Excessive Temperature Research Articles

Development of Readily Available & Robust High Heat Flux Gardon Gauges

Concentrated solar power (CSP) technologies deliver concentrated solar energy as a heat source to industrial processes, power generation cycles, and chemical cycles. CSP systems require accurate and reliable high flux measurements, and next generation CSP systems will require flux measurement up to 1000 W/cm2. Existing flux measurement devices do not comprehensively meet the flux rating, cycle life, cost, and lead-time needs of stakeholders, necessitating the development of an improved flux sensor. In this study, Sandia National Laboratories (SNL) partnered with Hukseflux Thermal Sensors to develop a low-cost, short lead-time, and robust flux sensor rated to 250 W/cm2. Three prototype circular foil gauge designs were assessed for performance at the National Solar Thermal Test Facility (NSTTF) at SNL. Each gauge design measured flux up to 250 W/cm2 with <5% measurement error. Following baseline error quantification, gauges were exposed to flux above 500 W/cm2 to assess gauge failure mechanisms. Gauges physically survived >500 W/cm2 flux exposure, but measurement error was found to increase after foil coatings reached 400 °C. The results of this study suggest that coating optical properties change at excessive temperatures and that foil coating temperature, rather than heat flux level, dictates the acceptable gauge measurement range.

Two-phase active immersion cooling for vertically mounted electronics with interchip component-assisted bubble departure

To address growing heat dissipation demands in high-performance computing chips, there is a transition from conventional cooling methods to advanced two-phase immersion cooling techniques for electronics thermal management. Here, we present a numerical investigation into the fluid dynamics and heat transfer in two-phase immersion cooling systems with vertically mounted chips on a printed circuit board (PCB) with interchip components such as capacitors, switches, and inductors. Leveraging a combined phase tracking and volume of fluid model, we study how the physical layout and geometries of interchip components affect the flow paths of bubbles, bubble coalescence phenomena, vapor coverage on chip surfaces, and cooling rates of heated chips. In an optimal PCB topology, a maximum heat flux of 18 W/cm2 and a heat transfer coefficient of 9650 W/m2K are observed for dielectric hydrofluoroether (HFE) - 7100 at an excessive wall temperature of 20 K under a constant wall temperature boundary condition. The research offers insights into the electronic system design to achieve efficient cooling for high-performance computing applications, demonstrating the critical role of interchip components in heat transfer.

Layer-by-layer assembled aramid nanofiber/MXene aerogel: Exceptional resistance to extreme temperatures and robust anisotropy for advanced applications

Aerogels are characterized with unique morphology and physical properties, thus are serving as essential elements in advanced applications. Nowadays, the delicate intelligent devices are frequently exposed in harsh environments, leading to multiple issues during application of functional aerogels including the limited resistance to extreme temperatures, requiring encapsulation prior to usage, and accumulation of Joule heat. In this study, we fabricated a multilayered aramid nanofiber (ANF)/MXene aerogel with the layer-by-layer stacking ANF and ANF/MXene layers. Attributing to the multilayered and porous structure, the aerogel displayed proper EMI shielding performance which maintained stable in harsh environments of excessive high temperature (200 °C) and low temperature (−196 °C). More importantly, obvious anisotropy in electrical conductivity (∼8 orders of magnitude) and thermal insulation (ΔT = 32 °C) was obtained along the in-plane and out-of-plane directions. As two demonstrations of potential applications, the sensing performance and thermal insulating property of the ANF/MXene aerogel was displayed. Inspiringly, the aerogel sensor exhibited significant durability and notable sensitivity to different deformations. Also, the aerogel displayed rapid heat dissipation along the in-plane direction while efficient thermal insulation along the out-of-plane direction, thus, can be applied in thermal management to protect the electronic devices. Therefore, the as-prepared ANF/MXene aerogel can serve as EMI shielding parts, encapsulation-free flexible electronics as compression sensor and anisotropic thermal insulator, which has great potential in the application of intelligent devices.

Study of indoor local thermal comfort for impinging jet ventilation combined with ductless personalized ventilation under different cooling loads

Excessive temperature stratification and draught are two prominent drawbacks for impinging jet ventilation (IJV). Using IJV together with ductless personalized ventilation (DPV) (i.e., IJV + DPV) has been proved to be an effective way to reduce temperature stratification, but the draught rate around occupant would be increased. In the current work, an in-depth study on the characteristics of indoor local thermal comfort for IJV + DPV operating with different scenarios is done. Predictive models for the local thermal comfort indicators are developed to optimize the operating parameters (including supply velocity of IJV (Vs) and intake airflow rate of DPV (Df)) with different room cooling loads (Q). The results show that the application of IJV can be extended to spaces with high cooling loads (e.g., larger than 60 W/m2) by using together with DPV, but the risk of thermal discomfort increases. To avoid local thermal discomfort, the combination relationship between Vs and Df should be properly matched and this relation becomes more stricter with the increase of Q. It also obtains that the maximum cooling load that IJV + DPV can eliminate is less than 170 W/m2. At last, to ensure the IJV + DPV create a good local thermal comfort environment, design chart about the feasible ranges of Vs and Df are established for different values of Q. On the whole, the current study not only can provide a basis for the application of IJV + DPV in spaces with high cooling load, but also can provide theoretical guidance for the operation control and optimization design of the IJV + DPV.

Numerical investigation on thermal management performance of soft packing Li-ion batteries with oblique multi-channel cold plates

During the driving process of electric vehicles (EVs), the continuous high-rate discharge of the power battery causes significant heat accumulation. An efficient battery thermal management system (BTMS) is critical for the safe and stable operation of EVs. In this study, an oblique channel cold plate (OCCP) is designed based on the traditional straight channel cold plate (SCCP) in order to addresses the problem of excessive and uneven temperatures during the high-rate discharge of soft packing lithium-ion batteries. Effects of glycol solution concentration, coolant mass flow rate, coolant inlet temperature, oblique angle for cooling channel, ambient temperature and discharge rate for the cell on the performance characteristics of BTMS, including the cooling efficiency (φ) and pressure drop (ΔP), are analyzed numerically with Ansys Fluent software. The results show that the OCCP has better cooling performance and lower pressure loss than the SCCP. Based on the analysis with the orthogonal design method, when the glycol solution concentration is 20 %, the mass flow rate is 1.0 g/s, and the inlet temperature is 25 °C, the BTMS with SCCP could obtain the optimal performance, corresponding to that the maximum temperature (Tmax) of the battery is controlled at 32.056 °C, while the φ is 0.581, and the ΔP across the cold plate is 52.652 Pa. Furthermore, the cooling efficiency φ of the cold plate decreases with the increase in the oblique angle. When the ambient temperature is 35 °C, the OCCP with a 20° oblique angle provides the best cooling effect for the battery during a 10C discharge. This work is helpful for the design of liquid cold plates in BTMS under high-rate discharge conditions for power battery of EVs.

Phillyrin and its metabolites exert antipyretic effects by targeting the NAD+ binding domain of GAPDH, MDH2 and IDH2

BackgroundFever is one of the main pathophysiological reactions that occurs during the acute phase of various diseases. Excessive body temperature can lead to various adverse consequences such as brain tissue damage and abnormal immune responses. Phillyrin (Phr) is the main active ingredient in Forsythia suspensa (Thunb.) Vahl (Lian Qiao) and has antipyretic effects; however, its antipyretic mechanism of action remains unclear. PurposeThis study aimed to explore the antipyretic mechanisms of Phr and provide a new treatment plan for fever. MethodsThe antipyretic effects of Phr were evaluated using a mouse model of pneumonia fever. The main metabolites of Phr involved in its antipyretic function were identified using a mitochondrial temperature-sensitive probe. Further synthesis of the main metabolite, phillygenin (Phg), an alkynylated probe, was performed, and chemical proteomics was used to capture and analyze its direct target for antipyretic effects. The mechanism of action of Phg and its antipyretic targets was explored using metabolomics and various molecular biology methods. ResultsPhr showed significant antipyretic and anti-inflammatory effects in a mouse model of lipopolysaccharide-induced fever. Phg reversibly targeted the nicotinamide adenine dinucleotide (NAD+) binding domain of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), malate dehydrogenase 2 (MDH2), and isocitrate dehydrogenase 2 (IDH2) to inhibit their enzymatic activity. In-depth analysis of cellular metabolomics and mitochondrial stress testing indicated that inhibition of GAPDH, MDH2, and IDH2 enzyme activity by Phg led to a decrease in cellular energy supply and heat production regulated by glycolysis, tricarboxylic acid cycle, and oxidative phosphorylation signaling pathways. Phg specifically targeted macrophages and inhibited LPS-induced macrophage activation by downregulating GAPDH enzyme activity, thereby exerting anti-inflammatory effects. In vivo experiments also confirmed that the antipyretic effect of Phr in LPS-induced fever model mice was related to its main metabolites, Phg and Phg-sulfonate (Phg-S), which directly targeted the NAD+ binding domain of GAPDH, IDH2, and MDH2, inhibiting the activity of these enzymes, thereby reducing energy supply and regulating febrile-related inflammatory factors. ConclusionThis study reported for the first time that the antipyretic effect of Phr is produced by targeting GAPDH, IDH2, and MDH2 to regulate energy supply and febrile-related inflammatory factors through its main metabolites Phg and Phg-S. This study not only provides potential drugs for fever treatment but also provides new ideas for improving clinical fever treatment plans.

Densely stocked neighborhood reduces the risk of tree mortality in drylands: Evidence from Populus euphratica forests along the Tarim River corridor

To mitigate forest loss under current environmental challenges, it is increasingly urgent to model how tree mortality is mediated by both biotic and abiotic agents. However, the role of neighborhood interactions in mediating tree survival in dryland forests has been poorly understood, as it is often presupposed to be irrelevant in low-density stands coupled with overriding drought stress. Here, we conducted a failure time analysis of Populus euphratica forests (known as Tugay forests) in the Tarim River corridor (NW China) to examine the presupposition. We collected a spatial-explicit population inventory dataset with >7000 trees on ca. 14-ha land area with varying vapor pressure deficit (VPD), groundwater table depth (GWD), and stand density. Hegyi's competition index (CI) and stand density index (SDI, the number of large trees with an equivalent diameter of 25.4 cm) were employed to characterize neighborhood structures of each individual tree. Aridity stresses (higher VPD and GWD) tended to elevate tree mortality risk, and showed weaker effects than neighborhood structures did. Tree mortality risk increased drastically with higher CI, suggesting a strong role of competition for critical water resource. However, tree mortality risk reduced with higher SDI, likely due to ameliorated stresses of excessive light and/or temperature under less open canopies. This study highlights the importance of localized inter-tree interactions in regulating tree populations under prevalent drought stress and reiterates classic cautions against inferences about competition/facilitation in absence of spatial-explicit contexts. We recommend the priority of preserving large trees aggregated as closed stands in dryland forest conservation.

Advanced Deep Learning Techniques for Battery Thermal Management in New Energy Vehicles

In the current era of energy conservation and emission reduction, the development of electric and other new energy vehicles is booming. With their various attributes, lithium batteries have become the ideal power source for new energy vehicles. However, lithium-ion batteries are highly sensitive to temperature changes. Excessive temperatures, either high or low, can lead to abnormal operation of the batteries, posing a threat to the safety of the entire vehicle. Therefore, developing a reliable and efficient Battery Thermal Management System (BTMS) that can monitor battery status and prevent thermal runaway is becoming increasingly important. In recent years, deep learning has gradually become widely applied in various fields as an efficient method, and it has also been applied to some extent in the development of BTMS. In this work, we discuss the basic principles of deep learning and related optimization principles and elaborate on the algorithmic principles, frameworks, and applications of various advanced deep learning methods in BTMS. We also discuss several emerging deep learning algorithms proposed in recent years, their principles, and their feasibility in BTMS applications. Finally, we discuss the obstacles faced by various deep learning algorithms in the development of BTMS and potential directions for development, proposing some ideas for progress. This paper aims to analyze the advanced deep learning technologies commonly used in BTMS and some emerging deep learning technologies and provide new insights into the current combination of deep learning technology in new energy trams to assist the development of BTMS.

Effect of sawtooth wave distribution plenum with linearly increasing amplitude on the performance of battery thermal management system

Battery heat generation that occurs during battery charging and discharging can lead to excessive and non-uniform battery temperature in the battery pack. As a result, the battery is more vulnerable to rapid degradation and short cycle life. Effective heat dissipation methods therefore become crucial. In the present study, sawtooth waves with linearly increasing wave amplitude and an inlet notch on the distribution plenum (DP) have been introduced in a typical Z-type battery thermal management system (BTMS) to maximise the cooling effectiveness of the System. Numerical analysis is carried out to investigate the effect of various geometric parameters such as saw tooth wave position, saw tooth wave amplitude, saw tooth wave base width, inlet notch width, and inlet notch height on the performance of BTMS. Velocity contours, streamlines, temperature contours, and maximum battery temperature plots are used to discuss the effects of various factors on the operation of a BTMS. Compared with the typical Z-type BTMS, the modified enclosure design reduced the maximum average battery temperature ( T max ) and maximum temperature differential within the battery pack ( Δ T max ) by 5.11 and 9.01 K respectively, which are 1.56% and 94.90% less than the typical Z-type BTMS respectively.

Enhanced electrical performance in graphene field-effect transistors through post-annealing of high-k HfLaO gate dielectrics

High-k gate dielectrics have attracted a great deal of attention in the investigation of transistors due to their unique properties such as superior gate controllability. However, their integration into graphene field-effect transistors (GFETs) remains problematic and the physical mechanisms governing the performance of these devices are still not fully understood. In this study, the effects of post-annealing on GFETs utilizing the high-k HfLaO ternary oxide as the gate dielectric were comprehensively investigated. The HfLaO film was deposited on top of graphene by magnetron sputtering, and the device performance with various post-annealing temperatures was conducted. It was found that post-annealing temperature can effectively increase the dielectric constant through balancing the oxygen-vacancy defects and moisture absorption. Both the surface morphology of HfLaO and performance of GFETs were investigated, and the fabricated GFETs exhibit notable electrical performance enhancements. Specifically, GFETs with a 200 °C post-annealed HfLaO gate dielectric demonstrate the optimal device performance, featuring a minimal Dirac point voltage (VDirac) of 1.1 V and a minimal hysteresis (ΔVDirac) of 0.5 V. The extracted hole and electron mobilities are 4012 and 1366 cm2/V · s, respectively, nearly one order of magnitude higher than that of GFETs with as-deposited HfLaO. This work outperforms other existing GFETs utilizing high-k gate dielectric and chemical vapor deposition grown graphene in terms of both carrier mobility and on–off ratio. It is also noted that the excessive post-annealing temperature can negatively impact the GFET performance through introducing oxygen vacancies, increasing the surface roughness, lowering the breakdown voltage, and inducing recrystallization.

Effects of spraying parameters and heat treatment temperature on microstructure and properties of single-pass and single-layer cold-sprayed Cu coatings on Al alloy substrate

Exploring the deposition of single-pass and single-layer pure Cu coatings on Al alloy substrate through high-pressure cold spray technology is a crucial endeavor with significant implications for advancing the utilization of such coatings. Regrettably, research in this specific area remains scarce, highlighting the need for further investigation and understanding. This study examined the characteristics of cold-sprayed Cu coatings deposited on a 6061 T6 aluminum alloy substrate under varying gas temperatures and pressures, and explored the effects of subsequent heat treatment on the microstructure and mechanical properties of the Cu coatings. The morphology, phase composition, surface roughness, thickness, porosity, microstructure, shear strength, and microhardness of the cold-sprayed Cu coatings were systematically analyzed. The findings indicated that the spraying parameters had a substantial impact on the properties of the Cu coatings. Specifically, increased gas pressure led to rougher surfaces and lower porosity, whereas higher gas temperature produced smoother surfaces and also reduced porosity. At 800 °C and 4.0 MPa, the Cu coatings exhibited the lowest surface roughness, measuring 8.03 μm. Conversely, at 800 °C and 5.5 MPa, the Cu coatings demonstrated the lowest porosity, at 0.26 %. Moreover, the microstructure analysis showed evidence of dynamic recrystallization in the deposited Cu particles, contributing to enhanced mechanical properties. Following this, the influence of heat treatment on the microstructure and properties of the cold-sprayed Cu coatings was examined. The results demonstrated that annealing at different temperatures induced changes in the interfacial microstructure, with the formation of intermetallic compounds between the Cu coating and Al alloy substrate. This interdiffusion phenomenon led to improved bonding strength and mechanical properties of the Cu coatings, as evidenced by increased shear strength. After undergoing heat treatment at 400 °C, the Cu coatings exhibited the highest shear strength, measuring 49.89 MPa. However, excessive heat treatment temperatures resulted in the formation of cracks and a decrease in mechanical properties.

Surface oxygen vacancy regulation and active metal doping for Cu-Al based spinel catalysts synthesis toward high-efficiency reverse water-gas shift reaction

The reverse water-gas shift (RWGS) reaction is of great significance to convert CO2 to valuable feedstocks. Reasonable design and preparation of catalysts is necessary to achieve high CO2 conversion and CO selectivity. In this study, a series of Cu-Al based spinel catalysts were synthesized by coprecipitation-calcination method or A-site doped with active metal (Co, Zn, Mg, and Fe) for the RWGS reaction. The results indicated that the surface oxygen vacancies and crystal structure of CuAl2O4 can be regulated by calcination temperature. Remarkably, the CuAl-800 catalyst exhibits the highest CO2 conversion rate (62.7 %) with 100 % CO selectivity at 500 °C. Excessive calcination temperatures (> 800 °C) resulted in a well-defined spinel structure, but decreased surface oxygen vacancies and CO2 conversion rate. At calcination temperatures < 800 °C, surface oxygen vacancies increased, but the formation of CuO impurities which irreversibly converted to Cu2O during reduction, decreased catalytic activity. Compared with Zn, Mg and Fe, Co doping can significantly improved the reactivity of CuAl2O4 catalyst in RWGS reaction at 500 °C, increasing the CO2 conversion rate by 8 % while maintaining 100 % CO selectivity. The main reason is that Co doping not only effectively improves the integrity and stability of spinel structure of CuAl2O4, but also enhances its ability to dissociate and activate H species through interfacial sites of CuO-OV-CuXCo1-XAl2O4, thus further enhancing its catalytic conversion ability of CO2 to CO. These results enrich the understanding of surface chemistry of CuAl2O4 spinel and lay an important theory foundation for design of spinel-based catalysts for RWGS reaction.

Improving the shelter design process via a shelter assessment matrix

Millions are living in shelters around the world, often for decades. Architects are rarely trained in shelter design and as a result speculative designs are frequently impractical or insensitive to occupants. In addition, aid agency staff can lack engineering or architectural knowledge, so need support during shelter procurement. Evidence gathered by the authors in seven countries over three years revealed poor conditions within many shelters, including condensation, excessive temperatures, lack of privacy and poor air quality, all of which contribute to increased morbidity and mortality. To address this, the paper proposes a design assessment platform, the Shelter Assessment Matrix (SAM), covering 34 issues. SAM also includes guidance documents that allow users to upskill themselves on a range of topics. The tool was tested in three ways: (i) 11 agency staff were asked to assess the same shelter. The mean score was 45.7/100, standard deviation (SD) 2.96. The narrow SD indicated that SAM provided consistent scoring. (ii) 187 previously deployed shelters were evaluated and scored between 27 and 78. This suggests that SAM generates a range of scores, and that shelters could be improved. This evaluation also provides the first contextualised performance analysis of shelters around the world, and a repository for others to judge their designs against. (iii) Use of the platform resulted in considerable measured uplifts in building science and cultural knowledge. SAM has been made freely available online and has been used by agencies to materially improve the design of shelters for thousands of individuals in four countries.

One-step preparation of highly efficient adsorbents: Adsorption study of DMP on porous carbon macrobody based on sodium alginate

Porous carbon is a carbon material with a high surface area and abundant pore structure, holding extensive potential applications in the adsorption field. However, current porous carbon materials are complicated to prepare, and most are in powder form, making them difficult to separate from water after adsorption and prone to secondary pollution. This study uses sodium alginate (SA) as a precursor and K2CO3 one-step method to prepare sodium alginate-based macromaterials that can skillfully solve the above problems and explore its adsorption kinetics and thermodynamic characteristics for dimethyl phthalate (DMP). This study's meticulous control of experimental details enabled the fabrication of macroscopic materials. The appropriate temperature and activator blending ratio are critical to material agglomeration. (At 800 °C in a small ceramic boat, macroscopic material C800–2 was prepared with an activator ratio of K2CO3: sodium alginate at 2:1 and under low acid concentration acid washing (0.2 mol/L HCl)). Excessive pyrolysis temperature can lead to severe chemical bond loss, potentially preventing material agglomeration. Excessive doping of the activator may result in carbon framework collapse. While maintaining the macroscopic structure, C800–2 enhanced a 3.8-fold increase in total pore volume and a 4.6-fold increase in surface area. Moreover, at 313 K, its saturated adsorption of DMP reached an impressive 614.98 mg/g. C800–2 material exhibits excellent interference resistance and regeneration capability. The study achieves one-step fabrication of macroscopic materials while retaining superior adsorption performance, providing fundamental data for material engineering applications.

Flow Distribution in Molten Salt Receiver Panels at High Flux Gradients

This paper presents a simulation study on critical mass flow distributions in receiver panels of commercial-scale molten salt towers (MST). Despite sophisticated aimpoint optimizations, the flux density distribution on an MST receiver in actual operation contains significant vertical and horizontal gradients. This study investigated how the latter affects the mass flow distribution among the parallel absorber tubes in each panel. A parametric study applied a discretized dynamic thermohydraulic model of a commercial scale receiver design, highlighting at which mass flow rates, flux density gradients and mean flux densities the flow distribution can become critical. Excessive temperature developments were observed, suggesting maintaining appropriate minimal mass flow rates to avoid damaging tube walls and the molten salt chemistry.

Effects of Foliar Protector Application and Shading Treatments on the Physiology and Development of Common Bean (Phaseolus vulgaris L.).

High solar radiation, combined with high temperature, causes losses in plant production. The application of foliar protector in plants is associated with improvements in photosynthesis, reduction in leaf temperature and, consequently, improved productivity. Two experiments were conducted. The first aimed to assess the efficacy of foliar protector versus artificial shading in mitigating the negative impacts of excessive radiation and temperature on the physiology, growth, and yield of common bean plants. The second experiment focused on comparing the timing in cycle plants (phenological phases) of foliar protector application in two different bean cultivars (BRS Fc 104 and BRS MG Realce) under field conditions. Artificial shading provided better results for photosynthesis, transpiration, growth and production compared to the application of foliar protector. In the field conditions experiment, the application timing of the foliar protector at different phenological phases did not increase productivity in the cultivars. The application of foliar protector under the conditions studied was not effective in mitigating the negative impacts of high solar radiation and temperature on common bean cultivation. However, it is opportune to evaluate the application of foliar protector in bean plants grown under conditions with water deficit, high solar radiation and high temperature.

Research on the Design of a MIMO Management System for Lithium-Ion Batteries Based on Radiation–Conductivity–Convection Coupled Thermal Analysis

In this study, the heat transfer model of a radiation–conduction–convection coupled lithium-ion battery pack is established through theoretical analysis. The temperature distribution and flow field distribution inside the battery pack are obtained by simulation using ANSYS Fluent software 2022 R1, and the reasonableness of the simulation model is verified with an experiment. This study also analyzes in detail the improvement effect of adding heat dissipation ribs, applying heat dissipation coatings, and adjusting the fan speed on the heat dissipation performance of the system. Under the same heat sink rib height conditions, the relationship between its thickness and total heat dissipation and thermal efficiency is studied in depth, and the temperature distribution of the cell under different rib thicknesses is obtained. At the same time, the emissivity of the heat sink coating under different coating thicknesses was measured by infrared thermography, and the relevant design values were determined through simulation experiments. Finally, based on the experimental test results of fan performance, a corresponding control strategy is proposed to construct an efficient and high-performance multiple-input multiple-output (MIMO) battery thermal management system. The experimental results show that optimizing the structure of the forced air cooling system through the above measures can ensure that the Li-ion battery operates within the efficient operating temperature range, thus extending its cycle life, improving its stability, and reducing the risk of thermal runaway. Meanwhile, the problem of excessive temperature difference between different modules is improved, and the output capacity of the energy storage system is increased.

Revealing the deterioration mechanism in gelling properties of pork myofibrillar protein gel induced by high-temperature treatments: Perspective on the protein aggregation and conformation

The purpose of the present study was to investigate the mechanism of gel deterioration of myofibrillar proteins (MP) gels induced by high-temperature treatments based on the protein aggregation and conformation. The results showed that the gel strength and water holding capacity of MP obviously increased and then decreased as the temperature increased, reaching the maximum value at 80 °C (P < 0.05). The microstructure analysis revealed that appropriate temperature (80 °C) contributed to the formation of a more homogeneous, denser, and smoother three-dimensional mesh structure when compared other treatment temperatures, whereas excessive temperature (95 °C) resulted in the formation of heterogeneous and large protein aggregates of MP, decreasing the continuity of gel networks. This was verified by the rheological properties of MP gels. The particle size (D4,3 and D3,2) of MP obviously increased with larger clusters at excessive temperature, and the surface hydrophobicity of MP decreased (P < 0.05), which has been linked to the formation of soluble or insoluble protein aggregates. Tertiary structure and secondary structure results revealed that the proteins had a tendency to be more stretched under higher temperature treatments, which resulted in a decrease in covalent interactions and non-covalent interactions, fostering the over-aggregation of MP. Therefore, our present study indicated that the degradation of MP gels treated at high temperatures was explained by protein aggregation and conformational changes in MP.

Prediction of surface roughness using different features in vortex cooled turning process of Ti6Al4V alloy

Despite their superior mechanical properties, titanium alloys cause excessive temperatures in turning operations due to their low thermal conductivity. This situation reduces workpiece quality and shortens tool life. Therefore, it is necessary to determine the type of coolant that will provide the desired product quality at the optimum cost. Surface roughness (Ra) is one of the most important indicators of product quality. The goal of this work is to accurately predict the Ra in various cooling conditions prior to turning the Ti6Al4V alloy. Models built using various machine learning algorithms were used to compare the cutting parameters and features taken from sensor signals. While the lowest Ra values were obtained in dry cutting, the highest Ra values were obtained with vortex CO2. The highest performance success was achieved with the XGBoost algorithm. The model created by enhancing the cutting parameters performed better in predictions than the models created using statistical information taken from the sensor signals. The suggested approach eliminates the need for extra sensors and allows for the low computational cost and high success rate estimation of Ra.

Nonlinear free vibration analysis of multi-directional functionally graded porous sandwich plates

Multi-directional functionally graded materials (MFGMs) have attracted significant research attention due to their advantages over one-directional FGMs. In MFGM structures, material properties can be tailored to grade in the required direction, overcoming practical problems like excessive temperature gradients or extreme deflections. This paper aims to investigate the nonlinear free vibration of MFG porous sandwich plates to improve their application in sandwich structures. The two outer layers of the plates are composed of three-directional functionally graded material (3D-FGM), with a bi-directional functionally graded material (2D-FGM) core layer. Additionally, the porosity distribution within the material matrix is assumed to be either even or uneven across the plate thickness. A higher-order finite element model based on Shi's plate theory and the von Kármán assumption is developed. The nonlinear free vibration frequencies are determined through the maximum vibrational amplitude using an iterative algorithm with a displacement control strategy. The accuracy and effectiveness of the proposed model are demonstrated through a comparison with published data. The results show that the vibration response is significantly influenced by various parameters. Specifically, increasing the material gradient indexes in the thickness direction enhances the frequency ratio, while increasing the gradient indexes in the length and width directions reduces it. Higher porosity coefficients in the core layer decrease the frequency ratio, whereas higher pore coefficients in the outer layers increase it. The additional knowledge gained from this study can help with future analysis and design procedures related to the nonlinear responses of these complex structures.