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AbstractAuxetic materials are characterized by a negative Poisson’s ratio (NPR), which expands when stretched and shrinks when compressed. Due to the synclastic curvature of auxetics, they have good formability. These properties make them useful in applications requiring formability, such as composites, fashion and clothing, medical, protective, and sports fields. In this research, auxetic weft-knitted fabrics based on foldable structures were knitted. The effect of structural parameters including fabric pattern, yarn count, and loop length on the formability of auxetic weft-knitted fabrics was investigated and compared to plain weft-knitted fabric (Jersey). Auxetic fabrics with three distinct patterns and three different loop lengths were knitted using polyester yarns of varying three counts. Then, the formability experiment was conducted using the hemisphere mold, and the forming energy of fabric samples was obtained. The results demonstrated that auxetic fabrics exhibit superior formability to conventional (non-auxetic) fabrics, attributed to their synclastic curvature. Among the auxetic fabrics, those with larger zigzag angles, finer yarn counts, and larger loop lengths showed higher formability. These findings enhance the potential applications of auxetic fabrics in various industries such as medical and protective, emphasizing their ability to conform to complex shapes with minimal wrinkling. [ABSTRACT FROM AUTHOR]

Gummed Guangdong silk a green ecological textile is a national geographical indication product of China. Its popularity among the public can be attributed to its distinctive double-sided heterochromatic structure and outstanding wearing properties. The glossy black front side and dull reddish-brown back side contribute to its unique appeal. This exclusive fabric structure imparts numerous commendable wearing characteristics to gummed Guangdong silk such as coolness softness breathability waterproofness electric resistance anti-friction wrinkle resistance antibacterial activity insect prevention electric resistance flame oxidation resistance and environment friendliness. The dyeing and finishing techniques of gummed Guangdong silk involve the formation of fabric structure and style playing a crucial role in determining its exceptional wearing properties. Consequently it is imperative to elucidate the alterations in fabric structure and style during the preparation of gummed Guangdong silk. Surprisingly despite numerous articles on the structure and properties of gummed Guangdong silk there is a conspicuous absence of explanations or reports regarding the evolution of the structure and style of gummed Guangdong silk. Therefore in this study samples were prepared according to the traditional dyeing and finishing techniques of gummed Guangdong silk. The pigment extracted from Dioscorea Cirrhosa Lour was utilized to dye the silk fabric repeatedly. When the pigment layer on the fabric reached a certain thickness the dyed fabric was coated with mud. By testing and characterizing different samples in the process of making Guangdong silk the changes of fabric structure and style in the preparation of gummed Guangdong silk were studied. Firstly a comprehensive analysis of structural parameters such as density square meter mass and thickness for each sample was conducted throughout the preparation process. The findings reveal that there is negligible alteration in both warp and weft density during the preparation. Notably the preparation process demonstrates no discernible impact on the fabric's density structure. However it is crucial to highlight that both the dyeing and mud-coating processes exert a considerable influence on the weight per square meter and thickness of the fabric. Results indicate a gradual increase in the weight per square meter and thickness during the dyeing and mud-coating finishing with no significant change observed after finishing by sand washing. An in-depth examination of the fabric' s surface morphology was undertaken to further clarify structural changes. SEM images reveal that the dyeing and mud-coating finishing processes lead to the formation of a tight coating structure on the fabric providing an explanation for the observed increase in weight per square meter and thickness. Although some damage and fluffing occur on the fabric's surface after sand washing it does not result in extensive harm to the fabric coating. This outcome elucidates why the weight per square meter and thickness remain largely unaffected even after sand washing. Secondly the evolution in the style of gummed Guangdong silk was elucidated by conducting tests and characterizing various samples based on style parameters throughout the preparation process. Results indicate that both dyeing and mud finishing processes lead to a reduction in the softness score and an increase in the stiffness score and drape index. Conversely these trends reverse after sand washing. Notably there is no significant change in the smoothness score of the fabric during the preparation. The findings emphasize that dyeing and mud finishing impart stiffness to the fabric necessitating further finishing by sand washing to achieve softness and smoothness for a comfortable touch. Subsequently an analysis of the wearability style of gummed Guangdong silk was conducted by testing color fastness to domestic laundering and color fastness to rubbing. Evidently the K/ S value of the fabric gradually increases during the preparation and the color fastness to domestic laundering is 5 demonstrating good color fastness. However the color fastness to dry / wet rubbing is 2 approximately demonstrating undesirable color fastness. Therefore further modification is required to achieve excellent color fastness of gummed Guangdong silk. Finally the UV protective characteristics were subjected to testing and characterization. It was observed that the UPF value increases significantly after dyeing with Dioscorea Cirrhosa pigment for five times surpassing 40. Furthermore there is a substantial reduction in UVA and UVB transmittance. Continuous dyeing and mud coating processes do not bring about significant changes in the UPF value UVA and UVB transmittance. However after finishing by sand washing the UPF value experiences a sharp increase accompanied by a considerable reduction in UVA and UVB transmittance. These findings underscore the exceptional UV protection style exhibited by gummed Guangdong silk. This study clarifies the alterations of the structure and style in the preparation of gummed Guangdong silk provides a theoretical basis for the structural and stylistic evolution of gummed Guangdong silk and may pave the path for the standardization of industrial manufacturing. [ABSTRACT FROM AUTHOR]

Accurately predicting the performance of gas foil bearings (GFBs) is important. This paper presents a new fully coupled elastic–aerodynamic model for analyzing the static performance of gas foil journal bearings (GFJBs). The gas compressible lubrication model was solved in MATLAB to obtain the gas pressure. The foil structure deformation was solved in COMSOL by considering the Coulomb friction and allowing the contact surfaces to be separated from each other. Under given load and rotational speed conditions, the calculated minimum gas film thickness and attitude angle match well with the literature data, validating the accuracy of the developed model. Based on the model developed, a comprehensive and systematic analysis of the effects of the structural parameters on the static performance was performed. The results showed that as the bump height, top foil thickness, and bump foil thickness increased, the load capacity could be improved to different degrees. The bump foil thickness had the greatest effect on the load capacity. These results provide theoretical guidance for the structural design and practical applications of GFJBs. [ABSTRACT FROM AUTHOR]

Currently, the primary method for controlling red tides in the ocean involves spraying water solutions with special chemicals as solutes. High-pressure spraying results in the formation of typical jet structures. In this study, numerical simulation methods are employed to investigate the velocity variations, turbulent characteristics, and gas content distribution of jet flow fields under different initial jet flow pressures, cone angles, and nozzle diameters. Based on practical application scenarios, cluster analysis is used to explore the similarities and differences in jet equivalent diameters under different parameter conditions. The research findings indicate the following. (1) The difference of jet velocity distribution at the far field exit will be enlarged with the increase in the nozzle cone angle. When the nozzle cone angle is 4 mm, the velocity uniformity at the outlet is the best. (2) The TKE of the flow field has no consistent change law along the central axis. At the jet exit, the TKE shows an obvious multi-peak structure. (3) The gas content demonstrates a typical "double-valley" feature at the jet outlet cross-section. Increasing the initial pressure leads to a decrease in the gas content within the jet due to reduced entrainment, while the entrainment range remains largely constant. (4) Cluster analysis reveals that the similarity of jet flow width when it reaches the water surface is minimal compared to other operating conditions when the initial pressure is 0.36 MPa, the cone angle is 115°, and the nozzle diameter is 2 mm. All conditions can be categorized into two or three groups to ensure jet effectiveness. The study results provide scientific guidance for selecting spray devices for controlling red tides in the ocean. [ABSTRACT FROM AUTHOR]

Fabric structure parameters have a significant impact on the comfort of heat and moisture transfer in garments. Previous numerical simulations required extensive mathematical calculations and mostly investigated one- or two-dimensional models of fiber assembly without considering the weave structure, which is a key parameter, that significantly influences the porosity of the woven structure and consequently its heat and moisture management. While the finite element method supports the simulation of the optimal shape and material properties with better visibility, previous finite element models focused on heat transfer and neglected water vapor transfer in fabrics. In this article, the finite element simulation of heat and moisture transfer in woven fabrics is established based on the testing principle of thermal resistance and moisture resistance tester using COMSOL Multiphysics software. In this simulation, three-dimensional parametric geometrical models of the fabric are created using curve interpolation methods by acquiring the control point coordinates of different weaves (plain, 2/2 balanced twill, and 4/1 unbalanced twill weaves). Heat and moisture transfer properties of fabric models in the horizontal and vertical directions were analyzed, including the heat flux, moisture resistance, water vapor permeability, and water vapor concentration. The article also deals with the effects of weave structure and fabric cover in a range of 72.1–85.1% on the fabric heat flux and water vapor concentration. Comparison between model and experimental results revealed that the three-dimensional simulation can accurately predict the impact of weave pattern and fabric cover on the fabric heat and moisture transfer performance. In addition, this model can be utilized to study the distribution of heat and water vapor within fabrics, providing a theoretical foundation for optimizing heat and moisture comfort in woven fabrics. [ABSTRACT FROM AUTHOR]

Highlights Carbon black (CB) with different structural parameters together with graphene oxide were formed into uniformly dispersed filler network for enhancing the abrasion resistance of natural rubber/cis‐1,4‐polybutadiene rubber/trans‐1,4‐poly(isoprene‐butadiene) rubber blended composites. It showed that the CB structural parameters, such as specific surface area, surface activity and structural degree affected the formation of bound rubber. With the increase of bound rubber content, the homogeneity of filler network structure was improved and the filler‐rubber interaction was enhanced, resulting in a remarkable increase in the mechanical properties, thermal performance and abrasion resistance of the composites. Among the different types of CB, the composites filled with high‐structural‐degree CB of N134 had DIN wear volume as low as 76 mm3 and exhibited 19.5% higher abrasion resistance than N330. Wear surface observations and wear mechanism analyses showed that the increase in abrasion resistance was related to the improvement in tear resistance, hardness and thermal properties of the composites. Multiple linear regression analyses yielded that the structural degree in the structural parameters of CB had a significant correlation effect on the formation of bound rubber, and there was a strong linear relationship between the abrasion resistance of the composites and the content of bound rubber. Trans‐1,4‐poly(isoprene‐butadiene) rubber as compatibilizer for NR/BR blends. Synergistic enhancement of rubber using carbon black and graphene oxide. Carbon black with high structural degree promotes the formation of bound rubber. Described correlation between CB structural parameters and abrasion resistance of rubber. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, a novel air‐cooled supercapacitor thermal management system (STMS) based on the corner deflectors and the inclined inlet and outlet was proposed. The temperature and velocity fields were simulated and analyzed by CFD. Moreover, the heat dissipation effect of different STMSs was analyzed against each other. The results showed that the STMS proposed had a better heat dissipation effect when the inclined angle of inlet and outlet was appropriate, in which the maximum temperature (Tmax) and the maximum temperature difference (ΔTmax) of the module could be reduced by 10.3% and 34.6%. And it is shown that the structure with inclined inlet and outlet plays an important role for the heat dissipation capability of the STMS proposed. And it has experimentally proven its heat dissipation ability. Consequently, the impacts of inclined angle (α), monomer spacing (dc), and the distance between monomer and module shell (dx, dy, and dz) on the heat dissipation effect were deeply analyzed. For the STMS arranged in four rows and three columns, it had a better heat dissipation effect when inclined angle was in the range of 40° to 50°. The results showed that the structural parameters had a large influence on the Tmax and ΔTmax. Besides, it had shown that the temperature curves of the Tmax and ΔTmax had a main trend of "decreasing and then increasing" when the monomer spacing as well as the distance between monomer and module shell are taken from 1 mm to 5 mm. It implies that a small spacing (1 mm to 2 mm) will hinder the air circulation and reduce heat dissipation, and a large spacing (3 mm to 5 mm) will reduce the average flow rate of air and reduce the efficiency of heat transfer. [ABSTRACT FROM AUTHOR]

For the research on real-time accurate testing technology for the explosion point spatial coordinate of munitions, its currently commonly used methods such as acoustic–electric detection or high-speed imaging are limited by the field conditions, response rate, cost, and other factors. In this paper, a method of spatial coordinate testing for the explosion point based on a 2D PSD (position-sensitive detector) intersection is proposed, which has the advantages of a faster response, better real-time performance, and a lower cost. Firstly, a mathematical model of the spatial coordinate testing system was constructed, and an error propagation model for structural parameters was developed. The influence of the position of the optical axes' intersection as well as the azimuth angle and pitch angle on the test accuracy of the system was simulated and analyzed, thus obtaining the distribution and variation trend of the overall error propagation coefficient of the system. Finally, experiments were designed to obtain the test error of the system for validation. The results show that the system test accuracy is high when the azimuth angle is 20°–50°, the overall error propagation coefficient does not exceed 48.80, and the average test error is 56.17 mm. When the pitch angle is −2.5°–2.5°, the system has a higher test accuracy, with the overall error propagation coefficient not exceeding 44.82, and the average test error is 41.87 mm. The test accuracy of the system is higher when the position of the optical axes' intersection is chosen to make sure that explosion points fall in the region of the negative half-axis of the Z w -axis of the world coordinate system, with an overall error propagation coefficient of less than 44.78 and an average test error of 73.38 mm. It is shown that a reasonable selection of system structure parameters can significantly improve the system test accuracy and optimize the system deployment mode under the long-distance field conditions so as to improve the deployment efficiency. [ABSTRACT FROM AUTHOR]

The optimization of flow channel structures significantly impacts the performance enhancement of proton exchange membrane fuel cells (PEMFCs). In this paper, the influences of the loop radius, inclination angle, and presence of the island in the Tesla valve flow field on the performance of a fuel cell were investigated numerically. The results indicated that increasing the inclination angle and curvature radius of the Tesla valve increased the voltage by 16.3% and 31.1%, respectively, compared to the parallel flow field at 0.8 A/cm2. Elevating the inclination angle amplified the resistance effect exerted by tributaries on the main stream, consequently fostering channel-to-membrane mass transfer. Increasing the curvature radius contributed to a heightened total oxygen concentration, but also led to water accumulation problems. The removal of islands increased the reactant contact area, but also created more dead zones, resulting in an observed improvement compared to the parallel flow field, but only marginal improvements over the basic Tesla flow field. [ABSTRACT FROM AUTHOR]

This article studies the influence of solid-phase (type 1 samples) and melt-quenching (type 2 samples) technological modes of obtaining Na3Fe2(PO4)3 polycrystals on their structures and ion-conducting properties. α-Na3Fe2(PO4)3 polycrystals of the 1st type are formed predominantly under an isothermal firing regime, and the synthesis of the 2nd type is carried out under sharp temperature gradient conditions, contributing to the formation of glassy precursors possessing a reactive and deformed structure, in which the crystallization of crystallites occurs faster than in precursors obtained under isothermal firing. The elemental composition of α-Na3Fe2(PO4)3 type 2 polycrystals is maintained within the normal range despite the sharp non-equilibrium thermodynamic conditions of synthesis. The microstructure of the type 1 Na3Fe2(PO4)3 polycrystals is dominated by chaotically arranged crystallites of medium (7–10 μm) and large (15–35 μm) sizes, while the polycrystals of type 2 are characterized by the preferential formation of small (3–4 μm) and medium (7–10 μm) crystallites, causing uniaxial deformations in their structure, which contribute to a partial increase in their symmetry. The advantage of type 2 polycrystals is that they have higher density and conductivity and are synthesized faster than type 1 samples by a factor of 4. The article also considers the issues of crystallization in a solid-phase precursor from the classical point of view, i.e., the process of the formation of small solid-phase nuclei in the metastable phase and their growth to large particles due to association with small crystallites using phase transitions. Possible variants and models of crystallite growth in Na3Fe2(PO4)3 polycrystals, as well as distinctive features of crystallization between two types of samples, are discussed. [ABSTRACT FROM AUTHOR]

To improve the vibration performance of oil-lubricated tilting pad bearing systems, this paper investigates the impact of different structural parameters on the vibration reduction effect of piezoelectric actuators on flexible tilting pad bearings. Four sets of flexible tilting pad bearings were designed and manufactured, including a flexible hinge tilting pad bearing and three sets of double-layer spring-supported flexible tilting pad bearings with different parameters. The radial displacement of the bearing load pad was controlled to varying degrees using a piezoelectric actuator, and semi-active control experiments were conducted on the flexible tilting pad bearings. The experimental results show that appropriately reducing the radial clearance and the stiffness of the bearing's flexible structure can effectively suppress vibrations, enhance the vibration reduction effect of the piezoelectric actuation, and increase the stability of the bearing-rotor system. This study is of significant importance for the design of flexible tilting pad bearings and the vibration suppression of rotor systems. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the influence mechanism of structural type and size on the hydrodynamic performance of vertical curved V-type otter board, this paper based on the computational fluid dynamics method, a three-dimensional numerical model of vertical curved V-type otter board is established to calculate and analyze its hydrodynamic performance, and the validity of the numerical simulation results is verified by designing and constructing a scaled model for dynamic flume experiments. On this basis, the effects of different structural parameters, such as the deflector angle, camber, and spacing, on the hydrodynamic performance of the vertical curved V-Type otter board are investigated and the optimal structural design scheme is determined. The results demonstrate that single or synchronous changes of the angle, camber, and spacing of the two deflectors have varying degrees of impact on the hydrodynamic performance of the vertical curved V-Type otter board. To improve the expansion effect of the otter board, setting the angle of the deflector A to 40° and that of the deflector B to 30°, or setting the camber of deflectors A and B to 18%, or setting the spacing between deflectors A and B to 380 mm and that between the deflector and the main panel to 670 mm can increase the lift coefficient of the vertical curved V-Type otter board to its maximum value. Considering the overall performance of the otter board, when the angle of the deflector A is set to 25° and that of the deflector B is set to 30°, or the camber of the deflector A is set to 6% and that of the deflector B is set to 9%, or the spacing between deflectors A and B is set to 340 mm and that between the deflector and the main panel is set to 610 mm, the lift-to-drag ratio of the otter board can be increased to its maximum value.

The acoustic performance of metal hollow sphere (MHS) A356 aluminum matrix composites has a significant impact on their application, making it worthy of in-depth investigation. To investigate the acoustic performance and mechanism of MHS A356 aluminum matrix composites, in this study MHS A356 aluminum matrix composites with different structural parameters were fabricated using a casting method. The density of the MHS A356 aluminum matrix composites was measured using the direct measurement method, and the acoustic performance of the composites was measured using the impedance tube. The research results indicated that the average sound absorption coefficient of MHS A356 aluminum matrix composites increased with the decrease in sintering temperature and diameter of MHSs, and the increase in volume fraction of MHSs. When the sintering temperature of the MHS was at 1,100°C, with the volume fraction being 48.50% and the diameter being 1.88 mm, the average sound absorption coefficient of the MHS A356 aluminum matrix composites reached the optimal level, which was 0.23. Conversely, the sound transmission loss of MHS A356 aluminum matrix composites decreased with the increase in sintering temperature, volume fraction, and diameter of MHSs. When the sintering temperature of the MHS stood at 1,100°C, with the volume fraction being 40% and the diameter being 2.88 mm, the average sound transmission loss of the MHS A356 aluminum matrix composites attained the maximum value, which was 24.6 dB.

In order to decouple structural parameters of silica aerogels like particle size, pore size and fractal dimension on the one hand from aerogel properties such as aerogel density, thermal and mechanical characteristics on the other hand, the structural properties were varied in a wide range. It has been a challenging task to find synthesis parameters still resulting in gels, but also covering a wide property space. For this goal, three synthesis routes, based on the classical tetraalkoxysilane route, were chosen. The structural properties of the silica aerogels produced cover more than two orders of magnitude in particle and pore sizes, whereas the variation of density and porosity is limited by the Si-content of the silica source. Due to physical limitations, not all combinations of pore size correlated to an aerogel density are possible, leading to a gap for small densities and small pores as well as for high densities and large pores. For increasing particle sizes, the structure generation mechanism seems to alter from particle generation and subsequent cluster formation to phase separation. Along with that, the mechanical stiffness drops down for larger structures (pores and particles). For the mechanical and thermal properties, only the solid thermal conductivity scales roughly with the Young's modulus, thus giving the opportunity of decoupling mechanical and thermal conductivity at ambient pressure from each other. [ABSTRACT FROM AUTHOR]

Cigarette draw resistance and filter pressure drop are both critical physical indicators for the tobacco industry, which use testing equipment to measure the two parameters. Pressure drop standards are used as transfer standards to ensure the accuracy and reliability of the testing equipment. Pressure drop standards are generally cylindrical rods having a certain number of parallel capillaries. To address the issue of how to design and fabricate pressure drop standards quickly and conveniently, this paper proposes a design method for pressure drop standards based on structural parameters. The method uses a mathematical model of the internal airflow of the standard including the entrance effect into a circular capillary and uses an iterative calculation algorithm accordingly. By iterative calculation, the structural parameters of the pressure drop standard, namely, diameter and length of the capillaries, were obtained, along with the relationship between the draw resistance of the standard and the flow rate in each capillary. The accuracy of the mathematical model was validated by comparing and analyzing the experimental and theoretical draw resistance of standards with different structural parameters. The experimental results showed that the relative error between the measured draw resistance and the calculated draw resistance was below 8%, which proves the reliability and validity of the mathematical model, and provides theoretical support for the design and fabrication of pressure drop standards.

Abstract In this study, Density-functional theory/Time-dependent density-functional theory (DFT/TDDFT) and Molecular docking method was used to investigate the effect of methyl acetate, tetrahydrofuran and cyanobenzylidene substituents on the electronic structure and antiviral activity of favipiravir for treating COVID-19. The DFT and TDDFT computations were employed using the Gaussian 09 software package. The values were calculated using the 6-311++G(d, p) basis set and the hybrid B3LYP functional method. Autodock vina software was used for simulations to better predictions and to validate the modified compounds' binding affinities and poses. Results of the study indicate that compounds 1 to 6 all displayed a planar structure, where the pyrazine ring, carboxamide, hydroxyl groups, and other substituents are all situated within the same plane. In addition, the energy gaps (Egap) of these six compounds (Cpd 1, 2, 3, 4, 5, and 6) were compared. The significant dipole moment and binding affinity achieved implies a particular orientation for binding within the target protein, signaling the anticipated strength of the binding interaction. In all six compounds, the electrophilic domain is situated in the vicinity of the amine functional group within the carboxamide compound, whereas the nucleophilic domain encompasses both the carbonyl and hydroxyl groups. The most negatively charged sites are susceptible to electrophilic interactions. In conclusion, compounds 5 and 6 exhibit a high binding affinity of the target protein, while compound 6 has a high energy gap, which could enhance its antiviral activity against the COVID-19 virus.

Tree-cut width is a parameter that has been introduced as an attempt to obtain an analogue of treewidth for edge cuts. Unfortunately, in spite of its desirable structural properties, it turned out that tree-cut width falls short as an edge-cut based alternative to treewidth in algorithmic aspects. This has led to the very recent introduction of a simple edge-based parameter called edge-cut width [WG 2022], which has precisely the algorithmic applications one would expect from an analogue of treewidth for edge cuts, but does not have the desired structural properties. In this paper, we study a variant of tree-cut width obtained by changing the threshold for so-called thin nodes in tree-cut decompositions from 2 to 1. We show that this "slim tree-cut width" satisfies all the requirements of an edge-cut based analogue of treewidth, both structural and algorithmic, while being less restrictive than edge-cut width. Our results also include an alternative characterization of slim tree-cut width via an easy-to-use spanning-tree decomposition akin to the one used for edge-cut width, a characterization of slim tree-cut width in terms of forbidden immersions as well as approximation algorithm for computing the parameter. [ABSTRACT FROM AUTHOR]

Tapered roller bearings (TRBs) can withstand axial loads, radial loads, and overturning moments. The performance, safety, and efficiency of rotating machinery are directly influenced by the friction moments within the TRBs. However, most current research has relied on empirical formulas that focus on axial loads. Additionally, the friction coefficient between the rollers and the inner ring rib has been defined using simple empirical methods. In actual applications, the loads on TRBs are not purely axial or radial, and simple empirical friction coefficients do not adequately account for the varying lubrication conditions. To address this challenge, this study proposes an improved method for calculating the friction moments of TRB under combined axial and radial loads. This study employs a calculation method for sliding friction coefficients that can model dry, boundary, elastohy-drodynamic, and mixed lubrication conditions. To demonstrate the advantages of the proposed method, the friction moments obtained using the existing and proposed methods are compared. Additionally, the influence of TRB structural parameters on the friction moment is discussed. An experimental study is conducted to validate the effectiveness of the proposed method. The findings provide valuable insights for designing TRB structural parameters to minimize friction moments. [ABSTRACT FROM AUTHOR]

In this study, Density-functional theory/Time-dependent density-functional theory (DFT/TDDFT) and Molecular docking method was used to investigate the effect of methyl acetate, tetrahydrofuran and cyanobenzylidene substituents on the electronic structure and antiviral activity of favipiravir for treating COVID-19. The DFT and TDDFT computations were employed using the Gaussian 09 software package. The values were calculated using the 6-311++G(d, p) basis set and the hybrid B3LYP functional method. Autodock vina software was used for simulations to better predictions and to validate the modified compounds' binding affinities and poses. Results of the study indicate that compounds 1 to 6 all displayed a planar structure, where the pyrazine ring, carboxamide, hydroxyl groups, and other substituents are all situated within the same plane. In addition, the energy gaps (Egap) of these six compounds (Cpd 1, 2, 3, 4, 5, and 6) were compared. The significant dipole moment and binding affinity achieved implies a particular orientation for binding within the target protein, signaling the anticipated strength of the binding interaction. In all six compounds, the electrophilic domain is situated in the vicinity of the amine functional group within the carboxamide compound, whereas the nucleophilic domain encompasses both the carbonyl and hydroxyl groups. The most negatively charged sites are susceptible to electrophilic interactions. In conclusion, compounds 5 and 6 exhibit a high binding affinity of the target protein, while compound 6 has a high energy gap, which could enhance its antiviral activity against the COVID-19 virus. [ABSTRACT FROM AUTHOR]

The time for smoke gas to reach a smoke detector would depend on its structural characteristics. However, previous studies have neglected to explore this issue. In this paper, three structural variables of a cylindrical smoke detector with a cover are chosen, and the response surface method is used to carry out the experimental design. Furthermore, the incidence point velocity and center point velocity are calculated using the computational fluid dynamics simulation, and the alarm time is obtained using a homemade device. The three parameters that influence the outcomes are then examined to obtain empirical formulas and the best solutions. Comparatively, we observe that the smoke ingress effect is most significantly influenced by the top cover height. After optimization, the incidence point velocity is increased by 115.94 %, the center point velocity is increased by 119.64 %, the alarm time is reduced by 68.57 %, and the gas flowability performance is noticeably improved. [ABSTRACT FROM AUTHOR]

Flexible graphite foils with varying thicknesses (S = 282 ± 5 μm, M = 494 ± 7 μm, L = 746 ± 8 μm) and an initial density of 0.70 g/cm3 were obtained using the nitrate method. The specific electrical and thermal conductivity of these foils were investigated. As the density increased from 0.70 g/cm3 to 1.75 g/cm3, the specific electrical conductivity increased from 69 to 192 kS/m and the thermal conductivity increased from 109 to 326 W/(m·K) due to the rolling of graphite foils. The study showed that conductivity and anisotropy depend on the shape, orientation, and contact area of thermally expanded graphite (TEG) mesoparticles (mesostructural factor), and the crystal structure of nanocrystallites (nanostructural factor). A proposed mesostructural model explained these increases, with denser foils showing elongated, narrowed TEG particles and larger contact areas, confirmed by electron microscopy results. For graphite foils 200 and 750 μm thick, increased density led to a larger coherent scattering region, likely due to the rotation of graphite mesoparticles under mechanical action, while thinner foils (<200 μm) with densities > 1.7 g/cm3 showed increased plastic deformation, indicated by a sharp reduction in the coherent scattering region size. This was also evident from the decrease in misorientation angles with increasing density. Rolling reduced nanocrystallite misorientation angles along the rolling direction compared to the transverse direction (TD) (for 1.75 g/cm3 density ΔMA = 1.2° (S), 2.6° (M), and 2.4° (L)), explaining the observed anisotropy in the electrical and mechanical properties of the rolled graphite foils. X-ray analysis confirmed the preferred nanocrystallite orientation and anisotropy coefficients (A) using Kearns parameters, which aligned well with experimental measurements (for L series foils calculated as: A0.70 = 1.05, A1.30 = 1.10, and A1.75 = 1.16). These calculated values corresponded well with the experimental measurements of specific electrical conductivity, where the anisotropy coefficient changed from 1.00 to 1.16 and mechanical properties varied from 0.98 to 1.13. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

One of the outstanding advantages of aerostatic bearing is high speed, which is the basic component for various ultra-precision machining. Compared with thrust bearing, journal bearing is less studied and more complex. Structural parameters have great influences on the static properties of the bearing. However, due to the strong coupling, the study of the structural parameters on the bearing dynamic properties at high speed is insufficient. The fluid–structure interaction model of the bearing is formed by directly combining the pressure distribution equations of the gas film, the spindle motion equation, and the flow balance equations. The coupled equations are numerically solved using the two-way alternating implicit scheme method, the Newton iteration method, the Thomas algorithm, and the Newmark method. The influences of orifice diameter, bearing clearance, recess length, and recess height on the dynamic properties of the system are investigated. The results show that the structural parameters play a prominent influence on the bearing flow field and the spindle motion. With the change of the structural parameters, the system appears as T-periodic motion, multiple T-periodic motion, and quasi-periodic motion. The research contributes to the structural optimization and performance enhancement of aerostatic journal bearing. [ABSTRACT FROM AUTHOR]

Cementing technology is crucial to the development of oil and gas resources, and the quality of cement slurry required is an important factor affecting the cementing effect. Previous studies ignored mixing speed effect on cement slurry quality. CFD numerical model is established to simulate the flow filed of the agitated slurry tank under various operation and structural parameters. The multiphase flow model and the k-ε turbulence model are used to describe the turbulence characteristics in the agitated slurry tank. The multiple reference frame (MRF) model is used to realize the rotation of the area near the stirring blade. The results indicate that the density of the cement slurry in the agitated slurry tank can finally reach a stable state, and the concentration distribution is uniform. Increasing the rotational speed, the stirring time needed to achieve stability becomes shorter, and the uniformity of the cement slurry will also be improved. Reducing the distance between the impeller and the bottom of the agitated slurry tank, the mixing effect can be improved. It provides certain theoretical guidance for the practical application of this agitated slurry tank and has certain reference significance for research on improving the quality of cement slurry required for cementing. [ABSTRACT FROM AUTHOR]

Tire acoustic cavity resonance (TACR) noise is one kind of low-frequency and narrowband noise that particularly annoys passengers, especially becomes more prominent in electric vehicles. This paper demonstrates a numerical investigation on the TACR noise via the acoustic-structural coupling finite element model. The accuracy of this coupling finite element model is validated both by the analytic method based on the superposition theory of traveling waves and experimental modal tests of tire cavities. According to the simulated models, the influences of external factors including the inflation pressure and road load on the TACR noise are studied. Meanwhile, as the main constituent component in the tire model, the effect of belt cord is also discussed. To design the low-TACR noise tire, various design parameters of the inner contour in tire cavity are analyzed. By the orthogonal test and range analysis, it is found that the contour parameters can slightly affect the modal frequency and sound pressure of TACR noise. Among these, the curvature radius of the tire shoulder ρ 4 , tire sidewall ρ 5 , and half-section height H have a more obvious influence on the TACR noise than the curvature radius of the tire crown region ρ 2 and transition region ρ 3 . Meanwhile, it also illustrates that increasing the curvature radius at the tire shoulder ρ 4 and reducing the half-section height H has a reduction effect on the TACR noise. This study can contribute to the design of low road noise tires. [ABSTRACT FROM AUTHOR]

In order to investigated the main influencing factors of the error averaging ability of the orifice-compensated air bearing, an error motion prediction model of a single air pad was established, and the defined averaging coefficient was used to discuss the quantitative relationship among the error motion of the air pad,the form error of the rail and the structural parameters of the air pad. The results show that, for the long waves of the rail form error (with wave number from 0 to 1), when the wave number gradually increases, the averaging coefficient gradually decreases from 1 to close to O. For the short waves of the rail form error (with wave number from 1 to 10), when the wave number is close to or equal to a positive integer, the average coefficient takes the minimum value close to 0. And when the wave number is close to or equal to a positive integer plus 0.5, the average coefficient takes the local maximum value less than 0.25. Among the structural parameters,the width of the air land has a great influence on the error averaging ability,while the air pad gap and the diameter of the orifice restrictor basically have no influence on the error averaging ability. When the moving speed is less than 10 000 mm/s, the moving speed has a very weak influence on the error averaging ability. [ABSTRACT FROM AUTHOR]

The so-called ORC (Organic Rankine Cycle) heat recovery technology has attracted much attention with regard to medium and low temperature waste heat recovery. In the present study, it is applied to a Tesla turbine. At the same time, the effects of the disc speed, diameter and inter-disc gap on the internal flow field and output power of the turbine are also investigated by means of CFD (Computational Fluid Dynamics) numerical simulation, by which the pressure, velocity, and output efficiency of the internal flow field are obtained under different internal and external conditions. The highest efficiency (66.4%) is obtained for a number of nozzles equal to 4, a disk thickness of 1 mm, and a gap of 1 mm between the disks. The results of the study serve as a theoretical basis for the structural design and optimization of Tesla turbines. [ABSTRACT FROM AUTHOR]

Reducing energy consumption during textile production processes has currently become one of the key concerns. In order to design the nozzle of the vortex spinning machine with reduced air consumption, numerical simulation of the airflow in the nozzle is performed to investigate the effect of the length and the inlet diameter of the conical chamber in the intermediate section of the vortex tube on the air consumption and the mechanical energy characteristics of the airflow. A spinning experiment conducted to measure the flow rate and yarn tenacity is adopted to verify the numerical simulation results. The simulation results show that the air consumption of the nozzle is insignificantly affected as the length increases from 7.3 mm to 7.7 mm, while a decreasing trend has been found as the length increases from 7.7 mm to 8.1 mm. As the inlet diameter increases from 4.6 mm to 5.0 mm, the air consumption of the nozzle increases monotonically. The mechanical energy of airflow in the nozzle exhibits a minor difference between cases of lengths of 7.3 mm, 7.5 mm, and 7.7 mm, while it decreases significantly in cases of lengths of 7.9 mm and 8.1 mm. The mechanical energy of airflow in the vortex chamber increases as the inlet diameter increases. The experimental results are consistent with the numerical predictions. This work is expected to provide a reference for the design of the vortex spinning nozzle and an approach to reducing the energy consumption in the yarn production process. [ABSTRACT FROM AUTHOR]

This research aimed to develop wound dressings from weft-knitted spacer fabrics as an alternative to existing dressing options. A Stoll Type CMS530 HP electronic flat knitting machine was used to develop spacer weft knitted fabrics, which were tested with various experimental configurations by adjusting the linking distances, spacer yarn ratios, and inlays for proper optimization. Fabric physical and performance properties were evaluated to determine the application of wound dressings and the influence of structural differences. The result showed that the fabric with nylon-to-cotton yarn containing a linking distance setting of 6 needles at a ratio of 1:3, had the highest total performance value, making it the most appropriate fabric for exudate dressing in humid environmental conditions. The fabric with the highest water absorption capacity, and moisture management fabric type was the most effective.

In this article, using the structural parameters called the concentration-concentration fluctuation factor in the long wavelength limit, the number-number factor in the long wavelength limit, the partial number-mole fraction structural factor, the mixed structural factor in the long wavelength limit and calculating the short order factor Chemical field, we have studied the structure and relative investigation of interactions in binary mixtures including butyl acetate and normal alcohols (1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol) at a temperature of 298.15 degrees. Using the experimental values of molar volume and compressibility coefficient of the mixtures, the mentioned structural parameters were calculated. The effect of increasing the length of the alcohol chain on the mentioned parameters was studied, and using the obtained results, a discussion was made about the regularization or disorder of the solutions. The experimental values of the additional molar volume for all the mentioned systems are positive and increase with the increase of the length of the alcohol chain. The analysis of the mentioned structural parameters for binary mixtures also led to similar results for the strength of bonds and the amount of disorder in them. In general, it can be concluded that the intermolecular bonds in two-component systems containing butyl acetate and normal alcohols are weak, and the amount of disorder in these solutions is greater than the amount of disorder in ideal solutions, and this disorder increases with the increase in the length of the alcohol chain. The increase of these irregularities, which is caused by the weakening of the bonds in the solution, can be considered as a result of the spatial hindrance caused by the non-polar chain of alcohols. With the increase in the length of the chain, the amount of this spatial hindrance also increases.

The effects of adding Si to Fe45−xMn30Cr10Co15Six high entropy alloys on martensitic transformation temperatures, structural parameters and strain energy is analyzed. Three different Si amounts are considered, 2, 4, and 6 atomic percent and results are compared with the alloy free of Si. It was verified using x-ray diffraction and energy dispersive spectroscopy that the alloys are substitutional solid solutions and completely homogeneous, in agreement with the prediction of the phenomenological theory of high entropy alloys. The phases present and their corresponding crystalline structure parameters were identified and measured. A thermally induced martensitic transformation FCC-HCP was found in all alloys. The addition of Si leads to a decrease in the paramagnetic to antiferromagnetic transition temperature of the FCC structure in a similar way as found in ternary Fe–Mn–Si alloys. However, it was found that the relative phase stability between the FCC austenite and the HCP martensite is strongly affected by the addition of Si. In fact, the critical martensitic transformation temperatures decrease 20 °C for each additional at% of Si, within the analyzed composition range. From the measurement of lattice parameters, it is shown that the volume change between FCC and HCP decreases after adding Si. The strain energy of the martensitic transformation is obtained and its contribution to the nucleation of HCP martensite is also discussed. [ABSTRACT FROM AUTHOR]

The aviation intelligent pump system is an effective solution to aircraft hydraulic systems' inefficient power consumption and temperature increase. A self-supplied aviation intelligent pump (SAIP) has a high power-to-weight ratio and compact structure, making it the optimal choice for an intelligent pump. To analyze the output characteristics of a novel aviation intelligent pump, it is crucial to establish an accurate mathematical model that describes its dynamic characteristics. This can be achieved by analyzing the working principle and exploring the influence of critical parameters. The paper introduces the composition and working principle of a self-supplied electro-hydraulic servo variable displacement pump. It then establishes a mathematical model of the whole pump, with a detailed analysis and modeling of the critical variable mechanism and the swash plate assembly's load moment. A simulation model was created to examine the impact of crucial structural parameters, such as the offset spring's stiffness and control piston's diameter, on the output characteristics of the intelligent pump. An experimental platform was also constructed, and the experimental results confirm the accuracy of the SAIP model presented in this paper. The investigation of the output characteristics fully reveals the dynamic performance of the SAIP. This provides the basis for the subsequent design of high-performance flow and pressure control strategies and aids in researching intelligent aircraft hydraulic systems. [ABSTRACT FROM AUTHOR]

Copyright of Chemical Engineering (China) / Huaxue Gongcheng is the property of Hualu Engineering Science & Technology Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Electric vehicles (EVs) are propelled by electric traction drive systems (ETDSs), which consist of various components including an electric motor, power electronic converter, and gear box. During manufacturing, end-of-line testing is the ultimate step for ensuring the quality and performance of electric motors in electric vehicle (EV) traction drive systems (ETDSs). The outcome of end-of-line testing of electric motors is significantly influenced by the tolerances of their structural parameters, such as stator inner and outer diameters, magnet dimensions, air gaps, and other geometric parameters. The existing literature provides insights into parametric sensitivity, offering guidance for enhancing the reliability of end-of-line testing. In this manuscript, the importance of end-of-line testing and the role of manufacturing tolerances of e-motor structural parameters in the manufacturing process of ETDSs are discussed. The impact of tolerances of e-motor structural parameters on the test results, such as torque, efficiency, back EMF, and e-NV (noise and vibration), is investigated. Finally, key challenges and research gaps in this area are identified, and recommendations for future research to mitigate the drawbacks of end-of-line testing are provided. [ABSTRACT FROM AUTHOR]

The bacterial spread can pose a significant risk in the transmission of infectious diseases. Nanomaterials, including synthetic antibacterial nanoparticles, have emerged as a promising solution to combat bacterial infections due to their unique physicochemical properties. Metal nanoparticles have been shown to exhibit potent antimicrobial activity against a broad spectrum of bacteria, including both gram-positive and gram-negative strains. One of the main advantages of using metal nanoparticles as antibacterial agents is their ability to penetrate the bacterial cell wall and disrupt cellular processes. This disruption can lead to the inhibition of bacterial growth and ultimately, bacterial death. Furthermore, metal nanoparticles can be engineered with specific surface modifications that enhance their antibacterial activity and improve their biocompatibility. These modifications can include the attachment of targeting ligands, peptides, or antibodies to the nanoparticle surface, which can increase their specificity toward bacterial cells and reduce their toxicity toward mammalian cells. Overall, the use of metal nanoparticles as antibacterial agents holds great promise for the development of novel therapeutic strategies to combat bacterial infections, both in vitro and in vivo. In this paper, we highlight the development of metal NPs, particularly those based on Mn, Fe, Co, Zn and Cu for their antimicrobial properties and related mechanisms. [ABSTRACT FROM AUTHOR]

Taking the maximum contact pressure as the objective function for, the optimal design model of the offshore flange connector was established to analyze the impact of the flange cone's angle and the curvature radius of the lenticular gasket's contact surface on the sealing performance of the connector. An optimized three-dimensional model of the offshore flange connector was constructed using the MATLAB software's fmincon function to obtain the optimal size of the cone angle and curvature radius. The maximum contact pressure and maximum equivalent stress values of the nonoptimized and optimized offshore flange connectors under the cross combination of two design pressures and six operating temperatures were analyzed by Workbench software, and the sealing performance of the non-optimized and optimized offshore flange connectors was compared according to the sealing judgment basis. The results show that compared with the previously studied offshore flange connector, the sealing structure of optimized offshore flange exhibits maximum increase in contact pressure increase but maximum decrease in equivalent stress. Under actual operating circumstances, the optimized offshore flange connection performs better in sealing and is less prone to breakage. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this article, using the structural parameters called the concentration-concentration fluctuation factor in the long wavelength limit, the number-number factor in the long wavelength limit, the partial number-mole fraction structural factor, the mixed structural factor in the long wavelength limit and calculating the short order factor Chemical field, we have studied the structure and relative investigation of interactions in two-component solutions including butyl acetate and normal alcohols (1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol) at a temperature of 298.15 degrees. Using the experimental values of molar volume and compressibility coefficient of the mixtures, the mentioned structural parameters were calculated. The effect of increasing the length of the alcohol chain on the mentioned parameters was studied, and using the obtained results, a discussion was made about the regularization or disorder of the solutions. The experimental values of the additional molar volume for all the mentioned systems are positive and increase with the increase of the length of the alcohol chain. The analysis of the mentioned structural parameters for binary mixtures also led to similar results for the strength of bonds and the amount of disorder in them. In general, it can be concluded that the intermolecular bonds in binary systems containing butyl acetate and normal alcohols are weak, and the amount of disorder in these solutions is greater than the amount of disorder in ideal solutions, and this disorder increases with the increase in the length of the alcohol chain. The increase of these irregularities, which is caused by the weakening of the bonds in the solution, can be considered as a result of the spatial hindrance caused by the non-polar chain of alcohols. With the increase in the length of the chain, the amount of this spatial hindrance also increases. [ABSTRACT FROM AUTHOR]

The offshore gangway is a new type of offshore transfer equipment, equivalent to an offshore passage. This device makes it convenient for people to transfer between a vessel and an offshore structure. The control algorithm of the gangway system demands adjusting its control parameters to deal with harsh sea conditions and ensure personnel safety. Thence, it is essential to foreknow its time-varying structural parameters, such as the moment of inertia, the mass, the location of the mass center, and so on. However, due to the highly complex structure, these parameters are difficult to obtain through measurement directly. To adaptively identify these time-varying parameters for better controller design, this paper proposes a novel structural parameter identification approach based on the idea of interval division. During the identification process, the entire period is uniformly divided into several intervals. The time-varying model of the offshore gangway system can be represented in each interval by a quadratic regression equation, the coefficients of which can be derived by the least-squares algorithm. Furthermore, to adapt to the different variation frequencies and amplitudes of the parameters, the divided intervals are of distinct sizes according to the characteristics of each identification parameter. In addition, the particle swarm algorithm is employed to obtain the optimal interval sizes, the cost function of which consists of a series of output error terms. Verified by simulation, the method presented in this paper can effectively estimate the structural parameters of the offshore gangway with high accuracy, with mean square errors reduced by at least 2/3 compared to other methods proposed in previous research. [ABSTRACT FROM AUTHOR]

In the present work, we investigate the impact of structure dimensional parameters on the short channel effects which occurs especially below 20 nm regime particularly gate induced drain leakage (GIDL) current. Using technology computer aided design simulation (TCAD), we have examined the GIDL for SiGe as source/drain in NTJLFET. The structural dimensional parameters such as the nanotube thickness, core and outer gates thickness and gate electrode work function shows the significant impact on the band to band tunneling in lateral direction (L‐BTBT) which induced GIDL current. It is analyzed that increase in the nanotube thickness and physical oxide thickness increase the GIDL current, while increasing the gate electrode work function, core gate and outer gate thicknesses gives reduced GIDL current. The SiGe S/D NTJLFET produce a remarkable high ION/IOFF ratio ~ 1011. A compact model for GIDL current is also developed which shows the dependency of structure parameters on leakage current. The SiGe has been incorporated as source and drain in NTJLFET which creates the energy band discontinuity. Furthermore, SiGe S/D NTJLFET is fairly compared with the conventional NT JLFET and nanowire (NW) JLFET and shows an improved performance. [ABSTRACT FROM AUTHOR]