Search Results (370)

Defensive pessimism, an important emotion regulation and motivation strategy, has increasingly attracted scholarly attention in psychology. Recently, sensor-based methods have begun to supplement or replace traditional questionnaire surveys in personality research. However, current approaches for collecting vital signs data face several challenges, including limited monitoring durations, significant data deviations, and susceptibility to external interference. This paper proposes a novel approach using a NiCr/NiSi alloy film temperature sensor, which has a K-type structure and flexible piezoelectric pressure sensor to identify and predict defensive pessimism personality traits. Experimental results indicate that the Seebeck coefficients for K-, T-, and E-type thermocouples are approximately 41 μV/°C, 39 μV/°C, and 57 μV/°C, respectively, which align closely with national standards and exhibit good consistency across multiple experimental groups. Moreover, radial artery frequency experiments demonstrate a strong linear relationship between pulse rate and the intensity of external stimuli, where stronger stimuli correspond to faster pulse rates. Simulation experiments further reveal a high correlation between radial artery pulse frequency and skin temperature, and a regression model based on the physiological sensor data shows a good fit (p < 0.05). These findings verify the feasibility of using temperature and flexible piezoelectric pressure sensors to identify and predict defensive pessimism personality characteristics. Full article

An oat protein isolate is an ideal raw material for producing a wide range of plant-based products. However, oat protein exhibits weak functional properties, particularly in emulsification. Casein-based ingredients are commonly employed to enhance emulsifying properties as a general practice in the food industry. pH-shifting processing is a straightforward method to partially unfold protein structures. This study modified a mixture of an oat protein isolate (OPI) and casein by combining a pH adjustment (adjusting the pH of two solutions to 12, mixing them at a 3:7 ratio, and maintaining the pH at 12 for 2 h) with an atmospheric cold plasma (ACP) treatment to improve the emulsifying properties. The results demonstrated that the ACP treatment significantly enhanced the solubility of the OPI/casein mixtures, with a maximum solubility of 82.63 ± 0.33%, while the ζ-potential values were approximately −40 mV, indicating that all the samples were fairly stable. The plasma-induced increase in surface hydrophobicity supported greater protein adsorption and redistribution at the oil/water interface. After 3 min of treatment, the interfacial pressure peaked at 8.32 mN/m. Emulsions stabilized with the modified OPI/casein mixtures also exhibited a significant droplet size reduction upon extending the ACP treatment to 3 min, decreasing from 5.364 ± 0.034 μm to 3.075 ± 0.016 μm. The resulting enhanced uniformity in droplet size distribution signified the formation of a robust interfacial film. Moreover, the ACP treatment effectively enhanced the emulsifying activity of the OPI/casein mixtures, reaching (179.65 ± 1.96 m²/g). These findings highlight the potential application value of OPI/casein mixtures in liquid dairy products. In addition, dairy products based on oat protein are more conducive to sustainable development than traditional dairy products. Full article

Antimicrobial food packaging with natural antimicrobials and biodegradable polymers presents an innovative solution to mitigate microbial contamination, prolong freshness, reduce food waste, and alleviate environmental burden. This study developed antimicrobial hemicellulose-based films by incorporating carvacrol (1% and 2%) as a natural antimicrobial agent through micro-emulsification produced by high-pressure homogenization (M-films). For comparison, films with the same formula were constructed using coarse emulsions (C-films) without high-pressure homogenization. These films were investigated for their antimicrobial efficacy, mechanical and barrier properties, and physicochemical attributes to explore their potential as sustainable antimicrobial packaging solutions. The M-films demonstrated superior antimicrobial activity, achieving reductions exceeding 4 Log CFU/mL against Listeria monocytogenes, Escherichia coli, and Salmonella enterica, compared to the C-films. High-pressure homogenization significantly reduced the emulsion’s particle size, from 11.59 to 2.55 μm, and considerably enhanced the M-film’s uniformity, hydrophobicity, and structural quality. Most importantly, the M-films exhibited lower oxygen transmission (35.14 cc/m²/day) and water vapor transmission rates (52.12 g/m²/day) than the C-films at 45.1 and 65.5 cc/m²/day, respectively, indicating superior protection against gas and moisture diffusion. Markedly improved mechanical properties, including foldability, toughness, and bubble-free surfaces, were also observed, making the M-films suitable for practical applications. This study highlights the potential of high-pressure homogenization as a method for enhancing the functional properties of hemicellulose-based films (i.e., M-films). The fabricated films offer a viable alternative to conventional plastic packaging, paving the way for safer and greener solutions tailored to modern industry needs. Full article

Maintaining the required relative humidity values in the vehicle cabin is an important HVAC task, along with considerations related to the temperature, velocity, air pressure and noise. Deviation from the optimal values worsens the psycho-physiological state of the driver and affects the energy efficiency of the train. In this study, a model of liquid film formation on and removal from various cabin surfaces was constructed using the fundamental Navier–Stokes hydrodynamic equations. A special transport model based on the liquid vapor diffusion equation was used to simulate the air environment inside the cabin. The evaporation and condensation of surface films were simulated using the Euler film model, which directly considers liquid–gas and gas–liquid transitions. Numerical results were obtained using the RANS equations and a turbulence model by means of the finite volume method in Ansys CFD. Conjugate fields of temperature, velocity and moisture concentration were constructed for various time intervals, and the dependence values for the film thicknesses on various surfaces relative to time were determined. The verification was conducted in comparison with the experimental data, based on the protocol for measuring the microclimate indicators in workplaces, as applied to the train cabin: the average ranges encompassed temperature changes from 11% to 18%, and relative humidity ranges from 16% to 26%. Comparison with the results of other studies, without considering the phase transition and condensation, shows that, for the warm mode, the average air temperature in the cabin with condensation is 12.5% lower than without condensation, which is related to the process of liquid evaporation from the heated walls. The difference in temperature values for the model with and without condensation ranged from −12.5% to +4.9%. We demonstrate that, with an effective mode of removing condensate film from the window surface, including recirculation modes, the energy consumption of the climate control system improves significantly, but this requires a more accurate consideration of thermodynamic parameters and relative humidity. Thus, considering the moisture condensation model reveals that this variable can significantly affect other parameters of the microclimate in cabins: in particular, the temperature. This means that it should be considered in the numerical modeling, along with the basic heat transfer equations. Full article

This study presents a computational fluid dynamics (CFDs) investigation of the hydrodynamic behavior of surface-textured lateral bushings in external gear pumps (EGPs), emphasizing the effects of combined sliding and squeezing motions within the lubrication gap. A comprehensive numerical model was developed to analyze how surface texturing implemented through different dimple shapes and texture densities influences pressure distribution and load-carrying capacity under transient lubrication conditions. The analysis demonstrates that the interaction between shear-driven flow and squeeze-film compression significantly amplifies pressure, particularly when optimal dimple configurations are applied. Results indicate that dimple geometry, depth, and arrangement critically influence hydrodynamic performance, while excessive texturing reduces effectiveness due to increased average gap height. Cavitation was intentionally not modeled in the early single dimple evaluations to allow clear comparison between configurations. The findings offer a design guideline for employing surface textures to enhance tribological performance and efficiency in EGP applications under realistic dynamic conditions. Full article

The contact pattern between gear teeth is one of the most significant indicators of proper gear operation. This paper presents an analysis of the contact pattern of gears with a sinusoidal profile. The gear geometry was obtained through direct solid simulation of the machining process. Generally, analytical, numerical, and experimental methods are used for contact pattern analysis in gearboxes. This article presents contact pattern investigations using numerical methods and a novel experimental method that utilizes pressure measurement films. A proprietary program using image analysis was used for the contact pattern analysis. The numerical studies utilized the Finite Element Method (FEM) and the CAD method. The results obtained from the presented methods show good convergence. Full article

The impact of water on CO₂ sequestration and enhanced oil recovery processes is significant. In this study, a CO₂–water-film–crude-oil–rock molecular system was established. Then, the influence of water-film thickness on the dissolution and dispersion of CO₂ and crude oil under different temperature and pressure scenarios was examined through molecular dynamics simulations. The results indicate that water films hinder CO₂ diffusion into the oil, reducing its ability to lower oil density. When the thickness of the water film increases from 0 nm to 3 nm, the oil density increases by 86.9%, and the average diffusion coefficient of oil decreases by 72.30%. Increasing the temperature enhances CO₂–oil interactions, promoting CO₂ and water diffusion into oil, thereby reducing oil density. Under conditions of a 2 nm water film and 10 MPa pressure, increasing the temperature from 100 °C to 300 °C results in a decrease of approximately 32.1% in the oil density. Pressure also promotes oil and water-film density reduction, but its effect is less significant compared to temperature. These results elucidate the function of the water film in CO₂-EOR processes and its impact on CO₂ dissolution and diffusion in water-bearing reservoirs. Full article

In high-pressure thermal power systems, corrosion-induced wall thinning in steam pipelines poses a significant threat to operational safety and efficiency. This study investigates the effects of gas–liquid two-phase flow on corrosion-induced wall thinning in pipe bends of high-pressure heaters in power plants, with particular emphasis on the mechanisms of void fraction and inner wall surface roughness. Research reveals that an increased void fraction significantly enhances flow turbulence and centrifugal effects, resulting in elevated pressure and Discrete Phase Model (DPM) concentration at the bend, thereby intensifying erosion phenomena. Simultaneously, the turbulence generated by bubble collapse at the bend promotes the accumulation and detachment of corrosion products, maintaining a cyclic process of erosion and corrosion that accelerates wall thinning. Furthermore, the increased surface roughness of the inner bend wall exacerbates the corrosion process. The rough surface alters local flow characteristics, leading to changes in pressure distribution and DPM concentration accumulation points, subsequently accelerating corrosion progression. Energy-Dispersive Spectroscopy (EDS) and Scanning Electron Microscopy (SEM) analyses reveal changes in the chemical composition and microstructural characteristics of corrosion products. The results indicate that the porous structure of oxide films fails to effectively protect against corrosive media, while bubble impact forces damage the oxide films, exposing fresh metal surfaces and further accelerating the corrosion process. Comprehensive analysis demonstrates that the interaction between void fraction and surface roughness significantly intensifies wall thinning, particularly under conditions of high void fraction and high roughness, where pressure and DPM concentration at the bend may reach extreme values, further increasing corrosion risk. Therefore, optimization of void fraction and surface roughness, along with the application of corrosion-resistant materials and surface treatment technologies, should be considered in pipeline design and operation to mitigate corrosion risks. Full article

The current effect of passive devices is crucial for device testing. The current effect of a suspended graphene pressure sensor in the range of 0–2 mA is studied in this paper. The results show that the resistance of graphene films and the piezoresistive effect of devices exhibit stable performance within the current threshold range of 400 μA and 300 μA, respectively. Auger electron spectroscopy and Raman spectroscopy tests indicate that the resistance of graphene increases first and then decreases at high current intensity, resulting from the electrostatic adsorption of oxygen atoms in the initial phase of electrification and the Joule-induced desorption in the later phase. This study presents guiding significance for the electrical testing of suspended graphene devices. Full article

This study aims to enhance the understanding of film cooling performance in an actual turbine vane by investigating influencing factors and developing more precise numerical prediction methods. Pressure sensitive paint (PSP) testing and Reynolds-Averaged Navier–Stokes (RANS) simulations were conducted. The findings indicate that the current design blowing ratio of S1 holes (0.89) is too high, resulting in poor film cooling effectiveness. However, the blowing ratios of P3 (0.78) and P4 (0.69) holes are relatively low, suggesting that increasing the coolant flow could improve the film cooling effectiveness. It is not recommended to design an excessively low blowing ratio on the suction surface, as this can lead to poor wall adherence downstream of the film holes. A slight increase in turbulence intensity enhances the film covering effect, particularly on the suction surface. Additionally, a novel superposition method for multirow fan-shaped film cooling holes on an actual turbine vane is proposed, exhibiting better agreement with experimental data. Compared with experimental results, the numerical predictions tend to underestimate the film cooling effectiveness with the examined k-ε-based viscosity turbulence models and Reynolds stress turbulence models, while the SST demonstrates relatively higher accuracy owing to its hybrid k-ω/k-ε formulation that better resolves near-wall physics and separation flows characteristic of turbine cooling configurations. This study contributes to the advancement of turbine vane thermal analysis and design in engineering applications. Full article

The stress sensitivity of shale caprock permeability is a critical factor influencing the long-term security of CO₂ geological sequestration systems. Substantial amounts of clay minerals and nanoscale pore structures reduce shale permeability by trapping water films and throat contraction. Conventional permeability models, which are based on homogeneous pore compressibility, tend to overestimate the contribution of non-effective pores to water mobility, resulting in significant inaccuracies in predicting stress-dependent permeability. Therefore, this study conducted NMR–seepage experiments under varying confining pressures on four shale samples with distinct lithologies to investigate pore compression deformation and permeability stress sensitivity. The T₂ cutoff was subsequently determined through displacement tests to distinguish seepage and adsorption pores. Two distinct constitutive models were calculated with respective compressibility coefficients. Finally, the effects of seepage and adsorption pores on shale permeability stress sensitivity were investigated. The results indicate the following. (1) Increasing confining pressure from 15 to 19 MPa reduces porosity by 14.2–39.6%, with permeability exhibiting a significant decline of 35.6–67.8%. (2) Adsorption pores, stabilized by bound water films of clay minerals, exhibit limited closure under stress. In contrast, seepage pores, influenced by brittle minerals, experience significant deformation, which predominantly contributes to permeability decline. (3) A dual-spring model, differentiating the compressibility of seepage and adsorption pores, reduces prediction errors by 92–96% compared to traditional models. These results highlight that neglecting pore-type-specific compressibility leads to overestimated permeability in heterogeneous shale, with critical implications for optimizing CO₂ storage integrity and hydrocarbon recovery strategies. Full article

Film cooling has been increasingly applied in turbine blade cooling design due to its excellent cooling performance. Although film-cooled blades demonstrate superior cooling effectiveness, the perforation design on blade surfaces compromises structural integrity, making fatigue failure prone to occur at cooling holes. Previous studies by domestic and international scholars have extensively investigated factors influencing film cooling effectiveness, including blowing ratio and hole geometry configurations. However, most research has overlooked the investigation of fatigue life in film-cooled blades. This paper systematically investigates blade fatigue life under various cooling air parameters by analyzing the relationships among cooling effectiveness, stress distribution, and fatigue life. Results indicate that maximum stress concentrations occur at cooling hole locations and near the blade root at trailing edge regions. While cooling holes effectively reduce blade surface temperature, they simultaneously create stress concentration zones around the apertures. Both excessive and insufficient cooling air pressure and temperature reduce thermal fatigue life, with optimal parameters identified as 600 K cooling temperature and 0.75 MPa pressure, achieving a maximum thermal fatigue life of 3400 cycles for this blade configuration. A thermal shock test platform was established to conduct fatigue experiments under selected cooling conditions. Initial fatigue damage traces emerged at cooling holes after 1000 cycles, with progressive damage expansion observed. By 3000 cycles, cooling holes near blade tip regions exhibited the most severe failure, demonstrating near-complete functional degradation. These findings provide critical references for cooling parameter selection in practical aeroengine applications of film-cooled blades. Full article

This study analyzes the effects of varying H₂S and CO₂ concentrations and temperature on the pH of geothermal fluids flowing through superduplex S32750 stainless-steel pipelines, classified as corrosion-resistant alloys (CRAs). Corrosive decay is evaluated by comparing OLI Studio software simulations with experimental data from the literature. The results indicate that an increase in the partial pressure of either gas lowers pH levels, with temperature exerting a more pronounced exponential effect on corrosion than gas partial pressure. When both gases are present, the dominant gas dictates the corrosion behavior. In cases where CO₂ and H₂S are in equal proportions, FeS₂ forms as the primary corrosive product due to the higher potential corrosivity of H₂S. The H₂S/CO₂ ratio influences the formation of passive films containing chromium oxides or hydroxides (Cr₂O₃, Cr(OH)₃), iron oxides (Fe₂O₃, Fe₃O₄), or iron sulfides (FeS). Full article

This study investigates the current-carrying tribological properties and wear mechanisms of copper–graphite composites under varying contact loads. Two copper–graphite composites with different graphite content were prepared using the pressure sintering method. Current-carrying tribological tests were conducted at three distinct contact loads. Scanning electron microscopy, X-ray diffraction, laser confocal microscopy, and pin-on-disk tribological testing were utilized to examine the current-carrying tribological properties and the worn morphologies of the materials. The results indicate that, under the three contact loads, the friction coefficient of the copper–graphite materials ranged from 0.3 to 0.5, the wear rate was on the order of 10⁻¹³ m³/(N·m), the average voltage drop varied between 0.7 and 1.6 V, and the average electrical noise ranged from 0.2 to 0.9 mV. The wear mechanism included delamination wear and a minor amount of abrasive wear, and the lubricating film formed on the surface was mainly composed of C, PbO, and CuO. Notably, copper–graphite composites with lower graphite content exhibited superior hardness, electrical conductivity, and relative density compared to those with higher graphite content. At a contact load of 0.31 N, the copper–graphite composite containing 30wt% graphite demonstrated the most favorable current-carrying tribological performance, characterized by the lowest wear rate (1.09 × 10⁻¹³ m³/(N·m)), voltage drop (0.943 V), and electrical noise (0.234 mV). Full article

The detection of fish freshness is crucial for ensuring food safety. This study addresses the limitations of traditional detection methods, which rely on laboratory equipment and complex procedures, by proposing a smartphone-based detection method, termed FreshFusionNet, that utilizes a pitaya peel pH intelligent indicator film in conjunction with multimodal deep learning. The pitaya peel indicator film, prepared using high-pressure homogenization technology, demonstrates a significant color change from dark red to yellow in response to the volatile alkaline substances released during fish spoilage. To construct a multimodal dataset, 3600 images of the indicator film were captured using a smartphone under various conditions (natural light and indoor light) and from multiple angles (0° to 120°), while simultaneously recording pH values, total volatile basic nitrogen (TVB-N), and total viable count (TVC) data. Based on the lightweight MobileNetV2 network, a Multi-scale Dilated Fusion Attention module (MDFA) was designed to enhance the robustness of color feature extraction. A Temporal Convolutional Network (TCN) was then used to model dynamic patterns in chemical indicators across spoilage stages, combined with a Context-Aware Gated Fusion (CAG-Fusion) mechanism to adaptively integrate image and chemical temporal features. Experimental results indicate that the overall classification accuracy of FreshFusionNet reaches 99.61%, with a single inference time of only 142 ± 40 milliseconds (tested on Xiaomi 14). This method eliminates the need for professional equipment and enables real-time, non-destructive detection of fish spoilage through smartphones, providing consumers and the food supply chain with a low-cost, portable quality-monitoring tool, thereby promoting the intelligent and universal development of food safety detection technology. Full article