Search Results (295)

The skeletal and immune systems are intricately linked, forming a dynamic interface that regulates both bone homeostasis and immune function. This bidirectional relationship, central to the field of osteoimmunology, highlights how bone and immune cells interact via shared progenitors and signaling pathways. Osteoclasts and osteoblasts not only coordinate bone remodeling but also influence hematopoietic and immune functions within the bone marrow microenvironment. The concept of the “bone immune system” underscores this crosstalk, particularly in pathological and regenerative contexts. Despite progress, contradictory findings complicate our understanding of cytokine activity. Pro-inflammatory mediators such as TNF-α and IL-17 are typically associated with bone loss, yet under certain conditions, they paradoxically promote repair by stimulating osteoblast differentiation. Conversely, anti-inflammatory cytokines like IL-10 and TGF-β are generally protective, but their effects vary depending on local context, sometimes even impairing regeneration. These inconsistencies highlight unresolved questions and gaps in mechanistic insight into immune–bone interactions. Bone tissue engineering (BTE) has advanced through biomimetic scaffolds, osteogenic cells, and bioactive molecules, offering hope for large defect repair. However, clinical translation remains limited, largely because immune modulation is not fully integrated into scaffold design. Current preclinical models often fail to capture the complexity of immune–skeletal interplay, reducing predictive value. Addressing these gaps requires improved models and systematic evaluation of immunoregulatory biomaterials, paving the way for more effective and personalized regenerative therapies. Full article

Hybrid electric vehicles (HEVs) frequently cycle their internal combustion engines (ICE), potentially cooling the three-way catalyst (TWC). This challenges the use of compressed natural gas (CNG), as methane (CH₄) requires high temperatures for TWC oxidation. This study experimentally investigates the performance, engine-out emissions (CO, NO_x, CH₄, NMHC, CO₂), and catalyst temperatures of a Toyota RAV4 hybrid vehicle on gasoline (G), CNG, and dual fuel (MIX) during the WLTC. Engine-out emissions were measured upstream of the TWC. Results showed similar engine work output (~17.8 kWh/100 km), while CNG significantly reduced fuel mass consumption (−18.7%) and CO₂ emissions (−27.5%) compared to gasoline, driven by both its higher LHV and higher average BTE. CO (−32.3%) and NO_x (−34.0%) emissions were lower with CNG, linked to leaner operation and significantly retarded ignition timing for NO_x control. However, CH₄ emissions drastically increased with CNG. This study reveals a synergy between the same retarded ignition timing strategy used to successfully control engine-out NO_x (−34.0%) and created a positive secondary effect, raising pre-TWC temperatures by 4.5%. Higher thermal condition is essential for the aftertreatment of chemically stable methane, highlighting a direct link between the engine’s NO_x control logic and the potential to mitigate methane slip. Full article

To address the dual challenges of fossil fuel depletion and environmental pollution, developing clean, renewable alternative fuels is an urgent need. Biomass gas, including biomass syngas and biogas, offers significant potential as an internal combustion engine alternative fuel due to its widespread availability and carbon-neutral properties. This review summarizes research on biomass gas application in dual-fuel diesel engines. Firstly, biosyngas and biogas production methods, characteristics, and purification needs are detailed, highlighting gas composition variability as a key factor impacting engine performance. Secondly, dual-fuel diesel engine operating modes and their integration with advanced low-temperature combustion technologies are analyzed. The review focuses on how biomass gas affects combustion characteristics, engine performance, and emissions. Results indicate dual-fuel mode effectively reduces diesel consumption, emissions, while its carbon-neutrality lowers life-cycle CO₂ emissions and generally suppresses NO_x formation. However, challenges include potential BTE reduction and increased CO and HC emissions at low loads. Future research should prioritize gas quality standardization, intelligent combustion system optimization, and full-chain techno-economic evaluation to advance this technology. Overall, this review concludes that dual-fuel operation with biomass gases can achieve high diesel substitution rates, significantly reducing NO_x and particulate matter emissions. However, challenges such as decreased brake thermal efficiency and increased CO and HC emissions under low-load conditions remain. Future efforts should focus on gas composition standardization, intelligent combustion control, and system-level optimization. Full article

Roadway anti-icing requires low-carbon alternatives to chloride salts and electric heating. This study evaluated a seasonal thermal energy storage system that couples a geothermal hydronic heated pavement (HHPS-G) with borehole thermal energy storage (BTES), operated without auxiliary heat. A coupled transient HHPS-G–BTES model was developed and validated against independent experimental data. A continuous cycle was then simulated, consisting of three months of summer pavement heat harvesting and BTES, followed by three months of winter heat discharge. A parametric analysis varied borehole depth (10, 20, and 40 m) and number of units (1, 2, and 4). Results indicated that depth is consistently more effective than unit number. Deeper fields produced larger summer pavement surface cooling with less long-term drift and yielded more persistent winter anti-icing performance. The 40 m 4-unit case lowered the end-of-summer surface temperature by 3.8 °C relative to the no-operation case and kept the surface at or above 0 °C throughout winter. In contrast, the 10 m–1-unit case was near 0 °C by late winter. A depth-first BTES design, supplemented by spacing or edge placement to limit interference, showed practical potential for anti-icing without auxiliary heat. Full article

The Bagley–Torvik equation (BTE) is an important model in mathematical physics and mechanics, but obtaining its analytical solution remains challenging. For its numerical treatment, the presence of composite functions in the generalized BTE poses additional difficulties, and efficient approaches for handling nonlinear terms are still lacking in the literature. This study proposes an improved numerical method for the fractional BTE with integral boundary conditions. By employing an integration technique, the original problem is transformed into a weakly singular Fredholm–Hammerstein (F–H) integral equation of the second kind. To address the nonlinear terms, an enhanced piecewise Taylor expansion scheme is developed to construct the discrete form, while the uniqueness of the solution is proven using the contraction mapping theorem in Banach spaces. The convergence and error analyses are rigorously carried out, and numerical experiments confirm the accuracy and efficiency of the proposed approach. Full article

This study examines the effects of injection timing and cerium oxide (CeO₂) nanoparticle (NP) size on NOx emissions and brake thermal efficiency (BTE) in a compression ignition engine, contributing to Sustainable Development Goals 7 and 13. Experiments were conducted at four load conditions (25–100%) using NP sizes of 10 nm, 30 nm, and 80 nm. An artificial neural network integrated with multi-objective particle swarm optimization (ANN-PSO) was employed to identify optimal operating parameters. The optimized configurations improved BTE and reduced NOx emissions across all loads; for example, at 75% load, BTE increased from 30.38% (average) to 32.13% (optimum), while simultaneously reducing the NOx emissions from 1322 ppm (average) to 1272 ppm (optimum). Analysis of variance (ANOVA) confirmed load as the most significant factor (p < 0.001), followed by injection timing and NP size. The model predictions closely matched experimental results, validating the optimization approach. The optimization suggests an interpolated optimal NP size of approximately 45 nm, highlighting the potential for further exploration. This integrated experimental and computational approach offers a promising framework for improving combustion efficiency and reducing emissions, thereby advancing cleaner and more sustainable fuel technologies. Full article

The temperature of the thermal energy storage unit is a critical parameter for the stable operation of seasonal borehole thermal energy storage (BTES) systems. However, existing temperature prediction models predominantly focus on estimating single-point temperatures or borehole wall temperatures, while lacking effective methods for calculating the average temperature of the storage unit. This limitation hinders accurate assessment of the thermal charging and discharging states. Furthermore, some models involve complex computations and exhibit low operational efficiency, failing to meet the practical engineering demands for rapid prediction and response. To address these challenges, this study first develops a thermal response model for the average temperature of the storage unit based on the finite line source theory and further proposes a simplified engineering algorithm for predicting the storage unit temperature. Subsequently, two-dimensional discrete convolution and Fast Fourier Transform (FFT) techniques are introduced to accelerate the solution of the storage unit temperature distribution. Finally, the model’s accuracy is validated against practical engineering cases. The results indicate that the single-point temperature engineering algorithm yields a maximum relative error of only 0.3%, while the average temperature exhibits a maximum relative error of 1.2%. After employing FFT, the computation time of both single-point and average temperature engineering algorithms over a 10-year simulation period is reduced by more than 90%. When using two-dimensional discrete convolution to calculate the temperature distribution of the storage unit, expanding the input layer from 200 × 200 to 400 × 400 and the convolution kernel from 25 × 25 to 51 × 51 reduces the time required for temperature superposition calculations to approximately 0.14–0.82% of the original time. This substantial improvement in computational efficiency is achieved without compromising accuracy. Full article

In this study, cottonseed oil biodiesel and waste lard biodiesel were produced through a transesterification process and blended with conventional diesel at different ratios (B10 and B20). The performance and emission characteristics of these fuels were systematically evaluated in a single-cylinder, four-stroke, water-cooled diesel engine operating at speeds of 1000–1800 rpm under a constant 50% load. The physicochemical properties of the fuels were analyzed, and engine parameters including brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), exhaust gas temperature (EGT), and emissions of carbon monoxide (CO), hydrocarbon (HC), carbon dioxide (CO₂), and nitrogen oxides (NOx) were measured. The results demonstrated that, compared with diesel, biodiesel blends significantly reduced CO, HC, and CO₂ emissions. At 1800 rpm, the LB20 blend showed reductions of 31.03% in CO, 47.06% in HCs, and 19.14% in CO₂ relative to diesel. These reductions are mainly attributed to the higher oxygen content and lower hydrogen-to-carbon ratio of biodiesel, which promote more complete combustion. However, all biodiesel blends exhibited higher NOx emissions than diesel, with the increase being more pronounced at higher blend ratios. At 1800 rpm, the LB20 blend recorded the highest NOx emissions, which were 20.63% higher than those of diesel under the same condition. In terms of performance, biodiesel blends showed higher BSFC and lower BTE compared with diesel, mainly due to their lower calorific value and higher viscosity. The lowest BTE and the highest BSFC were both observed with the LB20 blend, at 22.64% and 358.11 g/kWh, respectively. Full article

The growing dependence on fossil fuels has raised concerns over energy security, resource depletion, and environmental impacts, driving the need for renewable alternatives. Coffee husk, a widely available agro-industrial residue, represents an underutilized feedstock for biodiesel production. In this study, biodiesel was synthesized from coffee husk oil using a two-step transesterification process to address its high free fatty acid content (21%). Physicochemical analysis showed that Coffee Husk Oil Methyl Ester (CHOME) possessed a density of 863 kg m⁻³, viscosity of 4.85 cSt, and calorific value of 33.51 MJ kg⁻¹, compared to diesel with 812 kg m⁻³, 2.3 cSt, and 42.4 MJ kg⁻¹. FTIR analysis confirmed the presence of ester carbonyl and C–O functional groups characteristic of CHOME, influencing its combustion behavior. Engine tests were then conducted using B0, B10, B30, B50, and B100 blends under different loads, both with and without fuel preheating. Results showed that neat CHOME (B100) exhibited 11.8% lower brake thermal efficiency (BTE) than diesel, but preheating at 95 °C improved BTE by 5%, with preheated B10 slightly surpassing diesel by 0.5%. Preheating also reduced brake-specific fuel consumption by up to 7.75%. Emission analysis revealed that B100 achieved reductions of 6.4% CO, 8.3% HC, and 7.0% smoke opacity, while NOx increased only marginally (2.86%). Overall, fuel preheating effectively mitigated viscosity-related drawbacks, enabling coffee husk biodiesel to deliver competitive performance with lower emissions, highlighting its potential as a sustainable waste-to-energy fuel. Full article

This work provides a systematic evaluation of the performance and regulated emissions of binary n-pentanol–diesel blends under steady-state conditions, thereby clarifying condition-dependent efficiency–emission trade-offs across multiple loads and speeds. A single-cylinder, air-cooled diesel engine was operated at two speeds (1700 and 2700 rpm) and four brake mean effective pressure (BMEP) levels (0.25–0.49 MPa) using commercial diesel (D100) and three n-pentanol–diesel blends at volume ratios of 10%, 30%, and 50% (designated D90P10, D70P30, and D50P50, respectively). Brake thermal efficiency (BTE), brake specific energy consumption (BSEC), and brake specific fuel consumption (BSFC) were measured alongside exhaust emissions of nitrogen oxides (NO_x), carbon monoxide (CO), hydrocarbon (HC), carbon dioxide (CO₂), and smoke opacity. The results show that due to a lower cetane number, high latent heat of vaporization, and reduced heating value, n-pentanol blends incur efficiency and fuel consumption penalties at light to moderate loads. However, these disadvantages diminish or reverse at high loads and speeds: D50P50 surpasses D100 in BTE and matches or improves BSEC and BSFC at 2700 rpm and 0.49 MPa. Emission data reveal that the blend’s fuel-bound oxygen and enhanced mixing provide up to 16% NO_x reduction; 35% and 45% reductions in CO and HC, respectively; and a 74% reduction in smoke opacity under demanding conditions, while CO₂ per unit work output aligns with or falls below D100 at high load. These findings demonstrate that optimized n-pentanol–diesel blends can simultaneously improve efficiency and mitigate emissions, offering a practical pathway for low-carbon diesel engines. Full article

Without changing any of its constituents, tyre pyrolysis oil energy (TPOE) has frequently been subjected to Diesel-RK (D-RK) analyses in diesel engines in an effort to serve as a substitute for diesel fuel. Environmentally beneficial TPOE features, such as biodegradability, renewability, and ease and safety of handling, are highly sought after. In addition to its beneficial aspects, TOPE also has drawbacks. The BTE and SFC of performance metrics, as well as the smoke and NO_x of emission parameters of alternative fuel, do not meet the emission limits specified by regulatory authorities. Nano-additions have been shown to be effective for boosting fuel quality for improved performance and production characteristics. In this study, TPOE–diesel blends are blended with ceramic oxide (CeO₂ of 50 and 100 ppm) nanoparticles and subjected to a performance and production investigation of engine working physiognomies in diesel engines. For the blend TPOE10CDF80 + D, the numerical results show a positive outcome of a 1.0% rise in BTE, a 2.0% decrease in SFC, a 17.7% decrease in smoke emission, and an 18.2% increase in NO_x emission as compared to diesel fuel (CDF). Full article

Additive manufacturing (AM) has emerged as a cutting-edge technology for fabricating biomimetic scaffolds with controllable architectures and compositional diversity, showing great promise in the fields of bone tissue engineering (BTE) and regenerative medicine. However, due to limitations in printing resolution and single-process capabilities, AM alone struggles to replicate the complex multiscale hierarchical structures inherent in native bone. Traditional fabrication techniques provide valuable complementary strategies to address these limitations. This review systematically summarizes recent advances in the construction of heterogeneous scaffolds from a multiscale design perspective, encompassing macro-, meso-, and microscale approaches. Emphasis is placed on the integration of major AM techniques—such as extrusion-based and light-based printing—with conventional methods including freeze-drying, gas foaming, and electrospinning. Particular attention is given to emerging in situ fabrication strategies, such as in situ foaming and mineralization, which enable spatially resolved and functionally graded architectures. Furthermore, this review explores pathways for constructing multiscale-integrated scaffolds and examines the current challenges and opportunities in clinical translation. Collectively, this work provides a comprehensive framework to guide the development of next-generation bone tissue scaffolds with enhanced biological performance and translational potential. Full article

As internal combustion engines (ICEs) remain dominant in maritime transport, reducing their greenhouse gas (GHG) emissions is critical to meeting IMO’s decarbonization targets. Ammonia (NH₃) has gained attention as a carbon-free fuel due to its zero CO₂ emissions and high hydrogen density. However, its low flame speed and high ignition temperature pose combustion challenges. This study investigates the combustion and emission performance of NH₃-diesel dual-fuel engines, applying Response Surface Methodology (RSM) for multi-objective optimization of key operating parameters: ammonia fraction (AF: 0–30%), engine speed (1200–1600 rpm), and altitude (0–2000 m). Experimental results reveal that increasing AF led to a reduction in Brake Thermal Efficiency (BTE) from 39.2% to 37.4%, while significantly decreasing NO_x emissions by 82%, Total hydrocarbon emissions (THC) by 61%, and CO₂ emissions by 36%. However, the ignition delay increased from 8.2 to 10.8 crank angle degrees (CAD) and unburned NH₃ exceeded 6500 ppm, indicating higher incomplete combustion risks at high AF. Analysis of variance (ANOVA) confirmed AF as the most influential factor, contributing up to 82.3% of the variability in unburned NH₃ and 53.6% in NO_x. The optimal operating point, identified via desirability analysis, was 20% AF at 1200 rpm and sea level altitude, achieving a BTE of 37.4%, NO_x of 457 ppm, and unburned NH₃ of 6386 ppm with a desirability index of 0.614. These findings suggest that controlled NH₃ addition, combined with proper speed tuning, can significantly reduce emissions while maintaining engine efficiency in dual-fuel configurations. Full article

Bone-related defects present a key challenge in orthopaedics. The current gold standard, autografts, poses significant limitations, such as donor site morbidity, limited supply, and poor morphological adaptability. This study investigates the potential of scaffold geometry to induce osteogenic differentiation of human adipose-derived stem cells (hADSCs) through mechanotransduction, without the use of chemical inducers. Four distinct poly-(L)-lactic acid (PLA) scaffold architectures—Traditional Cross (Tc), Triangle (T), Diamond (D), and Gyroid (G)—were fabricated using fused filament fabrication (FFF) 3D printing. hADSCs were cultured on these scaffolds, and their response was evaluated utilising an alkaline phosphatase (ALP) assay, immunofluorescence, and extensive proteomic analyses. The results showed the D scaffold to have the highest ALP activity, followed by Tc. Proteomics results showed that more than 1200 proteins were identified in each scaffold with unique proteins expressed in each scaffold, respectively Tc—204, T—194, D—244, and G—216. Bioinformatics analysis revealed structures with complex curvature to have an increased expression of proteins involved in mid- to late-stage osteogenesis signalling and differentiation pathways, while the Tc scaffold induced an increased expression of signalling and differentiation pathways pertaining to angiogenesis and early osteogenesis. Full article

The synthesis of bioplastics from renewable resources is essential for green living. PHBV (poly(3-hydroxybutyrate-co-3-hydroxyvalerate)) is a biodegradable and biocompatible material ideal for various industrial applications. The impact of levulinic (LA), valeric acids (VA), and sodium propionate (SPr) as co-substrates in biomass and the synthesis of 3-hydroxy valerate (3HV) and co-polymerization of PHBV by Burkholderia thailandensis E264 (BtE264) was assessed. Thermogravimetric, XRD, NMR, and mechanical characterization were performed on the homopolymer (PHB) and co-polymer (PHBV), and compared to the PHBV-STD. BtE264 produced the co-polymer PHBV when adding any of the three co-substrates. LA showed a higher positive effect on microbial growth (8.4 g∙L⁻¹) and PHBV production (3.91 g∙L⁻¹), representing 78 and 22 mol % of 3HB and 3HV, respectively. The PHBV obtained with LA had a melting temperature (Tm) lower than the PHB homopolymer and presented lower values for melting enthalpies (ΔHf); the degree of crystallization and TGA values indicated that PHBV had better thermal stability. Additionally, FTIR and NMR revealed that BtE264 synthesizes PHBV with an organization in monomeric units (3HB-3HV), suggesting differentiated incorporation of the monomers, improving 3.4 times the break elongation the co-polymer’s tensile properties. This study highlights the co-substrates’ relevance in PHBV synthesis using BtE264 for the first time. Full article