iacob Gheorghe , Ghiţă Mihai , Stănescu Mariana-Mirela , Petrescu Mircea-Ionuţ , Niculescu Emanuel-Laurenţiu , Buţu Mihai , Stăncel Constantin-Domenic , Şerban Nicolae , Şolea Roxana-Marina , Ilie Andrei-Alexandru
Published: March 2024

Properties such as lower melting temperature, good tensile strength, good reliability, and well creep resistance, together with low production cost, make the system Bi-Sn an ideal candidate for fine soldering in applications such as reballing or reflow. The first objective of the work was to determine the thermodynamic quantities of Bi and Sn using the electromotive force measurement method in an electrolytic cell (Gibbs’ enthalpies of the mixture, integral molar entropies, and the integral molar excess entropies were determined) at temperatures of 600 K and 903 K. The second objective addressed is the comprehensive characterization of three alloy compositions that were selected and elaborated, namely Bi25Sn75, Bi50Sn50, and Bi75Sn25, and morphological and structural investigations were carried out on them. Optical microscopy and SEM-EDS characterization revealed significant changes in the structure of the elaborated alloys, with all phases being uniformly distributed in the Bi50Sn50 and Bi75Sn25 alloys. These observations were confirmed by XRD and EDP-XRFS analyses. Diffractometric analysis reveals the prevalence of metallic Bi and traces of Sn, the formation of the Sn0.3Bi0.7, Sn0.95Bi0.05 compounds, and SnO and SnO2 phases.
The Effects of Heat Treatment on the Microstructure and Mechanical Properties of a Selective Laser Melted AlCoFeNi Medium-Entropy Alloy
Authors: Han Xinyang , Li Xiangwei , Liao Bokai , Zhang Youzhao , Xu Lei , Guo Xingpeng , Zhang Shuyan
Published: March 2024

A single body-centered cubic (BCC)-structured AlCoFeNi medium-entropy alloy (MEA) was prepared by the selective laser melting (SLM) technique. The hardness of the as-built sample was around 32.5 HRC. The ultimate tensile strength (UTS) was around 1211 MPa, the yield strength (YS) was around 1023 MPa, and the elongation (El) was around 10.8%. A novel BCC + B2 + face-centered cubic (FCC) structure was formed after aging. With an increase in aging temperature and duration, the number of fine grains increased, and more precipitates were observed. After aging at 450 °C for 4 h, the formed complex polyphase structure significantly improved the mechanical properties. Its hardness, UTS, YS, and El were around 45.7 HRC, 1535 MPa, 1489 MPa, and 8.5%, respectively. The improvement in mechanical properties was mainly due to Hall–Petch strengthening, which was caused by fine grains, and precipitation strengthening, which was caused by an increase in precipitates after aging. Meanwhile, the FCC precipitates made the alloy have good toughness. The complex interaction of multiple strengthening mechanisms leads to a good combination of strength, hardness, and toughness.
Modelling the Flow Behaviour of Al Alloy Sheets at Elevated Temperatures Using a Modified Zerilli–Armstrong Model and Phenomenological-Based Constitutive Models
Authors: Abd El-Aty Ali , Xu Yong , Hou Yong , Zhang Shi-Hong , Ha Sangyul , Xia Liangliang , Alzahrani Bandar , Ali Alamry , Ahmed Mohamed M. Z. , Shokry Abdallah
Published: March 2024

The flow behaviour of AA2060 Al alloy under warm/hot deformation conditions is complicated because of its dependency on strain rates (ε˙), strain (ε), and deformation modes. Thus, it is crucial to reveal and predict the flow behaviours of this alloy at a wide range of temperatures (T) and ε˙ using different constitutive models. Firstly, the isothermal tensile tests were carried out via a Gleeble-3800 thermomechanical simulator at a T range of 100, 200, 300, 400, and 500 °C and ε˙ range of 0.01, 0.1, 1, and 10 s−1 to reveal the warm/hot flow behaviours of AA2060 alloy sheet. Consequently, three phenomenological-based constitutive models (L-MJC, S1-MJC, S2-MJC) and a modified Zerilli–Armstrong (MZA) model representing physically based constitutive models were developed to precisely predict the flow behaviour of AA2060 alloy sheet under a wide range of T and ε˙. The predictability of the developed constitutive models was assessed and compared using various statistical parameters, including the correlation coefficient (R), average absolute relative error (AARE), and root mean square error (RMSE). By comparing the results determined from these models and those obtained from experimentations, and confirmed by R, AARE, and RMSE values, it is concluded that the predicted stresses determined from the S2-MJC model align closely with the experimental stresses, demonstrating a remarkable fit compared to the S1-MJC, L-MJC, and MZA models. This is because of the linking impact between softening, the strain rate, and strain hardening in the S2-MJC model. It is widely known that the dislocation process is affected by softening and strain rates. This is attributed to the interactions that occurred between ε and ε˙ from one side and between ε, ε˙, and T from the other side using an extensive set of constants correlating the constitutive components of dynamic recovery and softening mechanisms.
Comparative Study on Selected Insulating Materials for Industrial Piping
Authors: Porzuczek Jan
Published: March 2024

This paper describes the results of an experimental assessment of the thermal conductivity of pipe insulation. The need for reducing energy loss in industrial piping systems makes the availability of relevant and reliable insulation materials of special importance. Several specimens of pipe laggings, made of different materials, including mineral wool, polyethylene foam (PEF), expanded polystyrene (EPS), flexible elastomeric foam (FEF) and polyurethane foam (PUR), were tested in accordance with the European standard ISO 8497. The thermal conductivity of the materials was measured for a wide range of temperatures. The results were compared with the values reported in the technical specifications as well as with the literature data. The assessment of measurement uncertainty was also described. The results showed that, in a few cases, thermal conductivity turned out to be greater than that declared by the manufacturer by as much as over 10%.
The Effect of SiO2 Particle Size on Crystallization Behavior and Space Charge Properties for SiO2/MMT/LDPE Composites
Authors: Jiang Hongtao , Yuan Hong , Yu Qunguang , Xie Jing
Published: March 2024

The matrix material used in this paper was low-density polyethene (LDPE), and the added particles selected were silicon oxide (SiO2) particles and montmorillonite (MMT) particles. The sizes of the SiO2 particles were 1 µm, 30 nm, and 100 nm, respectively; three kinds of SiO2/MMT/LDPE multi-component composites were prepared based on MMT/LDPE composites doped with MMT particles. The effect of the SiO2 particle size on the crystallization behavior and space charge properties of SiO2/MMT/LDPE composites was studied. The crystalline behaviors and crystallinity of the materials were analyzed. At the same time, the changes in the relative dielectric constant εr and loss factor tanδ for each material with the influence of frequency were studied, and the space charge accumulation, residual characteristics, and apparent charge mobility of each material were explored. The results show that the smaller the size of the added particles, the smaller the grain size and the clearer the grain outline for the multi-composite material. After adding 30 nm SiO2 particles, the crystallinity of the material increases significantly. The microstructure formed by the addition of 100 nm SiO2 particles effectively restricts molecular chain movement and makes it difficult to establish the polarization of the composite. The incorporation of large-size particles can reduce the proportion of the crystalline structure for the material as a whole, resulting in the formation of a new structure to promote charge transfer. Among the three kinds of SiO2 particles, the addition of 30 nm SiO2 particles can effectively suppress the space charge, and the composite material has the lowest residual space charge after depolarization. The addition of 100 nm SiO2 particles can cause the accumulation of many homopolar charges near the anode.
A Novel Two-Stage 3D-Printed Halbach Array-Based Device for Magneto-Mechanical Applications
Authors: Makridis Antonios , Maniotis Nikolaos , Papadopoulos Dimitrios , Kyriazopoulos Pavlos , Angelakeris Makis
Published: March 2024

This research unveils a versatile Halbach array magnetic device with promising biomedical applications, offering innovative solutions for targeted therapy and disease management in evolving biomedical engineering. This paper explores the potential of a novel Halbach array-based device for harnessing magneto-mechanical phenomena in biomedical applications. The study employs computational modeling using COMSOL Multiphysics to define the device’s magnetic properties and validate its operation within the theoretical prediction. The research catalogs the device’s operational modes and assesses crucial parameters related to magneto-mechanical biomedical modalities, including magnetic field strength, gradient, and force. Experimental validation of numerical findings through magnetic field measurements confirms the device’s multifaceted potential, particularly in targeted drug delivery and tissue engineering applications. Finally, the adaptability of the magnetic arrangements for various scenarios is also highlighted. This investigation provides valuable insights into integrating magneto-mechanical principles into biomedical engineering. It paves the way for further research and innovative approaches in theranostics, positioning the presented apparatus as a promising tool with untapped potential for future exploration and discovery in the evolving biomedical field.
Evidence of a Large Refrigerant Capacity in Nb-Modified La1.4Sr1.6Mn2−xNbxO7 (0.0 ≤ x ≤ 0.15) Layered Perovskites
Authors: Kumar Akshay , Kim Jong Woo , Sharma Mohit K. , Kumari Kavita , Vij Ankush , Koo Bon Heun
Published: March 2024

In this work, evidence of isothermal magnetic entropy change (∆SM) over a broad temperature region is presented in a series of La1.4Sr1.6Mn2−xNbxO7 Ruddlesden–Popper compounds with niobium modification (Nb) (0.0 ≤ x ≤ 0.15) at the manganese (Mn) site. The ceramic samples were obtained through a solid-state sintering method in optimized conditions. All compounds predominantly possessed Ruddlesden–Popper phase while a few additional reflections were resolved in Nb-doped compounds which indicates the separation of structural phases. These peaks are assigned to a separate layered perovskite and single perovskite with tetragonal symmetry and hexagonal symmetry, respectively. The microstructure of the pure sample reveals uniform grain morphology but in Nb-doped specimens chiefly three types of grains were found. It was assumed that the inter-connected large particles were of R-P phase which is dominant in both parent and x = 0.05 compounds, while the hexagonal and polygonal morphology of grains in higher concentrations of dopants directly corroborates with the symmetry of single perovskite and additional layered perovskite phases, respectively. The parent compound exhibits a single ∆SM curve, whereas all Nb-substituted samples display bifurcated ∆SM curves. This indicated two transition regions with multiple magnetic components, attributed to distinct structural phases. The highest ∆SM values obtained for components corresponding to the R-P phase are 2.32 Jkg−1k−1, 0.75 Jkg−1k−1, 0.58 Jkg−1k−1 and 0.43 Jkg−1k−1 and for the second component located around room temperature are 0.0 Jkg−1k−1, 0.2 Jkg−1k−1, 0.28 Jkg−1k−1 and 0.35 Jkg−1k−1 for x = 0.0, 0.05, 0.10 and 0.15 compositions, respectively, at 2.5 T. Due to the collective participation of both components the ∆SM was expanded through a broad temperature range upon Nb doping.
Investigating the Effect of Carbonyl Iron Powder Doping on the Microstructure and Magnetic Properties of Soft Magnetic Composites
Authors: Liu Yang , Wang Rui , Li Kaixuan , Chen Ran , Wu Zhaoyang , Li Yang
Published: March 2024

This study proposes the thermal decomposition of salt compounds and doping of carbonyl iron powders (CIPs) to optimize the preparation of an insulating layer through the solid-phase interface reaction. First, (Fe–Si–Cr + CIPs)/ZnSO4 composite powders were synthesized using the hydrothermal method and (Fe–Si–Cr + CIPs)/ZnO·SiO2·Cr2O3 SMCs with a ZnO·SiO2·Cr2O3 composite insulation layer were prepared through heat treatment and cold pressing. The effect of the CIP doping content on the microstructure and magnetic properties of the (Fe–Si–Cr + CIPs)/ZnO·SiO2·Cr2O3 SMCs were then investigated. During the heat treatment, ZnSO4 decomposed into solid ZnO and gaseous SO2 and O2. The O2 drives the solid-phase reaction, prompting the migration of nonmagnetic Si and Cr atoms from the interior of the Fe–Si–Cr soft magnetic powder to the surface insulation layer, finally forming the ZnO·SiO2·Cr2O3 insulation layer. The doped CIPs also show good plasticity during the coating process, combining with the coating layer to fill the internal pores of SMCs. Moreover, as the particles are small with a high surface area, they increase the number of reaction sites for ZnSO4 decomposition and facilitate the growth of the composite insulation layer, promoting its uniform distribution on the surfaces of the soft magnetic powders and CIPs. The lattice mismatch between the insulation layer and soft magnetic powder is reduced while the magnetic-phase content is increased, allowing the effective doping of CIPs sin the insulation layer. The magnetic properties of SMCs can be precisely regulated by changing the doping amount of CIPs. Unlike other insulating layer–preparation strategies based on the interfacial solid-phase reaction, the proposed method exploits the high plasticity and specific surface area of CIPs and removes the lattice mismatch between the insulation layer and soft magnetic powder.
Tiling Rectangles and the Plane Using Squares of Integral Sides
Authors: Sadeghi Bigham Bahram , Davoodi Monfared Mansoor , Mazaheri Samaneh , Kheyrabadi Jalal
Published: March 2024

We study the problem of perfect tiling in the plane and explore the possibility of tiling a rectangle using integral distinct squares. Assume a set of distinguishable squares (or equivalently a set of distinct natural numbers) is given, and one has to decide whether it can tile the plane or a rectangle or not. Previously, it has been proved that tiling the plane is not feasible using a set of odd numbers or an infinite sequence of natural numbers including exactly two odd numbers. The problem is open for different situations in which the number of odd numbers is arbitrary. In addition to providing a solution to this special case, we discuss some open problems to tile the plane and rectangles in this paper.
A Combined Model of Diffusion Model and Enhanced Residual Network for Super-Resolution Reconstruction of Turbulent Flows
Authors: Qi Jiaheng , Ma Hongbing
Published: March 2024

In this study, we introduce a novel model, the Combined Model, composed of a conditional denoising diffusion model (SR3) and an enhanced residual network (EResNet), for reconstructing high-resolution turbulent flow fields from low-resolution flow data. The SR3 model is adept at learning the distribution of flow fields. The EResNet architecture incorporates a long skip connection extending from the input directly to the output. This modification ensures the preservation of essential features learned by the SR3, while simultaneously enhancing the accuracy of the flow field. Additionally, we incorporated physical gradient constraints into the loss function of EResNet to ensure that the flow fields reconstructed by the Combined Model are consistent with the direct numerical simulation (DNS) data. Consequently, the high-resolution flow fields reconstructed by the Combined Model exhibit high conformity with the DNS results in terms of flow distribution, details, and accuracy. To validate the effectiveness of the model, experiments were conducted on two-dimensional flow around a square cylinder at a Reynolds number (Re) of 100 and turbulent channel flow at Re = 4000. The results demonstrate that the Combined Model can reconstruct both high-resolution laminar and turbulent flow fields from low-resolution data. Comparisons with a super-resolution convolutional neural network (SRCNN) and an enhanced super-resolution generative adversarial network (ESRGAN) demonstrate that while all three models perform admirably in reconstructing laminar flows, the Combined Model excels in capturing more details in turbulent flows, aligning the statistical outcomes more closely with the DNS results. Furthermore, in terms of L2 norm error, the Combined Model achieves an order of magnitude lower error compared to SRCNN and ESRGAN. Experimentation also revealed that SR3 possesses the capability to learn the distribution of flow fields. This work opens new avenues for high-fidelity flow field reconstruction using deep learning methods.
Scheduling with Group Technology, Resource Allocation, and Learning Effect Simultaneously
Authors: Li Ming-Hui , Lv Dan-Yang , Lu Yuan-Yuan , Wang Ji-Bo
Published: March 2024

This paper studies the single-machine group scheduling problem with convex resource allocation and learning effect. The number of jobs in each group is different, and the corresponding common due dates are also different, where the processing time of jobs follows a convex function of resource allocation. Under common due date assignment, the objective is to minimize the weighted sum of earliness, tardiness, common due date, resource consumption, and makespan. To solve the problem, we present the heuristic, simulated annealing, and branch-and-bound algorithms. Computational experiments indicate that the proposed algorithms are effective.
Geometric Approximation of Point Interactions in Three-Dimensional Domains
Authors: Borisov Denis Ivanovich
Published: March 2024

In this paper, we study a three-dimensional second-order elliptic operator with a point interaction in an arbitrary domain. The operator is supposed to be self-adjoint. We cut out a small cavity around the center of the interaction and consider an operator in such perforated domain with the Robin condition on the boundary of the cavity. Our main result states that once the coefficient in this Robin condition is appropriately chosen, the operator in the perforated domain converges to that with the point interaction in the norm resolvent sense. We also succeed in establishing order-sharp estimates for the convergence rate.
Updating to Optimal Parametric Values by Memory-Dependent Methods: Iterative Schemes of Fractional Type for Solving Nonlinear Equations
Authors: Liu Chein-Shan , Chang Chih-Wen
Published: March 2024

In the paper, two nonlinear variants of the Newton method are developed for solving nonlinear equations. The derivative-free nonlinear fractional type of the one-step iterative scheme of a fourth-order convergence contains three parameters, whose optimal values are obtained by a memory-dependent updating method. Then, as the extensions of a one-step linear fractional type method, we explore the fractional types of two- and three-step iterative schemes, which possess sixth- and twelfth-order convergences when the parameters’ values are optimal; the efficiency indexes are 6 and 123, respectively. An extra variable is supplemented into the second-degree Newton polynomial for the data interpolation of the two-step iterative scheme of fractional type, and a relaxation factor is accelerated by the memory-dependent method. Three memory-dependent updating methods are developed in the three-step iterative schemes of linear fractional type, whose performances are greatly strengthened. In the three-step iterative scheme, when the first step involves using the nonlinear fractional type model, the order of convergence is raised to sixteen. The efficiency index also increases to 163, and a third-degree Newton polynomial is taken to update the values of optimal parameters.
The Impacts of Payment Schemes and Carbon Emission Policies on Replenishment and Pricing Decisions for Perishable Products in a Supply Chain
Authors: Chang Chun-Tao , Tseng Yao-Ting
Published: March 2024

In the supplier–retailer–consumer system, the retailer’s replenishment and pricing strategies impact the entire transaction process, forming a comprehensive trading market. Suppliers offer advance-cash-credit payments to retailers, while retailers provide customers with cash-credit payment options. In the current health-conscious consumer market, purchasing decisions are influenced not only by commodity prices but also by the freshness of products, particularly perishable goods. Growing awareness of climate change and the advent of carbon emission policies have raised concerns about the environmental costs of business transactions. This study focuses on perishable products whose demand is influenced by both price and freshness. It explores the adoption of various payment methods by suppliers and retailers, as well as the impact of carbon emission cap-and-trade policies or carbon tax policies on management and pricing strategies. Suitable inventory models are established to determine the optimal replenishment and pricing strategies for maximizing the current value of total profit. We illustrate that the current value of total profit demonstrates joint concavity concerning both the selling price and the replenishment time. Finally, we verify the proposed models using numerical examples and present the findings of sensitivity analyses. The findings of this study yield several valuable insights for inventory management of perishable goods.
Simulation and Optimization of a Dual-Axis Solar Tracking Mechanism
Authors: Alexandru Cătălin
Published: March 2024

The work deals with the simulation and optimization of a tracking mechanism used to increase the efficiency of photovoltaic (PV) systems. The proposed solar tracker is one with two degrees of freedom (so called dual-axis, or bi-axial), of the equatorial/polar type. The actuation of the tracking system is carried out with two linear actuators, one for each of the two movements. The study is carried out using a virtual prototyping platform that integrates, into a mechatronic concept, the commercial software packages ADAMS and EASY5. The optimization process is approached from three points of view, which target the mechanical device, the control system, and the bi-axial tracking program. All these optimization processes positively influence, in a specific way, the energy efficiency of the tracking system, which was comprehensively evaluated considering the data specific to the longest light-day of the year (i.e., summer solstice), where a net energy gain of 58.66% (by reference to the equivalent fixed system) was obtained. Similar numerical simulations corresponding to several representative days of the year have revealed that the annual net energy gain is around 42%, which fully justifies the use of the proposed tracking system.
Optimizing OCR Performance for Programming Videos: The Role of Image Super-Resolution and Large Language Models
Authors: Alahmadi Mohammad D. , Alshangiti Moayad
Published: March 2024

The rapid evolution of video programming tutorials as a key educational resource has highlighted the need for effective code extraction methods. These tutorials, varying widely in video quality, present a challenge for accurately transcribing the embedded source code, crucial for learning and software development. This study investigates the impact of video quality on the performance of optical character recognition (OCR) engines and the potential of large language models (LLMs) to enhance code extraction accuracy. Our comprehensive empirical analysis utilizes a rich dataset of programming screencasts, involving manual transcription of source code and the application of both traditional OCR engines, like Tesseract and Google Vision, and advanced LLMs, including GPT-4V and Gemini. We investigate the efficacy of image super-resolution (SR) techniques, namely, enhanced deep super-resolution (EDSR) and multi-scale deep super-resolution (MDSR), in improving the quality of low-resolution video frames. The findings reveal significant improvements in OCR accuracy with the use of SR, particularly at lower resolutions such as 360p. LLMs demonstrate superior performance across all video qualities, indicating their robustness and advanced capabilities in diverse scenarios. This research contributes to the field of software engineering by offering a benchmark for code extraction from video tutorials and demonstrating the substantial impact of SR techniques and LLMs in enhancing the readability and reusability of code from these educational resources.
Existence, Uniqueness, and Averaging Principle of Fractional Neutral Stochastic Differential Equations in the Lp Space with the Framework of the Ψ-Caputo Derivative
Authors: Mohammed Djaouti Abdelhamid , Khan Zareen A. , Liaqat Muhammad Imran , Al-Quran Ashraf
Published: March 2024

In this research work, we use the concepts of contraction mapping to establish the existence and uniqueness results and also study the averaging principle in Lp space by using Jensen’s, Grönwall–Bellman’s, Hölder’s, and Burkholder–Davis–Gundy’s inequalities, and the interval translation technique for a class of fractional neutral stochastic differential equations. We establish the results within the framework of the Ψ-Caputo derivative. We generalize the two situations of p=2 and the Caputo derivative with the findings that we obtain. To help with the understanding of the theoretical results, we provide two applied examples at the end.
An IT2FS-ANP- and IT2FS-CM-Based Approach for Conducting Safety Risk Assessments of Nuclear Power Plant Building Projects
Authors: Ding Rui , Liu Zehua
Published: March 2024

This study proposes an approach for simultaneously treating fuzziness and randomness when conducting safety risk assessments of nuclear power plant building projects (NPPBPs). First, the interval type-2 fuzzy set (IT2FS) and analytic network process (ANP) were employed to establish an IT2FS-ANP method for modifying the solution for the weight vector and determining the mutual relationships between the assessment indexes and their weights. Second, the IT2FS and cloud model (CM) were used to establish the IT2FS-CM method to modify the solution for the expectation value. Third, the IT2FS-ANP and IT2FS-CM methods were combined to establish a model for ranking the safety risks and determining the overall safety risk level. Finally, the approach was applied to an NPPBP in northeast China to validate its applicability.
HEDV-Greedy: An Advanced Algorithm for Influence Maximization in Hypergraphs
Authors: Wang Haosen , Pan Qingtao , Tang Jun
Published: March 2024

Influence maximization (IM) has shown wide applicability in various fields over the past few decades, e.g., viral marketing, rumor control, and prevention of infectious diseases. Nevertheless, existing research on IM primarily focuses on ordinary networks with pairwise connections between nodes, which fall short in the representation of higher-order relations. Influence maximization on hypergraphs (HIM) has received limited research attention. A novel evaluation function, which aims to evaluate the spreading influence of selected nodes on hypergraphs, i.e., expected diffusion value on hypergraph (HEDV), is proposed in this work. Then, an advanced greedy-based algorithm, termed HEDV-greedy, is proposed to select seed nodes with maximum spreading influence on the hypergraph. We conduct extensive experiments on eight real-world hypergraph datasets, benchmarking HEDV-greedy against eight state-of-the-art methods for the HIM problem. Extensive experiments conducted on real-world datasets highlight the effectiveness and efficiency of our proposed methods. The HEDV-greedy algorithm demonstrates a marked reduction in time complexity by two orders of magnitude compared to the conventional greedy method. Moreover, HEDV-greedy outperforms other state-of-the-art algorithms across all datasets. Specifically, under conditions of lower propagation probability, HEDV-greedy exhibits an average improvement in solution accuracy of 25.76%.