Search Results (23,239)

Oleogels have emerged as promising alternatives to conventional solid fats by structuring liquid oils without increasing trans or saturated fat levels. This study therefore aimed to develop rice bran oil (RBO)-based oleogels using beeswax (BW), carnauba wax (CW), and their combinations, and to compare their physicochemical properties with commercial margarine. Thirteen formulations with varying wax concentrations were prepared and analyzed using differential scanning calorimetry, microscopy, rheology, texture profile analysis, oil binding capacity, slip melting point, peroxide value, color analysis, and fatty acid profiling. Our results demonstrated that the thermal behavior of the oleogels is dependent on the type and concentration of the wax, with CW oleogels exhibiting higher crystallization and melting temperatures than BW, while hybrid systems displayed intermediate and synergistic properties. Distinct crystal morphologies were observed, with BW forming needle-like and CW forming spherulitic structures, while the hybrids created interconnected networks. All samples exhibited shear-thinning and gel-like behavior, with greater viscosity and gel strength observed at increasing wax concentrations. The hybrid oleogels achieved hardness comparable to higher CW levels and approached margarine texture, while maintaining high oil binding capacity (>94%). The RBO oleogels contained higher unsaturated fatty acids but showed lower oxidative stability than margarine. Overall, BW–CW hybrid oleogels demonstrated strong potential as healthier, solid fat alternatives with improved structural and thermal characteristics. Full article

This work aims to investigate the interfacial tension characteristics of alkyl carboxymethyl betaines dispersed at the crude oil/formation water interface. Four alkyl dimethyl carboxymethyl betaines and one alkyl diethyl carboxymethyl betaine were synthesized, then the effects of surfactant molecular structure, crude oil component, and inorganic salt composition of formation water on interfacial tensions were studied systematically. The results show that the synthesized octadecyl diethyl carboxymethyl betaine has the highest interfacial activity and exhibits superior anti-dilution performance. In the presence of polyacrylamide, this betaine also displays good anti-adsorption capability. With respect to crude oil components, the resin component, especially the petroleum acid and alkali components, play important roles in tension reduction. For formation water, its alkaline inorganic salts are crucial to obtain an ultra-low interfacial tension by its saponification effect on petroleum acid. The octadecyl diethyl carboxymethyl betaine also exhibits good temperature and salt resistance, but poor tolerance toward divalent cations owing to the consumption of alkaline inorganic salts. Moreover, it is found that there exists synergism between octadecyl diethyl carboxymethyl betaine and dodecylbenzene sulfonate which can further reduce the interfacial tension. The above findings are conducive to the selection of betaine surfactants in chemical flooding. Full article

Jiaodong Peninsula is one of the regions with the most abundant medium–low-temperature convective geothermal resources in the eastern coastal area of China. Analyzing geothermal fluid characteristics can help understand its hydrochemical discharge characteristics and renewal capacity, and these characteristics also exhibit distinct geochemical symmetry that reflects the genesis and evolution of geothermal systems. In this study, we conducted a water quality analysis of 15 natural hot spring geothermal fluids, as well as their adjacent bedrock and Quaternary water, in the Jiaodong Peninsula. We measured deuterium and oxygen isotopes, and the γ Na/γ Cl and γ SO₄/γ Cl ratios of geothermal fluids, focusing on the geochemical symmetry of these indicators to reveal the evolutionary rules of geothermal fluids. The hydrochemical types of geothermal fluids in the Jiaodong Peninsula included Cl–Na, Cl–Na·Ca, HCO₃·SO₄–Na, and SO₄·HCO₃–Na, with mineralization degrees of 0.45–7.68 g/L and pH values of 7.3–8.63. The geothermal fluid primarily originated from the infiltration recharge of atmospheric rainfall and had no hydraulic connection with the shallow Quaternary water and adjacent bedrock water near the geothermal field. The geothermal fluid in the study area had not yet reached water–rock equilibrium. For geothermal fields with higher γ Na/γ Cl and γ SO₄/γ Cl ratios, the corresponding geothermal fluid circulation depth was relatively shallow, indicating a poorly sealed hydrodynamic environment with strong renewal capacity, where the geothermal fluid is in a continuous supply–runoff–discharge process. The γ Na/γ Cl and γ SO₄/γ Cl ratios of some geothermal fields were close to those of seawater; this symmetric difference was caused by the large circulation depth and long residence period of the geothermal fluid, which had experienced a high degree of decarbonization. Our findings on the hydrochemical characteristics and geochemical symmetry of medium–low-temperature geothermal fluids in the Jiaodong Peninsula will help deepen the understanding of the formation and evolutionary mechanism of this type of geothermal resource. Full article

Background and Objectives: Severe snowfall and icing are associated with weather-related trauma presentations, especially in cities unaccustomed to prolonged winter conditions. However, the clinical characteristics of these injuries and their implications for surgical management remain incompletely understood. This study aimed to describe injury patterns, treatment approaches, and factors associated with the need for surgery among patients presenting with extremity trauma during an intense snowfall and icing episode in Diyarbakır. Materials and Methods: This single-center retrospective observational study included patients presenting to the emergency department with extremity trauma during a severe snowfall and icing period. Demographic characteristics, injury features, imaging modality, ambient temperature, anatomical localization, and treatment approaches were analyzed. Patients were categorized according to nonoperative versus operative management. Factors associated with the need for surgery were evaluated using univariable and multivariable logistic regression analyses. Receiver operating characteristic analysis was used to assess the discriminative ability of age and ambient temperature for predicting the need for surgery. Results: A total of 943 patients were included. The largest age group was 18–44 years (38.6%), and 55.9% were male. Fractures were identified in 50.7% of cases, whereas 46.7% had no fracture and 2.7% had joint dislocation. Upper-extremity injuries predominated (65.2%), with distal segment involvement observed in 55.0% of cases. Most presentations occurred on days with mean ambient temperatures ≤ 0 °C (81.5%). Overall, 82.1% of patients were managed nonoperatively, while 17.9% required surgical treatment. In multivariable analysis, increasing age and the use of computed tomography were independently associated with the need for surgery, whereas ambient temperature was not. Conclusions: Fall-related extremity injuries during severe snowfall and icing were predominantly upper-extremity and distal injuries, and most were managed nonoperatively. The need for surgery was more strongly associated with patient age and injury complexity than with ambient temperature alone. These findings describe a distinct trauma profile during short-term winter events in mild-climate cities. Full article

Drilling in deep hard formations poses significant challenges for conventional polycrystalline diamond compact (PDC) cutters, which often suffer from low rock-breaking efficiency and premature failure due to severe cutter-face wear, high thermal loads, and stick-slip vibrations. To overcome these limitations, this study proposes a chisel-shaped PDC cutter and systematically investigates its rock-breaking and thermal characteristics. A coupled temperature–displacement finite element model (FEM) of cutter–granite interaction and a single-cutter indentation model were developed based on elastoplastic mechanics and the Drucker–Prager failure criterion. The rock constitutive parameters used in both models were validated through uniaxial compression tests. Using these models, the influences of cutter shape, back rake angle, and depth of cut (DOC) were analyzed. Compared with a conventional cylindrical cutter, the chisel cutter reduces the cutting force by 13.4% and the axial penetration reaction force by 22%. The cutting force of the chisel cutter remains consistently lower across all tested depths. The optimal back rake angle is 20–25°, and the optimal DOC is 1.5 mm. Full-bit simulations further demonstrate that the chisel-cutter bit creates a more concentrated bottomhole stress field, increases the rate of penetration (ROP) by 19.7%, reduces average torque by 11.34%, and produces smoother torque fluctuations, indicating higher drilling stability. Thermal analysis reveals that the chisel cutter exhibits lower and more stable cutter-face temperatures. Both simulation and experimental results confirm that the chisel design reduces the friction contact area between cuttings and the cutter face, thereby lowering temperature accumulation. Field drilling data corroborate the reliability of the conclusions. These findings provide guidance for the design of PDC bits intended for deep hard formations. Full article

The extreme thermal environment during the underground coal gasification (UCG) process poses a severe threat to the stability of the gasification cavity and the integrity of the surrounding rock. This paper aims to reveal the thermo-mechanical response characteristics and damage evolution mechanism of sandstone under true triaxial unloading conditions following exposure to high temperatures. Sandstone specimens were thermally pre-treated at five temperature gradients (25 °C, 200 °C, 400 °C, 600 °C, and 800 °C) and subsequently subjected to true triaxial loading and unloading experiments. The effects of varying temperatures on the strength, deformation parameters, dilation angle evolution, and macroscopic failure modes of the sandstone were systematically analyzed. The results indicate a significant critical transition point in the mechanical behavior of the sandstone at 400 °C. Below this threshold, thermal-induced microcrack closure leads to an increase in peak strength (with the peak strength at 800 °C increasing by approximately 67% compared to room temperature). Conversely, above 400 °C, thermal damage to the mineral grains intensifies, causing the crack propagation pattern to transition from brittle shear to a complex tension-shear splitting mode, accompanied by severe dilatancy (with a generalized Poisson’s ratio exceeding 0.8). Based on these findings, this study proposes a stage-wise damage evolution model alongside a targeted zonal support strategy, recommending the application of high-prestressed support in high-temperature zones above 400 °C to suppress tensile failure. Ultimately, this research provides a crucial theoretical basis for evaluating the long-term stability of high-temperature underground engineering projects and ensuring operational safety. Full article

This study investigates a 2D fractional order generalized thermoelastic problem in a homogeneous and isotropic thermoelastic hollow sphere. The sphere is exposed to a decaying heat source, and the governing equations are derived using a refined fractional-order Lord–Shulman (LS) model of generalized thermoelasticity. The Laplace transform technique is used to convert time-dependent PDEs into simpler ODEs in the Laplace domain. Its numerical inversion method is used to revert to the time domain. Numerical simulations are carried out to investigate the distributions of temperature, displacement, and stress fields within the hollow sphere. The obtained results reveal that both the fractional-order parameter and the variable thermal conductivity strongly affect the thermoelastic response, particularly the propagation characteristics of thermal waves, stress intensity, and relaxation behavior. In addition, the curvature of the hollow geometry plays an important role in modifying the radial and circumferential stress distributions and their attenuation throughout the medium. Full article

Current research suggests that the uranium enrichment in the Qianjiadian deposit, southwestern Songliao Basin (China), is closely related to hydrocarbon dissipation and deep thermal fluids. However, previous investigations have not carried out systematic in-depth research on the abundant calcite veins hosted in diabase within the ore district, especially regarding their types, genetic mechanisms, formation ages, and genetic links to uranium enrichment. In particular, whether their genesis is associated with the two critical ore-controlling factors (hydrocarbon dissipation and thermal fluid activities) remains poorly constrained and to be elucidated. Through analyses of major and trace element geochemistry, scanning electron microscopy, and fluid inclusion microthermometry on calcite veins within fractures of Lower Cretaceous diabase, this study confirms that the veins are products of epigenetic fluid infill with a medium-to-low temperature hydrothermal nature (115–215 °C). The direction of fluid migration was from north to south, consistent with the trend of hydrocarbon dissipation. In situ U-Pb dating yields Eocene (~42.9 Ma) and Pleistocene (1.57–2.82 Ma) ages for the calcite veins, which are highly consistent with the timing of diabase intrusion (early Eocene) and the main episodes of uranium mineralization (Eocene–Oligocene and Pleistocene). Carbon and oxygen isotope compositions and inclusion components indicate that the carbon source was mainly derived from dissipated hydrocarbons, rather than from sedimentary diagenesis or direct source rock generation. The C-O isotopic signatures reflect further carbon isotope fractionation following the interaction between dissipated hydrocarbons and groundwater, and the inclusion fluids, composed mainly of hydrocarbon gases and water, suggest that the carbon source for calcite vein formation was provided by dissipated hydrocarbons. The temporal coupling of hydrocarbon dissipation, calcite vein formation, uranium mineralization, and thermal input from diabase intrusion reflects the dynamic processes of basin evolution and tectonic reworking. The key dynamic backgrounds for this series of diagenetic and metallogenic events include Late Cretaceous tectonic inversion, Eocene–Oligocene tectonic uplift and erosion, and Pleistocene differential uplift and subsidence. The thermal effects from hydrocarbon dissipation and diabase intrusion were the primary factors driving the anomalous uranium enrichment that formed this super-large deposit. The formation of the calcite veins, along with their characteristics indicative of medium-to-low temperature hydrothermal activity and hydrocarbon dissipation, provides a critical window for understanding these processes and offers robust scientific evidence for this genetic model. This study, for the first time, systematically reveals that the calcite veins within the diabase of the Qianjiadian uranium mining area are of medium-to-low temperature hydrocarbon-bearing hydrothermal origin, and constrains their formation ages to the Eocene (~42.9 Ma) and Pleistocene (1.57–2.82 Ma), which are highly coupled with diabase intrusion and two episodes of uranium mineralization events. C-O isotopic and fluid inclusion evidence indicates that the formation of calcite veins directly records the process of hydrocarbon dissipation–groundwater mixing, providing a new mineralogical and geochronological evidence chain for thermal–hydrocarbon–uranium-coupled mineralization. Full article

This study focuses on the quantitative simulation of the spatiotemporal distribution characteristics of permafrost area, providing scientific value for Mongolian Plateau permafrost dynamics. Understanding the permafrost area of the Mongolian Plateau and accurately predicting future changes in permafrost area are crucial for sustainable environmental development. In this study, ERA5-Land surface temperature (LST) combined with the temperature at the top of permafrost (TTOP) model are used to calculate the annual permafrost area from 1980 to 2024. In addition, this study used the long short-term memory (LSTM) model to predict permafrost area on the Mongolian Plateau from 2025 to 2100. In this study, it is concluded that (1) the study area is not uniformly covered with permafrost, and its distribution is mainly limited to the northern part of the Mongolian Plateau, with a permafrost area of 53.20 × 10⁴ km²; (2) the permafrost area is estimated with an accuracy and precision of 0.94 when compared to the baseline value derived from borehole permafrost data; (3) under the CMIP6 three different shared socioeconomic pathway (SSP) 1-2.6, 2-4.5, and 5-8.5 future scenarios, the distribution of permafrost area shows a downward trend. This study provides a theoretical reference for distribution permafrost area in geographical space, which can help achieve the sustainable development of ice and snow resources. Full article

The growing field of nanobiotechnology could provide an alternative platform for the development of new therapeutic agents. A potential means for achieving these goals are nanoparticles of rare-earth metals, for example, nanoceria. According to the results of numerous in vitro and in vivo studies, not only oxide forms of lanthanides can demonstrate a pharmacological effect. A promising nano-object for biomedical application is cerium phosphate, which exhibits both properties characteristic of cerium dioxide and its own unique properties, due to the diversity of morphology. However, at present, a unified methodological approach has not been formulated that would make it possible to formulate principles for obtaining a compound with specified properties. This review was conducted on using the international databases PubMed, PubChem, Scopus and Google Scholar, and included original studies and reviews. The literature describes the preparation of cerium phosphate nanoparticles by the hydrothermal, chemical precipitation, microwave, and sol–gel methods. It was established that reaction temperature, pH value of the medium, use of organic solvents, ratio of reagents, and precursors have a direct influence on the size, shape, and structure of the obtained nano-object, making it possible to synthesize nanospheres, nanorods, and nanoneedles by regulating these parameters. In addition, the strategy of obtaining nano-objects with specified properties can be implemented by using excipients of predominantly polymer nature. The use of auxiliary substances is capable both of exerting a stabilizing effect and improving adherence to the nanoscale range, and of influencing pharmacological activity. The literature describes the possibility of using cerium phosphate as a redox-active, regenerative, antibacterial, sunscreen, and antitumor agent. However, the insufficient amount of data on the toxicological profile, as well as the results of in vivo studies, remains a significant limitation for the introduction of cerium phosphate into clinical practice. Thus, the purpose of the present review is to identify patterns that make it possible to formulate recommendations for the synthesis of cerium phosphate with specified properties, to assess factors affecting its suitability for use in biomedicine, and to consider its prospects and limitations. Full article

In our research, we developed a Distributed Relaxation Spectrum Delay Differential Equation (DRSDDE) model to simulate viscoelastic responses exhibited by materials with multiple-scale relaxation mechanisms and finite delay times. Our model expanded upon traditional integer-order viscoelastic models to include a continuum relaxation process using a log-time-space Gaussian distribution representing a continuum of relaxation processes, including a direct representation of the effect of delayed feedback via an explicit time delay term. Consequently, the resultant model can be viewed as a generalized Maxwell-type formulation where the viscoelastic behavior exhibits distributed relaxation dynamics and has finite signal propagation characteristics. We then used experimental data obtained from three representative materials: PDMS Sylgard 184, bovine brain white matter, and polyurethane foam to calibrate the model. Calibration was achieved by estimating model parameters through the use of Gauss-Legendre quadrature combined with non-linear optimization of the relaxation spectrum. The results indicate that the coefficients of determination for each of the materials exceeded R² > 0.83. Therefore, the proposed DRSDDE model outperformed the classical Zener model when simulating materials that exhibit a wide relaxation spectrum. The parameter values estimated for each of the examined materials provided additional insight into their physical behaviors. Specifically, the characteristic relaxation times for the studied materials were determined based upon \(\tau\)_c = 10^µ ranging from about 63 s to 158 s. These results illustrate different dominant relaxation regimes for the investigated materials. Additionally, both characteristic equations and frequency domain analyses were utilized to study the stability and bifurcation properties of the DRSDDE model. A significant finding resulted from identifying a delay-insensitive stability regime for materials with \(\tilde{K} < 1\) (as illustrated by bovine brain white matter). For materials with \(\tilde{K} > 1\), the analysis revealed Hopf bifurcation results illustrating critical delay thresholds and frequencies for the onset of oscillations. Further, it was established that all calibrated delay values were significantly less than these threshold values. This indicates that all identified models functioned well below the oscillation thresholds at realistic delay times. Ultimately, the proposed DRSDDE model represents a physically intuitive, robust, and flexible method for modeling complex viscoelastic systems. Future research will involve investigating temperature-dependent effects, nonlinear bifurcations, and experimental validations of predicted oscillatory dynamics Full article

Open-cathode Proton Exchange Membrane Fuel Cells (PEMFCs) are a promising technology for increasing the endurance of small Unmanned Aerial Vehicles (UAVs), ground robots, e-bikes, and light electric vehicles. However, their performance under realistic operating conditions is strongly influenced by rapid variations in load, temperature, and ambient pressure, which are often neglected in design-oriented or quasi-steady-state analyses. This study experimentally investigates a 1 kW open-cathode PEMFC system, including its balance of plant and a passive supercapacitor buffer, under a representative UAV flight power profile. Steady-state and dynamic tests were conducted to assess polarization characteristics, thermal behavior, parasitic power consumption, and hydrogen utilization. Results revealed significant thermal inertia and hysteresis effects during load transients, causing voltage deviations from steady-state performance and stabilization times exceeding 90 s. The supercapacitor effectively reduced stack current ramp rates, although some high-frequency oscillations remained. Under flight-representative conditions, the system achieved stable operation with average voltaic efficiency ranging from 55.3% to 60.7% and net efficiency ranging from 50.2% to 54.2%. Auxiliary components had a measurable impact on overall performance: cooling fans accounted for 2–6% of stack power during steady operation and approximately 2.5% of total mission energy, while hydrogen purge losses can significantly reduce vehicle endurance. The findings demonstrate the importance of energy-based performance assessment, including auxiliary loads and purge losses, to obtain realistic estimates of efficiency and endurance in dynamic PEMFC-powered applications. Full article

Multispectral temperature measurement technology based on blackbody radiation theory has been widely applied in the field of non-contact temperature measurement. However, its applicability is limited by the single-point measurement mode. To address this limitation, this study developed a spectral fusion temperature measurement device and proposed a new method for reconstructing the two-dimensional temperature field of deflagration fireballs by fusing spectral and imaging data. The device adopts a CCD sensor and a fiber optic spectrometer placed in parallel with parallel optical axes. To ensure the accuracy of the CCD’s response characteristics at different distances, the photo-response non-uniformity (PRNU) calculation method was used for precision validation. In this study, spectral and imaging data of deflagration fireballs were obtained through experiments. Spectral data of consecutive frames at 189 ms, 192 ms, 195 ms, and 198 ms were extracted and analyzed, confirming that the temperature range at the four time points is 1050 K to 1800 K. The proposed method generates temperature elements with equal temperature intervals and their probabilities within the temperature range, and calculates the theoretical radiation spectrum of each element. Then, least squares optimization fitting is performed on the experimentally measured spectra to obtain the optimal probabilities of the temperature elements in the temperature field. By combining these optimal probabilities with CCD grayscale images, the 2D temperature distribution of the deflagration fireball was reconstructed. Results show that: the PRNU value of the device at a distance of 9 m is less than 2.2% through experimental verification; fused images of the temperature field spectra of four consecutive frames of the deflagration fireball were obtained using the proposed method. The average temperatures reconstructed by the proposed method at 189 ms, 192 ms, 195 ms, and 198 ms were 1382 K, 1373 K, 1366 K, and 1357 K, respectively, while the corresponding temperatures obtained by conventional spectral inversion were 1430 K, 1422 K, 1414 K, and 1406 K. The relative errors were 3.2%, 3.4%, 3.3%, and 3.4%, respectively, with an average relative error of approximately 3.3%. Full article

With the global advancement of carbon peaking and carbon neutrality goals, the importance of carbon capture, utilization, and storage (CCUS) technologies has become increasingly prominent. As a critical component of CCUS systems, gaseous CO₂ pipeline transportation has emerged as a research hotspot due to its efficiency and cost effectiveness. However, there are invariably corrosion problems when it comes to gaseous CO₂ pipeline transportation. These issues pose a significant threat to both the safety and economic viability of pipeline operations. Therefore, it is of importance to investigate gaseous CO₂ corrosion during pipeline transportation. In this work, based on recent domestic and international research achievements, research progress in the field of gaseous CO₂ corrosion during pipeline transportation is systematically reviewed. First, the corrosion mechanisms and corrosion characteristics during gaseous CO₂ pipeline transportation are studied, and the synergistic mechanisms by which key parameters such as impurities, temperature, pressure, flow velocity, and water content jointly influence pipeline wall corrosion behavior are elucidated. Then, corrosion products in CO₂ transportation pipelines are analyzed, and protective measures applicable to gaseous CO₂ pipeline systems are synthesized. Finally, future research goals are proposed to promote research on gaseous CO₂ corrosion during pipeline transportation: the impact of interactions among multiple impurities on corrosion behavior should be clarified; the inhibitory effects of the dynamic evolution of product films on mass transfer processes should be considered in corrosion rate calculation models; and more economical and efficient anti-corrosion technologies should be developed to meet diverse operational requirements. This work can provide guidance for the corrosion protection of gaseous CO₂ pipeline transportation. Full article

Lithium-containing ceramics were significant tritium breeders for the fusion blanket concept, for which tritium release performance and mechanical properties serve as the core indicators for evaluating their performance as tritium breeders. The Li₄Si_0.8Ti_0.2O₄ material was designed as an advanced tritium breeder and fabricated into ceramic pebbles via the freeze-drying method. The tritium release properties of the Li₄Si_0.8Ti_0.2O₄ sample pebbles were investigated via temperature-programmed desorption (TPD). The mechanical properties of the same batch of tritium breeder pebbles were analyzed comparatively, specifically examining the change in their compressive strength before and after irradiation. The sample pebbles irradiated with different neutron doses show different tritium release characteristics, and the tritium release temperature was about 293–553 °C. This was due to the H₂-tritium isotope exchange reaction, and radiation with different neutron doses will lead to different release temperatures of tritium. The mechanical properties of the Li₄Si_0.8Ti_0.2O₄ ceramic pebbles decreased significantly after irradiation. The main reason was that the accumulation of lattice defects and helium bubbles produced by high-energy neutron irradiation leads to internal cracks and helium embrittlement in the material. These results indicate that Li₄Si_0.8Ti_0.2O₄ solid solution may be considered a potential candidate for tritium breeder materials. Full article