Search Results (8,263)

Polylactic acid (PLA) is considered as an attractive polymer due to its renewable origin, biodegradability, and promising tensile strength and modulus. However, its inherent brittleness, characterized by a low impact resistance and elongation at break, can significantly restrict its application. This work proposes a new insight to improve the toughness of PLA while keeping its biocompatibility by incorporating two biocompatible ionic liquids (ILs), 1-ethyl-3-methylimidazolium ethyl sulfate ([emim][EtSO₄]), and tris(2-hydroxyethyl) methylammonium methylsulfate ([Tris][MeSO₄]). The modified PLA systems were thoroughly characterized to evaluate their mechanical and thermal behavior. Results demonstrated that the addition of 1 wt% of either IL resulted in significant improvement in modulus. Increasing the amount of IL resulted in an increase in the toughness while maintaining the material’s original stiffness and also the thermal stability. Furthermore, the foaming potential of the modified PLA using supercritical CO₂ was investigated as an environmentally friendly processing method. The ionic liquids contributed positively to the foamability of the material, suggesting improved gas solubility and cell nucleation during the foaming process. The addition of both IL decreased the cell size and resulted in narrower cell size distribution. These findings highlight the potential of ionic liquid-modified PLA systems for the processing of lightweight, and high-performance packaging materials. Full article

Tin bronze/steel bimetallic is a widely utilized industrial material in the field of sliding bearing applications. Arc cladding technology represents an emerging method for fabricating tin bronze/steel bimetallic materials; however, research on their microstructure and mechanical properties remains limited. This study investigates the microstructural characteristics and mechanical behavior of tin bronze/steel bimetallic materials produced via the arc cladding process, with particular emphasis on the effects of annealing treatment on these properties. The tin bronze layer consists of a fine-grained zone, a columnar dendritic zone, and a freely dendritic zone. The tin bronze/steel bimetallic material exhibits high mechanical strength and strong interfacial bonding. Nevertheless, during three-point bending tests, cracks are observed in the tin bronze layer. When annealed at temperatures ranging from 300 °C to 700 °C, the tensile strength, shear strength, and hardness of the material decrease, while the elongation increases significantly. Moreover, no cracking occurs during three-point bending tests. Upon reaching an annealing temperature of 800 °C, the overall mechanical performance deteriorates rapidly. An annealing temperature of 300 °C is identified as an optimal parameter for achieving favorable mechanical properties. Full article

This study investigates the dynamic response of fracture networks and the evolution of waterflood fronts during fracture-flooding in low-permeability and tight reservoirs. By establishing a discrete fracture model that incorporates geomechanical heterogeneity and natural fractures, and utilizing the Barton-Bandis criterion to describe fracture stress-sensitive behavior, the fracture-flooding process was simulated and analyzed under two scenarios: considering versus ignoring the time-varying stress effect. The results demonstrate that when the time-varying stress effect is considered, fracture conductivity gradually recovers with increasing injection pressure, as the elevated fluid pressure within the fractures reduces the effective normal stress, promoting elastic dilation of the fracture aperture. This is evidenced by the average conductivity coefficient increasing from 0.4 (near-closure) to 0.99 (fully open) during the injection period. This recovery mechanism promotes a “wall-imbibition-dominated” flow pattern. In contrast, neglecting this effect leads to a “fracture-tip-breakthrough-dominated” mode, causing poor front uniformity. Quantitative analysis of the front morphology confirms this improvement: the perimeter-to-area ratio decreased from 2.507 to 1.647, and the coefficient of variation dropped from 0.490 to 0.324. This research provides an important theoretical basis for optimizing fracture-flooding operations and enhancing oil recovery. Full article

Boriding is a widely used thermochemical treatment to improve surface hardness and wear resistance in steels used in demanding mechanical applications. However, boronizing processes using new boron paste increase costs and generate waste, creating a need for more sustainable alternatives. In this context, the reuse of dehydrated boron paste has proven effective in the formation of Fe₂B layers on AISI 9254 steel. In this study, AISI 9254 steel was boronized using reused dehydrated boron paste at 1173 K, 1223 K, and 1273 K for 3600, 7200, 10,800, and 14,400 s. Optical microscopy revealed layer thicknesses ranging from 16.07 $\mathsf{\mu }\mathrm{m}$ to 69.35 $\mathsf{\mu }\mathrm{m}$ X-ray diffraction confirmed the formation of single-phase Fe₂B, while EDS indicated elemental redistribution within the layer. The Vickers microhardness profile characterized the mechanical behavior, and the adhesion force showed HF1-HF2 ratings. The activation energy for boron diffusion in Fe₂B was calculated at 106.567 kJ ${\mathrm{mol}}^{-1}$. Auto-affine analysis verified the fractal nature of interface growth, with a scale $\omega \left(d\right)$ according to $\omega \left(\delta \right)\sim {\delta }^H$. These results confirm that reused paste allows the formation of Fe₂B layers, supporting sustainable boronization strategies with controlled interfacial evolution. Full article

Diet influences brain health through many connected metabolic and molecular pathways, and these effects are stronger in obesity. This review links diet quality with cognitive decline and dementia risk. Ultra-processed, high-fat, high-sugar diets drive weight gain, insulin resistance, and chronic inflammation. These changes trigger brain oxidative stress, reduce DNA repair, deplete NAD⁺, disturb sirtuin/PARP balance, and alter epigenetic marks. Gut dysbiosis and leaky gut add inflammatory signals, weaken the blood–brain barrier, and disrupt microglia. Mediterranean and MIND diets, rich in plants, fiber, polyphenols, and omega-3 fats, slow cognitive decline and lower dementia risk. Trials show extra benefit when diet improves alongside exercise and vascular risk control. Specific nutrients can help in certain settings. DHA and EPA support brain health in people with low omega-3 status or early disease. B-vitamins slow brain shrinkage in mild cognitive impairment when homocysteine is high. Vitamin D correction is beneficial when levels are low. A practical plan emphasizes healthy eating and good metabolic control. It includes screening for deficiencies and supporting the microbiome with fiber and fermented foods. Mechanism-based add-ons, such as NAD⁺ boosters, deserve testing in lifestyle-focused trials. Together, these measures may reduce diet-related brain risk across the life span. At the same time, artificial intelligence can integrate diet exposures, adiposity, metabolic markers, multi-omics, neuroimaging, and digital phenotyping. This can identify high-risk phenotypes, refine causal links along the diet–obesity–brain axis, and personalize nutrition-plus-lifestyle interventions. It can also highlight safety, equity, and privacy considerations. Translationally, a pattern-first strategy can support early screening and personalized risk reduction by integrating diet quality, adiposity, vascular risk, micronutrient status, and microbiome-responsive behaviors. AI can aid measurement and risk stratification when developed with privacy, equity, and interpretability safeguards, but clinical decisions should remain mechanism-aligned and trial-anchored. Full article

The aim of this study was the valorization of brewer’s yeast waste as a low-cost, biodegradable filler for polylactide (PLA) and the evaluation of the effect of yeast biomass on the processing, mechanical, thermal properties, and biodegradation of the resulting composites. The materials were prepared using extrusion and injection molding techniques, with the addition of brewer’s yeast (Saccharomyces cerevisiae) in amounts ranging from 5 to 30 wt%. Fourier-transform infrared spectroscopy (FTIR) analysis revealed the absence of strong interfacial chemical interactions, indicating physical dispersion of the filler within the matrix. The addition of biomass significantly modified the properties of PLA. The results demonstrated increased melt flowability (melt flow rate increased from 18.8 to 39.8 g/10 min) and stiffness (a 13% increase in Young’s modulus for 20 wt%), accompanied by a considerable reduction in tensile strength (from 63.2 to 20.2 MPa) and impact strength (from 22.8 to 6.2 kJ/m²). Thermal analyses showed a systematic decrease in the glass transition temperature by approximately 5 °C and a dual effect of the filler on crystallization behavior. At low concentrations, the waste acted as a nucleating agent, while at higher loadings it limited crystallinity, leading to an amorphous structure. Thermal stability decreased with increasing biomass content (from 329.3 °C to 266.8 °C). Industrial composting tests indicated that at a 30 wt% yeast content, the mass loss (27.5%) was higher than that of neat PLA (25.5%), suggesting accelerated biodegradation. Despite the deterioration of mechanical performance, the developed biocomposites represent a promising material for single-use applications, combining low cost, easy processability, and an environmentally favorable profile consistent with the principles of the circular economy. Full article

AlSi and nitrogen-doped AlSi (AlSiN) coatings were deposited onto 22MB5 steel, while h-BN coatings were applied to H13 steel using the magnetron-sputtering method. The thermal stability and tribological properties of the AlSi and AlSiN coatings were systematically investigated from room temperature to 800 °C in ambient air. The results indicate that the AlSiN coatings with an FeAl transition layer exhibited outstanding wear resistance and high thermal stability behaviors at elevated temperature because the FeAl layer can inhibit the diffusion of Al and absorb Fe, forming iron-rich intermetallic compounds with a high bonding strength. The FeAl layer plays a critical role in enhancing the coating’s performance. Analysis of the wear mechanisms revealed that the AlSiN coating primarily underwent adhesive wear, while the AlSi coating suffered from abrasive and oxidative wear. These findings offer valuable insights for developing protective coatings for the hot-stamping-forming process. Full article

As a process fluid in oil reservoirs, carbon dioxide plays a dominant role in enhanced oil recovery by increasing volume and decreasing interfacial tension. To study the volume expansion behavior of a CO₂–oil system under reservoir conditions, ten hydrocarbon components with carbon numbers ranging from 8 to 26 were selected to represent crude oil. Systems of CO₂ with normal alkanes, cycloalkanes, and aromatic hydrocarbons were measured using a self-assembled high-pressure visible cell, with a temperature range of 313.15 K to 353.15 K and a pressure up to 25 MPa. Experimental results demonstrate that pressure and temperature significantly influence the relative volumetric expansion behavior. The expansion rate exhibits a positive correlation with pressure, whereas it shows a negative correlation with temperature. Among different molecular configurations, normal alkanes exhibit the most pronounced swelling effect. This study establishes that the volumetric expansion behavior of crude oil under CO₂ exposure is predominantly governed by n-alkane components with carbon numbers less than 16. In the heavy hydrocarbon (carbon number > 16) and CO₂ system, the influence of hydrocarbon structure and carbon number on the expansion extent is considerably reduced. This paper delivers critical theoretical foundations for elucidating the microscopic interaction mechanisms in CO₂ enhanced oil recovery and optimizing injection parameter strategies. Full article

In high-sulfur environments, the failure risk of completion tubing increases due to the coupling effect of mechanical and electrochemical corrosion during the acidification production process. The corrosion behavior of P110SS tubing steel was investigated by an HTHP corrosion weight loss experiment and an electrochemical corrosion experiment. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to analyze the surface morphology of the corrosion products. In addition, a prediction model for the remaining service life of completion tubing under the synergistic effect of corrosion and stress was established during the acidification production process. The results show that acidification operations have a significant impact on the subsequent service life of tubing; the corrosion rate of P110SS tubing in the full acidification production process is much higher than that after the produced gas field solution corrosion treatment alone. Obvious pitting marks, micropores, and microchannels are observed in the corrosion product film of P110SS steel after acidification treatment, and the corrosion product film structure of P110SS steel is loose and honeycomb-like after acidification production treatment. The corrosion products are mainly FexSy and FeCO₃ after acidification production corrosion treatment. The corrosion during the acidification production stage is controlled by cathodic polarization. The remaining service life of tubing after production corrosion treatment can reach up to 29 years, while the remaining service life of tubing after acidification production corrosion treatment is significantly reduced, with a maximum of only 8 years. The research results have guiding significance for the selection, optimization, and design of high-sulfur-gas well tubing. Full article

Polymer modification is a widely employed technique for optimizing specific properties of mortars and concretes. This process entails the precise tailoring of the binder phase to the requirements of the given application. The polymer addition exerts a significant influence on both the fresh and hardened states of mortar or concrete. In this study, a systematic, stepwise experimental campaign was carried out to investigate the effects of three different polymer dispersions on the time-dependent properties of cement pastes, mortars, and concretes at different temperatures in the service temperature range. The experimental findings demonstrate that polymer modifications significantly influence the behavior of hardened cement-based materials. In general, the strength and deformation resistance decreased with increasing temperature, with this effect being more pronounced in polymer-modified materials. This is indicative of the intrinsic temperature-dependent behavior of the polymers. Temperatures of −20 °C induced specific alterations in the mechanical behavior, particularly evident in the flexural strength and in the early age stiffness development of the pastes, mortars, and concretes. This phenomenon is attributed to the freezing of pore water, which results in the stiffening of the binder structure. In summary, the findings offer significant insights into the structure–property relationships of polymer-modified cement-based materials in relation to temperature. Full article

Neuronal membrane capacitance (Cm) has traditionally been viewed as a static biophysical property determined solely by the geometric and dielectric characteristics of the lipid bilayer. Recent discoveries have fundamentally challenged this perspective, revealing that Cm exhibits robust circadian oscillations that profoundly influence neural computation and behavior. These rhythmic fluctuations in membrane capacitance are orchestrated by intrinsic cellular clocks through coordinated regulation of molecular processes including transcriptional control of membrane proteins, lipid metabolism, ion channel trafficking, and glial-mediated extracellular matrix remodeling. The dynamic modulation of Cm directly impacts the membrane time constant (τm = RmCm), thereby altering synaptic integration windows, action potential dynamics, and network synchronization across the 24 h cycle. At the computational level, circadian Cm oscillations enable neurons to shift between temporal summation and coincidence detection modes, optimizing information processing according to behavioral demands throughout the day–night cycle. These biophysical rhythms influence critical aspects of cognition including memory consolidation, attention, working memory, and sensory processing. Disruptions in normal Cm rhythmicity are increasingly implicated in neuropsychiatric and neurodegenerative disorders, including depression, schizophrenia, Alzheimer’s disease, and epilepsy, where altered membrane dynamics compromise neural circuit stability and information transfer. The integration of circadian biophysics with chronomedicine offers promising therapeutic avenues, including chronotherapeutic strategies that target membrane properties, personalized interventions based on individual chronotypes, and environmental modifications that restore healthy biophysical rhythms. This review synthesizes evidence from molecular chronobiology, cellular electrophysiology, and systems neuroscience to establish circadian Cm regulation as a fundamental mechanism linking molecular timekeeping to neural computation and behavior. Full article

Additive manufacturing of polymer materials, also known as 3D printing, is becoming a key technology for the production of functional parts with the ability to customize the structure and properties according to the application requirements. Polylactide (PLA) is one of the most commonly used materials in this field due to its biodegradability, ease of processing, and adequate strength for lightweight functional components. An important factor that affects the resulting properties of parts is not only the filler structure and density but also the angle at which the material is deposited during the printing process. This article focuses on investigating the influence of the printing angle (0°, 30°, 60° and 90°) and the bulk density of the filler (20%, 40%, 60% and 80%) on the mechanical properties of PLA samples. Two series of samples were prepared—the first was subjected to direct mechanical tests, and the second series was first exposed to freezing conditions and then tested to evaluate the effect of freezing on the material behavior. The samples were tested for tensile strength according to ASTM D638 and for bending strength according to ASTM D790. The results showed that the highest values were achieved in tensile strength in the 60°/80% configuration with a strength of 39.27 MPa, which represents more than a twofold improvement over the weakest configuration (0°/20%–19.58 MPa). In the bending test, the best results were achieved by the 90°/80% sample with a strength of 58.89 MPa, approximately 18% higher than 0°/20%. Cryogenic treatment caused a deterioration of all monitored parameters, especially at low infill densities and at an angle of 0°, where the decrease in strength reached up to 10–13%. These results confirm that the combination of a higher printing angle and a higher infill density is key to optimizing the mechanical properties of PLA parts, while cryogenic treatment has a negative impact on their behavior. Full article

Land desertification in the Agropastoral ecotone of arid and semi-arid regions poses significant threats to ecological security. Elucidating the geochemical characteristics and provenance of surface sediments is crucial for understanding desertification mechanisms and developing effective sand-control strategies. This study focuses on Kangbao County in the Bashang region of Hebei Province. We systematically collected 57 surface sediment samples from four geomorphic units: low mountains-hills, gently sloping hills, gully depressions, and undulating plains. Major and trace element concentrations were determined using X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma mass spectrometry (ICP-MS). Elemental ratios, principal component analysis (PCA), and Non-metric Multidimensional Scaling (nMDS) were employed to decipher sediment geochemical signatures and provenance, emphasizing geomorphologically controlled source differentiation mechanisms. Key findings are as follows: (1) Geochemical characteristics reveal that sediment elemental enrichment or depletion patterns exhibit fundamental differences depending on the specific bedrock reference. When normalized against felsic versus mafic end-members, elements including Fe₂O₃, MgO, TiO₂, CaO, Cr, Ni, Co, V, Rb, and Ba demonstrate contrasting geochemical behaviors. (2) The sediments originate from a homogenized mixture derived from the weathering of regional bedrock, clearly distinct from the high-maturity aeolian sands of the Hunshandake Sandy Land. (3) The spatial geochemical differentiation of surface sediments follows a two-stage process: the initial formation of a homogenized sediment source from bedrock weathering products, followed by subtle modification through landform-specific geomorphic processes, resulting in weak but systematic geochemical variations across the landscape. Based on these findings, a zonal management strategy is proposed to disrupt the localized sediment cycle by intercepting sources in hilly areas, restoring gully depressions, and blocking aeolian pathways on the plains. This study provides a scientific basis for precise desertification control in Kangbao and supports ecological barrier enhancement for the Beijing–Tianjin–Hebei region. Full article

WAAM is a technique for fabricating large-scale metallic components in an efficient and cost-effective way. Inconel alloys are a nickel-based superalloy popular for their excellent mechanical properties and corrosion resistance. They have been widely investigated for fabricating components using WAAM. This review aims to fill the gap dedicated to the fabrication of WAAM-based Inconel alloy parts. The WAAM of Inconel alloys is then thoroughly reviewed in terms of microstructure and mechanical behavior, as well as the effect of relevant process variables, including heat input, travel speed, and shielding gas mixture. Furthermore, this article also highlights several challenges and defects that occurred during and after fabricating the component, providing valuable insights. Several strategies for improvement are presented to improve the performance of the WAAM of Inconel alloys. Full article

In the present study, aluminum matrix composites (AMCs) were fabricated by friction stir processing (FSP) using Ni-Cu particles. Ni-Cu particles were added to the Al matrix in two ways. First, without any treatment and in the form of a mixture of as-received powders. Second, treated through mechanical alloying to form Monel solid-solution particles. The particles were added to a groove to be processed by the FSP tool to produce a local AMC. To investigate the kinetics of intermetallic compounds (IMCs) growth in reinforcement particles, the produced AMCs were annealed at 500 °C for 2 h. To characterize the reinforcing particles, several analyses were performed on the samples. Field-emission scanning electron microscopy (FE-SEM) was used to study the size, morphology, and IMC thickness. TEM was performed to characterize the IMCs through high-resolution chemical analyses. Tensile testing was used to understand the mechanical properties and fracture behavior of AMCs. Tensile testing revealed a noticeable improvement in strength for the as-mixed sample, with a UTS of 90.3 MPa, approximately 22% higher than that of the base aluminum. In contrast, the mechanical alloying sample with annealing heat treatment exhibited a severe drop in ductility, with elongation decreasing from 17.98% in the as-mixed sample to 1.52%. The results showed that heat treatment thickened the IMC layer around the reinforcing particles formed during the FSP process with as-mixed particles. In the AMC reinforced with mechanically alloyed Ni-Cu powders, IMC formation during FSP was significantly suppressed compared to that of as-mixed particles, despite the finer size resulting from milling. Additionally, the heat treatment resulted in only a slight increase in IMC thickness. The IMC layer thickness after heat treatment in both the mechanically alloyed sample and the as-mixed sample was approximately 2 µm and 20–40 µm, respectively. The reason behind this difference and its effect on the fracture behavior of the composite were elaborated in this study, giving insights into metal-matrix production with controlled reaction. Full article