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The purpose of current research is to establish a theoretical size-dependent framework for estimating the amount of thermoelastic damping (TED) in miniaturized rings with circular cross section via the nonlocal dual-phase-lag (NDPL) generalized thermoelasticity theory, as one of the most exhaustive non-Fourier heat conduction models. The method used to achieve this goal is based on the definition of TED in the energy dissipation (ED) approach. To do so, after deriving heat equation in the context of NDPL model, the distribution of temperature all over the volume of the ring is specified. Then, the relations of dissipated thermal energy and strain energy in the ring are obtained. Lastly, by employing ED approach, a formula comprising the nonclassical parameters of NDPL model is rendered to determine TED value in small-scaled toroidal rings. By presenting various numerical examples, the dependence of TED on influential parameters including nonclassical thermal constants in NDPL model, ring geometry, vibrational mode number and ring material is surveyed. The Findings enlighten that the inclusion of nonlocal parameter into the model can have conspicuous impacts on TED value, especially in smaller rings or higher vibrational mode numbers. The results also reveal that among the investigated materials (i.e. silicon, copper, silver, and lead), rings made of lead and silicon exhibit the maximum and minimum TED values, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a conventional air source heat pump cycle (CHPC) and two dual-temperature air source heat pump cycles (DTHPC1 and DTHPC2). DTHPC1 employs two condensers, while DTHPC2 adds an extra compressor and combines the ejectors on top of DTHPC1. Compared with the conventional heat pump cycle, the new dual-temperature heat pump DTHPC2 can provide hot water at one additional temperature and still have high performance. In this paper, the refrigerants R1234yf and R1234ze(E) were selected as suitable for the cycle conditions. The cycle performance under different conditions was simulated and compared based on energy analysis methods and exergy analysis methods. The main performance parameters included COP h , η ex , etc. The results demonstrate that the COP h and η ex of DTHPC2 and DTHPC1 are greater than those of CHPC under identical conditions. Specifically, at an ambient temperature of approximately -10 °C, high-temperature hot water of approximately 65 °C, and low-temperature hot water of approximately 35 °C, the COP h of DTHPC2 and DTHPC1 increased by 45% and 32.7%, respectively, in comparison to CHPC. Similarly, the η ex of DTHPC2 and DTHPC1 increased by 27.1% and 28.9%, respectively. [ABSTRACT FROM AUTHOR]

• Thermodynamic analysis of a novel two-stage ejector refrigeration cycle is made. • Cycle performance and exergy efficiency are improved by the separation of mixtures. • COP improvement increased by 41.6 % and 89.6 % for 134a/R32 and R600a/R290. • Three largest exergy destruction occurs in the ejector, condenser, and generator. To improve the ejector refrigeration cycle performance, this paper presents a theoretical thermodynamic analysis of a novel two-stage ejector refrigeration cycle (TSERC) with a gas-liquid separator using R134a/R32 and R600a/R290 as refrigerant. By separating the relatively low-boiling-point and high-boiling-point refrigerants, the cycle compression ratio decreases, the cycle performance increases, and the energy utilization efficiency can be improved. Energy and exergy analysis were conducted for the traditional single-stage ejector refrigeration cycle (SSERC) and TSERC. The effect of the mixture mass fraction on cycle performance under a fixed external heat source operating condition was studied, and the cycle performance comparisons between TSERC and SSERC at different evaporation temperature, condensation temperature and generation temperature were conducted. Results show that for TSERC, the maximum COP values 0.126 and 0.11, the maximum exergy efficiency 4.51 % and 4 % are obtained as the low-boiling-point mass fraction equals 0.6 and 0.4 respectively for R134a/R32 and R600a/R290. It is found that exergy destruction mainly occurs in the low-pressure sub-cycle of TSERC, the top three largest exergy destruction components are ejector 1, condenser 1 and generator 1, while the smallest exergy destruction occurs in pump 2. In addition, cycle performance comparison between SSERC and TSERC shows that the maximum COP improvement increased by 41.6 % and 89.6 % for 134a/R32 and R600a/R290 for TSERC, while the maximum entrainment ratio improvement increased by 32.4 % and 87.6 %. Moreover, it is concluded that the cycle performance improvement of TSERC is more significant at lower evaporation temperature, higher condensation temperature, and lower generation temperature compared to SSERC. [ABSTRACT FROM AUTHOR]

Nonreplications of previously undisputed phenomena tend to leave a theoretical vacuum. This theoretical perspective seeks to fill the gap left by the failure to replicate unobtrusive facial feedback. In the emblematic original study, participants who held a pen between the teeth (i.e., requiring activity of the zygomaticus major muscle) rated cartoons more positively than participants who held the pen between the lips. We argue that the same social mechanisms (e.g., the presence of an audience) modulate facial feedback to emotion as are involved in the feed-forward shaping of facial actions by emotions. Differing social contexts could thus help explain the contrast between original findings and failures to obtain unobtrusive facial feedback. An exploratory analysis that included results only from (unobtrusive) facial-feedback studies without explicit reference to emotion in the facial manipulation provided preliminary support for this hypothesis. Studies with a social context (e.g., due to experimenter presence) showed a medium-sized aggregate facial-feedback effect, whereas studies without a social context (e.g., when facial actions were only filmed), revealed a small effect. Video awareness strengthened facial feedback considerably within an engaging social context, but seemed to reduce it without a social context. We provisionally conclude that a (pro-)social interpretation of facial actions facilitates feedback to (primarily positive) emotion, and suggest further research explicitly manipulating this context. [ABSTRACT FROM AUTHOR]

Hierarchical design and gradient design have proven to be effective in improving the crashworthiness of honeycombs. In this study, a novel graded hierarchical hexagonal honeycomb (GHHH) is proposed by introducing wall thickness variation into the vertex-based hierarchical hexagonal honeycomb (VHHH). The VHHH is obtained by replacing every vertex of the regular hexagonal honeycomb (RHH) with a smaller hexagon. Numerical simulations and theoretical analysis are performed to study the crashworthiness performance of GHHH under the out-of-plane impact. The numerical results show that the specific energy absorption (SEA) of GHHH can be 146.09%, 39.01%, and 50.23% higher than that of RHH, VHHH, and graded hexagonal honeycomb (GHH), respectively, while their peak stresses are nearly the same. In addition, a theoretical model for the plateau stress of GHHH is developed, and the theoretical values show good consistency with numerical results of GHHH with in-extensional mode. The findings of this study provide an effective guideline for the design of honeycombs with enhanced crashworthiness. [ABSTRACT FROM AUTHOR]

A rigorous analytical solution is developed for undrained cavity expansion problems in non-associated Mohr–Coulomb soil, based on a novel graphical analysis approach and on the Lagrangian description through tracking only the responses of a soil particle at the cavity surface. The mathematical difficulties involved with the flow rate calculation when the stress state lies on the corner/edge of two adjacent (Mohr–Coulomb) yield surfaces, for both cylindrical and spherical cases, are tackled by using the generalised Koiter theory for non-associated plasticity. In particular, through the unique geometrical formulation, the effective stress path pertaining to the cylindrical cavity problem can be very conveniently directly determined, and is found to consist of simple, piecewise straight lines in the deviatoric stress plane with the orientations dependent of the relative magnitude of Poisson's ratio and the friction angle. This thus renders possible the removal of the stringent intermediacy assumption for the vertical stress that is commonly adopted in previous formulations, and hence the development of a complete cylindrical cavity expansion solution in Mohr–Coulomb soil under undrained loading conditions. The stress and deformation responses of the cavity, including the typical pressure–expansion curves and limiting cavity pressure, are finally analytically obtained along with the Lagrangian form of the radial equilibrium equation in completely explicit forms. The closed-form solution provided in this paper is the first rigorous one of its kind, thus completing the analytical analysis of the cavity expansion problem with the classical Mohr–Coulomb model; this is deemed to be essential for the interpretation of in situ test results pertaining to cohesive-frictional soils. [ABSTRACT FROM AUTHOR]

The vacuum preloading method is commonly used to improve soft soils; however, it has rarely been studied from the perspective of energy consumption. The work done by the vacuum pump in the vacuum system can be consumed in various ways, including seepage consolidation of soil, water discharge along prefabricated vertical drains and horizontal drainage system (i.e. sand blanket or horizontal pipes), extraction of the air sealed in the drainage system and air leakage from the atmosphere. Equations governing these aspects of energy consumption were derived in this study. A theoretical model of the energy consumption of the vacuum preloading method was established and then solved to quantify the specific forms of energy consumption. Theoretical predictions and laboratory results demonstrate that the energy consumptions of seepage consolidation and water discharge are negligibly small compared with the total work by the vacuum pump, and most of the work done by the vacuum pump in the vacuum system is consumed during the extraction of leaked-in air. [ABSTRACT FROM AUTHOR]

Featured Application: This theoretical analysis examines the working principle of an online vibrating tube liquid densitometer. The analysis is based on the design and establishment of a series of experimental devices, the evaluation of device uncertainty, and the use of straight and curved-tube-type online densitometers to verify device reliability. The study also investigates the impact of pressure and temperature on the metrological performance of the vibrating tube densitometer. Density is a crucial parameter for quantitatively describing the physical properties of liquids. It serves as an important indicator for scientific research, production process control, pipeline transportation, and other aspects. In oil pipeline transportation and raw material processing, the real-time online measurement of liquid density is of great significance. This paper analyzes the working principle of an online vibrating tube densitometer and derives the fitting equation for temperature, pressure, and density; it also conducts experiments with an online vibrating tube liquid densitometer and establishes a traceability chain for the experimental device. The experimental setup includes a desktop densitometer system, a multi-temperature field constant-temperature stirring system, a walk-in constant-temperature box, an automatic blowing system, and a frequency acquisition and calculation system. The uncertainty of the device's evaluation is U = 0.08 kg/m3, k = 2. We built a set of pressure-density static test systems, statically testing the online vibrating tube's liquid-density meter vibration frequency at different pressures; the whole set of systems can be used to assess the specific density, temperature, and pressure range of online vibrating tube liquid density meters in the experimental research to derive the standard temperature. Through the experimental research, we can accurately derive the fitting coefficients under the standard temperature, specific temperature, and pressure of online vibrating tube liquid densitometers, and calculate the fitting error of online vibrating tube liquid densitometers under different temperatures and pressures within the experimental range through fitting equations and coefficients, so as to realize the practical application of online vibrating tube liquid densitometers in engineering by utilizing straight-tube-type and curved-type online vibrating tube densitometers. A preliminary study was conducted on the effects of different densities, temperatures, and pressures on the vibrating tube system's vibration cycle. The fit coefficient and error were calculated, and the experimental results were compared to the theoretical analysis to confirm the device's conformity. The study verified the device's scientific and reasonable design, and demonstrated that it is feasible to use the device for follow-up research. Using this device in subsequent experiments can verify the effects of viscosity, inlet, installation, and other factors on the online vibrating tube liquid densitometer's metrological performance. Further experimental research on the pressure–frequency–density test system and the establishment of a wide range of temperatures and pressures within the pressure standard density test system are needed to achieve a wide range of temperatures and pressures under the standard density test. [ABSTRACT FROM AUTHOR]

In the construction of a twin-shield tunnel in limited underground space, the design of the clear distance between the two lines needs to consider not only the safety issues related to the interaction during excavation but also the low-carbon effect, aiming to precisely shorten the distance and fully utilize the underground space, thus saving land resources. In this paper, the earth pressure patterns in a shallow-buried twin-shield tunnel with small spacing are clarified. Furthermore, based on the Mohr-Coulomb shear failure criterion of the middle bearing pillar, a theoretical decision model for safe clear distance in it, adaptable to different geological formations, is established. In addition, its accuracy is verified through numerical simulations. At last, the quantitative influence of various parameters on the safe clear distance is analyzed using the theoretical model. The results of the study offer a theoretical foundation for the design of a clear distance between a shallow-buried twin-shield tunnel with small spacing and the parameterized measurement of the ground reinforcement needed for its construction. [ABSTRACT FROM AUTHOR]

Focusing on the applicative setting represented by advanced big data analytics tools over data Cloud infrastructures, this paper introduces and theoretically proofs an innovative privacy-preserving OLAP framework against big query-workloads. The described applicative setting is common for big data analytics tools developed on top of commodity hardware solutions, where, rather than the execution of singleton big data queries, these queries are embedded into big data query programs, such that every elementary query evaluation step refers to one or more queries of the target query-workload. We complete our analytical and theoretical contributions by providing and experimentally assessing an innovative optimized approximate query answering algorithm for providing privacy-preserving approximate answers to OLAP queries. [ABSTRACT FROM AUTHOR]

Structural dynamic properties like frequencies and mode shapes have been widely adopted for bridge condition assessment and damage identification. One of the main challenges lies in environmental factors, particularly the varying temperature, which significantly influences the bridge’s natural frequencies. In some cases, the effect of temperature changes can be comparable to, or even exceed, the effect caused by damage, rendering the damage identification methods ineffective. This study investigates the influence of the cross-sectional non-uniform temperature distribution, as a result of surrounding environmental factors, on the frequency of concrete girder bridges. A theoretical analysis is conducted to derive the bridge’s frequencies considering the cross-sectional non-uniform temperature distribution. The upper and lower bounds of the frequencies are developed by using only the environmental temperature and the largest temperature gradient defined by codes. More importantly, the damage to the bridge can be detected if the frequencies exceed the bounds for a certain period. This approach is convenient and practical in real applications without embedding thermocouples in the main girder. Numerical simulations, laboratory experimental tests, and field measurements are carried out to validate the derived frequency considering the cross-sectional non-uniform temperature distribution as well as the upper and lower bounds of the frequency. In particular, the results of the Z24 bridge show that when the bridge is damaged, the measured frequency exceeds the bound continuously, verifying the capability of the developed upper and lower bounds to evaluate bridge conditions. [ABSTRACT FROM AUTHOR]

This study aims to derive the exact stretching and bending solutions of the radially FGM annular sandwich plate subjected to either radial pressure or transverse load. The radially FGM annular sandwich plate consists of two homogeneous rings and an FGM-undercoated layer with uniform Poisson's ratio and radially graded Young's modulus based on the power function. Although the radially FGM annular sandwich plate is nonhomogeneous, the stretching and bending problems can be analyzed separately based on the elastic plate theory. Then the exact solution corresponding to the power-law graded FGM can be evaluated by solving the simultaneous equations of the boundary and continuous conditions. The theoretical results are validated through the comparison with the finite element solutions. When degenerated, our results coincide with those of the homogeneous annular plate in the literature, making the obtained solutions reliable. Using the radial-FGM as the undercoated layer makes the strains and stresses smoothly continuous at the interfaces of the layers. The effects of the material index on mechanical behavior are under investigation. [ABSTRACT FROM AUTHOR]

The sugarcane field excitation, cutting forces and the engine excitation constitute complicated excitations acting on sugarcane harvesters. In this study, the sugarcane cutting mechanism under complicated excitations was analyzed. The dynamics and the mathematical models of sugarcane harvesters were established and simulated. Based on theoretical analysis, sugarcane cutting experiments were done on a self-built sugarcane harvester test platform (SHTP), designed as single-factor and the orthogonal experiments. Effects of the sugarcane field excitation characterized by the sugarcane field excitation device (SFED) output frequency, the engine excitation characterized by the actuating engine output frequency, the cutter rotating speed, the sugarcane harvester travelling speed simulated through the sugarcane transporting speed of the SHTP and the cutter inclination angle on the cutting quality of sugarcane harvesters were studied. Effects of the axial cutter vibration on three-directional cutting forces and the sugarcane cutting quality (SCQ) as well as effects of three-directional cutting forces on the SCQ were further studied. It is shown that the sugarcane field excitation, the axial cutter vibration amplitude and frequency as well as the three-directional cutting forces have significantly negative monotonic correlated effects on the SCQ while the cutter rotating speed, the sugarcane harvester travelling speed and the cutter inclination angle have significantly positive monotonic correlated effects on the SCQ. Significance levels of effects on three-directional cutting forces and the SCQ form high to low are as follow, the axial cutter vibration, the sugarcane field excitation, the cutter rotating speed, the engine excitation, the cutter inclination angle, the sugarcane harvester travelling speed. The theoretical analysis results were verified through experiment and an optimal combination was obtained with the cutter rotating speed of 700 r/min, sugarcane harvester travelling speed of 0.6 m/s and cutter inclination angle of 8°. This study can provide a reference for setting cutting parameters of sugarcane harvesters with a good SCQ. [ABSTRACT FROM AUTHOR]

The feasibility of Carrillo's method is confirmed for consolidation problems of unsaturated soils under instantaneous loading in this study. In the plane strain and axial symmetry consolidation models, the coupled governing equations expressed by the excess pore-air and pore-water pressures are transformed into the equivalent uncoupled equations expressed by two functions of excess pore pressure using a decoupled method. Then, two rigorous theorems are used to prove that Carrillo's method is suitable for unsaturated soil consolidation under the plane strain and axial symmetry conditions. Finally, the mathematical formulas by Carrillo's method for unsaturated soil consolidation under plane strain and axisymmetric conditions are presented, and are verified against those of the existing analytical solutions. It turns out that the combinations of existing solutions to the conditions of a single direction flow by the proposed formulas can directly furnish the solutions to unsaturated soil consolidation with both horizontal and vertical flows. [ABSTRACT FROM AUTHOR]

This paper presents a new analytical solution to predict the ultimate depth and holding capacity of plate anchors based on an integrated analysis of the anchor and mooring system. The configuration equations of the mooring line, both in soil and water, have been solved to obtain the complete line profile. A key advancement is that the mooring line angle at mudline varies compatibly with the whole anchor–mooring system. This is different from the solutions available in literature that neglect the mooring line segment in water and only assume a constant mooring line angle at the mudline. The system of equations is solved by using an iteration scheme, and parametric studies are demonstrated. The effects of line length, water depth, and seabed strength profile are explored by demonstrating the performance of a commercial plate anchor. It is found that neglecting the mooring line in water can significantly overestimate the ultimate embedment and capacity, especially when the mooring line length is relatively short. This paper can be used as an engineering tool to predict the ultimate capacity of an anchor–mooring system considering the integrated behavior of the whole system. [ABSTRACT FROM AUTHOR]

The following research paper concerns the analysis and characterisation of commercially available surface-enhanced Raman scattering (SERS) substrates. SERS has long been a potentially very powerful method with a great deal of interest around it; however, there are still many obstacles which do not allow SERS to be easily applied to real-world detection and analysis problems. As such, research around the various types of substrates is ongoing, in the hope of streamlining and improving the Raman enhancement mechanism. Scanning electron microscope images were obtained for each of the three substrates, and their features and scales were described. Enhanced Raman spectra for Rhodamine B were obtained for a range of concentrations using each of the three substrates, and, in addition, surface enhancement maps are presented. Enhancement factors were calculated for the 1358 cm−1 peak of Rhodamine B. Complementing the experimental work, theoretical FEM modelling in COMSOL Multiphysics was performed, with the resulting calculations yielding an enhancement prediction adequately accurate to the real substrates. [ABSTRACT FROM AUTHOR]

Accurate analysis of creep effects in finite element analysis depends on whether the exponential form of the creep coefficient can accurately reproduce the creep coefficient curve. This paper aims to develop a high-precision fitting method for arbitrary creep coefficient curves to achieve accurate finite element creep analysis. The core issue was examined, and an optimization algorithm was proposed. First, the simulated annealing algorithm was used to search for the global optimal solution, followed by the application of the Levenberg-Marquardt algorithm for precise calculations. Two examples were employed to verify the method. The results showed that: (1) The proposed creep coefficient curve fitting method could accurately fit the creep coefficient curve. (2) The case studies showed that the algorithm achieved a correlation coefficient ( R) above 0. 999 9 when fitting the creep coefficient curves according to highway and railway standards, indicating high fitting accuracy and strong general applicability. (3) The proposed algorithm featured a simple structure and clear hierarchy, allowing for easy implementation using common programming languages. This method provides valuable insights for the development of finite element program creep analysis modules or related scientific research on concrete creep behavior. [ABSTRACT FROM AUTHOR]

The low elastic modulus of glass fiber–reinforced polymer (GFRP) materials used in civil engineering may lead to insufficient structural stiffness in GFRP–aluminum space truss structures, limiting their ability to meet the service limit state requirements. To enhance flexural stiffness, a prestressed carbon fiber–reinforced polymer (CFRP) tendon system was developed and demonstrated. Full-scale three-point bending tests were performed to evaluate the flexural response of GFRP space truss girders, both with and without CFRP tendons. Four prestressing schemes were investigated, revealing the effect of the tendon system in enhancing stiffness. A simplified, design-oriented theoretical model using the equivalent continuum method and the force method was developed to aid structural design calculations. The model's formulas account for variable joint stiffness and equivalent shear deformation, enabling accurate stiffness evaluations. Parametric analyses were conducted on the prestress level, the girder-to-tendon stiffness ratio, and the geometric parameters of the CFRP tendon system. The results indicated that the four prestressing schemes enhanced the flexural stiffness and reduced the internal forces, validating the effectiveness of the novel prestressed FRP space truss structure. The proposed model accurately describes the prestressing enhancement mechanism and offers theoretical support for structural design. [ABSTRACT FROM AUTHOR]

Two‐phase flow displacement in rock fractures is crucial for various subsurface mass transfer processes and engineering applications. In fractures, the displacement of a less viscous fluid by a more viscous one (i.e., viscosity ratio M > 1) involves viscous forces help stabilizing the displacement front in presence of capillary pressure fluctuations. Although previous studies have reported displacement patterns in isotropic fractures, the impact of anisotropic fractures on displacement patterns has not been systematically examined. In this study, we conducted flow‐rate‐controlled drainage experiments to examine how anisotropic aperture fields affect displacement patterns. We observed the transition of displacement patterns from capillary fingering (CF) to crossover zone (CZ) to compact displacement pattern (CD) based on variations in transverse pore‐filling event (TPFE) frequency, which characterizes the competition between capillary and viscous forces. Increasing aperture correlation length in the transverse direction leads to increased TPFE frequency at a low flow rate, destabilizing displacement front. While the increasing aperture correlation length in longitudinal direction suppressed TPFE frequency, stabilizing displacement front. Therefore, the critical capillary number (CaCF‐CZ), which indicates the onset of the CF‐CZ transition, decreases as the aperture field varies from transversely to longitudinally correlated. At high flow rates, TPFEs almost disappeared, indicating that anisotropy did not affect CZ‐CD transition (CaCZ‐CD). Furthermore, we modified theoretical models of CaCF‐CZ and CaCZ‐CD by incorporating the aperture anisotropy factor, achieving a good fit with the experimental data. This study demonstrates the critical role of aperture field anisotropy in controlling two‐phase displacement patterns and provides a theoretical framework for predicting multiphase flow behavior in natural fractures. Plain Language Summary: Understanding how a viscous fluid displaces a less viscous one in rock fractures is important for various underground processes and engineering applications. Previous studies on two‐phase flow have mainly focused on isotropic fractures. Natural fractures are often anisotropic, and the impact of fracture anisotropy on two‐phase flow patterns has not been thoroughly studied. Here we conducted laboratory experiments to examine how anisotropy affects displacement process. We found that more viscous injection fluid forms thin fingers that penetrate fractures and sometimes forms a compact displacement (CD) front. The movement of injection fluid depends on anisotropy and fluid velocity. At low and intermediate flow velocities, when the aperture correlation length in the main flow direction is much shorter than that in transverse direction, fingering of injection fluid is enhanced and the front tends to be unstable. When large‐aperture patches extend in main flow direction, fingering is suppressed and the front tends to be compact. Additionally, at high flow velocities, formation of thin fingers is restrained, and impacts of anisotropy on displacement process diminishes. We have conducted theoretical analyses on the interplay between capillary and viscous forces to better understand whether two‐phase flow through anisotropic fractures will exhibit fingering or a CD pattern. Key Points: Aperture field anisotropy controls displacement pattern transitions by influencing the competition between viscous and capillary forcesTheoretical analyses of the competition between viscous and capillary forces are conducted to predict displacement pattern transitionsA phase diagram incorporating anisotropy, flow rate, and viscosity ratio has been developed to predict two‐phase displacement patterns in anisotropic fractures [ABSTRACT FROM AUTHOR]

In this work, we extend recent research on the fully mixed virtual element method based on Banach spaces for the stationary Boussinesq equation to suggest and analyze a new mixed-virtual element technique for the stationary generalized Boussinesq equations, where viscosity and thermal conductivity are temperature-dependent. Besides the original thermo-fluid variables, the pseudostress and vorticity tensors of the fluid and the pseudoheat vector of the thermal system are introduced as auxiliary unknowns, and the incompressibility condition is then used to remove the pressure, which is later computed using a postprocessing formula. The resulting highly coupled formulation is then written equivalently as uncoupled problems thanks to a fixed-point strategy, so that the classical Banach Theorem, combined with the corresponding Babuška–Brezzi theory, the Banach–Nečas–Babuška Theorem, smallness-of-data assumptions, and a slight higher-regularity assumption for the exact solution, are employed to establish the unique solvability of the continuous formulation. The virtual element discretization of the uncoupled problems is based on the H (div 6 / 5) - and H (div 6 / 5) -conforming virtual element techniques. The discrete analysis is conducted in a similar manner by establishing the discrete inf-sup condition and using the discrete versions of the aforementioned theorems to demonstrate the existence of the discrete solution and derive its stability estimates. In addition, a priori error estimates are established by utilizing the Céa estimate and a suitable assumption on data for all variables in their natural norms showing an optimal rate of convergence. Finally, several numerical examples are presented to illustrate the performance of the proposed method. [ABSTRACT FROM AUTHOR]

Aiming at the problems of harsh environment, frequent frost damage, multiple interference factors in lining images, inconsistent scale of frost damage targets, and low efficiency and high cost of traditional manual visual inspection methods for tunnel lining built in cold regions, a frost damage detection method for tunnel lining in cold regions based on HRNetV2 was proposed. Firstly, based on HRNetV2, an improved model was proposed, which combines the knowledge of transfer learning in the backbone feature extraction network, introduces attention mechanism in the structure to enhance the model's learning ability for frost damage features, and uses Focalloss as the loss function to solve the problem of class imbalance. In order to verify the performance of the improved model, frozen damage images of tunnel lining in cold regions were collected by high-definition cameras. After clipping and data enhancement, a semantic segmentation dataset containing 2 800 cracks, spalling and ice hanging was established. The experimental results show that the mean intersection over union(mIoU) of the improved model can reach 89. 05% on the freezing damage dataset, which is 5. 41% higher than that of the original model, showing good robustness in the face of complex forms of frost damage, and can be directly applied to high-resolution original images. Compared with DeeplabV3 +, U-Net and PSPNet three classical semantic segmentation models, the improved HRNetV2 model has more advantages in comprehensive performance. The proposed method can accurately and safely achieve intelligent detection of lining frost damage, providing certain technical support for intelligent operation and maintenance of tunnels in cold regions. [ABSTRACT FROM AUTHOR]

Improving the quality and efficiency of industrial land use is a key part of building a high-quality modern industrial system, playing a fundamental supporting role in enhancing industrial land factor productivity, strengthening industrial chain competitiveness, and promoting the development of emerging productive forces. This article delves into the connotation and significance of improving the quality and efficiency of industrial land use from three dimensions: industrial upgrading, intensive utilization, and market allocation. Furthermore, it systematically analyzes the development path of improving the quality and efficiency of the entire industrial land chain around the three levels of planning guidance, land supply, and post-supply utilization. Meanwhile, combining Shenzhen's practical experience, existing problems, and countermeasures, it achieves an organic combination of theory and practice, aiming to provide valuable theoretical and practical references for other cities in improving the quality and efficiency of industrial land use. [ABSTRACT FROM AUTHOR]

[Display omitted] • Impact of big data and green loans on firm's energy efficiency is analyzed. • Information and transaction costs are paths for big data affecting green loan choices. • Changes in firm's decisions due to improved energy efficiency are discussed. Green digital finance is an instrumental way to promote technological innovation, accelerate the low-carbon transition, and foster sustainable development. With the emergence of green digital finance, how does it affect firms' energy use efficiency? Using big data and green loans as an entry point, the impact of green digital finance on corporate energy efficiency and the role of big data are examined. We provided a simple theoretical model to analyze the green loaning behavior of the banking sector after applying big data and its impact on corporate energy efficiency. Our research finds that: (1) The application of big data can make it easier for the banking sector to obtain loan companies' information and reduce loan delinquency rates. This will reduce the information and transaction costs of the banking sector and expand the scale of optimal green loans. (2) The optimal green loan scale has a negative relationship with the optimal green loan interest rate. (3) The application of green loans by firms can improve energy efficiency and have a range of impacts on firms' decision-making, including an increase in the emission reduction ratio, innovation probability, output, and profit, followed by a decrease in energy consumption and pollution emissions. This paper further clarifies the channels through which green digital finance affects energy efficiency and specifies the role of big data in green digital finance. This could help relevant policymakers design more effective green digital finance policies, contributing to carbon peaking and carbon neutrality goals. [ABSTRACT FROM AUTHOR]

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To fill the gaps in the theoretical research on the internal force and deformation of the DSCG, the development law of the internal force and deformation of DSCG was explored in conjunction with the theory of elastic analysis. In addition, a finite element model was established to validate the calculation results. The results showed that using different pre-stressing increment calculation methods affected the calculation results of the composite interface deformation, with the equivalent section method accounting for 0.74% and the principle of the virtual work method for 0.03%. On the other hand, the development of internal forces and deformations in the DSCG was closely related to the magnitude of the load forms and axle weights. At the same time, material non-linearity had less influence on these factors. Finally, the development patterns of the internal forces and deformations of the DSCG with different spans were similar. The specific values were closely related to the span of the guideway, and the interfacial slip, axial force, and deflection of the DSCG with span L = 25 m were 0.60, 0.41, and 0.23 times those of the DSCG with span L = 35 m, respectively. The conclusions of this paper fill the gaps in the theoretical study of multi-system guideways. [ABSTRACT FROM AUTHOR]

This study specifically discusses the low-carbon emission production scheduling model and algorithm of intelligent manufacturing based on energy and environmental efficiency. This paper constructs a multi-objective optimization model and uses genetic algorithm to solve the problem, so as to verify the effectiveness of the model in many aspects, such as improving production efficiency, reducing energy consumption, and reducing carbon emissions. Using the experimental analysis results, it can be seen that the algorithm in this paper can improve the production efficiency of enterprises, reduce their energy consumption, reduce carbon emissions, and provide scientific basis and technical support for the vision of green manufacturing. [ABSTRACT FROM AUTHOR]

The developed article considers SIR problems for the recent COVID-19 pandemic, in which each component is divided into two subgroups: young and adults. These subgroups are distributed among two classes in each compartment, and the effect of COVID-19 is observed in each class. The fractional problem is investigated using the non-singular operator of Atangana Baleanu in the Caputo sense (ABC). The existence and uniqueness of the solution are calculated using the fundamental theorems of fixed point theory. The stability development is also determined using the Ulam-Hyers stability technique. The approximate solution is evaluated using the fractional Adams-Bashforth technique, providing a wide range of choices for selecting fractional order parameters. The simulation is plotted against available data to verify the obtained scheme. Different fractional-order approximations are compared to integer-order curves of various orders. Therefore, this analysis represents the recent COVID-19 pandemic, differentiated by age at different fractional orders. The analysis reveals the impact of COVID-19 on young and adult populations. Adults, who typically have weaker immune systems, are more susceptible to infection compared to young people. Similarly, recovery from infection is higher among young infected individuals compared to infected cases in adults. [ABSTRACT FROM AUTHOR]

The fabrication process of pretensioned prestressed concrete (PC) girders involves temperature changes, which affect the effective prestress and mechanical properties of the girders. Currently, there is a lack of a holistic understanding and accurate calculation methods for the prestress variation due to temperature change (PVTC), leading to technical challenges in calculating effective prestress in pretensioned PC girders. This study investigates the PVTC in three stages considering the time-varying interaction between concrete and tendons, proposes a new method to consider the effect of a deviator on the PVTC of a bent tendon, conducts an experimental study to validate the theoretical analysis, and develops measures for reducing the PVTC. The results show that the presented method provides reasonable predictions of PVTC, and the PVTC of the girder with steam curing is up to 80.3 MPa. Based on the presented method, measures for reducing the PVTC are proposed. This study provides new insights into computing the PVTC and improves the design and fabrication of pretensioned PC girders. [ABSTRACT FROM AUTHOR]

Ordinary nonlinear differential equations with classical and fractional derivatives are used to simulate several real-world problems. Nonetheless, numerical approaches are used to acquire their solutions. While various have been proposed, they are susceptible to both disadvantages and advantages. In this paper, we propose a more accurate numerical system for solving nonlinear differential equations with classical and Caputo–Fabrizio derivatives by combining two concepts: the parametrized method and the predictor–corrector method. We gave theoretical analyses to demonstrate the method’s correctness, as well as several illustrated examples for both scenarios. [ABSTRACT FROM AUTHOR]

This study introduces an innovative wedge anchor for double-layer carbon fiber reinforced polymer (CFRP) plate cable to address the current limitation of traditional wedge anchors. By employing the design concept of "secondary force transmission path", the friction force for anchoring the CFRP plate is effectively transferred into the barrel through its contracting wedge, thus reducing the clamping pressure requirement of traditional wedge anchorage for anchoring thick or double-layer CFRP plates. Based on this conception, this study presents a theoretical analysis model for predicting the influence of parameter variations on the compressive stress of the CFRP plate, which can serve as a tool for rapid configuration preliminary design. Through finite element analysis, the internal stress distribution of the anchor is thoroughly investigated, and the theoretical analysis model for fast predicting compressive stress of CFRP plate is also validated. The results also indicate that the anchorage conception is valid and effective, providing sufficient anchorage of CFPR plates with an anchorage length of 100 mm. [ABSTRACT FROM AUTHOR]

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With the advancement of urban underground space networks, there has been a rise in foundation pit projects near existing tunnels. The construction of these foundation pits adjacent to existing tunnels can result in soil disturbance and stress redistribution, leading to additional deformation and internal force within the tunnels. This paper delves into the two-stage analysis method, outlining the calculation of additional stress in the initial stage considering various engineering factors and the methods for determining tunnel displacement and internal force in the subsequent stage. Through an engineering example and numerical simulations, the theoretical calculations were validated. The maximum displacement generated by the tunnel is −4.85 mm and −5.10 mm, respectively. The maximum error is only 5.9%, which confirms the validity of the theoretical approach. The analysis demonstrates that incorporating the unloading model of the bottom and surrounding side walls of the foundation pit is essential when calculating additional stress in the first stage. Moreover, the presence of engineering dewatering and double-hole tunnels can counterbalance the additional stress, with deviations of only 4.4% and 2.5%, respectively. In the second stage, factoring in the shear action and lateral soil action in the foundation and tunnel model enhances the accuracy of stress mode representation (accuracy increased by 18.8% and 29.3%, respectively). Additionally, accounting for the buried depth effect of the tunnel, soil non-uniformity, and foundation nonlinearity helps prevent excessive foundation reactions. [ABSTRACT FROM AUTHOR]

To fully harness the design development potential of plastic angle sections, this study employs a theoretical analysis approach to examine the plastic behavior of equal angle sections subjected to axial force and biaxial bending. Based on the simplified angle section results, the full plasticity correlation equations were derived. Subsequently, section shape coefficients were computed. Finally, a methodology for calculating the plastic development coefficients of angle sections was explored. The findings indicate that the full plasticity correlation equations lack the necessary safety margins in designs. Notably, the angle sections possess a greater plastic development capacity along the weak axis compared with the strong axis. It is advisable, for both regular-size and large-size angle sections, to consistently adopt the plastic development coefficients in designs as follows: γu = 1.05 for the strong axis and γv = 1.15 for the weak axis, thereby addressing the shortcomings of the specification in design. [ABSTRACT FROM AUTHOR]

Among reinforcement methods for 3D concrete printing (3DCP) structures, steel cable reinforcement and reinforced concrete confined by 3DCP formwork (RC-3DPF) methods offer high design freedom and automation. However, the former lacks reinforcement in directions perpendicular to the printing direction, and the latter cannot satisfy constructional requirements. This paper proposed a hybrid approach: the steel rebar reinforced concrete column confined by the steel cable reinforced 3DCP permanent formwork (RC-SC-3DPF). Axial compression tests and theoretical analysis were conducted to study axial performances. Test results showed steel cables and fibres added to 3DCP formwork benefit RC-SC-3DPF structural performances. With a steel cable confinement ratio above 0.534%, RC-SC-3DPF outperforms the traditional case. Steel fibre, compared to PVA fibre, demonstrates greater potential for RC-SC-3DPF due to improved axial load resistance and reduced ductility loss. A theoretical model, based on experimental results, existing standards, and M&T model, was developed to effectively evaluate RC-SC-3DPF structural behaviour.

The subject of this article is the forming process of closed die forging with flashes and the optimal design of the flash gutter dimensions. The goal is to conduct an in-depth theoretical analysis of the forming process of closed die forging with flash and to research the optimal design of the flash gutter dimension, aiming to improve the scientificity and efficiency of the forging process, guide the optimization of process parameters in actual production, extend the service life of dies, reduce material waste, and enhance product quality and production efficiency. The tasks were to establish an accurate mathematical model for closed die forging with flash to analyze metal plastic deformation and stress distribution, to conduct in-depth research on key factors such as stress distribution, position of the neutral plane, and flash gutter design during the forming process, and to validate the mathematical model through finite element simulation using DEFORM-2D software. The methods used include theoretical analysis, mathematical modeling, and finite element simulation validation. The theoretical analysis provides a foundation for understanding the forming process and stress distribution, whereas the mathematical model allows for quantitative analysis. Validation of the finite element simulation provides a means to test and refine the theoretical analysis and mathematical model. The following results were obtained: the existing mathematical model underestimates the height of the main deformation zone, which results in an unreasonable flash gutter design. After verification and correction, the error in the optimized mathematical model did not exceed 10 %, and the flash amount was significantly reduced. Additionally, a stress analysis of difficult-to-fill cavity positions revealed that the entrance radius of the cavity significantly affects the final filling. Conclusions. The scientific novelty of the results obtained is as follows: A mathematical model of closed die forging with flash was established to analyze the metal plastic deformation and stress distribution, providing theoretical support for die design optimization, forging quality improvement, cost reduction, and productivity improvement. Using the Deform-2D finite element simulation, the optimal design criterion for the flash was refined, resulting in a substantial reduction in the flash amount and material savings.

IntroductionThe maintenance of health is a central objective of public health initiatives. Within the salutogenic paradigm, health promotion is focused on understanding the mechanisms of health development. Models serve as indispensable tools. One of the leading paradigms in the health sciences is the Salutogenic Model developed by Aaron Antonovsky. However, it lacks sufficient specification to reflect the complexity of the environmental dimensions that have emerged from research in environmental health science. The interactions and impact pathways between these dimensions on health status are not adequately distinguished. The objective of this study is to address this gap by extending Antonovsky’s model to encompass environmental dimensions, that is, the interactions between humans and their environment. Furthermore, the study will integrate examples of models and theories from various disciplines to illustrate how a more comprehensive and holistic explanation of health development can be provided from an interdisciplinary environmental public health perspective.MethodologyAs part of a three-step approach, a Basic Model was first developed that integrates the five environmental dimensions—Natural, Built-Material, Socio-Cultural, Psycho-Social, and Individual—into the Salutogenic Model. Subsequently, narrative non-exhaustive literature research was used to identify interdisciplinary example models. The models were used to identify gaps in the Basic Model through a critical lens and to synthesize them into a more holistic model.ResultsThe synthesis of fifteen interdisciplinary models resulted in the development of an integrative Salutogenic Environmental Health Model (SEHM), which comprises twelve principal components of health development and their interactions and pathways. Links to the original models permit the user to refer back to them.DiscussionThis integrative approach offers a comprehensive understanding of the development of health by synthesizing disparate explanatory models and theories from various disciplines through theoretical analysis. The various environmental dimensions and the determinants of health contained therein, as well as their mental and physical processing and the associated components of health development and their interactions, are summarized in this new model. The SEHM thus enables a differentiated analysis of health determinants and serves as an operational framework for health promotion and pathways to well-being in contemporary research contexts.

Abstract Precast Concrete Sandwich Panel (PCSP) is composed of concrete load-bearing panels, thermal insulation panels, and decorative panels, which are assembled through connectors, integrating load-bearing, thermal insulation, and decorative functions. The connector bears the main shear force between the wall panels, and the shear resistance and insulation performance of the connector largely determine the mechanical stability and insulation effect of the wall panels, which is a key component in PCSPs. The current common practice is to cross assemble stainless steel insulation (SSI) connectors and Glass-Fiber-Reinforced Plastic (GFRP) connectors into PCSPs, which can reduce building energy consumption and save resources while meeting strength and insulation requirements. A large-scale pull-out test on a PCSP with intersecting SSI-GFRP connectors was conducted in this paper. The damage process and damage pattern of PCSP were observed and the shear performance of SSI-GFRP connectors was analyzed. Secondly, a numerical analysis model of the test PCSP was built using ABAQUS finite element software and its validity was verified through the test data. In addition, parameters such as connector diameter, connector number ratio and concrete strength were analyzed for their effect on the shear performance of SSI-GFRP connectors and it was found that connector diameter and connector number ratio had a significant effect. Finally, it is found that there are some differences between the classical theory for calculating the shear performance of SSI-GFRP connectors and the actual results. A theoretical correction factor (ζ) is given to improve the accuracy of the calculation of the classical theory, and its influencing factors and changing rules are investigated.

This paper conducts a theoretical analysis of ground settlements due to shield tunneling in multi-layered soils which are usually encountered in urban areas. The proposed theoretical solution which is based on the general form of the Mindlin's solution and Loganathan-Poulos formula can comprehensively consider the in-process tunneling parameters including: unbalanced face pressure, shield-soil friction, unbalanced tail grouting pressure, unbalanced secondary grouting pressure, overloading during tunneling and the ground volume loss. The method is verified by comparing with the field data from the Qinghuayuan Tunnel Project in terms of the ground surface settlements along the longitudinal and transverse direction. Due to the local settlement or heave caused by the certain tunneling parameters, the ground surface settlements calculated using current solution along the longitudinal direction presents an irregular S-shaped curve instead of the traditional S-shaped curve. Results also find that the effect of the unbalanced secondary grouting pressure and the overloading during tunneling cannot be ignored.

Abstract Carbon fibre-reinforced polymer (CFRP) plates can efficiently repair or enhance the mechanical properties of the square hollow section. However, the loading end of such a CFRP-strengthened member is prone to local bearing failure under compressive load. Given this limitation, an innovative CFRP-plate-strengthened square hollow section composite member (CFRP-SHSCM) was raised, and the thick-walled section was welded on both ends of the thin-walled steel column. The mechanical properties of CFRP-SHSCMs were investigated through parameter finite element (FE) analysis, focusing on the influence of the amount of CFRP layers (n c ), the slenderness ratio (λ), the initial geometric imperfections (v 0 ), the CFRP layouts (2S and 4S) and the length of the exposed steel column (L e ). The load–displacement curves, the bearing force, and typical failure modes were also acquired. Results indicated that with increasing n c and v 0 , and decreasing λ, the conventional CFRP-SHSCMs were prone to local bearing failure with poor ductility, leading to the insufficient use of the CFRP plate, in contrast, the improved CFRP-SHSCMs primarily underwent overall buckling failure and exhibited better bearing force and ductility. Finally, the modified Perry-Robertson formula was put forward to predict the ultimate load of the CFRP-SHSCMs. The coefficients of variation between the FE simulation and the theoretical results were 0.00436 and 0.0292, respectively.

With accelerated urbanisation, the importance of urban characteristic planning has become increasingly prominent. It has been a focus on how to conduct scientific urban characteristic planning evaluation to ensure high quality and sustainable development of urban characteristic planning. Therefore, this study proposed an urban characteristic planning evaluation index system based on support vector machine (SVM). The process uses hierarchical analysis to determine the relative weight values, calculates fuzzy values for indicators that cannot be directly and objectively evaluated and then introduces SVM for precise processing of interval data. The test results showed that the accuracy of the research method was 0.9760, 0.9600 and 0.9750 when taking the maximum bias value of 0.5 in the three datasets. The optimisation time of the research method for the parameters of the UCI (University of California Irvine) dataset remained within 650–750 ms. The evaluation results of the research method fit well with the expert evaluation results. The above results show that the research method has high data accuracy and operational efficiency in the evaluation of urban characteristic planning, which can make reasonable evaluation of urban characteristic planning. This method can provide reliable reference basis for government decision making. [ABSTRACT FROM AUTHOR]

The erosion of the seabed around offshore structures has emerged as a critical factor impeding the operational safety of offshore engineering facilities. Prompt and precise identification and monitoring of the water–soil interface hold significant importance in mitigating the seabed erosion challenges facing offshore structures. To tackle this issue, a monitoring framework for the water–soil interface is proposed, grounded in heat transport theory. This framework exploits the thermodynamic variances between seawater and the seabed soil to examine the temperature changes in linear heat sources in water and soil under a constant power. In this study, a typical metallic material—iron (Fe)—and non-metallic material—polyvinyl chloride (PVC)—are considered the linear heat sources, and their temperature variations are analyzed within this framework. The findings reveal that the temperature of the linear heat sources rapidly stabilizes, with the ultimate temperature exhibiting a logarithmic correlation with the convective heat transfer coefficient. To further test the practicability of the framework, an indoor test is conducted. The errors between the theoretical calculation results and the experimental results are less than 14% in water and 19% in soil. The results of the framework and the indoor test have a high degree of coincidence. This framework has proved that it can be used in practical engineering. [ABSTRACT FROM AUTHOR]

The objective of this research is to investigate the characteristics of the deformation response in adjacent subway tunnels caused by deep foundation excavation of reclaimed land. Focusing on a deep foundation excavation project situated in proximity to Line 11 of the subway in Shenzhen, this study employs theoretical analysis, numerical simulation, and on-site measurements to thoroughly investigate the deformation issues induced by the unloading of the excavation. The research results are as follows: using the energy method to calculate the uneven deformation of adjacent subway tunnels caused by the excavation can overcome the limitations of traditional algorithms, which treat the subway tunnel as a uniformly elastic foundation beam, resulting in more reasonable calculation results. Increasing the self-stiffness (EI)eq of the tunnel can effectively reduce the maximum displacement (wmax) of the tunnel, and as (EI)eq increases, its "weakening effect" on wmax gradually diminishes. Underground continuous walls can effectively control tunnel deformation, with tunnel displacement decreasing as the thickness and concrete strength of the continuous walls increase. "Long excavation" deep foundation excavations can impact the displacement and uplift range of the tunnel, with the maximum tunnel displacement showing a nonlinear decrease with increasing excavation depth. Tunnel displacement decreases as geotechnical parameters (elastic modulus E, internal friction angle φ, and cohesion C) increase, with the elastic modulus being the most sensitive parameter. The research findings can be applied to tunnel construction, maintenance, and safety evaluations, providing valuable references for similar engineering projects in the future. [ABSTRACT FROM AUTHOR]